Thread: Clear coat for polished parts

Yes, clear powder coating. I haven't ever bothered with steel parts, but have done some brass and it works well. It will maintain the finish to which you take the part when it's powder coated ie if you want it looking almost like chrome then it needs to be polished to that level THEN powder coated, as once the PC is on that's it!

Otherwise just polish with simichrome (sp?) and oil it every few weeks to keep the rust off.

Pete

Hello Bryan,
I have an aerosol can of clear Wattyl "Incralac" which Wattyl says is suitable for copper, brass and other metals. On the can it states that it gives a tough,clear coating, so I assume it may be OK for parts which are subject to some handling, but powder coating would probably be more suitable (and more expensive) for parts which are handled regularly.
Regards,
Russell

I have used auto acrylic clear coat on aluminum and steel with good result's. It's no good for something like a Morse taper etc, but if the part is only for looks it's fine.
I usually polish until it's where I want it, then wipe it down with thinners before painting.

You can buy it at the local auto store in cans for around $10-$15, just make sure you paint it on a clear day because if it's raining it will go cloudy.
It will last 3-7 years outside in the sun and a lot longer inside.

I had a bloke visit me that had a old restored ute with a aluminum trim around the back window that needed constant polishing or it would tarnish. I told him to mask it up and paint it with clear coat and he has never had a problem since and that was years ago.

Dave

Bewdy! Thanks guys.

Clear nitrocelulose laquer is a good thing, low build, goes off fast and can be removed very easily with thinner.....mirrortone sell it by the bicket or in small preasure pack tins.

Acrillic laquer is a bit harder wearing, and still disolves with thinner but not quite as easily as nitro.

and you can just keep going thru the various laquers, in clear.

It all depends on how long ya want it to last and at that point what ya have to do to clean & recoat.

cheers

For something like a handwheel that's subject to wear I wouldn't coat it with anything other than PC as I mentioned above. The reason is that most of the other finishes mentioned wear quite poorly. After a while you'll notice a line where the finish has worn away and no matter how hard you try you won't be able to do anything about it other than stripping and refinishing again. Look at the typical brass parts you buy and how in a few years they look quite bad, despite being clear coated.

I have powder coating facilities here, but I expect most don't. PC is an extremely tough coating, hence why it's used so widely in objects sold. If you can't powder coat I'd suggest you simply drag out the polish every 6 months, and keep well oiled between times

Pete

I used to be big into powdercoating at one time..thaught it was great...I've gone off it a bit lately

On polished parts, it will chip and flake very easily due to lack of a key.
Once the chipping starts it looks very old very quickly.
Then ya have the get the stuff off, a real pain.

If you use one of the evaporation cured laquers, once the stuff looks a bit sad, ya just wipe it off with solvent and recoat.

most people forget that with a little skill and a bit of speed you can apply laquer with a brush or pad too.

People have been doing it to high end brassware for decades and it works... sure beats having to polish ya brass name plates, hand rails and door knobs every morning before the customers arrive.

cheers

Originally Posted by soundman

On polished parts, it will chip and flake very easily due to lack of a key.
Once the chipping starts it looks very old very quickly.
Then ya have the get the stuff off, a real pain.

Chipping and flaking hasn't been my experience with it, it requires no more "key" than any other finish. Bicycle parts for example are polished aluminium and then clear powder coated. However I agree it is difficult to remove.

One problem I've found with trying to coat parts with a clear coating is that moisture is trapped under the coating and that eventually leads to corrosion you can see through the finish. The PC process heats the part to 200 C and this moisture is effectively removed as the finish cures. The observations of clear coated brass parts is valid, they look great in the store, but generally crap within a few years, much less if exposed to the weather, though of course the latter is not a concern to the OP. While manufacturers will use finish on other parts of a machine, the components subject to wear will be left bare metal for good reason.

Pete

I can tell you that the powder coater that I have been using for over 20 years sand blasts everything that is not clear coated, I have friends and assocaites that use other powdercoaters and they often comment that their stuff does not stand up as well.

I have seen plenty of stuff that has been solvent dipped / wiped, acid / caustic etched or whatever.....none of it stands up as well as a sand blasted item.

As for any polished part....if you are expecting any polished part to stay pretty long term AND have it used and handled.....there are only two things I have seen that stand up...stanless and good chrome plate.

Laquering any functional polished part is truly only a short term thing......this is the view the modern high end brass lovers understand.......if they laquer the stuff it stays pretty for weeks or months, maybe a year or more if it is not handled like a name plate instead of less than 24 hours.

cheers

I don't want to argue with you as it's not solving the OP's question. What I can tell you is that I do the powder coat myself so have first hand experience with the process, and it requires no more "key" than any other finish. Take a look around you, pretty much all the commercial products purchased, the product will be PC as the finish. White goods, domestic appliances, parts washers, etc etc etc, they are ALL powder coated, and virtually none will be "sand blasted" before finishing. Furthermore there are no shortage of polished parts that are successfully powder coated; the bicycle components I mentioned, wheel rims on cars, etc. All polished, all powder coated! The process works just fine. Clearly a finish will not adhere to a polished part as well as one that has been sand blasted, but to single out powder coating as inappropriate for this reason is simply wrong; the same principles apply to any surface finish! I've seen FAR more conventional paint flaking off sheet metal than I've seen powder coat, that's for sure!

The problem with PC, and I've been told the reason it's not used on vehicles (unless this has recently changed), is that if damaged it's almost impossible to repair successfully. Since it's an extremely hard finish, it may chip on impact, however that is precisely the same with any other hard finish. When I restored my lathe I added isocyonate hardener to give a harder and hopefully more durable finish, a decision I'm still not sure if it was wise, as it will chip if impacted. Unlike PC however the chips can be "touched up".

Parts can be sand blasted to provide a better key, just as they would be if a solvent based finish was used. The difference with the latter is that in lieu of sand blasting an etch primer can be used to provide the key. Personally I normally use an etch primer as a matter of course, just as I generally sand blast before PC, however not always (and clearly that's not possible with a polished part), I can honestly say I have NEVER had any of my powder coat flake. However it is absolutely critical that the product is spotlessly clean before applying the finish, I have heard of too many commercial powder coaters taking a "she'll be right" attitude to the process. That may be ok and they may get away with it using conventional solvent based finishes, but won't fly with PC as any impurities will come back to haunt you once the ovens come on!

I'm not suggesting that PC is the panacea for finishes, indeed the "novelty" of the finish has certainly worn off for myself and more often than not I'm just using a standard solvent based finish. Typically that's simply because at the time I can't be bothered setting up to PC, when really all that part needs is a rattle can or lick with a brush. For the OP, I'd again suggest that the best finish for his application is ... none!

Pete

Bryan, it might not be appropriate, but when I have polished steel that I want to keep rust free, I just paint on some Penetrol (Bunnings sell it). Dries to a hard clear finish and seems to last forever - well, I guess that's a bit of an overstatement, but nothing I have put it one has had rust or anything. I've used it on handrails and things like that.
Scott

Bryan,
Here's an old trick I've used. When I polish rusty steel I usually do it on a powered grinder with a wire brush fitted and I take it back till you have a steel gray burnished finish. If I don't want to paint it I have a bottle of Raw Linseed Oil which I coat a rag with and apply the Linseed Oiled rag to the steel and coat it with this oil and leave it over night. Any excess oil I wipe off the next day, or you can leave it but if you've coated the steel to thickly it will become sticky hence the wipe down the next day. The metal stays rust free for some time but not indefinitely. Much depends on the atmosphere in your work place. Eg. If you get a sea breeze etc. I've had tools I've done this to within my work shed that have been rust free for many many months. It's a relatively cheap way of protecting steel.
Cheers