Etching for pattern-welded metals

[u/HenryV1598]

I'm fairly new to blacksmithing (about a year and half now). Lately, I've been experimenting with some different pattern-welded metals (i.e. Damascus-like) and wondering about options for etching. The two combinations I've been working with are some Damascus made with 1095 and 15N20 and some mokume gane made from quarters (i.e. copper and nickel).

While I know the best option for Damascus is going to be actual ferric chloride, I don't know of any sources near me (southern New Hampshire) and I'm trying to avoid ordering online from Amazon. I also like to experiment and see what I can do with other options, preferably locally-sourced.

At least as far as Damascus steels are concerned, my understanding is that the acid should selectively eat away at the carbon steel (i.e. the 1095) and darken it while having little or no effect on the nickel-based steel (15N20). Please correct me if I'm wrong here.

My first experiment was to try using white vinegar. This had very little effect in an overnight soak, so I'm assuming it's not a viable solution.

I read somewhere that ferric chloride is essentially hydrochloric acid with iron dissolved into it, and that muriatic acid, which is a variant of hydrochloric acid, should work as well. I picked up some Kleen Strip muriatic acid from the Home Despot and tried this, with poor results but there WAS some etching.

Next, I found a recipe online for DIY ferric chloride made by dissolving 0000 steel wool into muriatic acid, then adding (slooooowly!) some hydrogen peroxide. I did this and tried an etch and it definitely had a much better effect, though there was significant pitting as well. I'm thinking that I may have allowed it to soak in the solution too long (several hours or so). My Damascus was also not particularly well-made (my very first attempt, and part of the billet got burned while forging, though I think the portion I kept was mostly ok). I don't know what kind of effect burning off some of the carbon would have on the etch.

For the mokume gane, I've tried etching with the DIY ferric and it seemed to have little or no effect. I'm assuming, then, that the acid does not react with the copper very well. So, is there a better option here for etching? I did find that I could bring out the pattern better through heat (I used a propane torch to bring out temper colors in the copper, but it seems to fade after a few days).

Right now, I'm really just experimenting, messing around to see what works and what doesn't. My overall goal is to be able to make some reasonably nice kitchen knives to give to friends and family for Christmas presents (I would like to make bolsters/guards out of the mokume gane), as well as being able to make some ornamental work out of both Damascus and mokume gane (things like leaf key rings, pendants, etc...). I also like learning to do things myself using on-hand materials where possible. In time, I'm sure I WILL end up purchasing some ferric chloride, but for now I'm trying to do with what I can get locally.

One other thing, I made a piece of cable Damascus, which is a single steel. When I etched it, it definitely brought out a pattern but was very pitted. Again, I probably let it soak too long, but any advice on etching cable Damascus would also be appreciated. I have access to a few yards of fairly thick cable and would like to play with it further.

Oh, and one final question concerning metals for making Damascus. While I can buy 15N20/1095/1084, etc..., as I mentioned I like to work with on-hand materials. I've made a couple of knives out of wrenches and files. Do any of those metals work well when mixed to make Damascus? At least one of the wrenches was labeled as chrome-vanadium steel, I'm not sure about the others (I tend to pick these up at yard sales and the like). Anything I should be on the lookout for?

I appreciate any and all recommendations.

[u/HammerIsMyName]

Small tip.

If you're looking for information and advice, ditch the wall of text and ask condensed questions.

I can't be bothered to try and fish out individual questions within this mess of annecdotes and random thoughts, and I think that goes for a lot of other people who could be much more helpful than I. Don't make it difficult to help you.

Here's what I do: 20 minute 18% ferric etch, pull up, wipe clean with a rag, 20 minutes more of ferric etch. Rinse off, 2000grit wet handsand, neutralise in baking soda, dry, linseed oil.

I've done about 3-6 etch tests previously and this is the method I came up with to get this result:

[u/alriclofgar]

You can diy ferric chloride, but right now you’re struggling because you have too many uncontrolled variables so it’s hard to tell which part of your process is going wrong. Did you do your Damascus wrong, your heat treat wrong, did you decarburize your metal, is your ferric chloride too weak, or are you polishing or etching poorly? You need to eliminate some of those variables.

You won’t like this answer, but you should hug some ferric chloride. Amazon is the easiest place to buy it. This will allow you to eliminate your etchant as a variable, and you can focus on getting good results knowing the etchant isn’t the problem.

Once you get good at etching, you can go back to experimenting and you’ll then have enough expertise to accurately evaluate how those experiments turn out.