OT: Which Caulking Compound to Use?

Nothing's going to stick very well to both. I'd pack the gap with foam rope like they use for packing gaps on house window frames, then cover with something like a butyl caulk. Depends on what it's really going to be exposed to. If you're expecting things to stand up to something like live-steam cleaning or high-pressure wash-down, you're going to want to design something different.

Stan

Stan:

The gap varies between zero and about 1/8" so it might be difficult to pack it. It will not be exposed to harsh conditions - only splashed room temp water. I've done a little searching and found polyurethane mentioned by a crawl space renovator as a good choice (for polyethylene anyhow). Would you expect butyl caulk to be better than urethane?

Thanks again for the help....

Laurie Forbes

For autobody use 3M makes a urethane seam sealer that is some darn tough stuff.

Well what I will suggest isn't a caulking material. BUT it will stick like death to both of those materials as long as they are clean and dry.

Get a tube of 3m 08693 Auto Glass Urethane Windshield adhesive. Make sure the space is CLEAN AND DRY. Then apply it like caulk. Make sure you fill the entire gap. Then mist it with some water to set the skin. Now let it cure 24 hours and forget there is a seam there.

Or simply pick up the tank and put down a tank ring....s*it..stroke moment... the big plastic "bottlecap" that you can buy and put waterheaters, tanks and so forth on. They are quite cheap.

Gunner

"Somewhere a True Believer is training to kill you. He is training with minimum food or water,in austere conditions, day and night. The only thing clean on him is his weapon. He doesn't worry about what workout to do--- his rucksack weighs what it weighs, and he runs until the enemy stops chasing him. The True Believer doesn't care 'how hard it is'; he knows he either wins or he dies. He doesn't go home at 1700; he is home. He knows only the 'Cause.' Now, who wants to quit?"

NCOIC of the Special Forces Assessment and Selection Course in a welcome speech to new SF candidates

I'd use a bit of molding instead of just a bead of caulk. Vinyl base molding (like one uses around bathtubs) with the proper adhesive is nicely water-resistant, and there's a LOT of surface/surface area against the tank, in case the glue seam is weak. Big area/weak glue =3D strong joint.

Not a bad idea and thanks for suggesting it. I have applied a bead of urethane caulk however and, after it cures, will see if it stands up. If not, will try it with the molding.

Laurie Forbes