Darkroom sink construction plywood...

gphoto120 · Aug 30, 2006

I'm building a darkroom sink. The local Lowes carries a 23/32" B/C grade exterior plywood @ 25.00 per sheet. I called a local lumber supply and they have an A/B exterior 3/4" @ 50.00 and also th B/C 3/4 in B/C @ 45.00.

Does anyone know if I will be getting better plywood from the local shop , or just paying them an extra 20.00 per sheet. When I asked the locals about 23/32" plywood they said they've never heard of such a size.

Thanks for any input !

jovo · Aug 30, 2006

Yeah....23/32 dimension seems totaly unusual, but I looked it up, and that's how Lowes describes it. When I checked to see if they also carried a 3/4 inch plywood, there were no results for the search. So...it must be that 3/4" is now 'nominal' just like most other dimension wood products, and Lowes is just telling you more accurately what you're getting. BTW, I'd get the AC if I were you unless your going to laminate another layer on top. Too many knots in the lesser grade plywood you'd have to fill. I also think you could use 1/2" ply with good support unless you're going to have trays or tanks that weigh a great deal. Both my 'sink', and dry side bench for two enlargers are 1/2", there's never been a problem. We tend to overbuild things a good bit I think. (There's a pic of my homebuilt benches on the darkroom portraits thread on page 5 if you want to see. There are also tons of really good ideas to be gleaned from a lot of people's darkroom portraits. )

noseoil · Aug 30, 2006

23/32" is the nominal size now for this grade, just as 15/32" is with half inch ply, as John has mentioned. The second letter (C) denotes an exterior glue which is used for the laminations. AC is better on the finish side. I would be more concerned with how flat the sheet is when you purchase it than the actual grade and cost. Some of the sheetgoods sold are not stored properly and can take a set which makes them difficult to work with.

You might consider having it shot with a truck bed liner material (many colors available), if it will fit through the door when finished. This makes a bullet-proof sink and keeps the water out. Get the drain in place and bedded properly as this can be an area of concern with a wooden sink. Make sure to caulk the edges well and use lots of glue & drywall screws. Don't use a silicone caulk if it is going to be finished inside, nothing will stick to this stuff.

When I started as a cabinetmaker (back in '71), AD was $5.00 a sheet and AC was $10.00 a sheet. Seems like a long time ago now. Glad I have an office job now. tim

jovo · Aug 30, 2006

noseoil said:
When I started as a cabinetmaker (back in '71),...

I've been doing some work on a Habitat for Humanity, Presby-Build (my Presbyterian church affiliation) house in Newburgh, NY. The house is well over 100 years old and the studs, and joists are the real thing, i.e. a 2x4 is a 2x4 etc. It's a wonder that everything comes out right when 'new', dimensioned, nominal size wood has to team with the original stuff. I've not seen all the tricks used to make that happen yet, but it's been a hell of an education so far!

raucousimages · Aug 30, 2006

I worked for lowes, 23/32 is 3/4 that has had 1/32 sanded off to give a smoother finish. A/B grade will have no voids on the inside if the wood. B/C or C/D will have voids and might have more warp. A/B should be flatter.

BruceN · Aug 30, 2006

I used 3/4" A/C, with the "A" side as the inside of the sink. Pieces held together with "Liquid Nails" and screws every 3 inches. Covered with 2 coats of "Kilz Premium" then 5 coats of latex garage floor paint. Seems to be working wonderfully so far...

Bruce

Bruce Schultz · Aug 30, 2006

Go cheap. Resin and fiberglass can fix any flaws.

As long as the plywood isn't warped, why spend the extra money?

resummerfield · Aug 30, 2006

Even if the plywood is slightly warped (and most sheets do have some slight warp), the finished sink supports should eliminate the warp. Go with the cheaper material, and spend the savings on the interior finish (epoxy, etc).

Loose Gravel · Aug 30, 2006

Better plywood has fewer voids. I'm about to make a new plywood sink and I was going to use 3/4 birch. It is very flat and voids are few. I don't know if it is exactly 3/4", but it might be since it is used for furniture.

They take the 1/32" away from construction plywood because they can and still meet spec and it costs less.

fotch · Aug 30, 2006

The voids probably will not really be a problem. The A, B, C is more about the surface and if you cover it up with paint, epoxy, why pay more for smooth sanded A. Put the money into epoxy and a sturdy frame.

The sink I made about 25 years ago is still in almost new condition. I used a Marine Grade Plywood (overkill) and then used fiberglass cloth along the seams and epoxy the whole thing. The epoxy and fiberglass was purchased at a Marine dealer and used for making or repairing boats. It has held up extremely well.

However, the lack of drainage is always been a pain. Since I am in the process of setting up my darkroom again (after 15year absence) I am thinking of changing the bottom so it slopes to the center drain. I am thinking of both using epoxy with filler to create a sloping bottom or a mortar mix and epoxy/fiberglass over the top of the mortar.

I then can make some wood (epoxy coated) slats that would allow drainage while keeping items (trays, Jobo) level. Then again, maybe I will live with the flat bottom and continue to use a squeegee to move water to the drain.

Good Luck.

noseoil · Aug 30, 2006

Look up roof crickets. It is a term used for flat roof construction. tim

david b · Aug 30, 2006

Can 3/4" wood be purchased in 10 foot sheets?

Loose Gravel · Aug 30, 2006

10' are available. Special order. HEAVY.

Loose Gravel · Aug 30, 2006

I'm wondering about the drain. Of course you slant the bottom either by construction or by the legs and the drain is in the low corner. But what about the very very corner. Is there always a little water standing there or do you build up the corner a bit so it drains perfectly.

Robert Hall · Aug 30, 2006

I used plywood (oak faced) for my sinks. I have one 16' and one 8' in the next room. I decided to go all out and stained it mahogony then coated it with a couple coats of fiberglass resin. I used a 16 guage nailer to hold the pieces together. 34" wide and 7" deep. I did this for the last sink and they all have been great. I used a router to cut a hole for the drain. I used a plastic floor drain, drew a circle around the outside, then rabbeted a cut to fit the inside. I used silicone to seal it up. I've had them hold water for days, not a problem. You can get a look at the old sink at http://www.roberthall.com/dr I will post images of the new dr when I get the cabinets finished.

Bruce Appel · Aug 30, 2006

I made mine out of the cheap, not really 3/4", exterior grade, plywood from Home Depo. I used waterproof Tightbond glue on all the joints, and made a paste out of sawdust and glue to make smooth contours on all the joints. I thinned the same glue with water and a little vinegar, and gave multiple coats to the whole thing, using a brush and roller like you would use paint. The first coats need to be thinner so they soak into the wood, gradually use thicker coats. Finally a coat of white paint, and a coat of polyurethane, and this thing will outlast me. It is cheaper than epoxy resin, and no fumes to speak of.

gphoto120 · Aug 30, 2006

Thanks everyone for your help and suggestions !

david b · Aug 30, 2006

I have a 6 foot fiberglass sink that is too small for what I need.

So I am going to have a 9 foot sink made and then sprayed with LINE-X.

This will save me the head ache of painting and sealing myself.

B&Wenthusiast · Aug 31, 2006

darkroom sink

Unless you need a LOT of space, they sell a laundry tub also we use. Works like a charm! Still working on a stopper, though.

Monophoto · Aug 31, 2006

I framed my sink using "1 by" d-select pine. The bottom is 1/2" plywood. The bottom slopes toward one end. At the low end, I installed a small stainless steel sink (the kind designed for use in travel trailors).

The wood was primed and then coated with five applications of two-component epoxy. Four years ago, we move to a new home and I took it along as the foundation of my new darkroom. Decided that it was due a fresh coat of paint - after 20+ years of use.

df cardwell · Aug 31, 2006

You'd probably be fine with glossy paint ( really )

Fiberglass, epoxy, and Marine plywood is beyond overkill.

Any restaurants near you going out of businesss ?
Steel sinks are handy.

david b · Aug 31, 2006

I spoke to the Line-X folks this morning and was told that no prep is needed in applying their product. Just bring them the sink, completed, and then they spray it.

As for price, that said it would be about $300 and it's ready to use in 24 hours.

dancqu · Sep 4, 2006

df cardwell said:
You'd probably be fine with glossy paint ... Fiberglass,
epoxy, and Marine plywood is beyond overkill.

Many years ago I put sink and 4x5 tanks together.
They were coated with some sort of water-proof
rubberized paint. Today I'd consider going the
same rout.

I'm a counter type. Plenty of counter with sink only
large enough to wash up. But then again I don't slop
chemistry all over the place. Dan

Loose Gravel · Sep 4, 2006

Well, this got me all fired up and I built a sink this weekend. It is only about 3' square for a wash sink. I went to two national stores yesterday looking for some sort of waterproof paint and the best they could offer was oil enamel. Maybe that would work, but I want something more bullet proof. I haven't tried marine stores yet.

Curt · Sep 4, 2006

Many years ago I put sink and 4x5 tanks together.
They were coated with some sort of water-proof
rubberized paint. Today I'd consider going the
same rout.

I'm a counter type. Plenty of counter with sink only
large enough to wash up. But then again I don't slop
chemistry all over the place. Dan

That reminds me of the first time I stepped foot into the darkroom at the Art Center College of Design in Pasadena California. There were large square tables with people developing paper in trays on the table. It was really strange coming from a University where Darkroom sinks were where we put the trays. If you aren't messy and the room is the proper temperature I don't see a problem with less sink and more counter. you can do a lot more with counter space than in a sink.

I migrated to Brooks Institute and found the sink and tray line again. It's all up to the individual. I have a factory made 6' sink and two lab hard rubber over steel deep chemical sinks.

Darkroom sink construction plywood...

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