I was able to recover this PDF from "Guncraft" in 2015. You will need to cut and paste the link
https://web.archive.org/web/20151010095002/http://www.doubleguncraft.com/uploads/PDFs/GunCraft_Book.pdf

The pdf is a chapter in Vic Venter's "Gun Craft: Fine Guns and Gunmakers in the 21st Century" published in 2010, and which he posted on the internet in 2015. He graciously gave permission to post here.

Dr.drew there is. Video about aa brown co doing case hardening /case coloring on youtube

Robin Brown color case hardening video, click and scroll down to see it.

https://www.aabrownandsons.com/videos.html

Thank you, Stephen.

Don't forget to scroll down to the right video, as there are several others by AA Brown that may start playing if you don't.

One thing I noticed in the AA Brown CCH video, that is different from others' techniques I've seen, and read about, is that they don't worry about keeping the lid in place on the crucible. They slowly removed the lid in the oven and carried the open crucible outside. Evidently having the (poorly fitting) lid in place until the last second is totally unimportant. This is 180 degrees from what Oscar Gaddy believed and practiced. I'm beginning to wonder if the other variables, such as composition of the charcoal pack, temp achieved, and length of time the temp is held, aren't more important to the end result. It would appear, from this video, that oxygen will not invade the super-heated pack for a few moments, even with the lid removed.

Very interesting.

Douglas Tate in www.thefield.co.uk
http://www.aabrownandsons.com/assets/files/FieldCH.pdf

It all looks so simple though it is one of the best kept trade secret process. Just look how vibrant the colours are especially the blues and yellows are. just take a look at the colours of re case hardened guns look on your side of the pond using same process. In the AA Brown video it is all there but missing a few important pieces of information.

Over here people are trying to replicate lc smith Parker colt fox colors that may be different from what you expect to see the main point is surface hardness with the least amount of warping

MC I was under the impression the subject of this posting is British Case Colouring! People may be trying to duplicate American case colours on your side of the pond so why the hell do they put them on English guns surely gunsmiths can have more than one methodology ? English action hardness has never been an issue as far as I can recollect and back to the AA Brown Video warping was also not an issue. So as I said there is something more in the process than heat Charcoal bone and water that at first look is simple but if you look deeper you will see that there is more in colour hardening than at first site.

We have a need over here for a knowledgeable craftsman able to consistently get good British style colors with a hard surface and little to no warping. Proper color hardening and correct colors remains on my list of skills I hope to develop one day. It is an incredibly interesting subject and my first impression is that while based on science, a good bit of it is art, similar to browning damascus barrels.

If you have more details to share about the British process I'm all ears Ernie. I understand that most British Craftsmen use a higher percentage of wood charcoal than the average American color hardener.

Damascus, i thought in you statement you were saying the case colors over here were not vibrant colors like traditional English colors I was saying people who case color over here are going for American gun traditional colors.i think robin Brown said he used bone charcoal exclusively Mark

It could possibly be the volume of charcoal? Very generous appearing crucible.

Take a good look at the crucible packing what else do you see?

Looks like the charcoal has been burnt off at least once before? Coarser than what Dr. Gaddy was using in his mixes as well.

Nothing. But he inadvertently revealed his secret ingredient, a can of Raid bug spray...
JR

I'll take a swing at this. The sieve size seems to be quite course, and certainly the raw material sources would be different, but the charcoal in the video might be prepped a bit different than what we might see typically in the US. There was relatively little burn down of the char level after the heat cycle.

SKB,craigd. Very close indeed, The charcoal mixture is made only from from a coarser grain hardwood and carburised bone amongst other things. Next think about the water next?

Thanks damascus for digging into it a bit deeper, and apologies to Steve for completely missing his comment about charcoal coarseness.

The water? Apparently, the local tap water is just fine for this technique, unless there is a rain catch container, not visible, but distilled water might(?) not be dispensed with a hose. The water quench tank likely has used water in it. I was surprised that copper wiring used to bind some parts, so there may be a higher than normal copper component in the quench water. There were two different charcoal bins, and they appeared to be used in sequence. I'm guessing new material was used around the gun parts, and possibly used charcoal is a filler to top off the crucible, based on possible appearance differences.

He placed the crucible in a cold oven.

Gentlemen;

Here are some things that I saw in Robin's video.

The parts are de-greased via ultrasonic cleaner and then some of them are wired together with copper wire--this to me shows that his max temp is well away from 1984 degrees F for copper melting and I will comment on this later in this list of things I saw. Robin is not overly concerned with touching the just cleaned parts with his bare hands and his hands seem clean. Robin also did not place any additional steel supports wired to the side locks to prevent warping as some American color case hardeners are known to have done--another indicator of the control of max temp by Robin to my mind.

Robin carefully and strategically keeps the parts separated and I suspect they are placed in a pattern that he has developed from experience.

Robin surrounds the packed parts in the crucible with the charcoal and bone mix and it seems to me that the first part packed (the action) must have had about 2 inches of this mix to rest upon when Robin placed it in the crucible. The charcoal/bone mix is coarse as mentioned I would say that the mix is about 70/30 charcoal to bone and the bone looks very clean indicating that either Robin or someone else "burned" away all the animal flesh before it was mixed with the charcoal. As to the mix there is complete absence of fines as you see none when Robin dropped some of the mix on the floor. I think it is important to note that Robin placed 3-4 inches of mix on top of all the parts, then compacted it by tapping on the crucible and then before he placed the cover on the crucible he added more mix to completely fill the crucible--you have to look close to see that the crucible was filled to top. He wisely made the top 1 inch short so that he could place his tongs into the crucible to remove the top when he was taking the hot crucible to the water tank. This cover is very loosely fitted. The "shaking" and tapping down of the mix in the crucible gives Robin the proper mix surround of the parts that he desires as well, I suspect.

This filling of the crucible completely, the 3-4 inches of charcoal/bone mix cover over all the parts, and how Robin flipped the crucible over into the water tank, kept the ambient air contact with the parts to a bare minimum.

The tongs that Robin has with nearly 4 foot long handles are built for purpose and give him great leverage in holding the crucible as well as distance from the water splash and thermal reaction and allow him the leverage also for his final flip into the water quench.

I spent a couple of decades of my early life in a forging/blacksmith shop and learned how to judge temperature by color and the max temperature that Robin heated the crucible is of interest and important to my mind. You will note that he has a gas-fired furnace and there are no temperature gauges seen or any cable emerging from the furnace to indicate any remote temp devices. Therefore I think that Robin judges the temp by eye and the temp appeared to me to about 1500 degrees F when he opened the furnace door. And he lets the crucible heat for a time that he has learned in his years and from his mentor when he was a young man---I believe it was Billy Woodward.

As mentioned the water barrel has been air infused somewhat, but no continual air flow as some American hardeners advocate, and it is just local water and at whatever temp it is. However, the way that Robin holds the tongs and flips the crucible dumping the parts into the water quench is very important--he lowers the crucible into the water for a short distance as he flips pouring all the contents into the water so that there is the barest minimum contact with any ambient air. You will also have to look closely to see the front of the crucible enter the water during the flip.

In the video Robin shows that there is not warping of the side locks fitting into the action body. I believe his control of the max temp of the crucible and its contents of course is key to the warp control. Of course there is bound to be some minor warping such as with the triggers that will have to be relieved.

As a side note, after Robin made this film some time ago I wrote him an email and thanked him for doing the video for us amateurs and he wrote back saying that it was great fun for him to show the process. We are thankful for craftsmen like Robin who are kind to show us things that are not shown by others in the gun trade.

This is pure speculation, but there may be a PID, thermometer, on this oven. At the lid removal, there is a brief glance at a small gauge electric wire coming out of the top, a bit to the right. It would be too light to power a blower, but it appears the heat source comes in from the bottom anyway? Definitely, I do not dispute judging temp through experience, the crucible though seems to hover in the lower red, medium red spectrum? The crucible never seems really bright to my eye, the way part of the oven interior appear.

The thing that always is interesting to me is the delay from oven removal to quench, either counted off or part of the circumstance of walking the crucible out of the shop. I think there is a cut in the video, but it appears to be a continuous process that likely takes fifteen to twenty seconds from the oven to the quench. Particularly with the lid off, the parts are likely cooler than whatever temp they soaked at, in the oven. I have always wonderered if that was one of the tricks to low distortion, quenching games to catch the parts cooler than the nonmagnetic point on the way up? An edge to center of mass temp difference might also help with his color distribution control, ending up with those classic islands of blue framed by paler colors.

Craig;

Like you I am uncertain about the electric wire.

Your thoughts about the non-magnetic point on the way up and down brought to my mind a "color" non-case hardening event that occurred 7-8 years ago on a double 20 bore rifle I built with a Turkish action made of 4140. I contacted Turnbull and asked him if they would take a action from me made of 4140 alloy steel that I would pre-polish and then for them to heat it in in their charcoal mix and crucible in their furnace to only about 1350-1375 degrees F (keeping it below the transformation stage as 4140 alloy steel will through harden and not surface harden) and then quench it as they do for color case hardening. They agreed to do that and the colors turned out to be stunning---not a hard surface but never-the-less beautiful. From the email that Turnbull Co. send me after the coloring of the action, I believe they were also amazed at the beautiful coloring.

If someone reading will be so kind to receive a photo of this 20 bore action from me via email and then post it to this discussion I will email it to them. Just send me a PM with your email address and I will email the photo to you.

Thanks bushveld. It is actually pretty easy to observe that when relatively high carbon steel is heated, the non magnetic point as the heat increases is a very sharp point. As the piece cools, it will remain non magnetic till it is noticably cooler. I don't believe it is good metallurgy, but high carbon steel can still skate a file when quenched while its non magnetic and below the curie point. It sort of sounds technical, but there are simple videos of observing the recalescence point of steel, basically black heat color seeming to heat glow again, as it cools. I'd like to see how your 20 turned out. Take care.

Stephen, send me the pics. I'll be glad to post them this evening. stanhillis@gmail.com

I bought my oven from a friend in Arkansas, now deceased, who showed me some guns he had "colored" using a charcoal pack, but keeping the temps even less than bush veld requested. The colors were beautiful. We're having it wired in and tested now. It has an analog temp gauge on the door. May not be the most accurate, but it's what my friend went by when coloring his gun's actions. We're going to play with it this winter and see what we can accomplish.

Posted for bushveld, his 20 bore Double rifle with colors by Turnbull. More info on it in his post above.

A very interesting thread and subsequent discussion. Here is an example of what original case colours look like re: a circa 1920/1925, Clabrough & Johnstone, SLNE shotgun. Not too bad an effort for just a Colonial export trade gun.





_____
TC

The colour thing is obviously personal taste. THough I do remember our art teacher stressing that blue and brown are a "discordant" combination of colours.

Two of the most attractively colored guns I have come across were a Holland and a Dickson sidelock, both displaying a rich grey silver patina that I guess was left after the original colour case hardening wore off. Does anyone know how to speed up the process of colour fading to get to this beautiful grey patina faster? Without resorting to power brushes that polish old guns making them look like fake coins.

Sure. If you want to not only get the sliver look but the wear pattern itself, put a little Simichrome paste on a cotton glove and handle your gun as you would carrying it and operating it. The high points will wear most quickly of course and the inside corners will retain color as they would naturally. This happens pretty quick (minutes, not hours). Clean and inspect every minute or two as you go. Works really to highlight engraving. In fact, I have a lock that needs this treatment.

In the video it seems the quench tank was filled just prior to the quench so the temp of the water is fairly cool. The water doesn't seem to be oxygenated as many people in the states do with compressed air. It appears the amount of the char , which keeps the oxygen from the part, is more important than having a sealed crucible. Also by using the heat of the crucible to dry the parts may also normalize the parts also. I've seen the normalizing bring out more color than achieved from just the quench. I've seen decent color achieved with temps from 1325-1425 F. Most of the older American guns frames are some form of a 1020 steel. Are the British frames a similar low carbon steel? We also don't know how long the heat soak was. Is one hour enough? I've been told 1 1/2 -2 hours. Getting the colors you want once is cool, being able to do it on demand over and over is the art I feel.

the claybrough cc images above are reminiscent of the cc produced by the late, great tony treadwell... images of which may be found in his fine, now scarce book on engish gun restoration...

https://www.lulu.com/shop/tony-trea...duct-1ggvkn8v.html?page=1&pageSize=4

Does anyone know how these large areas of blue color are obtained? To me, this is really attractive esp. if birds or animals are engraved in the blue area as on the Rigby.

[img]https://imgur.com/38XwSkm[/img]
[img]https://imgur.com/9pxyKhq[/img]

CPA
I believe that a significant amount of the "blue" is a color balance technique

and not from the CCH process.

Could you please elaborate on that, Steve?

I was told once that all the current British makers outsource their case hardening to a firm called St. Ledger's in Birmingham, I'm not sure if it's an accurate statement.

Yes, please elaborate. I have never seen any suggestions, recipes, or techniques for getting a high percentage of blue colors during case hardening.

I've noted that high condition Syracuse Lefevers have a much higher percentage of blues and purple-blues than most makers. Many are predominately blue over the sideplates with only a bit of ghosting around screw holes or the edges. When I see a Lefever with a lot of mottled colors, I immediately start to look for other signs that it has been refinished.

There is a huge difference between refinishing and restoration. And very few so-called "restorations" on Lefevers have anything approaching the period correct case hardening colors. I have the name of one case hardening gunsmith who seems to be able to consistently pull it off in a convincing manner. Most cannot.

Here's a DS Grade Lefever that illustrates what I'm saying even though it has seen a fair amount of use.

Stanton Hills,
If you process your images through Photoshop, almost any color can be intensified.

Stanton Hills,
Please check your PMs.

Aa brown does it's own ,do any of the London shop farm or to Birmingham I doubt it. I think brown used to do Westly Richards

That may account for the intensity of the color, but how do you account for the large area of uniform color in the selected areas?

I couldn't open the pictures, but the Venters book mentioned early on in this thread, and the AA Brown excerpt from that book, elaborates a bit. The video shows a sample of one, but Brown explains how he believes proper British case colors has an area of blue in the center of a part, more or less framed by the other nonblue colors.

I would agree that color pattern is the most attractive, but how is it obtained?

There was a link to a video posted on here, awhile back, showing AA Brown's process, IIRC.

Here is a link to the video showing AA Brown's process, formerly posted by bushveld.


https://www.aabrownandsons.com/videos.html

If you go to Drew’s first post in the thread, and copy the link to Vic Venter’s book Gun Craft, on pages 92 & 94 there is an inset called “Colors on Brown Guns”. The author describes what Craigd was alluding to. It states that each hardener has their own signature style involving various techniques (secrets of the trade, jigs, fixtures, etc.) that he uses to achieve consistency of colour and pattern. Robin Brown’s colour case hardening technique involves how he packs the crucible container and positions the various components within the carbon pack in-order to achieve his desired colours, pattern and placement.

TC