Building a Plywood Sink / Question

[Scott Ridgeway]

I getting close to installing the drain on a plywood sink. I realize I need to drill a hole for the drain. I'm not sure how to get the drain flange to be below (or at least flush) with the surface of the plywood. Anyone else done this before?

 

[resummerfield]

Select a hole saw which is just slightly larger diameter than the diameter of the flange that is exposed in the sink. Then just slightly cut a ring in the plywood, scoring the wood about one ply or 1/8-inch deep. Next select the proper size hole saw for the thread part and cut the hole through the plywood. Finally, take a sharp chisel and cut-out a thin layer of wood (just one ply) inside the score line. I would then seal the raw wood with whatever you used to seal the plywood surface. Before installing the flange, fill this recess with plumber’s putty or silicone and then install the flange.

 

[erikg]

I used a hole saw that was the size of the outside diameter of the drain flange to countersink it into the surface of the sink. Then I used a smaller saw to drill all the way through for the drain itself. Seal it all up all nice-nice and it will last for years.

 

[Monophoto]

If you have access to a router, it could be used to cut a neat rabbet around the opening. Failing that, you might be able to simply cut through the top layer of the plywood with a mat knife and then peel off the layer using a chisel.

 

[dslater]

When I built my plywood sink, I just didn't worry about it - the flange is not quite flush and a small amount of water remains in the sink, but it evaporates quickly.

 

[colivet]

You could leave on top and fill around with epoxy resin so that the water can still flow into it. It would probably only work if there is enough slope.

 

[Mike Wilde]

J-cloth to the rescue

My plywood/fibreglass sink (now over 24 years since I built it - ouch, the reality of middle age bites you when you think of things like that) has the aforementioned non- recessed drain flange. I acually like it. The washer usually sits in, or drains into the sink, from a shelf beside the sink. The small amount of water that lays in the sink is under the slatted duckboards that I use to put my trays at a comfortable height. Any splashes from the trays land on a wet surface. At the end of a session I flip the duck boards over so evereything gets wet, then wipe the sink down.

This keeps the chemicals that we dissolved to make up developer and fix from re-forming once the spill dries out. Dried chemiostry floating around as dust will drive you nuts in spotting until you get it under control.

Wipe down is carried out with j-cloths salvaged from the kitchen sink when they are deemed too far gone to wash dishes with. The once wet are a great wick, when you lay one over the open drain.

 

[Kobin]

I used a double thickness of plywood for the bottom of the sink. The drain flange fits snug against the lower layer and the upper layer lies above it.

K.

 

[pnance]

After I drilled the hole for the body of the drain. I put the drain in the hole and drew around it. Removed the drain and used a chisel to remove the aproximately 1/8" so the drain would fit flush. Epoxyed the wood before installing the drain. Works great.

 

[pnance]

Incidently, I used a plastic drain. Since, the plumbing downline is mostly plastic, I felt there would be less problems with the various chemicals that might go that way. Not all drains that are marked "stainless steel" are good stainless. If they are magnetic, they are the cheaper, more chemically active varieties.

 

[pnance]

The plastic drain was thicker, thus the 1/8". Plus the fact I used 3/4" ply for the floor of the sink. This helped with the fact most drains are built to be installed in a wood sink. 3/4 - 1/8 = 5/8" just about the limit of the threads on the particular drain I found.

 

[Ben 4]

Use a chisel

When I built my sink, I followed the instructions in Buren & McDonald's excellent "Build Your Own Home Darkroom" book. They recommend tracing around the outside of the drain flange and then using a wood chisel to remove the top layer of wood inside the circle. This was tedious, but it worked well. Good luck.

 

[Loose Gravel]

I've always used a router. Just mark it and freehand the router.