Also, if you let the JB weld sit for a while (perhaps an hour?) it gets thicker and runs a bit less. Keep an eye on it. You don't want to go out shopping and then come back to a solid chunk.

I put release agent on the wood in the mag well on the last bedding job I did, and the drips of bedding compound into the magwell did not adhere to the wood, I simply snapped them off and then smoothed the edges with the dremel.

Good suggestion about respirator and eye protection. Hearing protection is a good idea too.