# coatings for DIY darkroom sink



## grokglock

Hello all I just finished constructing my first darkroom sink out of pine and mdf. It is an 8 foot by 2 foot beauty. I need to figure out what everyone is using to coat these. I hear alot of talk about a west marine coating but I was wondering if anyone has ever used concrete epoxy paint from home depot? or any other epoxy resin coating without the fiberglass?


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## Josh66

I would think that as long as it's waterproof you would be fine...


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## Gavjenks

Well the real answer is you shouldve just made (or bought) the stupid sink out of fiberglass or stainless steel or porcelain, and you would've been fine without any more work.

Wood finishes that resist strong bases and organic acids and all the other crap in photo chemistry (especially if you're using harsher things like pyro) are few and far between.

You might be able to find a good chemical resistant water based polyurethane, but don't just assume it is, it needs to be made for that.


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## grokglock

Gavjenks said:


> Well the real answer is you shouldve just made (or bought) the stupid sink out of fiberglass or stainless steel or porcelain, and you would've been fine without any more work.
> 
> Wood finishes that resist strong bases and organic acids and all the other crap in photo chemistry (especially if you're using harsher things like pyro) are few and far between.
> 
> You might be able to find a good chemical resistant water based polyurethane, but don't just assume it is, it needs to be made for that.



I appreciate your response but boy it sounds like somehow you believe I did something I didn't intend to. However let me be clear that as a traditionalist crafting a wooden sink to use in a home is a time honored tradition. Why would I spend hundreds on a sink when I could get just as much utility from less than half the cost? Add to that the enjoyment I get out of creating my own custom sink, photography for me is a holistic experience. Shooting photos is where I spend the least amount of time, processing is next, and then my entire life outside of photography is spent learning reading involving myself in everything I can to become a better photographer. 

I did become a bit peeved with your first line as it added no value to your otherwise well formed and respectfully phrased response. 

thanks for the rest of the comment, I will continue to search for the best coatings. It seems like the west marine coating is the most popular though somewhat expensive. 

What I might end up doing is sealing the entire sink with concrete sealer in grey because I like the color and then coating the entire thing again in clear fiberglass resin which is also a popular coating. 

Since I will be processing in trays my sink will perform only as a large work surface with easy cleanup drainage, it will never be used to flood or retain large volumes of chemistry at once.


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## Gavjenks

Believe me, I understand the "holistic experience" thing. I make homemade lenses all the time, and am all about a from scratch darkroom. That sounds cool.  But it doesn't change the chemical inconvenience of wood. If you want to handcraft something just to say you made the entire thing by hand, great. But you can hand craft a fiberglass sink pretty easily, just like wood. And it will be much less of a PITA as a surface to constantly dump strong acids and bases and organics onto.

If it is light duty, though, and you're willing to go to the trouble of doing a concrete and fiberglass monster coating, then that will certainly work!


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## terri

grokglock said:


> Gavjenks said:
> 
> 
> 
> Well the real answer is you shouldve just made (or bought) the stupid sink out of fiberglass or stainless steel or porcelain, and you would've been fine without any more work.
> 
> Wood finishes that resist strong bases and organic acids and all the other crap in photo chemistry (especially if you're using harsher things like pyro) are few and far between.
> 
> You might be able to find a good chemical resistant water based polyurethane, but don't just assume it is, it needs to be made for that.
> 
> 
> 
> 
> I appreciate your response but boy it sounds like somehow you believe I did something I didn't intend to. However let me be clear that as a traditionalist crafting a wooden sink to use in a home is a time honored tradition. Why would I spend hundreds on a sink when I could get just as much utility from less than half the cost? Add to that the enjoyment I get out of creating my own custom sink, photography for me is a holistic experience. Shooting photos is where I spend the least amount of time, processing is next, and then my entire life outside of photography is spent learning reading involving myself in everything I can to become a better photographer.
> 
> I did become a bit peeved with your first line as it added no value to your otherwise well formed and respectfully phrased response.
> 
> thanks for the rest of the comment, I will continue to search for the best coatings. It seems like the west marine coating is the most popular though somewhat expensive.
> 
> What I might end up doing is sealing the entire sink with concrete sealer in grey because I like the color and then coating the entire thing again in clear fiberglass resin which is also a popular coating.
> 
> Since I will be processing in trays my sink will perform only as a large work surface with easy cleanup drainage, it will never be used to flood or retain large volumes of chemistry at once.
Click to expand...


I think you're on the right track with the marine coating.   I want to cry that you will cover that gorgeous wood with a gray concrete sealer, why not just the typical clear coat?   I'm thinking some kind of polyurethane that's used on boats, would work just fine.   It can be painted on  in two or more coats, and might suffice, seeing as how it's really only meant to hold trays.   But, I don't know that dumped or splashed photographic chemistry wouldn't eat through it quickly, anyway - and it would be a PITA to have to keep re-touching it.       Ah well, just your preference and if it gives you a comfort level, you're entitled to go for it after all your hard work.     

I bet it looks amazing!!    You should post a picture.


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## amolitor

West System epoxy is quite likely what people use. I believe they make a clear penetrating epoxy, which will protect the wood quite nicely and will also not hide the wood grain. If West System doesn't, someone does.

You can also use the regular stuff which should cure white, I think, or you can use graphite powder additives to make it black.

West System is awesome stuff, and fairly chemical resistant I am given to understand. It will stain.


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## Cruzingoose

The last one I made was from regular plywood in 1977 and is still in use.  I layed fiberglass cloth and resin to coat the inside and "painted" the resin on the outside. No leaks or repairs to the sink, several on the faucets.


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## Gavjenks

Cruzingoose said:


> The last one I made was from regular plywood in 1977 and is still in use.  I layed fiberglass cloth and resin to coat the inside and "painted" the resin on the outside. No leaks or repairs to the sink, several on the faucets.



Isn't that just a fiberglass sink then?  Which happens to have a redundant wooden sink underneath it?


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## amolitor

Gavjenks said:


> Cruzingoose said:
> 
> 
> 
> The last one I made was from regular plywood in 1977 and is still in use.  I layed fiberglass cloth and resin to coat the inside and "painted" the resin on the outside. No leaks or repairs to the sink, several on the faucets.
> 
> 
> 
> 
> Isn't that just a fiberglass sink then?  Which happens to have a redundant wooden sink underneath it?
Click to expand...


No.


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## Cruzingoose

Fiberglass is the only easily available material I know of that resists acid and alkali. Even if damaged, the fiberglass can be repaired easily by sanding, cutting a patch of cloth mixing resin and layering on top of the damaged area. You will be ready to go in minutes. 

Most air-cure polyurethanes do not like acids or alkali, and once weakend by same, the product turns gooey and is not repairable. The fresh product on top of goo will remain goo. Paint will not seal the wood, it breathes and will breakdown quickly with harsh chemicals. 

Two-Part epoxy paint coatings sometimes work. At least for in-ground swimming pools and weak chlorine. They are prone to cracking as there is no "fiber" to bind the product together when flexed. 

Your homemade sink WILL flex with temperature, humidity and use. Fiberglass cloth adds strength, and seals the wood. There are not too many wooden boats out there that are raw painted wood. They are covered with......


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