The majority of suppliers and manufacturers do indeed specify JB Weld for use with heated grips.
From Aerostitch / Rider Wearhouse:
Because most adhesives soften when heated, Hot Grips recommends mounting grips with a two part slow-cure (8+hours) epoxy like JB Weld
, Duro, Devcon, etc. Fast setting (5 minute) epoxies are not always reliable above 200°F. Slow curing epoxies like this one are stable to over 250°F. Easy to use. 1.25oz.
And from the Hot Grips site:
Epoxy: You must use a slow-cure type 2-part epoxy
because the grips get hot, and excessive heat can break down the lower temperature quick-epoxy. J.B. Weld epoxy is fine, or Poxy-Weld Industrial Strength. Both are often found at auto parts stores, or at your local Wal-Mart store. At Wal-Mart it is in the aisle where they keep the automobile oil additives. If other brands are available to you, avoid any that discuss 5 minute cure on the packaging. Look for 250 degrees F. service duty.
More information can be found here: Brands may very, but the basic trouble shooting guidlines can be applied:
Finding a grip in your hand minus the handlebar is not good. Good Luck.