Tried the freeze spray method vs. hot air for stubborn lens elements and it's not even close

I had this old Pentax 50mm f1.4 with a stuck focus ring that wouldn't budge. Tried hot air from my rework station for 20 minutes, nothing. Then I grabbed a can of freeze spray from the hardware store, hit the outer barrel for about 10 seconds, and the thing practically unscrewed itself. The difference was night and day. Hot air expands everything together, freeze spray gives you that temperature differential that breaks the bond. Anyone else had better luck with one method over the other for seized threads?

2 comments

2 Comments

the_rowan1mo ago

Hot air worked WAY better for me on a stuck Canon 50mm 1.8 FD breech lock mount. The freeze spray just made the aluminum barrel contract too fast and I actually cracked the plastic focus ring on that one. Plus if you have ANY moisture in the threads, freeze spray can ice that up and make the grip even worse. I stick with a heat gun on low setting, directed at the lens mount ring for like 3-4 minutes, then use a rubber strap wrench. Never had a lens I couldn't free that way.

king.stella1mo ago

100% agree on that temperature differential thing, it is night and day. Totally get @the_rowan's warning about moisture though, I always hit the threads with some alcohol first to dry them out. That Pentax was crusty as hell and freeze spray was the only thing that saved it from becoming a paperweight.