Waterproof Foam Sealant

[cascadia]

Does anyone know of or have any experience with a waterproof expanding foam seal? Is there such a thing? I am putting together a modified air conditioner glycol chiller unit. I am having difficulty reaching a spot to fill with silicone to stop a leak in the reservoir. It needs to withstand being submerged in a glycol solution.

Thanks

 

[KowboyTrav]

Great Stuff is "water resistant." Not sure if it would work out if it were completely submerged, but I've seen people do some crazy stuff with it. I'm sure someone out there has tried it.

 

[patriqq]

I wouldn't count on the foam. However, you can fill in large voids with the foam and then coat with something else.

Could you use "self-leveling" sealants, or something else (like epoxy) that you could pour?

I've done some DIY self-leveling sealant. Get a caulk that is solvent-based (i.e. not acrylic, not silicone - gutter sealant is good), and squirt the entire tube into a sacrificial container. Put on a respirator and/or go outside, add solvent (I used acetone), and whip it up with a loop of wire in a cordless drill until it's like pancake batter (we used roughly equal amounts of caulk & solvent). Pour and let dry for a few days.

There are also some white roof coatings (not tar/asphalt) that do the same thing. I got some of that from Lowes.

 

[cdelap]

Do you think I could mix in more solvent to make a coating for the inside of my Gas manifold (1.25" square tubing with 3/8npt weld-ins for all my gas valves) I would love to do something to protect the inside from rust as well as any pinholes that could develop if a weld wasn't as clean as they look

 

[patriqq]

You can try! I used the caulk/solvent goo on a hydroponics application, not homebrew. I would personally not want to use it on the inside of anything that involved food/drink (OP wanted to use it to seal a glycol reservoir, which is presumably isolated from the food-grade side of things).

You can get food-grade caulk, but I think it's silicone based, and I'm not sure if you can 'thin' silicone caulk.

The more solvent you add, the thinner it gets. The thinner it is, the more it will settle or self-level. So it would be hard to evenly coat something like a manifold.

 

[BrewBeemer]

http://www.plastidip.com/

 

[cdelap]

In my case the only thing it will touch is propane gas, and as far as a even coating It seems if I was to put a decent amount in the manifold I could set it on my lathe at low speed and let it continually turn till it dries

 

[BrewBeemer]

In my case the only thing it will touch is propane gas, and as far as a even coating It seems if I was to put a decent amount in the manifold I could set it on my lathe at low speed and let it continually turn till it dries

Use back gear or else it's a spin dry thing slinging it off.

 

[bniesen]

JB Weld makes a "marine" product that should work for you
Water Weld

 

[patriqq]

In my case the only thing it will touch is propane gas, and as far as a even coating It seems if I was to put a decent amount in the manifold I could set it on my lathe at low speed and let it continually turn till it dries

Awesome. I was thinking CO2 for some reason. The lathe is a great idea.

 

[cdelap]

Thanks for all the help, I was also thinking about just dropping it off at the local radiator shop and letting them seal it, guess first I will have to see how my welds turn out and how concerned I am with leaks :-D

 

[audger]

ive actually used dryloc waterproofing paint for sealing foam pannels. its supposedly rated to 10PSI of hydrostatic pressure (on concrete, i would assume higher if the water was pressing against it instead of from behind it), its latex based so it wont eat foam. its cheaper than a lot of expoxy or silicone sealants.