Copied and pasted from where I posted elsewhere and posted all at once, but I thought there'd be some here who'd appreciate this; I'm a bit excited about it!:

I'm a sucker for the old, odd, weird and wonderful. Ideally it has hammers and/or damascus barrels. However some of these pieces come to me looking a little the worse for the century and more of wear. So I have some projects.
I also have a bit of spare time just now, so I thought I'd have a crack at refinishing an old damascus barrel.
Here's some pics:
before

some of the pits dressed down, and polished progressively finer back to 600 grit

dunked in a copper sulphate solution for a while:

Sludge left by the CuSO4 bath:

Sludge wiped off; the pattern is already showing through.

The actual browning solution has now been applied, and I just have to wait for it to rust, rub the rust off, reapply the browning solution etc through a few more cycles.
The other bits:

after first rusting, approx 24 hrs:

After rust rubbed back:

Justhave to keep rusting and rubbing for a while now...
Done:

After half a dozen or more cycles of rust, scrub, degrease, rust etc and the final scrub and degrease, I dunked it in a bath of hot water and bicarb soda to stop the rusting action. Dried it, rubbed a bit of linseed oil to highlight and protect it.

Came up better than I thought it would:

It's possible to see the join just ahead of the forend where a different, thinner riband was joined to the thicker breech end.

[img]http://i606.photobucket.com/albums/tt146/cadet450/IMG_0910_zps17591974.jpg[/img]
Some observations:
I was a bit concerned that the environment I had the barrel sitting in (cool, dark, dry) and this time of year (warm, dry) would not be humid enough to promote the rust I needed for browning. That proved not such an issue.
The value of thorough attention to detail, in the filing and polishing of the surface is important (but I suspect I didn't need to go as fine as I did); a few pits I could have taken deeper, some blemishing around the breech end I could have hit harder, as they've left some unsightly darker blemishing.
I had thought I wasn't going to get much pattern/contrast/colour, even after the final scrub (and it's not the most exciting pattern either), but I stopped as the barrel appeared not to be changing much after about 6-8 cycles. It turned out better than I'd thought after rubbing with linseed oil, though not as brown as I'd hoped.
Not sure whether it's "greys" in the metal, or whether I should have scrubbed harder after the copper bath, but in bright sun there's golden flecks in the metal ahead of the join near the forend; that they don't appear at the breech end makes me believe it's in the way the metal took the finish, rather than my attention to detail in re-finishing.

Nice!

I'm impressed. Very nice work. Wait till Drew sees it!
Jim

Great photos and description of your process. Thanks for sharing it.

Wow!
Nice Job!!!

Well done and thank you.
Here's another tube segment joint (also Laminated Steel). The patterns join in a straight line weld suggesting that one tube was flared, the other coned, and then butt welded together.

Nice job, but from my experience the Copper sulfate solution is a waste of time. If you have to use it try about a 5% solution for 10-15 minutes. I do not believe it gives and edge on etching as some of the instructions would leave you to believe.
Nice Browns are really hard to get without a high humidity atmosphereI have found.

Angier did not speak well at all of the use of Coper Sulfate in bluing. One of its problems is it will "Flash Plate" steel but not with a very adherent plate. Before the development of efficient & inexpensive layout inks many machine shops used to keep a vat of Copper Sulfate solution to dip parts to be layed out in. The layout lines could then be made in the copper & after machining it was easily removed.

Because Laminated Steel has a higher ratio of steel to iron, mixed together, and ‘puddled’ before being formed into rods it is harder to get a distinct contrast; esp 'browning' vs 'black & white'. Try a crolle damascus barrel next

Great work! Thanks for sharing.

Franchi

I've always used ferric chloride for the acid dip, then a browning. After enough coats it can be boiled in log wood to get a black and white color instead of brown and white. I've never heard of anyone useing copper sulfate. To each his own. Paul

I am no expert but I have not used any copper sulphate compounds in my browning since my early trials.
I found that it cut into steel as well as iron which could 'muddy' the final contrast. It also tended to promote after rusting which has not been a problem with the boric acid etch that I use now.
Another problem with copper sulphate is that it precipitates copper deep into pits and engraving which can be the very devil to remove. In one particularly bad case, I had to use a concentrated nitric acid bath to remove the copper which made a mess of the base metal as well. The air was blue after that event!
Yet another problem is that unless all the jointing areas are masked with varnish or paint, if a full immersion is used, the copper sulphate etch can actually loosen the jointing of a border line jointed gun to the extent of rendering it loose. Same can be said of using Ferric Chloride in a full immersion.
This can be avoided by applying the concentrated solution by cotton pad only to those areas that you wish to etch but this is tricky and very difficult to keep off breech ends etc.
This is not to diminish the great results that have been achieved by Cadet and all others that use copper salts for their etching, it is just beyond my modest abilities.

Thanks all for the feedback, comments and ideas.
Consensus seems to be that CuSO4 isn't the way to go; I was just following the instructions on the bottle! There seems to be plenty of different ways to arrive at the end result, and I probably will do things a little differently next time.

Toby;
I had wondered about using Boric Acid, but have not tried it. Can you give a few more details as what solution & how long do you etch with it. It is comparitively mild I believe in comparsion with the other acids mentioned.

Chemically, what's going on in the CuSO4 bath? Is it etching (eating metal away), or is it actually electroplating a layer of copper on, which is then later eaten away by the browning solution? I remember words like anode, cathode etc from y11 chemistry, but that was half my lifetime ago, and I didn't pay enough attention or do very well at it!

cool

The SO4 part of the Molecule is derived from the Sulfuric Acid treatment of Copper and it of course etches metal, but the real problem in my opinion is the layering of copper on the barrel which accopmlishes nothing but aggravation. As Tony said above, it is unnecessary and only a problem

Never having browned barrels myself (other than flintlock rifles) I am nothing more than an observer. However, after having studied many original damascus finishes that disply a brilliant contrast and are high gloss (no, they aren't varnished) and perfectly smooth I have a hard time believing any form of etching was used on them. What say ye?

2-Piper
The Boric acid etch comes direct from Angier's book and I don't think I do anything out of the ordinary.
I use a stainless steel bath, dissolve boric acid powder in distilled water (clean rain water would probably do) to about 5-10% w/v. This gives a saturated solution at about 50-80 deg C.
I grease the inside of the tubes, plug with hardwood dowels, carefully degrease the outside with whiting (you must do this thoroughly as the boric acid will not work well with a contaminated surface and once oil contaminates the solution one really has to throw it out and make a new batch).
I then warm the solution to 60-80 deg C and lay the barrels in the solution for between 30 min and 2 hours.
It is very gentle but if the surface is clean it quickly mattes the surface showing the full pattern of the damascus. After a bit longer, carbon from the steel starts to darken the surface and can make the pattern harder to see but a brush with a gloved finger wipes it away and all becomes clear again.
When the pattern is distinct over all the surface, rinse with fresh tap water, remove the plugs to check the bores are still dry, if not dry out, re-plug, degrease and start your browning.
The solution does not last for ever and needs replacing once you notice that the etching is getting too slow.

Toby;
Thanks, from Angier's book was what had caused me to wonder about its use as an etchant for damascus. As I recall he just mentioned it for removing the old browning, rust etc prior to polishing but not per se as for bringing out the pattern in damascus. From his description it struck me it could be uised for this purpose. Thanks for confirming that.

I had never heard of using Boric Acid for an etch before. Thanks Toby for sharing your technique. I recently bought a 5lb. tub of Copper Sulphate which I guess will now be used to kill tree roots in drains or prevent black algae growth on roof shingles. The CuSO4 did seem to bring up the Damascus pattern better than not using it, but I'm concerned about the weak adherence of the flash plating 2-piper mentioned and the potential for loosening jointing or precipitating into pits that Toby mentions. But if flash plating of copper occurred on both the iron and steel, rusting could not happen since copper doesn't rust. I had some old lathe tool-holders that ended up with a thin copper wash after I suspended them in an HCl pickle by copper wire. It seemed to prevent them from rusting.

Angier: P.139 Para. 4
2 Piper
Dead right: he doesn't mention etching damascus but does mention matting. He also mentions that derusted part don't tend to after-rust.
Another nice feature of Boric is that it cleans out rust pits very thoroughly down to good metal so you don't have to worry so much about dark spots in the pattern when there are small but deep pits that you don't want to/can't strike out.
Also, if you polish to about 800, it mattes the surface of the iron for the browning solution to 'get a grip' but doesn't matte the steel much at all so as the browning proceeds the steel gets re-polished simply by carding off the surface rust.
Keith
One of the tricks of the old 'fowlers and punt gunners was to copper plate their guns/cripple stoppers. I am at present restoring a Grant sidelever that was given this treatment and even though well worn in the wood, the engraving on the action is pristine!
However, some of the remaining copper plate is the very devil to remove! Other bits just flake off and most of the barrels were worn down to the damascus other than were it was deposited into scratches and pits.

One last thought, Boric Acid is used in various skin therapy concoctions I believe and in the concentrations I use it in, it is very gentle on the hands, other than drying out one's skin a bit.
I'm not suggesting bathing in the stuff and you should use protective gloves for the sake of your browning as well as your hands but at least you are not dealing with a really nasty chemical.

Dr.Oscar Gaddy who wrote about redoing damascus barrels in the Double Gun Journal recommended useing Ferric Chloride to etch the barrels. He has now passed on to a better life. If anyone wants a copy of those articles they can contact the DGJ and get them. He was the one responsible for just about all the activity and interest in redoing damascus barrel SxS's here in the USA. With gun barrels, as well as the damascus knives I make, when bring out the damascus pattern anything finer than a 400 grit finish is unnecessary because the action of the Ferric Chloride and browning solutions will get rid of any scratch marks. His articles are a very good read explaining the whole process.

Dr Gaddy's refinish articles, and a previous discussion here.

Double Gun Journal Vol 8, Issues 2 and 3, 1997 and Vol 14, Issue 1, 2003

http://www.doublegunshop.com/forums/ubbt...e=1&fpart=2

Toby, I think it might be worth a try to attempt reverse plating to remove the vestiges of copper plating. I'd want to try it on a non-valuable gun or part before doing it on anything collectible, but it should get the last atom of copper even in the deepest scratch or pit.

Keith,
Thanks for the thought on reverse plating. I have made enquiries about the possibility of removing copper by both chemical and electroplating techniques but all I got was much shaking of heads and grim warnings of damage to the underlying metal.
As you suggest, a trial on some scrap parts might be the best idea.
At present, the Grant I mentioned is free of the majority of the copper and I think what little remains will be of interest rather than a minus point for sale.
However, if I get another one I will consider your suggestion very seriously.
Thanks.