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Old 12-15-2011, 10:58 AM
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Default Paint problems

I need some help with a paint problem.

We recently pulled off some old decals on a 1988 International semi door. The decals had bubbled the paint and so we sanded the door down smooth, to the bare metal (aluminum) in some places.

Sprayed one coat on the door (rattle can) and let it dry 24 hrs. Finish looked ok, a little rough, but ok. The hired man put a second coat on (heavy) and it immediately started to get an "orange peel" texture to it in places.

Any idea what causes this?

I have re-sanded the door down, and took most of the new paint off to get all the texture out.

Would it help to use primer and fine sand it before doing it again?

Thanks!
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Old 12-15-2011, 11:25 AM
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Default ReCoat Window...

Bet you got some serious wrinkle or alligatoring as the new coat attacked the partially cured one under it....

Spray can enamels have what they call a recoat window. Here is some info from DupliColor....here is an excerpt..

7. Recoat: Take note of the type of paint you are applying. Lacquer or Enamel.
• Enamel paints have a recoat window. A recoat window means you only have an allowable time frame in which you can apply each coat of paint. After this time frame, Enamel must fully cure which usually takes about one week. The surface must then be scuffed before another coat is applied. Dupli-ColorĀ® Enamels have a 1 hour recoat window.
• Lacquer paints do not have a recoat window. You can reapply lacquer at any time.

8. Overcoat: Enamel vs Lacquer
• Lacquer CAN be applied over Lacquer
• Enamel CAN be applied over Enamel
• Enamel CAN be applied over Lacquer
• Lacquer CANNOT be applied over Enamel
• If you are unsure of the surface you are recoating test a small inconspicuous area for paint compatibility.

http://www.anthonythomas.com/garage/...ad.php?t=15346

There should be some RECOAT guidelines on the can of the paint you are using.....
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Old 12-15-2011, 12:37 PM
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Did you clean the bare metal well with mineral spirit or laquer thinner before painting. Other wise I think H80N gave some great insight too.
You might need special primer on aluminum. We have used some "Etching Primer" on aluminum rails in the past.
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Old 12-15-2011, 12:43 PM
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I think we may have waited too long. It did act like the new paint was pulling up the 1st coat, especially where he put it on thick. We did have the surface wiped down with mineral spirits, so it should have been clean.

I will read up on primer on aluminum. Maybe I will mix up some "real" paint and spray it on like it should have been done in the first place, and forgo the rattle can. (I figured it would take longer to clean the gun than to do the project, so we cheated)

thanks for the insight
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Old 12-15-2011, 01:31 PM
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most manufacturers provide recoat info on their container... if you can find the miniature english language version on the can... you may need to read it with a magnifying glass........
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Last edited by H80N; 12-15-2011 at 02:25 PM. Reason: spelling
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Old 12-15-2011, 03:35 PM
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AL must be primed with zinc chromate if you want a durable finish.
Special AL paint formulations can also be used - you will not get those at the local paint store
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Old 12-15-2011, 04:59 PM
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DD also try laquer thinner instead of the mineral spirits. Might help adhesion. I also agree with a primer over the bare metal.
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Old 12-15-2011, 08:27 PM
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DD when I repainted my 1970 Starcraft Jupiter boat . I was told by " the old boat guys " to use a self etching primer on " bare " aluminum and then paint with regular paint afterwards . I rolled and tipped rustoleum on it and it came out great . I got the etching primer from NAPA as I recall.


Rick
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Old 12-16-2011, 08:13 AM
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Quote:
Originally Posted by rickairmedic View Post
I got the etching primer from NAPA as I recall.Rick
I have used the rattle can version of that primer. Stinking damn stuff isnt it?
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Old 12-16-2011, 08:51 AM
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Sounds like solvent entrapment.
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