Frequently Asked Questions
How much heat can J-B Weld withstand?
Original J-B Weld can withstand a constant temperature of 500º F. The maximum temperature threshold is approximately 600º F for a short term (10 minutes). Refer to individual product packages for more temperature information.
Will J-B Weld work on an automotive exhaust?
Because of the extreme temperatures of exhaust systems, we do not recommend J-B Weld for use on exhaust manifolds and catalytic converters. Nor do we recommend the product for repairs within the combustion chamber. However, in areas where the continuous temperature is less than 450º F, we do recommend our HighHeat epoxy putty stick.
How can I remove J-B Weld after it is fully cured?
When fully cured, J-B Weld can only be removed by grinding or filing it off, or by directly heating the product above the 600º maximum temperature threshold.
Is J-B Weld toxic?
No. When fully cured, J-B Weld is non-toxic. However, we do not recommend consuming the product.
What can I use as a surface cleaner before using J-B Weld?
We recommend using acetone or lacquer thinner. In the absence of these two, soap and water can be used. Just be sure that the surface is completely dry before applying J-B Weld. DO NOT use alcohol or any "cleaner" that will leave a petroleum residue.
Will J-B Weld hold up to extremely cold temperatures?
Original J-B Weld has proven to maintain its characteristics to temperatures as low as -67º F.
Will J-B Weld conduct electricity?
No. J-B Weld is not considered to be a conductor. It is an insulator.
What is the difference between J-B Weld and KwikWeld?
KwikWeld is a great alternative to original J-B Weld when you need a quick-setting epoxy. It sets in 4 minutes and cures in 4-6 hours, while J-B Weld sets in 4-6 hours and cures in 15-24 hours. Because it is faster setting, KwikWeld has about two-thirds the strength of J-B Weld; however, they are both strong enough for most projects and repairs.
Is there anything that J-B Weld WON’T bond to?
J-B Weld will not adhere or bond well to:
- Any flexible rubber surface
- Polypropylene plastic
- Polyethylene plastic
Can I thin J-B Weld to make it easier to pour?
Yes. Add up to one teaspoon of acetone or lacquer thinner per two ounces (one full package) of mixed product.
Is J-B Weld microwave safe?
Yes, it is microwave safe.