doublegunshop.com - home Forums General Discussion DIY Gunsmithing @ doublegunshop.com Grey color case result

What would make the color casing of an LC Smith turn out predominantly grey in color? Iron had good colors, but frame and side plates were dark, grey, and a bit of a copper hue in spots.

I witnessed the process at school, and the process usually produces good results. Two attempts have been made with this same outcome, and wondering might be the cause.

I have been reading all I can on CCH as I am going to attempt it as well.

Do you have any air exposure before water quench?

There was a thread mentioned here that was on the Marlin collectors site that started out with gray and non-existent colors. Then changes were made that yeilded better results. I thinknit was aeratingthe quench.

Nope. The guy went straight from the furnace and dropped the load.

I think he is asking if the frame could have been exposed to air during the dunk. The parts must remain inside the oxygen free environment until they enter the water. The same thing happened to some parts I did at school. The next run we put them deeper into the pack and they colored well. I have talked to some professionals well and if a part gets hung up in the crucible the same thing happens. The transfer from the crucible to the water has to be really fast with no chance of the parts being exposed to air. Hope that helps.

Thanks SKB that is what I was asking.

I was having the same trouble with an LC smith 00 and fixed it by using a bit larger 4in diameter crucible as well as packing scraps of steel around the receiver without touching it. The scraps of steel I use are shaped similar to the side plates. I felt like the problem of getting mostly grey was because the coal was not staying around the receiver and air was coming in contact as it fell into the quench. By having a larger crucible there is more coal ensuring that it stays surrounded by coal as it cools in the quench as it drops. Someone I know recommend the steel scraps and it really made a difference as well as mimics the splash which probably occurred at the factory as I would expect they colored many receivers at one time. I am by no means an expert at this but have really learned a lot by trial and error and found this to help.

My crucible is a thin mild steel box with a square that just fits inside it acting as the lid. I seal the seams with clay.

I use normal BBQ charcoal which i think must be contaminated with something to make it light easier; anyway this honks like an oil refinery till the contamination has burnt off.. So i open my door and windows to get a goo through draft for ventilation and leave it too it just keeping an eye open in case of fire.

You would think i would stop using it but i have always got excellent results with it and its a lot less hassle and expense than bone charcoal and charred leather and such other such stuff.

The quench is a 55 gallon drum of rain water from the workshop roof which i put a couple of bags of ice in and then shove the air line into for 5 minutes or so before hand.

As for conducting the quench i see lots of clever systems for removing the lid and tipping the crucible; again i have not found this to be necessary. I have a long iron to withdraw the crucible from the furnace with. The crucible with the lid sealed on with the clay is submitted whole into the quench and swirled around. The pressure usually blows the lid off.

The key is to keep the charcoal in contact with the metal parts and also for them not to be exposed to air. My method solves both of these issues.

I will link some pictures of my CCH results from two previous projects.

Im not saying im an expert just that someone getting in to it might learn something from my method and someone who already does it might too. Its all about learning. I seem to get a lot of blues and yelows and straws sometimes some greens

cch by james reynolds, on Flickr

edit - The grey colour on the handle of the RTO tool was because it didn't quite fit in the little crucible i had made and poked out the corner ( sealed with clay ) so obviously it scaled up - Since this was my first time playing with CCH process and that tang would be covered by a handle anyway i wasn't too bothered.

As I have gathered information about CCH over the last few years, in preparation of "taking the plunge" myself, pardon the pun, I have often wondered why you couldn't just drop the crucible into the quench, as you described. But, then I wondered that, if cold water is supposed to be better, maybe the water that entered the crucible after the lid came off would be warmed so much upon entering that it wouldn't give the desired effect. Evidently not, by your nice results. Any thoughts on that?

Any way you could post some pics of your crucible?

Thanks, SRH

I thought it was an interesting quenching strategy also. I'd guess if the technique is worked out, the only down side would be the crucible get eaten up by turning into scale relatively quickly.

I wonder if there's a difference between the Kingsford (or?) we might pick up here and BBQ charcoal available in England.

I do not think scale is increased during the quench. Any scale forming on the crucible happens inside the kiln. I think the crucible being dunked as well will not hurt it.

What happens when the internal pressure does not blow the lid off? Failure to get proper colors?

SRH

the first result ( RTO tool ) the lid was only partially lifted by a few mm, the crucible cooled very quickly; as in by the time i had grabbed a screwdriver from 4 feet away it was cool enough to pry off. - The lid is never violently blown off and i introduce the crucible to the quench quickly and the box entering at something shy of 90 degrees the pressure seems to do the rest.

True the crucible does create a lot of scale and has a limited lifespan; my crucible is a steel tray made from bending some ~2mm sheet steel, its about 4 inches high by about 5.5inch square, its drawn onto the steel like a box packed flat, the lid is just a square piece of the same steel that sits inside the tray and is sealed in place by clay.

The biggest issue with the process is the BBQ charcoal, its of the "light in the bag" variety and im sure it has some parafin or something on it to help get it going, this finds its way out of the crucible - it would be an interesting experiment to see weather using special charcoal VS this BBQ stuff would yeild different results. I don't have the time or funds at the moment to conduct this as an experiment but may do in the future.

I think you're correct Steve. My thought was some of the scale is probably blown off in the quench. What I have noticed is when I dump my cover in with the rest of the quench material, it gets consumed relatively quicker than the crucible. Then again, I can't say I'm perceiving it correctly.

Thanks Demonwolf for your write up, follow up comments, and pictures.

I have tried this exactly once - much the same as demonwolf - but more crude. My "crucible" was a bean can with the lid laid on top and not sealed. The kingsford was pulverized, the butt plate wrapped in wire and suspended in the can. My furnace was a Weber kettle grill and the quench was rainwater circulated with the garden hose. I had a helluva lotta fun and was pleasantly surprised. Hopefully the link will show a short video clip............
https://www.dropbox.com/s/tgl4101cc6y6yan/Backyard%20CCH.wmv?dl=0

Regards, Joe

Joe, Looks pretty darn good, better than many. Must be some magic in that Kingsford charcoal.
Chuck

Air got to the part

I was permitted to run my first color case project last week at class. The candidate was a early Lefever G grade. 3:1 ratio of charcoal to bone is what they use, and a temp of 1400 for an hour and half. The drop is short, and into ice water. I addition to learning this process, I was required to mill some braces for the tang and side plate screw.

The pictures could be better; more vibrant in person with stronger blues.

https://drive.google.com/open?id=1bWHLOrLeks7yfCNsqOysR1vxnG1M2_eW

https://drive.google.com/open?id=1WGX8AxAZw5IU557BAxYePL-ciljPNQK_

https://drive.google.com/open?id=1vM3tBQDNjH3Rm8gQtU2nXO74l10y3-Cl

WELL DONE!!!

Thanks Mark! Kind of you to say, and that means a great deal.

Looking for a used kiln or similar to do this some outside of class.