PLASTIC GAS TANK REPAIR

OK GUYS THIS SITE HAS BEEN SLOW LONG ENOUGH, SURE SOMEONE HAS SOMETHING TO SHARE. LOOKING FOR OPINIONS ON HOW TO REPAIR A CRACK IN A PLASTIC GAS TANK, HAVE TRIED JB WELD, USED A SOULDERING IRON TO MELT AND WELD UP THR HOLE, WITH NO SUCCESS. BORROWED A PLASTIC WELDER, THAT LOOKS LIKE A SOUPED UP SOULDERING IRON IS A KIT WITH DIFFERENT TYPE PLASTIC FILLER STRIPS FOR DIFFERENT TYPE PLASTIC, WELL I DID WHAT WAS INSTRUCTED AND THE FILLER DON'T WANT TO STICK TO THIS OLD POLPROPLYNE PLASTIC TANK. THIS KIT WAS DISIGNED TO REPAIR AUTO PLASTIC BUMPERS,TRIM AND RADIATOR TANKS. THERE IS DOZENS OF TYPE & BRAND OF TWO PART PLASTIC CEMENT TO PUT BODY PANELS ON AUTOS, AMASING HOW MUCH PLASTIC CEMENT IS USE TO ASSEMBLE CARS, GOOD STUFF, BUT DON'T KNOW IF IT WILL HOLD UP TO GASOLINE. ANY IDEAS.
HAVE A GOOD ONE
JIMMY

Wish I could help Jimmy, but you did everything I would have done.....probably more. :-)

Jimmy,

I have a GT18 with plastic tank and the spout on the bottom that the gas line attaches broke off. I replaced it with a steel tire valve stem by working the stem thru hole from inside with a piece of rubber on both sides of the hole. After putting the nut on and snugging the nut up, I trimmed the rubber seal up, it still leaked a little bit, so put some contact adhesive/sealant called SEAL-ALL which is gas and oil resistant. I did the repair about a year ago and I have not had any leaks, so far. You will need to make sure the surface of the repair area is clean and lightly sanded to a dull finish (not shiny or real smooth) so the sealant can adhere to the surface better. Also, depending on where the crack is, I'm not sure how the sealant will hold up if it's rubbing on something.

Jimmy,

Other than testing out some of the many plastic weld/glues on the market by using them and leaving them in a bit o gas for a spell, the only other suggestion I can make is perhaps considering the gas tank liner products that classic car restorers put into metal gas tanks to stops leaks and rust. I think you would have to glue your crack first before coating the inside with the sealant.

Let us know how you fare.

BTW, picked up a few late 60's models this year. ('67 10 HP Suburban, '68 12 HP Suburban, '67 SS12). As fast as I can fix them, my Dad seems to break something on them. So once I have the extra machines sorted out, he should have sufficient inventory to keep mowing. At least that is the plan.

best,
Sean

Hi Guys
Report on my plastic tank repair, the problem was the nipple was broken off by the po, drilled and tapped 1/4" w/ a brass fitting, so when I got the tank used off ebay it seemed to have some resideau all over the bottom that was very nasty, took a lot of black max to scrub clean, after cleaning I decided to change fittings, capped off fitting poured in some gas let set a week looked and bottom of tank was damp but not dripping, determined at that point the po had a seepage causing all the gunk on tank, well a bit of air press. and some soapy water revealed a crack at the fitting, probably the tapered fitting had split the threaded hole, head scratching time, got a 1/4" to 1/8" black plastic fitting screwed all way down to shoulder screwed in 1/8" metal nipple to fit line, got out the plastic welder, v out the crack, stitched up the crack and all way around the fitting, completly sealing the plastic fitting to the tank. Gas in and installed, so far so good. Thanks for the replys.
Jimmy