Debate: Is heat actually helpful for loosening old lens elements or does it cause more damage?

I keep seeing people online say to heat up a stuck lens ring with a hair dryer to break the seal. But I spent 5 years at a shop in Chicago and we never did that because the thermal shock can crack the glass or warp the brass helicoid. Last month I had a customer bring in a 1960s Nikkor that someone torched and the front element was totally seized from the expanded metal. On the other hand I get that some old lubricants get like glue after decades. What's your experience been with heat on old lenses has it ever worked for you without ruining things?

3 comments

3 Comments

mark4361mo ago

Yeah nah, heat is a crapshoot and more likely to ruin things than fix them.

murphy.mason1mo ago

Actually read something the other day about how thermal pads can shift under pressure and create uneven spots that actually make things run hotter. @mark436 you're spot on that it's risky, especially with how hard it is to get consistent pressure across a chip these days. Most of the time if a device is running OK, best to just leave the heat sink alone and not tempt fate.

the_jennifer1mo ago

Oh man, @mark436 is completely right on this one. I've pulled apart enough laptops to know that once a heat sink is seated right, you're playing with fire by messing with it. The thermal paste job matters way more than people think, and even a tiny air bubble can spike temps by 10 degrees.