doublegunshop.com - home Forums General Discussion DIY Gunsmithing @ doublegunshop.com Case Coloring Metal Prep

Anyone know of a thread to link to?

Here's a few questions of my own.

Is power buffing, either with a regular large or Dremel type wheel appropriate? Contingent on avoiding engraving. If so, what compound is suitable? Red Rouge is recommended for soft metals, not steel. Green compound is recommended for steel. Blue compound is finer than Green, and is recommended for materials like plastic, would it work as a final buff on steel?

If power buffing is not recommended, what materials and grits are appropriate for the hand polishing process?

Regards
Ken

Ken:

JUST A SHORT OVERVIEW:

1. First you have to anneal the part/parts packed tightly in your crucible, preferably in an adjustable fixture with bone & charcoal. You must anneal the parts at the 'critical temperature' and then let the furnace "cool down" at it's own rate without opening the door, usually at least a 24-36 hour cool down period. A natural 'cooling period' is critical IMO.

2. The better the surface condition, the better the results.

3. A high carbon steel wire wheel at slow speeds works well and shines up the parts quite nicely. Many folks bead blast instead of the wire wheel.

4. Then polish to a "mirror finish" with any of the numerous compounds available at most hardware stores.

5. Then clean to a spotless condition, removing all fingerprints and any other impurities on the surface of the parts. Acetone works well as do several other powerful cleaners such as Berryman's Carb Cleaner.

6. Re-pack in your crucible/fixture with bone and charcoal 70/30 or 60/40 etc. and fire with your furnace set to hold the temperature for 2 hours.

7. Quench.........

****8. Read and prepare for CCH if you are a beginner. Use test junk parts if you are a beginner. There are NO short cuts, each step is critical for good work.

****There is a lot written about CCH and I suggest you read everything you can.

I INTENTIONALLY DID NOT MENTION SPECIFIC TEMPERATURES, AS THIS IS A HIGHLY DEBATABLE TOPIC AND PROPRIETARY WITH MOST PEOPLE WHO CCH. AFTER STUDYING PUBLISHED PAPERS AND BOOKS YOU WILL READ WHAT IS RECOMMENDED BY SUCCESSFUL CCH SMITHS. EVERYONE HAS THEIR OWN SET OF STANDARDS WHICH HAVE PROVEN SUCCESSFUL FOR THEM.

JUST ABOUT ALL OF THE THREADS ON THIS BOARD END UP "A BIG ARGUMENT" WITH LOT'S OF PEOPLE WHO "HAVE NEVER" DONE ANY CCH THROWING IN THEIR TWO CENTS WORTH.....THEREFORE IT IS COUNTER PRODUCTIVE TO PASTE ANY OF THOSE THREADS UNLESS YOU WANT TO BE CONFUSED.

Best Regards,

Thanks Doug.

I've probably read them all over the last two years. Sounds like it's all going to require experimentation.

Hand polishing is by far the preferred method! If you use a buffer and compound you will dish out pin holes and lettering and round off edges...all of which will stick out like the proverbial sore thumb. I start with 320 wet or dry paper then 400 then 600 and final finish with well worn 600. The better the polish the brighter the colors.

PS...I back the paper with either a hardwood block or a file and for the best results with the 600 I glue the paper to a flat hardwood piece using CA.

Thanks Sam.

Have you ever bead-blasted before sanding? I've used it to clean up locks that were rusty, using very fine beads.

First, please accept that I'm not trying to stir any problem up.

I see anneal mentioned regularly. I think the process can be important for specific reasons. I have noticed that annealing doesn't seem to improve routine metal prep or the crucible heat charcoal process to get the new case colors.

Even though I was hugely reluctant to post this comment, I figured, why not just ask. How does the annealing seem to benefit here, only if you had a thought or two?

Ken, I have not tried bead blasting and avoid items with rust problems...I am working from the approach of an engraver which leads me to Craig's comment. I have only done the prep with the intent to engrave the item and without toning down the case hardened surface engraving is very problematic to totally not doable. Like trying to cut glass with a graver. None of this is directed to modern metal firearms that are through hardened...those I either cut as is or turn down the job. Some of the stainless guns can be very very difficult or impossible to cut.

Most of the engravers who have commented on annealing cch parts say temps in the 500 to 900 degree range are all that is necessary and coating with something like Brownell's pbc scale preventer works well.

You need to anneal in order to effectively polish the metal or do any engraving work. It softens the metal and makes it easier to work with.

It is best to avoid any sort of power buffing for reasons mentioned above. Careful hand work pays off big time in doing the job right when it comes to this stuff.

The main reasons for annealing other than what has already been mentioned are to avoid over carbonizing the metal which can create brittle portions especially on thin parts and to relieve stress to avoid warping upon re hardening. I stick with the method Doug has outlined above and it has been very good to me.
Steve

That's interesting, considering that it's usually pointed out that the parts need to be brought to above 1333F for annealing. The lower temp would "Draw the Temper", (semantics, I know, but is really a stress relief measure usually used after case hardening) but would not be true annealing. Annealing, as was mentioned by Doug, requires parts being packed in a crucible with charcoal, (I think wood charcoal only for this could be used, no need for an energizer like bone) the crucible then being brought to above 1333F and allowed to cool down inside the oven. If this is incorrect, someone please speak up.

Temperatures used for the coloring heat seem to be all over the place, but from several sources I've read it was stated that after the crucible was brought to above the critical heat (1333F) and held for a period, the temp could be reduced 200C before quenching. This would prevent warpage yet still result in excellent colors.