Well, with 3 coats of this stuff it looks pretty good. The only problems areas are the little "boats" that they mill uses to fill imperfections (they look like ovals with sharp ends). Something about the glue used has caused the epoxy to avoid a very tiny area around the boat. I'm thinking about trying a 24 hour epoxy glue to seal these tiny areas.
Everywhere else looks great. In some areas it's almost like a bathtub. This stuff reaks though! Smelled up half the house and my furnace isn't even in the garage. It's starting to die down now though thankfully. Talk about off-gassing!
I see you have all used epoxy paint for your sinks but over here in the UK I am having trouble getting epoxy paint. I can get garage floor paint but I don't think it is epoxy as it isn't a 2-part package. Does anybidy know where I could get some epoxy paint in the UK without much trouble or is there some other safe alternative I can use for my darkroom sink?
Just a quick bit of info to share.
Most epoxy paint (the two part stuff) is simply a thin fiberglass resin. The only difference when you do fiberglass is that you add fiberglass cloth and then spread the resin on top. (of course there is a bit more skill required). The idea behind the cloth is that it adds strength to your project.
I used to work making houseboats and doing the fiberglass parts. The difference between that and a sink is mostly the smooth finish. A boat has to beautiful to sell where as a sink only has to be functional. I have recently (2 months ago) made a plywood/fiberglass sink for my darkroom and am just doing the plumbing changes over the next two weeks.
I suggest that anybody who wants to waterproof the sink obtain a beginner's book to fiberglassing from the library and read a bit. All that you really need to do is have fresh air, mix the epoxy resin /catalyst and lay the stuff down. (a bit simple but it actually works). The paint stuff that sells is usually more diluted (easier to spread) and sometimes they give you some grit to add so that it is not as "slick as grease" when it gets wet.
I would not place caulking under fiberglass resin. I would do all my resin first, let the resin cure and then if necessary do caulking.
In my sink I did not require any caulking, the resin sealed everything. Even though as mentioned it does not have to hold water like a bathtub I tested mine anyways. I filled it with water in the garage and left it to sit overnight.
Watertight and nary a leak. :P
I thought of doing the same thing, cove my inside corners. I also did 1/2 round on the top edges so that I could lean against the sink without the sharp corners.
Just had to be careful not to get air bubbles on the inside edges. I did a triple coat of epoxy (needed to use it up) on all of the inside seams. A bit crude for a boat show.... but only I will be looking.
From out of the blue...
If you are a woodworker, you know that you don't need a diamond hone to make your tools sharp, good sandpaper will do and if you are working on the cheap for dark room stuff, try using beach coolers for water temperature control. It is hard to beat the price and time investment is small.
PS, I made my "sink" (more so a splashway really) out of Luan subfloor material and 1x4 pine, coated with Polyester resin. $40, works fine!
I am not sure what exactly it is that you need for ULF film. I can share with you what I have built. (If you want I can take a couple of digital pics and post them or send them)
My sink is fairly large as I only wanted to do this once. I can fit 3 16x20 trays along the length (cross ways - sink is 32" across) and I still have the deep well at the end. My design criteria was to be able to do (4) 11x14 trays along the length and still have a 12" x 32" x 10" deep well at the end.
My sink slopes very gently from the top end to the deep well. The deep well then slopes from both sides towards the middle where I have made a fiberglass seat for placing the drain. (exact same drain as a standard kitchen sink). I wanted a deep well for washing up mostly and a place to dip my hands and rinse before going back top the dry side of the darkroom.
The "coupe to grace" is that I won on Ebay early this spring a brand new "unused" Noritsu temperature control board for less than $200. This thing is all premounted on a slab of white ABS like board, has both a cold and hot inlet cannister filters, a flow meter and of course the temperature control valve. Rather excited about getting this in place in the next couple of weeks before Xmas holidays.
I also wanted my sink to accommodate (3) 11x14 trays and the print washer at then end. (Versalab 11x14 courtesy of Bmac....thanks). I'll be placing the plumbing in place this weekend and working throughout the next week or two fine tuning all of the parts. When it is done I'll do a digital picture for you.
After blabbering away about this, I hope I did not leave the impression that the sink was a real work of art. On the contrary... anybody who can attach plywood together with glue and screws can build something like this. The fiberglassing is relatively easy once you understand what to do and what to watch out for.
Perhaps you can tell us what you are building for ULF?
I have a right angle shaped sink that I process a lot of 20x24 prints in and what I did was to stack the trays with a wooden homemade shelf system. I have stacked, dev, stop, fix 1, fix 2, and permawash at the bottom. This leaves me room for a bleach tray (for sepia) a wash tray, a toning tray as well as a archival print washer. I am able to do the entire process at one time.
Some people don't like the stacking system but it is easy to get used to and the space savings are great.
Just and idea,
Take the built sink to one of these spray on truck bed lining places. It works great!
I'm a little late to the party, and it may have been mentioned above, but an excellent alternative to the expensive epoxy paint is PPG's Coal Tar Epoxy.
I put this on my sink when I built it (3/4 inch regular plywood) and have had zilch problems with it. It's *real* heavy-duty stuff that is used where you want to coat something ONCE and never have to do it again; I think I read somewhere it's used on the inside of septic tanks...
I used it because one of the 'how to build a darkroom' books I was using recommended it. I have not been sorry; it's held up very well and I cannot complain about the cost ($25/gallon?), which easily allowed two coats of my 7 foot by 2.5 foot sink. The paint was not available 'off the shelf' here in Des Moines, (it's an industrial, not a consumer product) but a nearby dealer ordered it for me and had it delivered to my door.
It comes only in black, it's thick (imagine what you would get if you mixed coal tar and exoxy together and you will not be far off the mark), but it works well.
If you're looking for a tough paint and don't want to spend a fortune, you might give it a try.