Fixing a crack in plastic gas tank?

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May 26, 2006
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#1
I posted this here since it'll probably take an old school fix to keep the pre-mix off my shop floor.

I've got a gas tank sitting on a new purchase that just happens to be lime green in color, leaking all over the floor from the shutoff valve.

I assumed an O-ring was shot, pulled the tank and noticed that the valve mount surface was covered in JBweld compound. After cleaning up the JB and replacing the 3 rubber pieces in the valve, I learned that the TANK itself has a 1 inch crack or split on the seam the valve mounts to.

Does anyone have a quick-n-dirty ( and permanant!) fix for a plastic tank. The shutoff is good for another 15 years of service so sealing it up along with the crack ain't a problem.

JBWeld? PVC Cement? SealzAll?

What works?

Thanks, Tim
 
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#2
All that will come off, try taking a soldering iron and melting the crack back together. Spray it with some contact cleaner before to get the gas/oil residue off first. This has worked for me.
 
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#3
Im not sure but could it be glassed over ........??? I know there is a certain product out there for sealing gas tanks. Although it may only work on meatal tanks
 
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#4
Thanks for the help, I found an atomic plastic-only 2 part epoxy made by 3M at Lowes and after roughing up the surrounding area and V-ing out the crack, worked it all in including the shut-off.

It's still curing but I'll let you'all know if it works or not, if 4 bucks will save me from buying a $250 tank for a bike I paid $600 for, I will just as amused as hell :)

Tim
 
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#6
Only once have I faced a plastic tank problem..it was on a 93 Kx....somehow one of the pipe mounts had rubbed a 4 inch long cut into the tank. I tried several epoxies and putties, they all peeled off after about a week or two. the regular JB weld worked the best. (Not the quick) sanded up the surfaces and cleaned the heck out of them. This tank was an inner tank you know, weird black pastic....

Ive heard of people loading up a cheap hot melt glue gun from the crafts store with plastic scraps from fenders and 'welding' plastic that way....never tried it though. sort of heat up the surrounding ares with the glue tip and pump in the melted scraps I guess? I dunno....
 
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#7
Tested the repair this weekend, and its holding up so far.

I did notice that the epoxy DID NOT stick to any surface that was not brutally roughed up with 60 grit paper. I also didn't use any surfacing agents on the area, just blew the dust off and loaded it up.

Thanks again!

Tim
 
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#8
I have used the soldering gun before and it worked great... no leaks after 4 years, finally sold the bike.
 
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#9
I had the whole filler neck of my son's chinese "crf110" break loose.
(got smaked in shipping.)
The soldering gun trick worked for me too.
Took a while to do that extensive of a repair.

Ive got pics of it in my photo gallery.
 
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#10
O.A.S and MotoGp , if the epoxy fails Your trick will be employed next! Held up over the second weekend w/my stepson aboard and still smiles all around.

But I trust plastic about as far as rusty steel, maybe it'll hold forever, maybe it'll hold until you're as logisticly as far away from the truck as you can get and THEN fail!

Thanks! Tim
 
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#11
I've tried epoxy and all of the sealers. Never did try melting it back. The KDX175 tanks just didn't last, cracking at the mounts, at the petcock and along the lower edge seam. Every repair seemed to hold until some hard riding! I found a used Clarke tank (oxidized and sans petcock and cap) at a salvage yard for $20 and ordered the petcock for it from Clarke for $8.
 
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#12
Was this a Clarke tank designed for the KDX175 or was it a different style? I’m looking to replace my tank but am not trying to spend $200 on a new remold of the original tank if a different style tank will fit.