doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Trial run of damascus B&W finishing

Dear Chuck -

The browning method I am using now is a variation on the process developed by Dr. Oscar Gaddy, a university professor from Illinois. Briefly, it works as follows:

1 - Polish the barrels to 400 grit or finer (400 is usually enough). If you have tested the barrels for pattern, using acid, this area will have to be polished bright again, before proceeding.

2 - Apply a diluted solution of Laurel Mountain Forge Browner and Degreaser (see below).

3 - Hang barrels in a warm, humid location until a coating of rust forms (may take 4 hours to overnight, depending on ambient temperature and humidity). I use a steam box, powered by a percolator bottom (for the water vapor), and a light bulb (for the heat).

4 - Dip rusted barrels in a 15% solution of Radio Shack circuit board etchant and water (I keep a capped piece of 3" PVC pipe as a dipping tank). Dip for no longer than 5 seconds (important)! That's 15% RS etchant (a solution of Ferric Chloride and water) and 85% water. I am lucky enough to live where the tap water is almost chemically pure. It may be necessary for people in other psrts of the country to use distilled water.

5 - Immediately after dipping, flush barrels clean with a garden hose and lots of water. I do this outside my shop in the yard. It is important to stop the etchant from working any longer than 5 or 10 seconds.

6. - Card (scrub down barrels) with medium steel wool under water. This will make the pattern begin to appear.

7 - Repeat steps 2 through 6 until the barrels are dark enough to suit you. This may take a lot of passes, maybe as many as 8 or 10.

In step 2, dilute the LMF with 2 parts water for the 1st pass only. The next couple of passes can be 5 parts water to 1 part LMF. After that, the remaining passes can be 8 - 10 parts water to 1 part LMF. I no longer use the browner diluted any more than this. The dip in Radio Shack etchant serves to remove the rust from the white striations without affecting the brown striations.

If you prefer a black and white finish, boil the barrels for 5 minutes after step 6, each pass. Dr. Gaddy also used a logwood solution dip on his black-and-white barrels, which I haven't tried, yet. Logwood is a stain used by trappers to darken steel traps.


Hope this helps, Bill

Bill,
So my 3 parts water to 1 part RS etch is too strong? It sure seems to take almost all the blueing off.

I started to reduce the time in the etch....45 seconds was too long. Now dipping less than 10 seconds. Shop temp is around mid 60's. Am I mistaken, I thought the total percentage of ferric chloride was suposed to be 15%, or there abouts? I took my 29% solution obtained from radio shack and cut it 1 to 1 with water, giving me 14.5%. From reading bills post above, it seems he is running about 1 part RS etch to 6 parts water....maybe I'm still too strong. I'm doing a piece of english twist with a brown and white finish now too. Pics when I get a chance.
Steve

I etch first, and do it long enough till I can see a pattern. Sometimes I'll etch 2,3, or 4 times with a tap water rinse in between. Then a TSP rinse to stop the Ferric Cloride from working, another water rinse, then Laurel Mount. browning is applied. I do it only for myself and from my experience from etching the damascus knives I make. Ferric Cloride is not very strong, so I don't think you can hurt anything if it's left on a little longer. I'm not very tech minded, don't worry about temps, and when rusting just put the barrels in a small bathroom where the shower has been run with the door closed to bring up the humitidy. Don't have a tank for etching, just apply it with big cotten swabs. I suppose I should measure and record how much the F.C. is cut with water [ about 3 to 1 or what ever looks good ], temps, humidity, and all that stuff; but I don't. The barrels still come out looking ok. Just my take on doing damascus barrels, right or wrong. Paul

Steve,
I have gone to Bill's ratio. Yes, almost 6:1 water. I did one etch with it lastnite at 5 seconds and it stripped the blue off very quickly. I'm getting ready to do it again in a few minutes after having rusted 3 times and gotten a decent deep blue. I recall Oscar mentioning that he sometimes blued several passes to one etch.

Currently, the solution Bill proposed is about 6% as near as I can figure. The RS MSDS on the web says it's between 32% to 45%, so I swagged at 40. But if this etch produces little contrast, I'm going to dilute further.

I'm playing with several rusts to one etch too, might be the way to go. When I rust blue I use VERY short rustings, after the first pass usually 1/2 hour then down to 15 min. I'm going to give that a go too. Its a learning curve for sure.
Steve

Steve,
I just etched again. 5 seconds didn't take off much of the 3 rusts and boils. Had to re-immerse for another 7-8 seconds and scrub with 0000 sw. Got a decent pattern although contrast is still low, all kinda gray like my first pic. rusting again.

Steve,
I'm going with longer rusts, mainly because I have to work during the day. I'm going with several rusts to get a pretty deep blue on this next one as well.

Cut your solution as Bill recommends. I'm also going courser on the steelwool. Currently using 0000.

I'm thinking Bill may be on to something about the weak etch and more agressive steelwool. I'm going to give a little less etch and more agressive carding a try.

Thanks to everybody for their input. Chuck, I didn't intend to hijack your thread, but maybe I can answer a few of the questions that have been raised.

First, a little history - I first tried using one of the formulas for Damascus barrels given in Greener's book "The Gun and Its Development." This was recommended to me by the well-known engraver and firearms historian, Lynton McKenzie, now deceased. The results, on my guns, at least, were awful. Don't know why.

Then I tried Clorox bleach, straight out of the bottle, swabbed onto a sizzling hot set of barrels, this recommended by Bob Watts, the gunmaker from Georgia, also deceased. This worked a little better, but the figure was still weak.

Then Dr. Gaddy published his instructions in Double Gun Journal, and suddenly, Damascus barrels became a whole lot easier. The only substitution I made was to use a commercial preparation (Laurel Mountain Forge) in lieu of the rusting formula used by Dr. Gaddy Why? It is readily available, and I don't like messing around with potentially toxic and dangerous chemicals.

Now, to address some of the comments:

Chuck - The Radio Shack etchant will remove rust from both the brown and white striations if applied with too strong a concentration. It needs to be a weak solution to provide maximum contrast between the white and the brown. The 15% cut (15% RS to 85% water) was recommended by Dr. Gaddy. It works very well, so I have never felt it necessary to experiment with other dilutions.

SKB - The final strength of my diluted LMF Browner is around 1 part LMF to 10 parts water. The first few passes are stronger - seems to bite better in starting the browning process. If the browner is applied too strongly, it will brown both the white and the brown striations equally, producing a solid brown barrel, with no pattern, and that is not what we want. After the first 2 or 3 passes, I go to 1 to 10.

Bladesmith - From your board name, I'm guessing you're a knife maker. Knifemakers have been using the RS etchant longer than we have, but they use it differently. They use a stronger solution (I don't know the strength), and soak the parts until the Damascus pattern shows, very similar to your description. In other words, they are using the FeCl as a rusting agent, rather than an etching agent, to remove rust. From the few examples I've seen, I don't think the knives turn out as contrasty as the barrels rusted and etched by Dr. Gaddy's method.

Chuck - The pattern after the first few passes will be gray, sometimes a very faint gray. Subsequent passes will build on the dark striations, increasing contrast. This is why it is important not to etch too long, or with too strong a solution of the RS etchant. Stronger solutions or longer etching time simply erase the darker striations which we are trying to build up, not erase.

Now, a few other observations: Simple twist patterns, such as the ones I showed, will produce more contrast than fancy "fingerprint" or "Crolle" patterns. Dr. Gaddy also said that the contrast in English barrels and Belgian barrels will be noticeably different, although I don't remember which is which.

Additional contrast can be produced by varnishing or lacquering the barrels after they are finished. I am using 1 part Tru-Oil (stock finish) to 2 parts paint thinner (Varsol, mineral spirits) So far, this has produced a tough, durable, easily applied cover-up that makes the colors look twice as contrasty.

A new problem has cropped up recently. It is my understanding that Radio Shack will no longer stock their circuit-board etchant in the future. Since a major part of Dr. Gaddy's method relies on the use of a Ferric Chloride solution as an etchant, we very much need to find another source for this important chemical. Angier's book on browning refers to the use of acids and acidic salts as an after-etch, but none of the details have been worked out yet. Anybody have any suggestions?

Hope this helps. Bill