doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Ithaca 28 Gauge Double

The good news is that the frame can be annealed and recasehardened properly.

I'll stand by my assessment that the only way to know for sure if the internal parts have been tempered inappropriately is to disassemble the gun and examine it. I'll also stand by my assessment of the temperature required to get the colors in the picture.

The gun is very rare and I think it's worth re-doing it right.

chuck: you are certainly entitled to express your opinion, as we all are on this forum.

my opinion regarding this gun is to leave it as is...

to subject the receiver metal to temps in the neighborhood of 1500 degrees F aint worth the risk of damaging the receiver beyond repair. this is true, particularly, because we really do not know what has been done this receiver after market, now do we?

chuck: a question:

how does one determine if internal receiver parts have been tempered inappropriately? one of the reasons i ask is that i have read other threads where the high heat bone charcoal guys discuss wether a receiver should be rehardened assembled or unassembled. seems to me that if you cooked it assembled, you could do some damage to the internal parts?

Ed,
The discussion you cite was about assembling the triggerplate on the frame, not the moving parts.

To tell if the internal parts may have been affected, I'd look for tempering colors on the parts.

chuck: if you find tempering colors on internal parts, would you suggest rehardening with kasenit of some other product?

Ed,
The springs contain plenty of carbon and don't need to be casehardened, nor do they do well with that process. The other internal parts likely have high enough carbon for hardening without carburizing and quenching (casehardening). They likely can be simply brought up to their critical temp (1450F ish) and quenched in oil, polished to see the silver color, then heated to 300-400F and quenched again, depending on desired hardness.

I was in Kesselrings back in March. Didn't see anything I'd make safe space for.

chuck: in a previous post, you suggested that temper colors are achieved by using a torch to heat the receiver to from 500 to 600 degrees F...

how does the torch mechanic determine that he has heated the metal to that temperature range?

and are any chemicals used in the process or is it just heat?

I am not sure the photos posted are good enough to say if this gun's cc were restored by torching or not. A lot of "glare or flash on that close-up.

Ed,
There are many common sources of tempering color references. Machinery Handbook and Marks have it as well.

The primary chemicals in this particular job are:
C2H2, O2, Fe, C, S.