How do I protect turned copper finish?

[kyfho]

Working on a small project for a friend that will end up being some copper weights for her craft projects.

I really like the look of turned and patterned copper and would like to be able to retain that nice, highly polished copper finish.

I'm looking for ideas for coatings that I can apply to the finished weights that will be long lasting and wear resistant.

The weights are to hold her cloth and paper patterns flat while she marks and cuts the templates.

I'm also looking in to possibly nickel plating some just for variety.

Any suggestions are highly appreciated.

[Tungsten dipper]

Clear powder coat.

[Tom S]

I've had bad results powder coating copper. We sent a batch of 18ga copper sheet to be powder coated, and every piece came back a slightly different orange hue and lost it's luster. The best we could figure was that the oven temperature was just high enough to cause some oxidation before the powder cold seal it, and once the powder sealed it that color was now locked in. We ended up stripping, re-brushing, and lacquering the sheets - which has held up well to this day inside a cold/wet environment.

[polaraligned]

Mohawk makes a lacquer for brass.

[Mcgyver]

I thought at first powder coating a great suggestion, but reading Tom's comment started me looking about. The following makes it pretty clear there will be oxidization at 200C (they're be oxidation at room temp, albeit slowly) and that the dept is very much time dependent, i.e. the longer its a temp the more the oxidization will effect the appearance

https://www.scielo.br/scielo.php?scr...lng=en&nrm=iso

Lacquer works but is not very durable. Better than nothing, but it really excels on the mantle piece. You have to hunt for a good lacquer, the big box stuff is absolute garbage. Good clock repairmen use lacquer as do musical instrument repairmen. If found the good stuff at a vendor catering to horology. It can be dipped or sprayed, I usually airbrush it slightly diluted.

[CCWKen]

I see the oxidation frequently. I use copper strips for backing up welds to auto body fabrication/repair tasks. Probably no need but I wire wheel the strip(s) before use. It usually takes quit a bit of Course Wheel brushing to get to shinny copper. I suspect it's from the heat of welding. The copper strip is always discolored afterward.

[mklotz]

Rustoleum Crystal Clear Enamel

[thaiguzzi]

Metal polish and elbow grease once a month.

[BCRider]

I've tried a few different clear coatings on metal plates of various sorts over the years. You clearly want to maintain the specular look of the machined surface for the look. I found that clear lacquer worked well for this on brushed or turned aluminium. Never tried it on copper but Clickspring dipped or sprayed his brass parts for the clock he made with clear lacquer. It's near impossible to find clear lacquer in aerosol cans any more but you can buy it in regular cans as "brushing lacquer". That might be worth a try.

I did find that Krylon clear seemed to be the "best" of the worst at making the specular shine of the brushed or machined surfaces turn dull. So that would be a last suggestion.

I've done a couple of turned pieces with oil based clear polyurethane as well and that seemed to maintain most of the nice specular look from the machining. So that might be an option.

[mickeyf]

There is a clear acrylic spray you may find in art supply stores. I have not used it on copper, or on anything long enough to know if it will last for years, but it's quick, simple, and a possibility.

[CCWKen]

"Rustoleum Crystal Clear Enamel" Hmmmm. Really? I wouldn't paint my garbage cans with Rustoleum anything. The stuff never dries. At least not down here in south Texas. You'd think with the heat, it'd dry coming out of the can. Must be the humidity.

[nickel-city-fab]

Dip them in walnut oil and wait 6 weeks. Walnut oil was favored by the Old Masters because it remains optically clear (doesn't yellow) and it dries nearly as tough as linseed, which is what they use for most paints.

[nickel-city-fab]

"Rustoleum Crystal Clear Enamel" Hmmmm. Really? I wouldn't paint my garbage cans with Rustoleum anything. The stuff never dries. At least not down here in south Texas. You'd think with the heat, it'd dry coming out of the can. Must be the humidity.

Nah, Its just as humid up here (I'm wedged in between two of the Great Lakes) and Rustoleum dries just fine. Takes a while is all -- I usually get the tractor enamel and let it dry for a couple months indoors -- I usually do all the painting jobs in the winter though. , it comes out rock hard.

[Galaxie]

I quit using Rustoleum because the damn cans kept clogging up inside the pickup tube.

[Fasttrack]

The good thing about lacquers is that they are easily repaired. If the part is handled a lot, the lacquer will wear off but the part may "polish itself" just by being handled regularly. And, if not, it's easy to clean it and re-apply a lacquer. I've seen too many decorative metal things that were coated with "more durable" coatings like powder coat and polyurethane that look awful after a few years of use because they chip or peel in areas where they are handled a lot. Unlike lacquer that blends really well when re-coating, these coatings have to be removed before being repaired.