doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Annealing for engraving work?

Can any one describe how to anneal previously case hardened parts in a home shop setting? I want to anneal several parts before engraving work. Thanks for your help.

I have a heat treat oven in which I place a crucible filled with used charcoal, heat to 1450 degrees F and let cool slowly. Hope that helps.

Steve,

Are you saying you put the receiver, or other parts, in the charcoal pack? I have heard of packing it in lime.

SRH

Stan,
The receiver or what ever else I need anneal.
Steve

You may not need to anneal. I have had a Winchester 21 engraved and the engraver said he commonly does not anneal them before engraving.

I am currently annealing a forend iron that I will then fit to the frame of a Parker. The key is to thoroughly clean the steel of all grease and oil with solvents and scrubbing. Then, using a lidded crucible, put the work inside and bury it completely in pure wood charcoal granules like those sold by Brownell's. Put the crucible in your kiln or furnace and heat to 1450 F. Hold it at that temp for an hour and then turn the oven off and walk away. Let it cool down over night before opening the kiln or crucible. It is very important that the atmosphere does not touch the work until it has cooled to room temps, or it can be ruined by the instant formation of hard gray scale all over the surface. But so long as its buried in the wood charcoal in the hot lidded crucible, it will be enveloped by a cloud of carbon gases that will prevent hard scale formation. When you remove it from the charcoal pack the next day, it will be fully annealed. After engraving, it will need to be bone charcoal case hardened again, which is best left to a pro if you want to achieve accurate case colors on the finished product.

Steve/Julio:

Will wrapping the work in the .002 Stainless Steel foil that Brownell's sells work in place of the charcoal?

Craig

I believe it will, I have not tried it though.

I use Brownells stainless foil to make pouches to hold small pieces like screws so they don't get lost in the charcoal. I fill the foil pouch with charcoal and the small parts and bury the pouch in charcoal in the crucible. I have never heard of wrapping gun parts and annealing without charcoal. I would not try it myself, as the parts will be ruined by hard gray scale formation if touched by the atmosphere while still hot. Not worth the risk when its so easy and cheap to simply do it right by submerging the work in charcoal for annealing.

Craig,
Yes. wrapping in stainless foil is the classic toolmaker way of heat treating while preventing scale. The thing that is left out of your post is that newspaper is wrapped around the part first then the foil. The newspaper will burn the oxygen out of the foiled envelope and prevent oxidation from forming on the part. The issue with foiling is to get it airtight.

Whoever asked about using lime, yes it can also be used. It simply provides a barrier to oxygen contacting the part while it's heated. The use of charcoal powder accomplishes at least three things I can think of. First it provides a barrier to O2, second it has a combustible to consume the O2, third it has the potential to provide additional carbon into the surface which will ensure hardening during the casehardening process later.