JB Weld not adhering

[Joe G]

There is a pin sized hole in my fuel tank (literally a sowing needle tip would plug it) and i have tried to JB weld it unsuccessfully a few times now. I have sanded the area down to bare metal with 80grit automotive sand paper, cleaned and prepped the area thoroughly, however when it all dries (24hrs in 80 degree heat) the JB weld always has a small bubble/hole where the fuel tank hole is located.

What can i do to prevent this? I think the hole is venting fumes out thus preventing the JB from curing. I opened the gas cap so it would vent from there but still no luck. And yes, there is <1 gallon of fuel in the tank and the car is jacked way up on one side so all the fuel is away from the hole.

Any suggestions on how to get the JB weld to cure fully and seal the hole?



Cliffs:

JB weld wont plug a pin sized hole. Need help.

[ak-]

Plug it with a needle

[euro2fast4u]

did you prop the valve open near the gas cap?

cliffs, use lighter

[danny4nasty]

Have you tried using more hardener when you mix it? Also I'd recommend using the quick drying JBweld.

[bimmerteck]

I usually pull the fuel tank out grind the area clean and weld it. Be sure to fill the tank with exhaust fumes from a running vehicle first to evacuate the oxygen from it. You can also use shielding gas but exhaust is cheaper. :)

[411]

they sell many different brands of [2] component sticks that are specifally made for what you are attempting to do

http://www.permatex.com/products/Automotive/specialized_maintenance_repair/radiator_fuel_tank_repair.htm

[Cletonius]

they sell many different brands of [2] component sticks that are specifally made for what you are attempting to do

http://www.permatex.com/products/Automotive/specialized_maintenance_repair/radiator_fuel_tank_repair.htm

This. I have used pig putty to repair the fuel tank holes before. Works really well, you just cut some off the stick and knead until its all one color. Form and stick it, presto.

[rustybullet]

used the quick weld putty on the ole maverick and it worked. has been holding for 3 years now.

[nrubenstein]

When I did an emergency repair on the race car's fuel tank, I sealed the hole with a screw. The JB weld was just to keep that in place and seal any tiny gaps.

[jlevie]

You can get an epoxy mix that is formulated specifically for this task. That would be a better choice than JB Weld. Probably safe to use on the top of the tank but I'd be hesitant to use that if will be routinely covered by fuel. On the top of the tank I'd use the gas tank putty and a sheet metal screw to plug the hole (like nrubenstein suggests).

[Kershaw]

how about undoing the fuel pump so any expanding and contracting gases (from the heat and cold of the weather) have a place to go besides the soft jb weld?

[rThor432]

It's a metal tank, why not weld it?

[Kershaw]

probably because it has gas in it.

derp.

[Thizzelle]

Plug it with a needle

this then jb weld

[maniacmatt]

JB weld a penny over hole.