Rookie Mistake
 

Recently purchased an ultra sonic cleaner from a large concern. Mixed up a batch of Simple Green and water 50/50. Inserted a Parker frame and 2 sidelocks from an English hammer gun. Ran 2 cycles of 180 seconds with heat. Let them soak awhile, then pulled and scrubbed with toothbrush. Did one more 180 second cycle with heat and let them soak for the night. Sometime during the night I think I heard a loud snap. Next morning gave one more 180 second bath. When I pulled parts out Parker frame looked great but both hammer springs were broken on the English gun. What happened? Will attempt pictures but have new computer.

wow - that is heart breaking

when you say heat - how much

I think the harmonic vibration waves did it, not the heat.

Hard to say exactly what caused it. Interesting though...

I normally just use my ultra sonic on stripped frames in order to get the crud out of the nooks and crannies.

It looks like the springs were under tension Full cock?

I wonder if that caused the stress

I had a similar experience with the lock off of a reproduction 1861 Springfield Rifled Musket. It was not cocked.

I put the rusty lock in a room-temperature solution of Brownells Steel White, mostly water after it is mixed. The solution cleaned all of the rust, but the spring that had been used a thousand times just snapped in half! I'll never do that again, and I don't know why it did.

Thanks all. Hammers were cocked. Heat is either on or off. I may have done one more cycle and remember the liquid being quite warm, but could still stick my hand in it. Glad it was not my WC Scott. Have a lazer thermometer and will monitor furture experiments.

ultrasonic cleaning -Model 12
 

I had a gunsmith put a model 12 trigger assembly in an ulra-sonic cleaner. The purpose was to remove built up dirt, which it did. It also removed the red paint on the safety button. No real "damage", but most M12 buyers check that as an indication of refinnish. Now I have to either figure out how to get the red lacquer back on, or explain what happened to any future potential buyer.

Mr. Romig may be onto the best path here. Read this month's American Rifleman story on metal stress and "stress risers" - then consider that ultrasonic cleaners can penetrate even the smallest existing stress flaws. And remember, springs under stress "open" those micro flaws...

Cocked, or un-cocked, Hammer springs are still under compression. The safest procedure would be to fully relax the spring by removing it.
Simple Green, while perhaps environmentally friendly, is still caustic, as are all citrus based cleaners. I would suggest it's best left in the garage, for cleaning engines. While it will simply remove paint (completely) at room temperature, it becomes even more potent at elevated temps.
Lock springs are made from a very high carbon steel (Ironically called spring steel) Making the material bend 180 degrees, even when heated cherry red, opens up edges on the outside of the radius. The best springers will carefully grind and polish the springs after bending, and tempering. Lesser quality springs probably don't get this skilled attention.