Clear Coat Questions

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Valor

Sr Member
RPF PREMIUM MEMBER
So, I'm having trouble with the clear coat I'm using on my Captain America shield. Specifically where I'm laying it over pain aluminum. I'm getting a ton of white smudges forming under the clearcoat after a few days. The smudges are under the clear, and cannot be buffed out. I've attached an image that shows what I'm talking about. You have to angle the piece at a certain view to see it.

This has happened twice to the back of the shield. I've stripped the back twice and recoated and they reappear.

I clean the metal with acetone and seal with a Laquer, although I have tried an acrylic as well. I'm thinking MAYBE I'm clearcoating too soon and the acetone is leaving a residue that I'm sealing in.

I'm going to try to leave the metal dry for a couple days after cleaning with acetone. See if that helps

Anyone have any ideas?

Smudges are forming on the front of the shield now. I want to figure this out before I strip the front of the shield and start over :(
 

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terryr

Sr Member
You should goggle 'clear coat crazing'. Clear coats are common on cars now. Also called blushing or clouding.

I know temp and humidity can cause stuff like that.
 

Valor

Sr Member
RPF PREMIUM MEMBER
Thanks for the follow up. I Googled for a good hour on "crazing" ... seems like a catch-all term for clearcoat failure. What's weird with my situation is the clear looks fantastic after applied ... for maybe a week or more. THEN the clouding spots come in.
 

mvmagic

Active Member
RPF PREMIUM MEMBER
To me that looks almost like grease/oil on the surface of the shield. Have you properly cleaned it before you clear-coat? When I coat metal, I degrease with a degreaser and wipe with acetone just before I coat.

Other options that come to mind are humidity (possible you think?) and physical contact with something during curing.

Whats your clear-coat? One component, two component etc.?
 

Valor

Sr Member
RPF PREMIUM MEMBER
My process has been clean with acetone then clear. I'm just using rattle can lacquer.
 

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dropshipbob

Sr Member
Maybe wipe the metal off with a damp cloth after the acetone has dried and let the whole thing sit for a week or so?
 

mvmagic

Active Member
RPF PREMIUM MEMBER
And you are using raw acetone, right? Nothing with additives, such as nail polish remover? (just checking!) Acetone in itself can leave a residue on a surface. I cant remember having such a problem with acetone and clear coat myself, but perhaps your clear coat reacts to the residue.

I would use isopropyl alcohol (rubbing alcohol) instead of acetone in this case. It is a better degreaser than acetone and I think it doesnt leave any residue (I could be wrong though).

If IPA doesnt work, then its a curing problem with the lacquer.
 

Aragorn

Member
You might want to use 100% isopropyl alcohol (rubbing alcohol) that you can get at a hardware store.

The stuff you buy from the pharmacy usually only has 40%alocohol and the rest is water and moisturizer for your skin.
 

mvmagic

Active Member
RPF PREMIUM MEMBER
Oh yes, good point Aragorn!

100% IPA is also sold at gas stations as a gasoline additive against ice. The one I use is just called "anti-ice". Just check the label it is pure isopropanol. At least here, 100% IPA sold as anti-ice is cheaper than the hardware store stuff-or the 100% IPA pharmacies here sell. 5$ for 100ml 100% IPA at a pharmacy, 5.20$ for 1000ml 100% IPA at a gas station!
 
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Valor

Sr Member
RPF PREMIUM MEMBER
Thank you, thank you everyone, These are great suggestions. I suspect, at this point it was me using nail polish remover acetone, then sealing in the residue. I'm running some tests now.
 

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mvmagic

Active Member
RPF PREMIUM MEMBER
I'd say thats the problem right there! There's usually oil in nail polish remover and thats likely the culprit and not the acetone residue in itself. Try 100% IPA and I am sure its gonna be just fine!
 

Rylo

Master Member
RPF PREMIUM MEMBER
After you get the shield clean, try Krylon tripple clear acrylic.

You may be clouding up from laying on the coats too thick and fast. By the way, stick with straight acetone and wear gloves when handling the metal; otherwise, your fingerprints (oils) will show up as smudges under the coat.

-Rylo
 

Chris Fields

Well-Known Member
RPF PREMIUM MEMBER
I was just about to ask if you were using nail polish remover over plain acetone. I'm pretty sure that is the cause. I get my acetone from homedepot or lowes in a large can.
 

Valor

Sr Member
RPF PREMIUM MEMBER
Just to clarify, check out the pics I posted. The smudges are only visible at a certain, extreme angle. Otherwise the finish looks crystal clear. So it's not clouding from too thick. And there is no perceivable smudges in the color areas of the shield. Only the clear. ... I think the bad acetone is the answer. Along with my own impatience.

So, if this resolves it, here's the plan with my shield. I'm going to attempt to remove the clear coat from the clear strip only. and reclear only that stripe. I really don't want to strip the whole shield. I'll need a steady hand with the acetone and some q tips.

Thanks everyone for talking this trough with me. Love the rpf!! well, I mean the thereplicapropforum .. well, you know what I mean :)
 

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Chris Fields

Well-Known Member
RPF PREMIUM MEMBER
I have had to remove either all of the blue paint, or all of the inner red ring paint before, so I understand. Acetone and a lot of paper towels, and the steady hand, work very fast. :)
 

Aragorn

Member
Also one other thing to note about Isopropyl alcohol; when you buy a bottle with 100% content it will work like a treat initially, but after a while when you have opened and reopened the bottle a few times, the alcohol actually dissolves some air moisture so when you are spraying it on, you are actually spraying on some water that do not evaporate as fast/easily as the alcohol and it may leave water stains if you do not buff the surface with a clean cloth after spraying.

But this water stain is not very obvious, you can only see it when you hold it up at an angle against a light source.
 

Valor

Sr Member
RPF PREMIUM MEMBER
Okay, this is ridiculous. Here's what has happened to the back of my shield after 3 weeks. The spots coincide with the places where the leather harness touched the clear-coated metal. There's also spots elsewhere. At this point I'm following the advice of some other posters that think it might have been residue left from the nail-polish-remover acetone I used to clean the metal before I cleared it ... So I'm stripping the back brackets (again) and using paint store acetone. Everytime I think I'm done futzing with this shield, something drags me back in!

I wanted to share, see if anyone has encountered anything like this.
 
That's a common problem when a clearcoat is directly applied to the bare metal.

Also, I would refrain from using acetone, since it is very aggressive. Just use anti-silicone degreaser like they use in a body shop.

The only clearcoat that is made for bare metals is the zapon clearcoat. Dupli Color makes a zapon-spray though.It might not be as shiny as a 2K polyurethan clearcoat, but you can buff it to that shine. Always use thin layers.

Thomas
 

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