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concerns on my paint job on engine case and head
Posted: Thu Nov 20, 2014 1:15 pm
by mikefealk
so i used rattle can Napa auto paint 1000 degree aluminum on the upper engine case and cylinder head. prep was good, soda blasted and cleaned with acetone. I sprayed 2 coats on both parts, and look pretty good. they have been curing in my house for 5 days now, and if i rub the paint with my finger, i still give a silver smudge on my hand. im concerned that this paint isnt going to fully cure? and if gas gets on it from the carbs it will wash it right off? do i need to blast it all off or put it in the oven or will the engine heat cure it or what? need to decide before i put motor back toghether. thanks.
Re: concerns on my paint job on engine case and head
Posted: Thu Nov 20, 2014 3:08 pm
by jabcb
Was a bit curious so I looked this up, but I would expect the experts to know more.
Duplic-Color has info on their website:
https://www.duplicolor.com/products/enginePaint/
https://www.duplicolor.com/pdfs/tips.pdf
The tips include: "Enamel paints have a recoat window … enamel must fully cure which usually takes about one week."
So that might be your answer & you just need to wait a few more days + perhaps a few more if your shop is chilly.
Re: concerns on my paint job on engine case and head
Posted: Thu Nov 20, 2014 3:24 pm
by Coyote
After 5 days it should be plenty dry. That's my biggest gripe about rattle can paint. I have found that Dupli-color aluminum paint is the only rattle can stuff that works really well. Dry to touch in 15 minutes and totally bullet proof in under 24 hours. See the thread "as opposed to polishing" in this section. Granted it's only good to 500 as opposed to 1000, but to me that's plenty. You're not painting exhaust pipes.
I think it's time to get that stuff off there and return any unused cans. Give Dupli-Color a shot. The head may exceed 500 but I doubt it. Dupli-Color is available in most automotive stores. I get mine at Advanced Auto.
Re: concerns on my paint job on engine case and head
Posted: Thu Nov 20, 2014 3:54 pm
by mikefealk
Crap I really don't want to blast the parts again do you think baking it in the oven would harden the paint I've heard that before
Re: concerns on my paint job on engine case and head
Posted: Thu Nov 20, 2014 6:26 pm
by Coyote
Sure wouldn't hurt anything to try the oven at maybe 350. Best get the wife drunk first.
Re: concerns on my paint job on engine case and head
Posted: Thu Nov 20, 2014 7:42 pm
by mikefealk
well it was in the oven about twenty minutes when the wife got home. she is not happy. all my fresh powdercoated parts all over the floor and the house smells like a chemical plant. they just never understand
Re: concerns on my paint job on engine case and head
Posted: Thu Nov 20, 2014 8:47 pm
by Cliff
mikefealk wrote:well it was in the oven about twenty minutes when the wife got home. she is not happy. all my fresh powdercoated parts all over the floor and the house smells like a chemical plant. they just never understand
I can relate!! Been there, done that!! Still get told about it! Over and over and over again!!
Re: concerns on my paint job on engine case and head
Posted: Fri Nov 21, 2014 3:39 am
by Suzukidave
Just wait till you get caught using the dish washer to clean engine parts

Re: concerns on my paint job on engine case and head
Posted: Fri Nov 21, 2014 7:13 pm
by mikefealk
thanks for the responses. i wish i had known that duplicolor was the best to use before hand. well i baked the case and head in oven at 225 for 30 minutes. seems to have hardened up a bit. i think ill just go with it instead of blasting it all off and repainting. can i do dupli color clear over this paint? im not sure if its a laquer or enamel it doesnt say. but it does say you can recoat at any time (no window) so i assume it is laquer
Re: concerns on my paint job on engine case and head
Posted: Fri Nov 21, 2014 9:27 pm
by 2strokelove
+1 on the Duplicolor. Works fantastic but be careful when spraying, keep moving and very light coats. This stuff runs super easy!!
Re: concerns on my paint job on engine case and head
Posted: Fri Nov 21, 2014 9:52 pm
by Coyote
I know you hate waiting around, but better safe than sorry. Put some of that Napa paint on something you really don't care about. Let it harden or bake it. Then try the duplicolor on the test piece
Re: concerns on my paint job on engine case and head
Posted: Sat Nov 22, 2014 11:55 am
by mikefealk
hell i dont know what to do. i guess i could wash it off with acetone, repaint it with duplicolor...is that stuff gas resistant? or i can leave on what ive got? maybe its fine i dont know!!!
Re: concerns on my paint job on engine case and head
Posted: Sat Nov 22, 2014 2:50 pm
by yeadon_m
Mike,
You sound like me
You won't sleep, knowing it may not be OK. Take the non-hardening paint off and do it the way you wished you had. Its annoying but so much easier to do it now when the bike's in bits. Imagine your rebuild and the paint isn't right? a few bucks and some of your time, you'd trade it 10x after the fact.
Cheers,
Mike
Re: concerns on my paint job on engine case and head
Posted: Sat Nov 22, 2014 7:37 pm
by mikefealk
Maybe I'll just strip it with aircraft cleaner and leave it bare f it or try high heat clear over the existing paint
Re: concerns on my paint job on engine case and head
Posted: Fri Nov 28, 2014 9:40 am
by Eddie
not sure which paint you used, I just read it and forgot , I cant believe im getting that bad, ohh well , im not sure but some of that high heat paint requires a high heat primer especially on bare metal , read the can and see if it needs primmer, I personally don't like rattle can stuff anymore it all just seems way less durable than it used to be, dupli color is pretty good but iv never used it on a motor so not sure. I like the high heat enamel stuff because a lot of it is chemical resistant, but like what was said in the other post you have to put light coats and it doesn't fully cure until it has gone through a couple of heat cycles, but I have used it on other parts that don't get hot and it did cure and worked perfect, I think the problem is that for aluminum it might need a primer first but im not sure, just my two cents,,,,,,