Custom Sink - How to get the drain "in sump"?

[Salmo22]

I'm pleased to be getting started on my home darkroom. I'm expanding our unused pantry and will be pouring concrete later this week.

As part of this work, I'll be building a 2'-6" x 10' custom sink from plywood. I've watched YouTube, read posts on this forum, and I am currently reading the "Build Your Own Home Darkroom" by Duran and McDonald. Maybe I'm missing something, but what do I do to insure the drain is at the low point of the sink? Every example I've seen or read about shows putting the drain "near" the low point - but not exactly at the low point. That leaves me to believe that some water will get by the drain and collect next to one edge/corner of the sink. I'd like the drain to be "in sump", but need some assistance figuring out how to achieve that goal. Accordingly, I am seeking the wise and experience comments from you fine folks. As I said, maybe I'm missing something that is obvious to others. If so, please enlighten me.

Thank you;

Jeff

[Richard Wasserman]

In my sink I made sure that it sloped to 1 corner about 1/8 inch per foot and installed the drain in the low corner as close to the edge as possible. I recessed the flange of the drain using a hole saw and chisel. It works just fine— a tiny bit of water remains, but it dries up pretty quickly.

[Drew Wiley]

Easy. Just put the sump under one end and slightly slope the whole sink downhill that direction. Otherwise, if you want a center drain, you have to make a moulded sink.

[Willie]

Set it up as you will be using it and before cutting the drain hole drop some marbles, ball bearings or BB's in it and watch where they finally stop. If they group a bit in one area - you have the low spot.

Planning for a gentle slope at the beginning does make it easier. Either way a squeegee to clean off the surface and make sure the water goes to the drain is helpful.

[MrFujicaman]

What are you going to use to coat the sink?

[Salmo22]

What are you going to use to coat the sink?

My eldest son owns a polymer coating business. He will be coating the sink with some type of high-end epoxy.

[MrFujicaman]

my eldest son owns a polymer coating business. He will be coating the sink with some type of high-end epoxy.

cool !!!!!

[Doremus Scudder]

I built my own 33" x 10' sink out of marine plywood. I opted for a center drain. The sink bed is two equal-sized pieces of marine plywood set on a 2x2 framework. I simply designed the frame to that it tilted in and back so I could place the drain in the center rear of the sink. Edges, corners and center seams were sealed and fared with marine epoxy, then the whole thing was primed and painted with marine paint.

This design has the advantage of not having one end of the sink being significantly lower than the other. The drain itself is just a standard 3" fixture, but I have a 12" funnel that fits in the drain for emptying trays etc.

I have my plans still if you're interested in seeing them.

Hope this helps.

Doremus

[Salmo22]

I built my own 33" x 10' sink out of marine plywood. I opted for a center drain. The sink bed is two equal-sized pieces of marine plywood set on a 2x2 framework. I simply designed the frame to that it tilted in and back so I could place the drain in the center rear of the sink. Edges, corners and center seams were sealed and fared with marine epoxy, then the whole thing was primed and painted with marine paint.

This design has the advantage of not having one end of the sink being significantly lower than the other. The drain itself is just a standard 3" fixture, but I have a 12" funnel that fits in the drain for emptying trays etc.

I have my plans still if you're interested in seeing them.

Hope this helps.

Doremus

I'd be very interested in seeing your plans. Thank you for that kind offer.

[Jim Noel]

In my sink I made sure that it sloped to 1 corner about 1/8 inch per foot and installed the drain in the low corner as close to the edge as possible. I recessed the flange of the drain using a hole saw and chisel. It works just fine— a tiny bit of water remains, but it dries up pretty quickly.

Mine is similar. I achieved the desired slope not only from end to end, but front to back. the drain is in the left rear corner and recessed. The slope was achieved by cutting supports for the bottom of varying thicknesses. There are 8 supports in the eight feet including the ends. the supports were glued in first being sure their bottoms were on a flat surface. Then once the plywood was glued down the whole sink was covered with 3 coats of West Systems Epoxy. It was built in summer of 1989, and has never leaked.