IF YOUR TRAINING LENS IS EPOXIED IN:
I recently received my Arctic and began following the steps in this thread to get my laser up and running to its maximum capability. When I started the process of removing my training lens from its housing, I found that the screw plate holding it in place was epoxied in. I fashioned a tool to fit the threads and attempted to muscle through and unscrew it - but had no such luck.
As some others have tried, I first used an adhesive remover (goo gone, goo away, etc) and soaked the lens housing for 10 hours. This proved unsuccessful in loosening the epoxy, so I moved on to the next idea: heat.
As one other person noted, the lens housing is made of aluminum and the lens itself is glass, meaning it should be able to withstand a relatively high amount of heat. I know what you're thinking: "Crap, i dont have a butane torch!" Fear not, you just need a heat source, like... Your gas burner stove top! I gripped the lens housing with a pair of needle nose pliers, then turned the stove on high, placed the housing in the blue flame and slowly rotated it back and forth to get even heating on all sides of epoxy. After a few minutes of heating and a few unsuccessful attempts at loosening, i noticed the epoxy started to disappear/burn away. After a solid 5 minutes of heating (USE VERY INSULATED MITS/PADS TO HANDLE LENS) I was FINALLY able to unscrew the lens assembly and remove the training lens. Success!
NOTE: there was absolutely no discoloration, flaking, or ANY type of damage (visual or physical) to the lens housing using this heating process.
Best of luck - I'll try to post pics of the methods used and unassembled lens pieces, as well as the tool i made (fashioned on a grinding wheel)
Poultron