Heating blued parts

[edwardware]

I have a section of barrel with a hot blued (not cold blued, or rust blued) barrel band, epoxied on. I need to remove the band, and the epoxy manufacturer says it softens at >500degF.

Is it reasonable to think I can heat the part to 550degF without ruining the bluing? Should I use a hotplate or lead bath vs a propane torch? The hot gas seems more likely to damage the surface.

Kroil boils at 270degF, so I'm not sure soaking will help. Any tips?

Edit: I see references to acetone or MEK softening epoxy over a few days. Any experience?

 

[Mizar]

500 F are not that much to worry about. Heat it with a propane torch, slowly, moving it across the band and watch for smoke - as soon as it starts, stop heating and try to remove the band. You won't damage the bluing, unless you get carried away and heat that barrel red hot. Clean the remaining epoxy with acetone (brake cleaner).

 

[Blue68f100]

Depending on the allow used you may be getting into the zone that effect tempering of the steel. With that said it based on soak time, so heat it up as fast as you can using a small micro torch to limit the heat to the band only.

Most epoxies can be dissolved using carburetor vat cleaner made by Berrymens Chemtol. I used that to dissolve epoxy paint that was left in spray guns. It's not a fast process, took nearly 5 days to get it all out. The user sprayed the epoxy paint on a friday and did not clean the gun. So the epoxy setup hard in the spray head on monday. This cleaner is safe for all metals but may impact the blueing, have not tested to know. It will dissolve most all lac and varnishes, and plastics. You use to be able to get these small cleaning vats at the local parts houses not sure if its still available.

 

[N.Schafer]

What Mizar said. Heat till just starting to smoke. The epoxy may lose its grip sooner than the softening temperature.
If it gets too hot it can be reblued.

 

[Mizar]

Barrels are somewhere around 40 HRC (that's in general!) - 500 F is too low temperature to affect the heat treatment. If one is afraid of overheating, just put a drop of Sunflower cooking oil on top of the detail in question and watch for it starting to smoke - it's smoke point is about 450 F. Olive oil smoke point, depending on the grade, is about 50 to 100 degrees lower.

 

[edwardware]

Thanks gents. In this case the barrel is a section of barrel, and is scrap anyway. I'll heat gently and see how it goes.