Plastic tank Repair

That might just work too. I thought maybe the hot glue might do ok as when it cools it would never dissolve even if fuel was there in the tank. Does JB weld dissolve a bit or soften in nitro? You mean just the normal JB Weld stuff? Not the one for plastic right?

Thanks
Ice

All I have on hand and have ever used is the standard regular JB Weld. I have used it on a stunt tank vent tube replacemet and has held up very well, and has not softened. This may be because when I do use it I let it sit for 24 hours minimum before attempting to do anything with the part, and usually 2-3 days for added safety in case the mix was not exactly 50/50. As for their plastic stuff, I have never used it, but would assume it may be better suited for plastics, but again, this is just a guess.

I just looked at JB Welds website and saw a few plastic and a couple other neat new products. With that said, the plastic one I looked at was quick set, 5 minutes and cure in 1 hour. 3990 PSI. Sounds good to me. The original however is 5020 PSI, sets in 4-6 hours, and cures in 15-24 hours. Now just from experience, I have always preffered a slower cure as they seem to be better. As well, the slower time allows you more time to work with it. But if what you have ther is a clean break and easily accessible, I may also be inclined to try the plastic variety if you think you can get it on and cleaned up before clamping and drying. And even though they say 1 hour, I would still wait for a bit longer before using whatever was repaired.

Yet I don't know the type of plastic, you can weld it with a hot thin steel or brass wire. Press the part on tank, then melt around of joint with a hot wire. Making zigzags is better. Perhaps this may work.

The problem with hot glue is that it gets soft again when heated. Not sure what kind of temperatures there is in that area, but still something to consider.

I don’t have any experience with the plastic tank, but I have heard they can be sometimes difficult to get to seal properly at the backplate area.

Still, it is worth a try definitely. With that type of tank you have the separate plastic reed retainer, right? So, with some JB weld on the thoroughly cleaned surfaces, and the plastic reed retainer pressed on, and everything tightened on the back of the crankcase... Maybe it will last.

Good luck and let us know the results

Ok for the plastique To use gb weld hot glue no bea bee tank get To hot have u ever hole one wile runing crankcase tank get hot To hot for glue To hold Not sur if posible To use soldering iron To melt around the joint and renforce wit gb weld y sugest use old crankcase empty put grase inside crankcase Good amount of gb weld on plastiques tank and insert in crankcase use back plate and Bolt in place Wait minimum cure time
and take it appart let it cure minimum 48 hours before use after 10 hours engines can be re asembling dont use oil fuel befor 48 hours if it Not working y be surprise hope its Not alredy set ??hope it work for u

Never had any luck with JB weld where any liquids were involved......ie ..radiators ,plastic carb fitings,or fuel tanks on lawnmowers,weed trimmers. They all eventually started leaking again.  I'd just pitch it!

There aren’t many options for gluing delrin. Ultrasonic weld might work. If it was ABS there are chemical bonding options.

That tank would be in the circular file. I wouldn’t risk it breaking off and getting sucked into the crank.

$6.95 USD for a brand new one. I wouldn't put in too much effort. A new tube of JB Weld would probably cost more than that.

Given the amount of heat and stress through vibration on a critical part, the reed holder on one side and fuel on the other, I'm thinking given the type of plastic that really doesn't lend itself to repairs, I'd replace it.

https://coxengines.ca/8cc-plastic-fuel-tank-for-cox-049-engine.html



Yes, I agree, Rod. Given it only costs $7 plus shipping (good time to order other parts with the part including the right reed holder if doesn't have), I think the OP have a lot less troubles replacing with new. But, that is my opinion.

Replacing the whole thing would be the best solution, I agree. But while waiting for the parts to arrive, a bit of experimenting doesn’t hurt

If it were mine, for a runner, I’d get an aluminum tank or a Horseshoe backplate for a replacement.