Greetings,

My sob water tank has a crack around the fitting where the air vent hose mounts. Any suggestions as to how to fix it and what to use? the tank appears to be made from white translucent plastic (abs???).

I was thinking a two part plastic weld epoxy followed by a couple coats of GOOP for strength.

Thanks

Epoxy is your friend... My fresh tank is plastic and the mfr glued the fittings with epoxy.

Rough up and clean up the area and smear well with epoxy. If the epoxy is runny mix in some glass fibers to make it into a paste. I often use a piece of plastic bag or wrap to place over the patch and smooth it out. Polyethylene plastic bags will usually peel off ok after cure.

Slow cure epoxies usually set harder and have a bit better adhesion than the quick set types, and gives you more time to mix and work the patch.

Richard, the tank is probably polyurethane (should read Polypropylene), as are most fresh water tanks. unlike styrene, Abs and a lot of other plastics, polyu (should read polyp) will not react to a solvent.

Epoxy works, but because that material is very non-porous, plastic welding to me is superior. Should be someone close to you that has the proper equipment. Either way, good luck!

REVISION!!!
Geez,,, did not notice but spell check or my feeble brain said Polyurethane and I meant polypropylene ,,, so sorry!!!

Richard, Depending on the water tank’s location and accessibility, the first thing I would do is drill a hole at the end of the crack if you can. The hole should relieve the crack’s fatigue to stop further cracking.

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Try your hand at plastic welding. The tool need not be the high end one for a few grand, but anything from a Harbor Freight to a Dewalt. Even the plastic strips and a heat gun may get you sealed up depending on accessibility to the damage.

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I have repaired a lot of things with Shoe Glue. You can use shoe glue after the plastic weld or instead of the plastic weld job. If that does not work you can do the water tank replacement.

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....Or don't fill the tank all the way up to the top and put a couble of rags around the leak while driving. While parked it should not be a problem on top at all.