Nickel Plating on Aluminum

[WilliamDahl]

I have an AR lower and upper that are bare non-anodized aluminum. Is it possible to have these nickel plated so that I could create a silver AR? Can I just take it to a local shop that does nickel plating of other items or is that anything special that I should be concerned about? Should the interior of the parts also be nickel plated?

[375RUGER]

never heard of that.
If you want a shiny finish, I would prep the aluminum really well, polish every nook and cranny till it looks like what you want. Then take it and get it clear anodized.
If you do a high polish, handle it only with cotton gloves and transport it wrapped well to prevent any scratches.
If you want it matte finish then bead blast before clear anodize will probably be the way to go. Don't bead blast it very hard.
If you are unsure about something, prep a scrap piece of alumumum and get it done first to see if you will like it before you do the real thing.

[David2011]

A friend has a nickle DPMS AR-15, so there must be a way. A quick search came up with these pages, searching for electroplating aluminum.

http://www.dalmar.net/aluminum_plating.htm
http://www.caswellplating.com/
http://www.finishing.com/123/11.shtml

Not a recommendation to try it yourself, though. Lots of opportunities to come in contact with very bad chemicals.

David

[btroj]

I think the shine would be distracting. I personally like a matt lack finish on an AR.

[WilliamDahl]

I think the shine would be distracting. I personally like a matt lack finish on an AR.

I already have an Evil Black Rifle, I'm thinking about creating an Evil Silver Rifle. :)

OK, if I had been able to buy a stainless lower and upper at the time that I bought the non-anodized upper and lower, I would have, but I couldn't find one back then. I want to create a "safe queen" with stainless / nickel and walnut furniture on it. Hey, at least it is not one that is pink anodized...

[Multigunner]

Don't know if it might be an issue but when I first got my S&W model 37 it had been buried in the mud of a lake bottom for many years, and while the plating on the steel barrel (possibly chromed rather than nickeled) was mostly intact the nickel plating on frame and cylinders had turned into a thick crusty deposit that could be scrape away with a fingernail.
The cylinder was the early alloy piece, replaced on most of these later on.

An article on South American guerilla weaponry captured in raids showed a couple of early M-16 rifles with the front of the magazine well corroded away. Apparently the early lowers were very prone to corrosion both from salt water and even more so from human sweat. Where ever the hands maintained contact with the metal for hours at a time the alloy would begin to etch away.

I figure this was likely a matter of electricity caused by an electrolyte working on the metal.

Also Nickel plating will be attacked by copper solvents, the process speeded up if stored in a sheepskin lined case.
Hoppes No.9 is a major cause of loss of nickel plating on old revolvers.

I'm sure there are forms of nickel plating that are more durable, one should investigate these before commiting to plating.

[W.R.Buchanan]

When plating aluminum you must first plate with copper, then the nickle goes on.

When chrome plating aluminum it is copper, nickle, chrome.

If you polish your receiver and then try to clear anodize it, the etching part of the anodizing process will flatten the polished finish. IE it will not be as shiney any more. This is just part of the game. Any anodizing you see that is very shiney(mirror like) has actually had the anodizing buffed!

Also any plating that involves deposition of another metal to the part will change dimensions. This is especially a problem on holes and really bad on holes with threads. On holes it closes the hole 2X the depth of the coating. IE if you deposit .001 of copper it will close the hole .002. On threaded holes it is 4X (both sides of the thread vee) and that ususally causes a problem.

When machining parts that must be plated allowances have to be made for the plating during the machining process. This is also the reason why they make oversize taps, so the threads are oversized to compensate for the plating. every critical dimension must be adjust to compensate for the plating.

This idea is much more complicated than it looks from the outside, and there are many places you could go wrong. Maybe have a look at silver paint.

Randy

[WilliamDahl]

Also any plating that involves deposition of another metal to the part will change dimensions. This is especially a problem on holes and really bad on holes with threads. On holes it closes the hole 2X the depth of the coating. IE if you deposit .001 of copper it will close the hole .002. On threaded holes it is 4X (both sides of the thread vee) and that ususally causes a problem.

When machining parts that must be plated allowances have to be made for the plating during the machining process. This is also the reason why they make oversize taps, so the threads are oversized to compensate for the plating. every critical dimension must be adjust to compensate for the plating.

This idea is much more complicated than it looks from the outside, and there are many places you could go wrong. Maybe have a look at silver paint.

So, does the nickel plating process on aluminum cause a lot more increase in plating thickness than anodizing?

[John 242]

http://castboolits.gunloads.com/imagehosting/thum_15334f308f91a7c9d.jpg (http://castboolits.gunloads.com/vbimghost.php?do=displayimg&imgid=3821)

This AKM/S is chrome plated steel, not aluminum but I think it illustrates, kind of sort of, what you're wanting. Besides, I think this is a cool picture.

[paul h]

So, does the nickel plating process on aluminum cause a lot more increase in plating thickness than anodizing?

Anodizing is not a plating process. Anodizing converts the surface of the aluminum to aluminum oxide, and then the oxide has a die is typically added which yields the various colors and thick porous anodizing is also sealed. Anodizing seldom adds significant thickness to the part being anodized.

[W.R.Buchanan]

Generally speaking plating does deposit more than anodizing. Plating itself is deposition process IE: you are depositing one material on top of another. Anodizing is more of a "surface conversion process."

Plating does build up thickness depending on how long you leave it in the tank. You can put several thousandth's on a part easily. Chrome plated barrels are machined oversize, and the plating brings them to size after the fact.

Regular Type 1 Anodizing, also known as cosmetic anodizing, doesn't add any significant amount of thickness. A couple of tenths at most.

Type 3 Anodizing or Hard anodizing does add thickness. Typically it penetrates the material the same amount that it builds up on the outside. If you call out .001 deposition then you will get .001 on the outside and .001 penetration into the material, which makes it very durable. An aluminum frame on a pistol that is hard anodized will generally wear the steel slide out before the frame..

I once had a job where the parts I made didn't comeout right, because my boring bar did not repeat worth a damn, The holes I was boring had to be all the same size +/- .0001 after anodizing. They were too expensive to just run over so,,, I measured all the holes and segragated the parts into all of the different sizes and then the plater put different amounts of anodizing onto the parts which brought all of the holes to the same size. Saved my **** big time!

IF you are hard anodizing and there are holes involved you must machine the holes oversize to compensate for the anodizing, and then specify exactly how much deposition you want. You must also allow the same amount on all critical dimensions because you can't put different thicknesses of anodizing on the same part,,,, at least easily.

You can't just fix it after the fact either because Aluminum Oxide is about 78 RC, and will size a reamer or drill or other cutting tool instantly!

Hope this helps your understanding of the process.

Randy