New motor on ball mill. Caked at end.

[cornbelt]

what I've got is an old Thumbler's Tumbler. I have replaced the old (small) motor with a good one. I'm running it at about 60 rpm. It didn't cake up before, but now when I take off the lid, it is caked so much, the barrel looks full. Bridged completely.
So what am I doing wrong? Should I slow it down some? Or...

[LAGS]

What tumbling media are you using ?

[indian joe]

caking rears its head occasionally and I always reckoned it was due to moisture in the mix someplace -just a teensy bit - a humid day would be enough - open the can at about four hours, break it up, go again - slower speed is better than faster I think - what diameter is your can?

[cornbelt]

Can is 8". Media is mostly 1/2", 5/8", and a few 3/8" lead filled copper tubing sections. I finally just swapped ends with the can every half hour. Its been pretty humid here.