August 2013

by George Taniwaki

The year 2013 marks the 100th anniversary of the invention of hemodialysis, a life saving procedure to removing waste product from the blood of people with chronic kidney disease.

An experiment using animals is described in the May 1913 issue of Trans Assoc Amer Phys. The work was done by three doctors, John Abel, L.G. Rowntree, and B.B. Turner, all of Johns Hopkins Medical School.


A screenshot from the article describing the invention of hemodialysis. Image from Google books

From the archives of Scientific American Sept 1913 comes a description of the experiment. The article contains this quote from the Times of London:

A demonstration which excited great interest was that of Prof. [John Jacob] Abel of Baltimore. Prof. Abel presented a new and ingenious method of removing substances from the circulating blood, which can hardly fail to be of benefit in the study of some of the most complex problems. By means of a glass tube tied into the main artery of an anesthetized animal the blood is conducted through numerous celloidin tubes before being returned to the veins through a second glass tube. All diffusible substances circulating in the blood pass through the intervening layer of celloidin. In this way Prof. Abel has constructed what is practically an artificial kidney.

In their experiment Dr. Abel and his colleagues use a dialysis membrane made of celloidin. Celloidin is an early plastic made from nitrocellulose (cotton or wood pulp reacted with nitric acid). It was translucent and water-repellent. Films or tubes made from celloidin were water permeable, which made them good osmotic filters. However, celloidin was highly flammable and dangerous to work with.

Today, dialysis membrane tubing is made from rayon fiber (cellulose reacted with carbon disulfide and mixed with glycerin, then extruded through a spinneret to form a thread) or cellophane film (chemically similar to rayon, except that it is extruded through a slit to form a thin sheet).

by George Taniwaki

As part of the kitchen remodel we replaced the fire-rated steel door between the kitchen and garage. Once the new door is installed, I need to repair the broken drywall, add casing, weather-stripping, and a threshold.

But of course, I also want to make a few other changes. (This is destined to become yet another side project that will take up too much time while adding only a little value to the house. )

The garage is about two feet lower than the main floor of the house. There are two concrete steps in the garage leading to the fire-rated door that opens into the kitchen. At the bottom of the stairs there is another fire-rated door from the garage to the backyard.

I forgot to take a “before” picture of the steps. A photograph showing the space after I finished demolition is shown in Figure 1a. An oblique view with dimensions of the steps  is shown in Figure 1a.



Figure 1a and 1b. Photo of the steps after demolition; Oblique view showing dimensions of concrete steps

These steps have bothered me ever since we moved into the house. First, the top tread of the steps is not level with the doorway, it is one step down. But given the tight space, I won’t be able to add another step to fix this problem.

Second, the risers are not evenly spaced. The first step down from the kitchen into the garage is about 9 inches high, which is way too large. The next step is about 7-1/4 inches high and the final step is about 8″ high. I spend a lot of time in the workshop in the garage, and can walk up and down these steps up to 50 times a day. I’ve never tripped going down them, but it is really annoying. You feel like you are falling into the garage.

Finally, the treads are not flat or the same length. They have bulges and dips in them. The middle step is about an inch longer than the bottom step.

In addition to being uncomfortable, the risers don’t meet building code. Code requires that no step be more than 8″ high (7-1/2″ for public spaces) and that the difference in height between the tallest step and the shortest one cannot exceed 3/8″. Similar rules apply to tread lengths.

Designing a fix for these problems won’t be easy. The stairs are not square to the walls, not level, and not plumb. The drywall that acts as the top riser has been severely damaged by years of wear. What a mess.

Another problem with these steps is that they abut the concrete foundation which leaves a gap between the steps and the drywall (about 3″ wide as shown in Fig 2) that constantly gets filled with sawdust and other debris and is hard to keep clean.

I suppose I could rent a jack hammer and demolish the steps and start over by building a new set out of wood. But that would be a lot of heavy labor and take a lot of time. Instead, I will build an enclosure over the existing steps to fix all the problems.

Figure 2a shows the evolution of my ideas to cover the gap between the steps and the wall. The last version shows the solution I came up with. Figure 2b shows the dimensions of all the pieces and shims to cover the gap and the steps themselves. For simplicity, the stair treads, stair nosing, and wraparound tread are shown already assembled.



Figures 2a and 2b. Sketches showing ideas to cover the gap between the steps and wall (top) and final drawing with dimensions (bottom)

The finished project is shown in Figure 3.


Figure 3. The completed project


Using a pry bar, remove the old casing around the two doors. Using a level and pencil, draw a horizontal line from the top of the kitchen floor to the left door. Using a utility knife and pry bar, remove the drywall below that line. Remove the drywall from underneath the right door and 3.7″ to the right. Use a cold chisel and hammer to remove any lumps from the concrete steps (Fig 1a).

Tile the floor

The floor around the steps will be covered with 12″ porcelain tiles. Adding tile to a garage floor sounds extravagant, but it does two things. First, it visually ties the two doors together and separates the entrance area from the rest of the garage.

Second, the tile raises the floor by a little over 1/2″. This leaves room to clad the bottom step with 3/8″ of oak without causing the rise to exceed 8″. Otherwise, you would need to chip away enough concrete to keep the rise low enough to meet code. It also reduces the total rise of the stairs to 23-1/2″. Since there are three steps, the average rise per step will be just under 8″ which is also needed to meet building code.

Since we are not covering the entire garage floor with tile you will need to add a protective edge banding. I use Schluter Shiene available from Home Depot.  Using a hacksaw, cut a 45° miter where the two edges meet. To ensure the strength at the corner, cut the edging material at a point where it will be mostly solid (Fig 4). Layout the edging to ensure it fits and mark the outside with masking tape (Fig 5).

Using a disk sander with a vacuum attachment, remove any dripped paint and adhesive from the floor and roughen the surface (Fig 6). Layout the tiles and cut the partial pieces using a wet saw (Fig 7).

Place a weighted 2×4 along the side of the edge banding so that it doesn’t move. Using latex adhesive or latex modified mortar, lay the tile. Put 1/4″ spacers between the tiles (Fig 8). After the mortar cures, apply grout mixed with latex (Fig 9).




Figures 4 to 9. Cut the edge banding; Dry fit the edge banding and add masking tape; Clean the floor; Dry fit the tiles, Mortar into place; Apply grout

To see the process for installing a tile floor that includes use of a waterproof membrane and floor drain, see the blog post entitled Build a laundry room.

Frame the knee wall

While the mortar is curing, build the knee wall on the side of the steps (Fig 8).

Since the wood framing will be in direct contact with concrete, it should be built from pressure treated 2×4 lumber. Normally, you use galvanized or stainless steel fasteners with pressure treated lumber. However, since this is interior framing that should never get wet, I use standard steel framing nails in my nail gun.

Use 1-5/8″ drywall screws to attach the loose drywall above the knee wall to the studs.

Make panels for staircase enclosure

The staircase enclosure and stair risers are built in a manner similar to a cabinet. Start with a sheet of 1/2″x4’x8′ plywood. Cut out all the pieces using a table saw or a handheld circular saw with a shooting board. To get a straight, clean edge on inside corners, cut as far as possible with the saw with a circular blade. Then finish the cut using a handheld scroll saw or a hand saw.

Any edges where two pieces meet are mitered at 45°. Cut these on a table saw using a crosscut sled or on a miter saw.

Dry fit all the pieces and glue shims as needed (Figs 10 and 11). Sand the pieces smooth and finish with three coats of gloss enamel latex paint.


Figures 10 and 11. Glue shims to the panels; View of assembled enclosure and shims

Make stair treads

Standard stair treads are 1″ x 11-1/2″. The bottom tread in this project will need a tread that are 3/8″ x 15-1/2″. Thus, we will make custom treads using hardwood flooring and stair nosing.

The front edge of the stair tread is made with 3/4″ x 5-1/2″ stair nosing, the return edge is made from 3/4″ x 3″ stair nosing. They meet at a 45° miter joint. The rest of the tread is made from three pieces of 3/4″x4″ hardwood flooring. Using a table saw with a cross-cut sled (or miter gauge), cut a tongue on the end of each piece of hardwood flooring to fit into the groove on the return. A layout of all the pieces is shown in Figure 12.

To make the 3/8″ thick tread, rip each piece of hardwood flooring on the table saw. This will take four passes. Make one pass at 1″ deep, flip the piece over and run it again. Raise the saw to 2.1″ and repeat. The table saw leaves rough saw marks. Clean the bottom of the flooring by running the boards through the planer.

The rabbet on the 5-1/2″ stair nosing is 3-3/4″ wide, which is too wide to rip it to the 3/8″ thickness on the table saw. To make this rabbet, run it through the table saw in multiple passes to make a groove as deep as possible. Then knock out the rest of the rabbet using a chisel. Clean up the underside of the nosing using a jack plane or hand sander.

Glue up the boards in three steps. First, glue the three pieces of hardwood flooring together. Since the tongue and grooves in hardwood floors have lots of play, you will want to use polyurethane glue rather than normal PVA wood glue. You may need to add clamps or weights to keep the boards flat.

Then glue the flooring and the front edge stair nosing together. Finally, glue up the long boards with the return nosing. This last glue up will require clamps and weights in all three directions. (Fig 13).

(I’m a bit concerned about the effect of cross-grain movement between the return and the glued up boards. Time will tell if either the miter joint or the bread board end joint opens up.)

GarageSteps_12 GarageSteps_13

Figures 12 and 13. Cut the tread pieces and glue them up

The glued up stair tread will need to be flattened. Coat the tread with trowel-type wood filler to identify the low spots. The tread is over 15″ wide and thus will not fit in a 12″ power planer. Plane it by hand using a smoothing plane. (I had never done this before. It’s actually quite fast and seeing the board become smooth before your eyes is an enjoyable experience. The absence of the roar from the power planer is nice too. Note, your hand planes must have a very sharp blade and be correctly tuned for this to work. Otherwise it will be a slow hard slog and you will gouge your wood.)

When planed correctly,there is no need to sand the stair treads. Finish with wood stain (I used 1 part MinWax red oak and 8 parts MinWax natural) followed by three coats of varnish (I used MinWax quick drying oil based polyurethane).

Make stair nosing and wraparound tread

The top stair nosing is custom fitted. Start with a piece of 5-1/2″ stair nosing. Cut it to be a few inches longer than needed. On the table saw, rip the stair nosing to the widest required width. Cut a groove in the back to accept the tongues of the boards from the hardwood floor. You can use either the table saw or router. Ease the bottom half of the groove and bevel it to allow for expansion of the wood.

Make cut outs in the stair nosing to fit around the door jamb.

Add a return on the open end. To do this, cut a 45° miter. Cut a triangular piece of stair nosing at 45° and join the two pieces using one or more biscuits and wood glue.

Use a piece of stair nosing to make the wraparound tread that will cover the knee wall. Rip it to width on the table saw. Add a return on the end in the same manner described above. You may need to chisel out the rabbet so that the return will not interfere with the left door closing.

Cut a 45° miter on both pieces to form the inside corner. Cut biscuit slots, but do not glue the pieces together. Do not finish the pieces.

Make door casing

Make traditional Craftsman style casing for both doors. Start with 1″x4″x8′ nominal (.75″x3.5″x96″ actual) S4S primed pine lumber. Cut them to length to leave a 3/16″ reveal around the door jambs. The design includes a 1/2″ bullnose accent as shown in Figure 3 of an Oct 2012 blog post.

Finish with three coats of gloss enamel latex paint.

Assemble the stairs

The stairs will be assembled in layers. At each step, dry fit the parts first to ensure they are snug and check the edges are level, plumb, and square. Any errors early in the assembly will make the following step harder to complete.

Use wood glue to attach the panel on the knee wall and tack in place with brads. Glue the back panel to the wall and tack in place with brads. Glue the bottom step riser to the stair side at 90° and tack in place with brads. Use a liberal amount of construction adhesive to attach this assembly to the concrete steps (Fig 14).

Cut a 3/8″ notch in the miter edge of the stair side to receive the bottom stair tread (Fig 15). Apply a liberal amount of construction adhesive to the bottom stair tread and on the concrete step. Slide the tread into place. Stack 50 kg (100 lb) of weight on the step. (I used boxes of tile.) Apply a liberal amount of construction adhesive to the back of the middle step riser and on the concrete steps. Push the riser into position. Slide the weights against the riser and let the glue cure (Fig 16).

After the glue cures, remove the weights. Use the same technique to assemble the middle step and the top riser (Fig 17).

GarageSteps_14 GarageSteps_15

GarageSteps_16 GarageSteps_17

Figures 14 to 17. Assemble the stairs. Glue the bottom riser, sides and back; Cut a notch for the bottom tread; Glue the bottom tread and middle riser; Glue the middle tread and top riser

After the glue cures, remove the weights. Use construction adhesive to attach the top stair nosing to the hardwood floor and the wraparound tread to the knee wall. Insert the biscuit and use wood glue to join the two pieces. Clamp the miter joint between the two pieces to ensure a tight fit (Fig 18).

After the glue cures, remove the clamp. Use trowel-type wood filler and coat the top stair nosing, hardwood floor, and wraparound tread. Use a disc sander and a detail sander to flatten surfaces.

Use construction adhesive to glue a threshold under the right door.

Finish all the wood surfaces with wood stain followed by three coats of varnish (Fig 19).

GarageSteps_18 GarageSteps_19

Figures 18 and 19. Glue the top stair nosing and wraparound tread; Sand, fill, stain and varnish stair treads

Finish carpentry

Remove both doors from the hinges. Carefully remove the weather-stripping. Inspect the door jambs, hinge mortises, lock mortises, and threshold of left door. (The right threshold is brand new so should be fine.) Fill any defects with polyester resin (Bondo), sand them smooth, and apply three coats of enamel paint. Using a chisel and drywall plane, flatten the walls to be flush with the door jambs (Fig 20). Attach the casing to the walls using 16ga nails. Apply touch up paint to the casing and the staircase.

Fill any screw holes or blemishes in the drywall with mud, sand smooth, and touch up paint (Fig 21). Fill, sand, and paint the two doors. Reinstall the locks, hinges, weather-stripping, and rehang the doors  (Fig 22).

To protect the stairs and floor, add non-slip stair runners and entry mat (Fig 23).



Figures 20 to 23. Fill, sand, paint door jambs; Nail casings to frame and fill, sand, paint walls; Fill, sand, paint doors; Add rugs to protect the new floor

In total, this project took me about 100 hours to complete and cost about $350. The costs are itemized below.

Tile, aluminum border, mortar or adhesive, grout $150
Lumber, hardwood flooring, outdoor carpet, paint, 2 thresholds, and misc. materials $200*
Carpentry, painting, and tiling labor $     0
TOTAL $350

*It may be difficult to buy small quantities of hardwood flooring or carpet like that used in this project (about 10 sq. ft. each). I already had these items left over from previous projects. The costs shown here are pro rata based on the original purchase.

Now that the steps are even, they are much easier to walk up and down on. Now that the crevasse is gone, they are easier to keep clean. And they have to be some of the nicest looking garage steps you’ll ever see.


Since many of the images in this blog post are taken from the same position, I combined them into a single animated gif file to create a crude stop motion video of the project(Fig 24). I used, a free online service to make the file.


Figure 24. A gratuitous animated gif of the project

For more ideas on home remodeling projects see the Home Remodeling Guide.

All photos and drawings by George Taniwaki

[Update: WordPress does not allow animated gifs to display in the blog body. Click on Figure 24 to open the gif file and view the animation.]

by George Taniwaki

I went to the local Washington Department of Licensing office last week to renew my driver’s license. Just like I did ten years ago, I registered to be an organ donor. I urge you to do the same and give the gift of life.

You don’t have to wait until your driver’s license comes up for renewal to do it. You can do it today on the web. Find your state’s registry at If you live in Washington state like me, you can go directly to LifeCenter Northwest’s web site at

Incidentally, I noticed something new on my new driver’s license. On the upper right is the word “DONOR” followed by a heart-shaped icon. On my previous license only the icon was displayed and its meaning was ambiguous. I like the change.


Figure 1. Register to be an organ donor


I notice a few other changes from the last time I renewed my driver’s license ten years ago.

  1. The lines were short and the process was efficient.
  2. Previously, driver’s licenses were printed while you waited at the DoL office. Now the ID photograph is taken at the DoL office, but the actual driver’s license is mailed to you. My guess is that centralizing the printing allows more sophisticated security measures to be embedded in the card. It also reduces the opportunity for local DoL employees to make counterfeit licenses.
  3. I had to take my glasses off for the ID photo. This is probably so that a photograph can be taken of me later (perhaps during an arrest) and my identity determined by using facial recognition software to compare the new photograph to the existing photograph in a DoL database. The facial recognition must compare features that don’t change readily like the eyes, nose, mouth, and ears. It ignores jewelry, facial hair, and facial expression.

[Note: Some of the tasks below require specialized knowledge and skill in plumbing and electrical installation. If you do not possess this, you should contact a licensed plumber and electrician.]

by George Taniwaki

The first floor of our house has a small powder room off the main hall (about 7’ x 3-1/2’, Fig 1). The previous homeowner remodeled this room a few years before we bought the house so it was in good condition (Fig 2). When we began our home remodeling project, we did not plan to do any work on the powder room.


Figures 1 and 2. Plan view of first floor bathroom (left); and view before remodel

That changed as soon as we began demolition work for the laundry room upstairs directly above the powder room (see Dec 2011 blog post). We discovered that one of the joists between the floors needed to be reinforced and the subfloor replaced. To do that, we had to remove the drywall on the ceiling of the powder room to slide in the new joist. This pretty much ruined the room, forcing a remodel.

The work plan

Once we knew that the powder room needed to be remodeled, we had to decide what work to do. Our plan was to have smooth painted walls rather than textured walls or wallpaper. We also want all the metal surfaces to be antique bronze. The following work would be required:

  1. Demolition
  2. Rough in plumbing, venting, and electrical
  3. Add sound insulation
  4. Add blocking for fixtures
  5. Install new ceiling and walls
  6. Tile the floor and baseboard
  7. Install door casing and door threshold
  8. Install lighting, sink, toilet, and fixtures

The following sections describe how to do all this.


Turn off the power to the bathroom. Remember the outlets and lights may be on different circuits. Remove all the old fixtures and drywall. Save any fixtures that will be reused.

Shut off the water to the sink and toilet. Remove the toilet tank lid. Flush the toilet and keep the flapper valve open to drain the tank. Pour a bucket of water into the toilet bowl to siphon out the remaining water. Disconnect the water line and check for slow leaks. Plug the shut off valve if necessary. Remove the bolts holding the toilet to the drain flange. Carefully lift the toilet and remove the wax ring. Place the toilet in a large garbage bag and set aside. Cover the toilet drain with aluminum foil to seal it while you are working (Fig 13).

Disconnect the water lines and drain lines from the sink. Check for leaks. Disconnect the sink from the wall and set aside. If necessary, remove the sink pedestal. To do this, use a reciprocating saw. Slide a blade between the floor and the pedestal and cut through the adhesive (Fig 3). This may ruin the floor tiles and they may need to be replaced.


Figure 3. Removing the sink pedestal

Rough in plumbing, venting, and electrical

The bathroom originally had 5″ long chrome nipples on the water supply line. Replace them with shorter nipples painted antique bronze to match the new faucet and fixtures. Also replace the leaky shut off valves with new quarter-turn ball valves.

The original powder room had an exhaust fan, as is required by building code. It was installed in the wall. A duct ran in the basement joist space and out the back of the house. It was wired to the same circuit and switch as the light fixture.

While working on the ductwork for the furnace in the basement (see XXX 2010 blog post), I discovered that the vent duct was made of 4” flex hose rather than rigid pipe, meaning it couldn’t carry much air. Further, the flex hose ran inside the return air duct for the furnace, reducing the volume of air available to the furnace.

To replace the fan, remove the old fan and vent hose. Repair the hole in the side of the house. Buy a replacement exhaust fan and mount it in the joist space above the ceiling. It is actually preferable to use a less expensive and noisier fan since that will enhances privacy. Vent the fan to the rear of the house using 4” rigid galvanized pipe. Tape all seams. Cap the vent with a flap to keep out cold air and birds (Fig 4). Insulate the opening with spray foam. Paint the cap to match the house.

Connect the new fan to the switch. You may need to splice the electrical line and add a junction box.

One more bit of electrical work, install a light fixture box for a wall sconce. The box should be high enough to fit the mirror and sink below it. But it should not be so high that the light fixture looks crowded against the ceiling.

Add sound insulation

The original powder room had no sound attenuation.

Wrap all the ABS drain pipes and vent lines with mass loaded vinyl (MLV) at 1 lb/sq ft to reduce the noise of water draining from the laundry room on the floor above. Fill the space between studs with R-15 glass fiber insulation to reduce sound transmission and increase privacy (Fig 5).

Add blocking for fixtures

The original framing did not include any blocking. The pedestal sink was screwed into the wainscoting, which did not provide adequate support. The sink would wobble.

Securely nail or screw 2″x4″ lumber into the studs as blocking behind the sink (Fig 6), mirror, towel bar, toilet paper holder, and any other fixtures. Also add blocking around the perimeter of the floor to support the tiles on the base molding.


Figures 4 to 6. Vent cap for new exhaust; insulation for sound control; blocking to support pedestal sink

Install new ceiling and walls

The original walls and ceiling in the powder room were standard 5/8″ drywall covered with knockdown texture plaster. During a remodel by the previous homeowner, the textured walls were  covered with wallpaper, which looked very odd.

To reduce the chance of water damage, cover the studs with moisture resistant drywall (green board, Fig 7). Use 5/8″ thick drywall for fire protection (required by building code for ceilings) and noise suppression. Use ceramic coated screws to avoid rust spots.

Tape the drywall using glass fiber tape . Cut the tape to a 90° point (Fig 8) when fitting the corners so that the tape does not overlap (Fig 9). Apply three coats of mud, sanding between coats to create a smooth finish (Fig 10).

Paint the ceiling, exhaust fan cover, and ceiling wall plate a dark accent color. Paint the walls to match the walls in all the other rooms (Fig 11).



Figures 7 to 11. Water resistant drywall installed; Glass fiber tape cut and applied; three coats of mud applied; ceiling and walls painted

Tile the floor and baseboard

The subfloor in the powder room is covered with 3/4″ particle board underlayment followed by 12” square ceramic tiles. When laying 3/4″ tongue-and-groove oak flooring in the hall we had to chisel out 3 tiles in the doorway. They will need to be replaced. Some of the tiles near the wall were too small (Fig 12) and will leave a visible gap next to the tile baseboard. The tiles around the toilet flange were cut too loose and leave a visible gap around the toilet (Fig 13). These tiles will also need to be replaced. Make sure you have enough spare tiles to do this. Otherwise, remove all the tile and buy enough new tile to complete the project.

Remove the unwanted tiles using a hammer and cold chisel. Be careful not to chip the tiles you want to keep. Remove the mortar or adhesive using a putty knife or oscillating saw with scraper attachment. Remove grout from between the remaining tiles using an oscillating saw with grout knife attachment (Fig 14). Don’t try removing the grout using a handheld grout knife. It is too much work. If you don’t own an oscillating saw, it is better to just remove all the tile and start over.

Decide whether you want the factory edge or the field cut edge facing up on the tile for the base molding and ensure you cut the tiles on the correct sides. (For this project the factory edge is facing up.) Remember to leave room for the door casing (see next section). Using a tile saw, make all the straight cuts for the new tiles (Fig 15). Spray paint the top edge of the tiles for the base molding to match the grout color (Fig 16).




Figures 12 to 16. Tiles next to wall are too small and need to be replaced; Tiles around toilet flange are misshapen and need to be replaced; Removing the old grout; Making the straight cuts for the tiles using a tile saw; Painting the edges of the baseboard tile to match the grout color

To tile around the toilet drain, make a paper template (Fig 17). Trace the template onto the tiles using a crayon or permanent marker and add 1/4″ extra to allow room for grout (Fig 18). Notice that the right side tile contains more than half a circle, which would be difficult to cut. Since this tile is mostly hidden under the toilet, we can cut about half of the circle out. This line is also marked on the tile. Cut a series of parallel grooves into the tile using a tile saw. Cut away the unwanted tile using a pair of tile nibblers (Fig 19).

Add flange extenders to the toilet drain to ensure the flange will be about 1/4″ above the finished level of the tile. Use plenty of silicone sealant to ensure a gap free (and thus odor free) connection. Use mortar or tile adhesive to attach all the tiles to the floor and walls. Wait a day and then grout the tile. Wait another two days and seal the grout (Fig 20).



Figures 17 to 20. Making a template for the toilet flange; Tracing the template onto the tiles; Making curved cuts using a tile saw and tile nibbler; The completed toilet flange

Install door casing and door threshold

The door to the powder room is fir and the exterior casing is made from stained hemlock (see Oct 2012 blog post on how to make this). However, I think stained wood looks too formal on the inside of the powder room, so I made the interior casing from 3-1/2″ wide primed pine.

Paint the casing with 3 coats gloss enamel to match the other trim in the house. Attach the casing to the studs using finish nails. Fill the nail holes, sand, and touch up paint (Fig 21).

To connect the tile floor in the powder room to the oak floor in the hall, insert an oak threshold. Stain it to match the floor and apply three coats of varnish. Use construction adhesive to attach it to the subfloor and use clear silicone sealant to attach it to the oak floor and tile (Fig 21).


Figure 21. Detail of door casing meeting tile floor and tile baseboard

Install lighting, sink, toilet, and fixtures

Install the fixtures from the top of the room down, starting with the cover for the exhaust fan and junction box.

Install the light fixture following the manufacturer’s instructions.

Install the mirror to a height that matches the light fixture and is centered beneath the fixture (not centered on the wall).

Install the towel bar at arm height. If the towel bar is made of thin gauge metal, reduce the rattle it makes by first filling it with foam insulation  (Fig 22). After the foam cures, cut off most of the excess, leaving about 1/4″ plug sticking out. When you insert the rod, it will not rattle and will sound solid when you tap on it.

Install the sink centered beneath the light fixture and mirror (not centered on the wall). First mark the pedestal with pencil or tape indicating the exact front, back, and sides. Place the pedestal and sink in position. Using masking tape and pencil, mark the floor with the alignment points for the front, back, and sides of the pedestal (Fig 23).

Mark the mounting holes for the sink on the wall.

Remove the sink and pedestal and set aside.

Drill holes in the wall and screw in 5/16″ anchor bolts for the sink. Add neoprene washers to the anchor bolts.

Attach the pedestal to the floor using clear silicone sealant. Add shims to ensure it is plumb. After the sealant to cures, apply foam tape to the top of the pedestal and slide the sink into place and onto the anchor bolts. Add more foam tape as needed to ensure the sink is level.

Slide on another neoprene washer, a steel washer and nut on each anchor bolt and tighten until the sink does not wobble.

Replace the faucet and pop-up stopper, with a new antique bronze set. Replace all washers on the p-trap and drain pipe and assemble the drain line. Note that there are two types of washers. Use the plastic and tapered kind for threaded connections. Use the rubber and square kind for slip fit connections (Fig 24). Sand the p-trap and drain pipe and apply two coats of antique bronze spray paint (Fig 25). Replace or paint the shut off valves, escutcheons, and water supply lines, if necessary. Turn on the water, fill the sink, and test for leaks.

Install the toilet paper holder and any other remaining fixtures.

Install the toilet using a new wax ring and hold down bolts. Replace or paint the tank lever, if necessary. Replace or paint the shut off valve, escutcheon, and water supply line, if necessary. Turn on the water and use a dye kit to test the toilet for leaks. (You can get the kits free at most hardware stores.) Replace the flapper valve if there is even a small leak.

You are done (Fig 26a).



Figures 22 to 25. Fill a hollow towel bar with foam; Align the pedestal to the light fixture and mirror; The two kinds of washers for the drain, threaded on left, slip-fit on right; Paint the water supply lines, escutcheons, and drain line to match the faucet color

For such a small room, there certainly was a lot of work involved in the remodel. And given the amount of work I did, there doesn’t seem to be a lot of change. Oh well.


Figure 26a and 26b. The finished powder room and the original.

For more ideas on home remodeling projects see the Home Remodeling Guide.

All photos by George Taniwaki, drawing in Figure 1 courtesy of Soderstrom Architects

by George Taniwaki

Last week I had two small electronic devices fail. I tried to fix them both and failed. Here’s a short description of my attempt to fix the first one, a USB KVM switch. Along the way I ponder the role of industrial design and intellectual property rights in China.

I have two computers, a desktop PC and an iMac. Rather than have separate keyboards and mice, I share them and toggle between the computers using a KVM switch (the abbreviation stands for keyboard, video, and mouse). My setup is shown in the photo below.


Figure 1. My home computer setup, the KVM switch is on the desk, above and to the right of the keyboard

Last week the KVM switch quit working (after only a year!). I opened it up but could not see any loose connections. My guess is that the clock chip failed. Clocks are cheap but so is a new KVM switch. So rather than spend time and money trying to debug and fix this device I bought a new one for $9.50 on Amazon.

When it arrived, I noticed it looked just like my old one right down to the fact that the button on the switch was slightly off-center (see photo below). The only apparent difference was the printing on the case and the UPC codes.


Figures 2a and 2b. The front of the old KVM switch on left, new one on right

A UPC code consists of two sets of 6-digit numbers. The first 6 digits is a unique identifier for a given manufacturer. Each manufacturer is then able to assign the next 5 digits to products as they wish and then calculates a checksum to assign as the last digit.

The two switch boxes shown above had different manufacturer IDs and different product IDs, indicating they were made by different manufacturers.

This intrigued me. Both KVM switches are made in China. This made me wonder about why the UPC codes don’t match. Some possibilities I came up with:

  1. One company reverse engineered (i.e., brazenly stole) the other’s design for the KVM switch (even given the poor reputation Chinese companies have for respecting intellectual property, this seems unlikely)
  2. One company made the original design and licensed it to the other (seems unlikely, once the first company did all the work to line up suppliers why would it want to help a competitor enter the market?)
  3. Both manufacturers licensed the design from a third company that only does design and lets others manage the supply chain and manufacturing details (given the low-cost of the item, this seems an unlikely product category for a successful design firm)
  4. Between the time I purchased the first KVM switch and the replacement, the company changed its name, was acquired, or changed its manufacturer ID and product ID for the switch for some other reason (this seems most likely)

I was a bit concerned about the reliability of my new switch. If it has the identical circuit design of my old switch, it might fail prematurely. So I opened up both KVM switches to see the circuit board.


Figure 3a and 3b. The circuit board of the old KVM switch on left, new one on right

Surprise! They are not identical. The new one has three chips compared to four for the old one. And some of the chips are smaller. These smaller chips in the new switch have more pins (indicating higher complexity).  Fewer chips should make it more reliable (hopefully). Both have a 12MHz clock chip (which is the full bandwidth speed for USB 1.0 specification). Both have an identification mark of MT-201UK-CH which indicates they were both designed by the same firm.

Someday, if this KVM switch fails, I might buy one that supports HDMI video connectors. Then I will have the left monitor dedicated to Windows, the right monitor dedicated to Mac and the center monitor toggle between them along with the keyboard and mouse.


Go back to the photo in Figure 1. Notice that the image on the monitors on the PC are much bluer than the image on the Mac. I’m a color printing expert and I’ve futzed with the white point and color balance on both machines and can’t get them to match. Why is it so hard to profile and calibrate monitors?


Part 2 of this story is posted Aug 2013.

All photos by George Taniwaki

by George Taniwaki

You would think that something as basic as the periodic table wouldn’t make the news. But recently two articles caught my attention. The Jun 2013 issue of Sci Amer (subscription required) points out that with the discovery of element 117 in 2010 (elements 1 through 116 and 118 had already been discovered), the periodic table has no gaps in it for the first time since it was first proposed in the 1860s. I found that pretty surprising. Of course, future discoveries of elements with higher atomic number may create new holes.

The article says that over 1,000 versions of the periodic table have been published. The arrangement that is most familiar was developed by Horace Groves Deming in 1923. An example table is shown below. It is color coded to indicate the date of discovery of each element. Note that four elements, shown in purple don’t have names yet.


Figure 1. Periodic table of elements showing era of discovery. Image courtesy of Wikipedia

The Deming chart starts with hydrogen (H) on the top left and helium (He) on the top right. The number of elements in each row tends to increase culminating in a separate block at the bottom for elements that start with lanthanum (La) and actinium (Ac). The elements in each column have similar chemical characteristics. For instance, the elements in the last column in each row are known as noble gases since they have high ionization energy potentials (the energy required to remove one electron). This makes it difficult, though not impossible, to make them react with other elements to form compounds.


Figure 2. Ionization energy to remove one electron from each element. Image courtesy of Wikipedia

Another way to lay out the elements in a table is to group them by their quantum electron structure rather than by their chemical behavior. One example is the Janet left-step table. It was developed by the chemist Charles Janet in 1928. It moves helium to the column next to hydrogen and moves the first two columns to the end of the table. Each element falls into a block. The lanthanum and actinium row of elements are given their place in the main table, rather than having to sit at the children’s table.


Figure 3. Janet left-step periodic table of elements. Image by George Taniwaki

Electron quantum numbers

Each row in the Janet left-step table indicates increasing electron energy level. This is represented by the integer n, called the principal quantum number. The first eight levels are named K, L, M, N, O, P, Q, and R respectively.

The number of blocks in each row is represented by the integer , which must have a value of < ((n+1)/2 ) and is called the azimuthal quantum number. The first five blocks are named s, p, d, f, and g respectively.

My version of the Janet left-step table above color codes each element to show which block new electrons are added, f (green), d (blue), p (yellow). and s (red). Note that there are exceptions to the block ordering. (An explanation is beyond the scope of this blog post.)

The number of orbitals in each new block is larger than the block to the right of it. Specifically, each block contains m pairs of cells = (2 * –1) cells, where m is an integer called the magnetic quantum number. You can predict that the g block in the next row of the periodic table will contain 9 pairs (18 total) cells.

Besides n,  ℓ, and m, electrons have a fourth quantum property called spin which is represented by s, an integer that can have a value of either +1 or –1. No two electrons in an atom can have the same 4 quantum values.

The images below show the orbitals for a single electron in a hydrogen atom as energy increases. Note there is a single s orbital, 3 p orbitals, 5 d orbitals, and 7 f orbitals. Each orbital can hold two electrons with spin +1 and -1, which explains why the s, p, d, and f blocks hold 2, 6, 10, and 14 electrons respectively.


Figure 4. Single electron orbitals. Image courtesy of Wikimedia Commons

Order in which electron orbitals fill

Each electron orbital has a different energy level. Orbitals with larger primary quantum number and larger azimuthal quantum number have higher energy than those with lower values. Electrons tend to fill the orbitals in what is called the Madelung rule which states that on average, orbitals with higher value of n + have higher energy. For orbitals with the same value of n +, those with higher value of n have higher energy. Thus, the order in which orbitals fill is a diagonal array as shown in the table below. This describes the layout of the elements in the Janet left-step table.


A pretty periodic table

In other periodic table news, the Aug 2013 issue of Pop Sci features a periodic table drawn by Alison Haigh, a London-based graphic designer. The article calls it beautiful and easy-to-read. I agree that it is beautiful. I don’t agree that it is easy-to-read or useful.


Figure 5. Periodic table without text. Image courtesy of Alison Haigh

First, showing both the cells and the dots is redundant. Just showing one or the other would be sufficient to convey the meaning. That’s because a periodic table is laid out in atomic number order. Thus, to find the atomic number of an element you can just count the number of cells from the top left or count the number of dots in the selected cell. To find which orbitals are filled for an element, you can see which row and column the element is in, or you can inspect the dot pattern in the selected cell.

The dots in each cell are arranged in an unusual order. They are grouped in concentric circles in order of their principal quantum number. The innermost circle has 2 dots, followed by rings containing 8, 18, 32, 32, 18, and 2 dots respectively. This means the dots are not arranged in the order that the electron orbitals are filled. This is a bit confusing.

Further, this arrangement only allows for up to 112 electrons, which corresponds to the element copernicium (Cn). The outer rings do not have room for additional dots to represent electrons for heavier elements that have already been discovered or predicted by quantum theory.

Finally, one of the most important uses of the periodic table is to help recall the names, abbreviations, and atomic number of the elements. There are no labels in this table. And counting the dots, or counting the number of cells to figure out the atomic number is tedious.

A modified version of Ms. Haigh’s periodic table is shown below. The elements are laid out in a spiral that follows the Janet left-step periodic table. Cells are color coded to highlight the s, p, d, and f blocks. Each cell is labeled with the atomic number and abbreviation of the element. It’s pretty, I guess; it looks like one of those eye tests for color blindness. But the layout is still not as useful as a standard periodic table.


Figure 6. Periodic table based on Alison Haigh design. Image by George Taniwaki


In 8th grade science class we were required to memorize the names of all the elements and their symbols. Do teachers make their students do that today? It seems rather pointless. How often do you use ruthenium (Rh)? There were only 98 named elements back when I was in school, so memorization was easier than it would be today where there are 114 and counting. Incidentally, based on that statement, can you can guess how old I am?

by George Taniwaki

I was driving on NE 8th Street in Bellevue last Saturday. As I was approaching 156th Ave. NE, I saw two of those ubiquitous sign spinners on opposite corners. I missed the light, so I had time to see that they were both advertising that the nearby Haggen Northwest Fresh was closing and everything was 30% off.

This is an unfortunate end to a misguided attempt by Haggen to compete with Whole Foods. Here’s the story.

When I moved to Bellevue in 2000, there were several supermarkets in my neighborhood. The closest is a small QFC, part of the Kroger chain, located inside the Crossroads Shopping Center, just north of the food court. Cater-corner to it was another small supermarket, an Albertsons. (I say “was” because it closed within a few months after I moved in and was eventually replaced by an Ace Hardware and a Bartell Drugs.)

A few blocks north of that is a Trader Joe’s, a chain that specializes in a small selection of fancy foods at low prices. Another few blocks north of that was an Uwajimaya, a local Asian food chain. (It moved a few years ago. More on that later.) A few blocks west of the Trader Joe’s is a Fred Meyer, another Kroger chain that sells a variety of department store goods and groceries. A few blocks north of the Fred Meyer (on the same street as Uwajimaya) is a Safeway. In addition, there are lots of small convenience stores and ethnic food stores in the neighborhood.


Figure 1. Map of east Bellevue showing locations of largest grocery stores from 2000 to 2013. Map image courtesy of Microsoft, logos courtesy of respective firms

There’s no shortage of places to buy food in east Bellevue. That’s why I was very surprised in 2001 when Haggen announced it was opening a big TOP Food and Drug just north of the Crossroads Shopping Center. Haggen is a regional supermarket, headquartered in Bellingham, WA.

Prior to the opening of the TOP store, I bought most of my groceries at Fred Meyer or Safeway. They were farther from my home than the QFC or Albertsons, but had a better selection of private label goods (aka store brands) and a bigger selection of fresh produce.

When the TOP store opened, I immediately switched to it. But I am not a loyal shopper. I shop for groceries every few days and will pull into a store whenever it is convenient (based on direction I am driving, time of day, etc.). Thus, I continued to occasionally shop at the other stores.

After a few years, I noticed that the prices were higher at TOP than the other stores. But since it was close to home, it remained my primary store. However, the parking lot at TOP was not as full as in the past. Price sensitive shoppers were abandoning the store.


The competitive landscape got tougher in 2004, when Whole Foods Market, a purveyor of high quality, high price groceries, built a large store near downtown Bellevue. This caused a lot of people to switch their purchases of meats, cheeses, and wines to Whole Foods. These are items that have high margins. This especially hurt a nearby competing store, called Larry’s Market, which ultimately led the entire chain to fail.

The space where Larry’s Market was became a Big 5 Sporting Goods store for a while, then was empty, and finally in 2011, Uwajimaya moved into part of the space. The remaining space was taken up by Total Wine, the biggest liquor store you have ever seen.

Uwajimaya realized that it was not a direct competitor to Whole Foods and could safely open a store across the street from it. In fact, the two stores are somewhat complementary. Also, even though Whole Foods in on a busy street, it is hard to get to. You can’t make a left turn out of the parking lot, forcing extra driving regardless of which direction you come from. Uwajimaya is easier to get to. Finally, Uwajimaya is one block from the Home Depot, a store I visit a lot. So I drive past the Uwajimaya frequently and thus shop there often.


In 2011, Haggen received a large capital infusion from Comvest Group, a private equity firm. Comvest decided that the TOP location in Bellevue would not be successful unless it switched from competing on price (apparently, TOP stands for Tough On Prices) to competing on quality. Thus, they changed the name of the store from TOP to Haggen Northwest Fresh and spent what I estimate was over $200,000 to remodel the store.

The remodeling effort took about three weeks. During that time, the store was open, but was a chaotic mess. So I stopped going the TOP and instead shopped at QFC and Trader Joe’s, two store that I rarely visited in the past.

I came back to the new Haggen store after the remodel. The biggest changes were to increase the spacing between stands in the produce aisle to give it the look of a faux farmers’ market, expand the wine section, and add a big exhibit stand in the center of the store. To make space for all this, they cut back on the private label brands, the very items that I visited the store for.

The other change they made was an effort to brand each of the sections of the store with names. For instance, the fish counter was renamed Lummi Bay Market and the deli counter was renamed Dot’s Kitchen. The idea was developed by the Hartman Group a local consulting firm, that called it a “store within a store” concept. Unfortunately, there didn’t appear to be any budget to change the look of the counters themselves, the offerings, or training for the personnel. So other than the new signage, nothing appeared to have changed. It seemed a waste.

Apparently, sales at the remodeled store did not meet expectations, so they began mailing $5 off coupons to customers. This must have been very expensive, and counter to the new high price, high quality image they were seeking. Ultimately, I decided to continue to patronize QFC and Trader Joe’s and only rarely stepped into the Haggen.


The remodel has been a disaster for Haggen and Comvest and led to the store’s closure. Hopefully, the company can find its footing and achieve success in its other stores. I liked the TOP store when it first opened and am sad it failed. The retail business is tough and is undergoing a revolution with companies like Trader Joe’s and Whole Foods taking the high-end, ethnic food stores catering to the immigrant population, and services like Amazon Fresh making inroads in the grocery delivery business.


Several months ago a Walmart Neighborhood Market opened west of our house. It occupies the space of a failed Kmart store that had been empty for years. Then last month, a new Grocery Outlet opened just across the street from Crossroads Mall in what previously had been a high-end appliance store that closed during the housing crisis. Apparently, there are still people who think the grocery business is worth investing in.