Hey everyone!

A customer of mine asked if I could do a custom finish on some items. The only problem is I’ve never done a finish like this one. I’m willing to give it a try though. Does anyone know what this type of finish is called and how it could be done? 
Here’s the pic the customer sent me

 

Probably wire brushed with a copper brush at a black heat.  Getting the proper brush and proper heat is a learning experience.  Using a brass brush is much more common and so you may read up on that and then try to apply and modify what you learn to copper.

Of course you can hot forge copper too; again some tricks to be learned to not end up with it dripping out the ash dump or cracking from too much O2 absorption...

I wondered if that would work. I’ve used a brass brush before but didn’t know if it’d work with copper. I’ll give it a try!

Thanks

I would expect it might need to be a bit hotter than for brass if you are using a pure copper brush.

This is referred to as "brassing" or "plating", and I've heard some even refer to it as "brazing".

Use a soft bristled brass or copper brush. A yellow brass brush will give a brighter (more yellow than copper) finish so the piece you posted looks like copper.

Get the piece to a dull red heat in the forge and quickly wire brush (steel brush) scale away to clean piece. As the heat comes down and has lost all color at a black heat start brushing on brass. You can apply to taste, anywhere from minor highlights to very heavy.

One tip, try to do this in one heat. If you put the piece back in the forge too long the brassing will burn off leaving a black residue. I believe this is the zinc burning away. So best to do it all in one heat. For a complicated shape you could also spot heat with an OA torch. Just be careful with reheats, too high and it will burn away the brassing.

Another way to get the plating is to use a etchant such as ferrous chloride contaminated with copper. Insert the clean steel item let sit, remove, neutralize (I use baking soda water, rinse let dry.

I used hydrochloric acid to "wash" a large copper and bronze rain gauge, about 25 years ago.

When I had finished I had several litres of pale green HCL.  I dropped a small piece of mild steel into this solution and left it for 2 days.  When I removed it, instead of the shiny clean steel I expected, I had a pinkish beige piece, that when rubbed, came up looking like fresh copper.

I used that on several items including a commercial hunting knife, all of which still have their copper coating today.

 

Has anybody figured this out? Ive played around with copper sulfate mixed with water. It gives bare metal a copper finish. But getting it to blend like in that picture might be a little iffy. So far I haven't had any luck finding a copper strand brush.

After you plated it what did you do next? Try taking some 000 steel wool or perhaps a little dry clay in an old T shirt and giving it a brisk rubdown? 

You can't expect these things to be one step, it takes a couple few to get good results with a brass / copper brush. Have you looked online for copper brushes? Last I looked there were a number of different brands out there.

Frosty The Lucky.

Most of what I looked at on line that was listed  as a copper brush, appeared to be brass in the picture. Maybe a gun cleaning brush?  They seem a little small but I'll try that. Haven't tried clay yet.  Thanks for the help.

Check auto parts stores. I believe 5hats where I got my last copper brushes. Seems it was larger than a toothbrush, but works fine. 

You also might want to try applying a hot oil finish after you are finished with applying brass/copper. Do it in the same heat. It creats a pretty cool antique brass/copper looking finish. 

 

I've used solutions to plate before, I ran across this when I tossed some harmonicas in a musical instrument sonic cleaning tank, and all the steel bits came out bright pink.  I've also got looks similar to the photos above by forging copper plated grounding rods at low temps.  Too much heating or beating and you can take the plating off.  Not too much, and it just kind of blends them together with a lot of copper on the outer surface and looks cool. 

 

I suppose you could forge it close to shape, clean it, do a full plating first with a solution, and then beat the metal enough to take the copper off in places.

A solution of copper sulphate powder in water can be used to give a copper finish to steel or iron.  This was the original way to coat steel before bluing was introduced for layout lines.  And copper sulphate can be found at your local plant nursery as a fungicide.

Keep it simple, just use a brass or copper brush at a black heat. Also, after applying the brass or copper, apply a hot oil finish such as 50/50 blo and turps with a little beeswax and you will get a beautiful antique finish.

I used undiluted copper sulfate on this steel frame.  It reacted almost immediately.  Be aware it should probably be diluted with water. if you don't neutralize that stuff it will eventually turn to brown rust.  Not really a good rust preventor like bluing or rust brown (aqua fortis).     

What do you finish plated steel with to prevent oxidizing? Hot brushing with copper or brass brush, copper sulfate solution or electroplating, will all degrade over time unless it gets a protective coating. Or you hide a zinc on it somewhere, even then . . .

Frosty The Lucky.

A recent video "How to put a copper skin on steel" by GS tongs, Its a different approach. Who knows how long the finish will last.

If not exposed to moisture, my experience has been pretty well, depending on how it was applied. I had some accidentally electroplated harmonicas on which it lasted about a year under heavy use and being put in my mouth a lot. I've still got some stuff I made forging copper plated grounding rod in 2008 and most of it has held up. If exposed to moisture it goes considerably faster. Kinda like sweet iron bits for horses. They start off coppery so the horse takes the bit better, then the copper wears off over time, with the idea the horse gets used to it.