Home built darkroom sink finish recommendation

Wilbur Wong · Oct 25, 2007

matti said:
I think that would be unnecessary. A darkroom shouldn't have a moist atmosphere like a bilge in a boat has. And epoxy will give enough protection from water and chemicals. Just skip fir if you want the surface to be fair later as the annual rings will always show through any kind of paint over fir plywood. Here in Sweden I would choose birch plywood and just check the ends for voids.

/matti

Birch plywood is an excellent choice for dimensional stability.

richard ide · Oct 25, 2007

Polyester resin is far inferior to epoxy when cladding a wood surface. The bond is weak whereas with epoxy, the resin permeates the surface. This is from a book on boat construction which is buried somewhere nearby.

RobertP · Oct 25, 2007

What about 3/8" plexiglass. I've been building trays out of 1/4" and they seem damn near bullet proof. I had all the parts precut and they must have been CNC cuts because they are within a thousandth or so. Just an idea. Robert

Deane Johnson · Oct 25, 2007

One word of caution on the marine resin. I did a sink in that a number of years ago. When it became stained, I sanded it and applied a new coat. Where there was still a little stain from the chemicals that didn't get sanded off, the new coat would not stick.

TracyStorer · Oct 25, 2007

Deane Johnson said:
One word of caution on the marine resin. I did a sink in that a number of years ago. When it became stained, I sanded it and applied a new coat. Where there was still a little stain from the chemicals that didn't get sanded off, the new coat would not stick.

Polyester or Epoxy Resin?

Deane Johnson · Oct 26, 2007

TracyStorer said:
Polyester or Epoxy Resin?

It was a number of years ago and I don't remember, but I remember mixing two ingredients, so I suspect it was epoxy resin. It was sold as a fiberglass boat repair kit, complete with the fiberglass mesh.

Steve Smith · Oct 26, 2007

Deane Johnson said:
I suspect it was epoxy resin. It was sold as a fiberglass boat repair kit, complete with the fiberglass mesh.

If it was for fiberglass, it would more likely be polyester resin. Especially if it was part of a kit.

Steve.

matti · Oct 26, 2007

Deane Johnson said:
It was a number of years ago and I don't remember, but I remember mixing two ingredients, so I suspect it was epoxy resin. It was sold as a fiberglass boat repair kit, complete with the fiberglass mesh.

then it was polyester. To be able to use polyester on old polyester you need to sand it down so you can smell uncured resin in the laminate to get a chemical bond to. Polyester would be ok to use on plywood when building a dark room sinkh. It is a bit more dangerous to use than epoxy, so it would be best to be outside.

Epoxy will work on sanded polyester but not the other way around.

/matti

Bruce Schultz · Oct 26, 2007

I bet this stuff would work:

http://www.herculiner.com/questions.html#f

Deane Johnson · Oct 26, 2007

Bruce Schultz said:
I bet this stuff would work:

http://www.herculiner.com/questions.html#f

The area I might raise a question on is the rough surface. Seems like it might be really tough to keep clean and rinse the chemicals off of.

Home built darkroom sink finish recommendation

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