Darkroom sink - slope help

[Serge S]

Hello!

I've decided to build a sink out of poplar (sides) & plywood (floor) to fit my space.
Quick question, a darkroom book recommended a 1 inch pitch to drain the water.
I spoke with a carpenter, he told me that was too extreme.

What do you recommend for a pitch?
The sink will be 58" long & it will drain in the center.

Thanks in advance!

Serge

[Graham Patterson]

1" over 24" (58/2) is very steep - unless you plan to put in a leveling duckboard, trays and tanks will be tilted just as much.

Sink drain /pipes/ usually have around 1/4" per 12" of horizontal run, so that would be 1/2" from each end to the drain, though with a center drain you will have a join in the base that itself will need a bit of a slope. I'd say that's the steepest I'd use for a general purpose sink.

[Serge S]

Thanks for the quick response Graham!

[Rick A]

You can easily get away with 1/16"- 1/8" slope per foot of run, you're only draining liquids, no solids.

[Conrad . Marvin]

I used even less with great success.

[John Layton]

My sink is 3 X 16 feet...marine epoxy over baltic birch ply - and is very sturdy with a very flat and slippery bottom, and with that I get away nicely with a 1" drop over the entire length, and about a 1/4 inch downward tilt from front to back...as the drain is located in the right rear corner. With these specs it will drain quite nicely...albeit a bit slowly, so at the end of a processing/printing session its typical for me to whip out my 18" rubber squeegee and help things along - which gives me (my sink, that is) a quite dry bottom.

Nice thing about establishing a minimal yet still effective slope is that solutions in trays are essentially level...but if a try is filled to overflowing it will still empty out over the downhill side.

A cool aspect of my sink is that when I was laying things out...I realized that the two sheets of plywood which I'd used for this happened to be "book matched," meaning that the visible grain pattern of the top layer of veneer on each sheet essentially mirror each other. It is for this reason that I decided against adding any pigment to the epoxy mix. Not sure how visible this is here, but if you look carefully at the back seam you just might see it:

[Tracy Storer]

I also have a self-made plywood, fiberglass cloth/ marine epoxy sink, 30" x 12'.
Slope is about 1/8" per foot, which drains well. Could have gone a bit less, but even so, like John Layton, I sometimes squeegee to floor of the sink to reduce any standing water.

My sink is 3 X 16 feet...marine epoxy over baltic birch ply - and is very sturdy with a very flat and slippery bottom, and with that I get away nicely with a 1" drop over the entire length, and about a 1/4 inch downward tilt from front to back...as the drain is located in the right rear corner. With these specs it will drain quite nicely...albeit a bit slowly, so at the end of a processing/printing session its typical for me to whip out my 18" rubber squeegee and help things along - which gives me (my sink, that is) a quite dry bottom.

Nice thing about establishing a minimal yet still effective slope is that solutions in trays are essentially level...but if a try is filled to overflowing it will still empty out over the downhill side.

A cool aspect of my sink is that when I was laying things out...I realized that the two sheets of plywood which I'd used for this happened to be "book matched," meaning that the visible grain pattern of the top layer of veneer on each sheet essentially mirror each other. It is for this reason that I decided against adding any pigment to the epoxy mix. Not sure how visible this is here, but if you look carefully at the back seam you just might see it:

[Drew Wiley]

Mine slopes 2 inches over 10 ft of length. But the exact angle isn't very important. You don't need much overall slope.

[Serge S]

Thank You for the informative replies.
Much appreciated!

[Salmo22]

I’d like to expand this discussion to include various design priorities for the base, beyond the important job of supporting the sink. What has worked best for your darkroom?