Polishing elbow cop mirror for the Medieval Reenactment and Living History Resource The Turnip of Terror

Polishing Experiment

On the Armour Archive forums, on armoring blogs, in armor care articles and videos there’s a lot of talk about metal armor maintenance, polishing, and metal surface conditioning. When it comes to getting a finish on armor there’s discussions that range from period techniques with pumice or sand and olive oil, to modern abrasive practices. 

At the modern end of the scale I find there to be a lot of discussion on sandpaper, generally from the automotive community. Hobby and professional auto body gurus spend quite a bit of time getting mirror finishes out of a variety of metals, generally chrome and aluminum, but steel as well. They recommend progressively finer grits up into the thousands, wet stuff, dry stuff, compounds, powders, etc. I read one article that talked about 5000 grit sand paper. I don’t even know where to find something like that.

In the armor community there seems to be a strong following for the 3m Scotch-Brite abrasive hand pads. Usually referred to by their color, the 3m gray Ultra Fine pad can put a pretty solid “satin” finish on a piece of plate. One of the benefits to keeping your armor at this level of finish is that a 3m hand pad can be packed in with your armor and used at your convenience. Buffing a piece of armor up to a high gloss means that if you develop rust or blemishes in the field, anything with grit that you try to clean it with will make the spot dull in comparison to the rest of your armor, and require a complete reworking back up to the mirror polish back at home.

The problem is, though I’ve brought some pieces of armor up to that level of finish, I find it to be very “streaky” and unappealing. What I mean by that is, it slowly (and laboriously) removes the rust and applies a bright finish to the piece, but doesn’t do much to remove imperfections underneath. The pitting or outline of the rust mark usually remains, any scratches or remnants of lower grits during the original finishing always show through. And the satin finish itself is visible, in that you can see the grain of the stroke in certain angles of light.

When it comes to trying to go “deeper” into the metal to remove blemishes and damage, most recommendations suggest going one level down to the purple 3m pad then going back up to ultra fine. If that doesn’t work, the rule of thumb I’ve understood was to try grittier sandpaper. In the past I’ve tried to use more aggressive sand paper and eventually transition back to a purple then gray 3m hand pad. The problem is, and I wonder if this is an issue with transition from one media (sand) to another (3m abrasive mesh), I never seem to be able to completely remove the scratches from previous grits.

I decided to experiment with continuity of medium, hoping it might make blending from one grit to another easier for me. I purchased the entire 3m Scotch-Brite hand finishing system from their coursest pad to the ultra fine, armoring community’s “satin finish standard.”

As I mentioned above, generally people refer to their hand pads by color, which doesn’t work well when you go through the entire line up, as purple and gray are the color of various different grits. So I’ve ignored the color of the pads and will be using both the product number, and the 3m name.

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This is the piece I started with, made by Josh Warren long ago and left in my basement. He was gracious enough to allow me to tear it apart for this project. I need practice removing rivets and disassembling armor without damaging things. This isn’t a total loss if I do damage it, as it was always intended as a teaching tool and beater/loaner SCA armor. I also need to figure out how to set a rivet, and those splints means a lot of practice in a confined area. Maybe I’ll fiddle with cleaning up and re-dying the leather too. (big maybe)

Last year I had gone over it with the ultra fine pad to get the rust off, then gave is a CLP rub down and packed it away. As you can see it cleaned things up, but did nothing to get rid of the tooling marks from where rivets were removed with an angle grinder in its past.

1 - Before Picture.jpg

I wanted to see if I could use hand pads to get the perfectly smooth and unblemished substrate for a mirror polish. I started with the grittiest 3m hand pad they have, their “Heavy Duty” (7440), which they say is equivalent to steel wool grade 4. Though it took some work, I was surprised at how well I was able to completely smooth out the grinder marks and many of the deep scratches. It seemed to remove material gently enough to not damage the metal too much, and it was easier to control than a wire wheel or grinder. Of course the surface was visibly abraded, but that’s kind of the point.

2 - First Pass.jpg

Next step was the 7446 “Blending” pad.

3 - Second Pass.jpg

Then the 8447 “Production” pad.

4 - Third Pass.jpg

Now we’re getting into the territory that most armor maintenance lives at, the 7447 “General Purpose” pad.

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Then, finally the 7448 ultra fine pad.

6 - Fifth Pass.JPG

It was odd, little pits on the side of the cop and the fans that I couldn’t see before started to become apparent when I jumped up to the ultra-fine pad. Obviously it got shiny, but it also got very smudge-y. It was easy to rub so hard that a grayish film would develop in spots that could only be removed by going back down to the purple general purpose pad, then smoothing those scratches back out. I left the dirt on the cop in that picture because it made it easier to notice the pits (which I couldn’t get on the camera well after I had cleaned it off.) Suffice to say, that’s not a bad level of polish to be at, and the dirt left over from polishing does wash off.

That’s technically the end of the experiment. I found that using the same abrasive type at every level of the process made it easier to get a consistent finish. Now that I did have a smooth (mostly) surface, I took it to my buffing wheel to see how mirror I could get it.7 - Polish.JPG

The answer seems to be, super shiny!

After thoughts: there were lots of imperfections in the surface of the metal that I didn’t notice when I was using the Heavy Duty pad. The irony is, that the Heavy Duty pad is the one that is aggressive enough to remove those imperfections, but I didn’t notice them until I had already gotten up to the general purpose level, for that’s when it was glossy enough to really show off the blemishes. Since I was doing this partly as an experiment, and polishing is a colossal time sink, I didn’t go back down to fix the pits. Instead I continued on, since that cop looks better now than it ever has before despite its anomalies.

And it really was a time sink. I wish I had the presence of mind to think to record my hours. Suffice to say, it took a long time and I did it over the course of many days. Anyway, for a piece I intend to wear, I probably would have bounced back down to the Heavy Duty pad until I had the smooth surface I really wanted.  As is, I’m going to go work on all the splints, when I have time. In the future I’ll post an article on my re-assembly, or at least I’ll put a picture of the finished product somewhere for your viewing pleasure.

There is no one-true-way to do anything. But success comes from having multiple methods to fit your purposes. Hopefully this demonstration will give you another tool at your disposal to finish whatever project it is you’re working on.

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