Has anyone tried this ?

[MrFujicaman]

Okay, I'm in Walmart wandering around the paint department and I see Kool-Seal elastomric (sp) roof covering for trailers. According to the can, it forms a strong water proof seal. Has anybody tried using this for a darkroom sink ?

[David Karp]

I think that Gordon Hutchings might have done something like this in his darkroom. If I remember right, there was an article about his new darkroom years ago in View Camera.

[David Karp]

Actually, now that I think about it, he took his sinks to one of those places that line truck beds. Sorry.

[shadow images]

As poorly as I've seen it work on trailers I wouldn't trust it in a sink.

[MrFujicaman]

Welll........so much for THAT idea !

[gleaf]

Check out Herculiner which is a $35 - $70 roll on brush on pickup truck bed liner. Most online and local auto parts folks should have it or something similar. Have not done it yet but it is in the plans for my sink.

[vinny]

west systems epoxy. do it right the first time.

[JW Dewdney]

Yeah I tried the company that does the truck beds - even though they will come to you to do your truck bed - they refused to do my darkroom - which seemed silly... but their loss I suppose.

[Drew Wiley]

It would be worthless. It's a cheapo DIY acrylic that will reemulsify in standing (puddled) water. Any roof coating would have to be an expensive true rubber-based product, which means either very nasty fume-wise during application (if you can legally get it at all), or heat-welded from sheets stock taken from a roll, which would
require a pro to do it. As already noted, the correct method is to use a penetrating marine epoxy.

[Drew Wiley]

The type of liquid rubber I used to sell for dkrm sinks and chemical vats was made of pure hypalon. Last time we handled any it required a special military exemption
which stipulated it be used only in international waters. It went to aircraft carrier decks; but now is deemed to nasty even for the military to acquire. Commercial
roofers can acquire it in sheets and heat weld the seams. But it would be cheaper just to buy a prefab stainless or ABS sink. I wanted an oversized sink for my own
dkrm, so had a fellow who heat-welds lead in nuclear reactors stitch me up some sheets of thick polypropylene. The technique is about the same. He'd lift lead
sheets all day, so had biceps like tree trunks, and a neck as thick as the Washington Monument. But I already knew the fellow so got the sink very reasonably.
But one day a bouncer outside a club punched this fellow - one punch back and the bouncer ended up with six months of facial reconstruction.

[Brian Ellis]

I used a Benjamin Moore elastomeric product called "Moorelastic" for my plywood darkroom sink. It worked very well for many years and was much easier to apply than epoxy (from what I've read about epoxy, never used it myself). When I've mentioned this product here before others have said they couldn't find it in a Benjamin Moore store so maybe they no longer make it or maybe they've changed the name.

[jnantz]

west systems epoxy. do it right the first time.

yep,
fiberglass epoxy, works / ed like a charm ..

[MrFujicaman]

Check out Herculiner which is a $35 - $70 roll on brush on pickup truck bed liner. Most online and local auto parts folks should have it or something similar. Have not done it yet but it is in the plans for my sink.

I've decided I'm going to try that. I'm building a 2' by 4' dry sink that will go on top of my washer and dryer so I can process film until I get the darkroom built. If it seems to hold up, I'm going to go with the Herculiner.

[Drew Wiley]

Moorlastic is a terpolymer never intended for horizontal waterproofing, though a number of people (including me) used it for such, provided there was enough pitch
to the roof to prevent ponding. The formula changed a couple years back and might have again, so I would not (and never did) recommend it for sinks. It is hard to
get on smooth and is prone to staining, just like all terpolymers. Fiberglassing with polyester resins is not very safe task unless you have your fume hood already
operative, or do the task outdoors prior to installing the sink. You can also simply cut down thick ABS sheets and solvent weld the corners, just like solvent welding
PVC pipe, provided you can cut the edges dead clean and square (I use a Festool rail saw for such tasks). Plywood would be my last option, though penetrating marine epoxy makes this route viable. These kinds of epoxies are made by Smith, West Systems, and Abatron, and avail in most boatyards and some plastics stores.

[Drew Wiley]

For a dirt cheap lightwt mini-sink (or huge deep tray) I'd simply pick up a large ABS mortar tray.

[Bogdan Karasek]

It would be worthless. It's a cheapo DIY acrylic that will reemulsify in standing (puddled) water. Any roof coating would have to be an expensive true rubber-based product, which means either very nasty fume-wise during application (if you can legally get it at all), or heat-welded from sheets stock taken from a roll, which would
require a pro to do it. As already noted, the correct method is to use a penetrating marine epoxy.

Hi, I'm planning an expansion of my darkroom as I want to install a second Omega D2v with cold light head, the other with condensors and a Durst 137 Laborator to do 5x7. But the main reason , is that I want lots of sink space. So far, the sinks will be the length of two 8 foot long marine plywood, basically 2 8 foot long sinks with drains in the middle and maybe there will be room for a shorter and narrower one, just for the large tanks to accomodate 8x10 film holders, plus a washing area for prints and film. Overall size of the room will be 10 wide x 24ft long.

Several people have suggested coating the sinks with marine epoxy. What is the correct method?

Regards,

[Robert Opheim]

I used Polyurethane to coat a plywood sink I made years ago. The only problem that I had was that the polyurethane got some stress cracks in it because I didn't make the wood frame strong enough not to bend. I made it out of 1/2 inch plywood. It was something like 3 feet deep x 8 feet long and 6 inches deep.

[cosmicexplosion]

I have been using an expoxy waterproof system I procured from a boat shop.
It's advantages over other systems is it flexibility You still need to paint it.

I would use, 'Form ply' used for concrete form work. It has a strong black water proof surface.

Better than marine ply which is not designed for use in water. It's just got better glues.

Using form ply, you only need a tube of sika flex for corner joints.

Easy

[cosmicexplosion]

The epoxy water proofer is an Australian product.

[Liquid Artist]

Before I would attempt to build a sink I would check out any Dairy Supply stores in the area.
While working in the industry, I have seen high quality sinks of almost every size and shape available, and it turns out they are not usually all that expensive (at least where I live)

[vinny]

1. You don't need marine plywood. I use birch though, not a/c. The epoxy will keep water out. Paint or polyeurethane the non-epoxied parts if you like to reduce warping/moisture absorbtion.
2. Look up west systems epoxy instructions. There's a helpful pdf.
3. Coat/let dry/ all mating edges before assembly. I can't seem to get a 100% bubble free surface.
I apply it with a foam roller and/or foam brushes and sand any bumps/bubbles betweet coats.
Get the 1 gallon size epoxy and quart size (i think) hardener. (105,205 are the numbers on the cans). Get the pumps that measure it for you. I got my current batch from Defender boats online. I think it was $130+ and will do both your sinks and more.


Hi, I'm planning an expansion of my darkroom as I want to install a second Omega D2v with cold light head, the other with condensors and a Durst 137 Laborator to do 5x7. But the main reason , is that I want lots of sink space. So far, the sinks will be the length of two 8 foot long marine plywood, basically 2 8 foot long sinks with drains in the middle and maybe there will be room for a shorter and narrower one, just for the large tanks to accomodate 8x10 film holders, plus a washing area for prints and film. Overall size of the room will be 10 wide x 24ft long.

Several people have suggested coating the sinks with marine epoxy. What is the correct method?

Regards,

[Brian Ellis]

Moorlastic is a terpolymer never intended for horizontal waterproofing, though a number of people (including me) used it for such, provided there was enough pitch
to the roof to prevent ponding. The formula changed a couple years back and might have again, so I would not (and never did) recommend it for sinks. It is hard to
get on smooth and is prone to staining, just like all terpolymers. Fiberglassing with polyester resins is not very safe task unless you have your fume hood already
operative, or do the task outdoors prior to installing the sink. You can also simply cut down thick ABS sheets and solvent weld the corners, just like solvent welding
PVC pipe, provided you can cut the edges dead clean and square (I use a Festool rail saw for such tasks). Plywood would be my last option, though penetrating marine epoxy makes this route viable. These kinds of epoxies are made by Smith, West Systems, and Abatron, and avail in most boatyards and some plastics stores.

Mine was prone to staining but I just re-coated the interior of the sink over the stains about once a year which only took maybe ten minutes to do (sink was about 9'x3'). Pooling was prevented by making the drain end of the sink a little lower than the other end. Plywood held up very well, I had the darkroom and used it extensively for about 7 years before we moved.

Your statement about horizontal use was interesting. Obviously it worked well for my horizontal sink but that wasn't a very large area. However, I used to own a beach condo that had some water leaks through the walls (heavy rain would soak the walls on one end and water would seep through to parts of the interior). The developer said the solution would be to coat the walls (obviously vertical) with an elastomeric product. So he did that and it didn't help at all.

[Peter De Smidt]

I built a sink out of a 4x8 foot sheet of plywood in about 1993. I still use it today. The best method for waterproofing plywood, as has already been mentioned, is fiberglass and marine epoxy, but I didn't have the know-how back then. Instead, I used two part epoxy paint (for tubs) from Menards. It was super stinky, and so use it outside. If I remember rightly, they came up with a less stinky version, which was much less glossy than the earlier one. It's held up just fine for 20 years, although it could use a another coat now.

Another alternative would be to line a sink with epdm pond liner or rubber roofing.

[Drew Wiley]

Brian - I have all kinds of products here that could hypothetically be used on a darkroom sink, including permanent totally waterproof brush-on elastomers which I'd
be reluctant to sell to just anyone due to fume issues during curing. I have a bit of such products drying on one of my own pieces of darkroom equip right now.
These are technically "kraton" copolymers using nasty solvents. Terpolymers are popular for vertical patching and waterproofing. I'd sometimes use them for a
temporary porch roof bandaid until I had time to do things right. Raccoon footprints typically stained the material pretty bad (not to mention their poop - they had a habit of holding raccoon frat parties on my roof, until I cut down their favorite access limb).

[Jim Andrada]

I used an Epoxy paint when I built a 12 x 3 foot sink many years back - used it for 10 years until I sold the hous and moved out - haven't had a darkroom since. It was exterior plywood "box"

I've used West system epoxy w fiberglass when I built an 18' canoe strip planked and the process is pretty straightforward.

[MrFujicaman]

Okay, I've made a 2' by 4' by 2" prototype and coated it with Rust-Oleum pickup truck bed liner. I glued the sides to the base and caulked them with black caulk. I forgot and let it sit outside last night....well, it rained. I have 1" of water sitting in it and no leaks so far. It's looking like I'll go with the roll on version of this coating for the full size sink ( I used the spray on for the prototype). I'm going to run more tests on the prototype before I make up my mind. The biggest problem with the prototype was that I'd forgotten that 1" x 2"s have a rounded edge..that's why I had to caulk- on the full size I plan to cut 3/4 plywood for the sides of the sink-no round edges.

I know everybody is talking up the West Systems epoxy paint, but they don't have a local dealer and I'm wondering if that's a Hazmat shipping item-which means far more in shipping charges. The Rust-Oleum bedliner paint I can get at Walmart with no problem.

[tomalb]

Back in the day I used shower pan liner for sink bottom. It' pretty thick and seemed to be inert.