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Old Jun 09, 2014, 04:38 PM
Raptor90
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United States, FL, Fort Myers
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Spray Can Basics

Trying to paint a glass fuse. Primer and color are same brand/type. Color dulls in sort of a marbling pattern minutes after applying. I thought it was humidity so painted indoors in climate controlled room. Same problem. What am i doing wrong?
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Old Jun 10, 2014, 08:30 AM
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Traverse City, Michigan
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Quote:
Originally Posted by raptor90 View Post
What am i doing wrong?
You may be doing nothing wrong.

Aerosols do not necessarily produce the showroom finish that many desire.

You haven't mentioned what brand of primer and top coat you are using. from your description, I have an idea, but I won't venture a guess.

Let us know, and we'll go from there.
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Old Jun 10, 2014, 05:18 PM
Raptor90
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I have painted more models than i can remember with spray cans. Even painted a few cars with moderate to excellent results, respectively. Just can't seem to have any luck lately with it. I thought it was the humidity but took it inside and got the same results with the addition of a smelly workshop. Primed with Dupli-Color sandable primer from Advanced Auto and painted with Dupli-Color "Perfect Match" cardinal red. The entire fuse was sanded ultra-smooth and looked great with the primer applied with no obvious issues. Only had problems when the color was applied. The primer had cured for more than 24 hours. Hope that is enough information to draw a response.
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Old Jun 14, 2014, 07:39 AM
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Did you sand the primer before applying the color coats ?

I frequently use Duplicolor primer. I like it. It comes in handy when I don't much to prime, and I'm too lazy to use my spray gun.
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Old Jun 14, 2014, 03:38 PM
Raptor90
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I did sand the primer before applying the color coat and it looked great. I tried to upload pics but my camera was confiscated for other uses. I will try to get some.
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Old Jun 14, 2014, 07:08 PM
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It sounds like you did things right.

Did you apply a single, heavy coat of color, or a bunch of light coats, waiting several minutes between coats ?
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Old Jun 15, 2014, 04:46 AM
Raptor90
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United States, FL, Fort Myers
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I applied several light coats of primer, sanding between each coat. I observed the re-coat window between coats and let the final primer coat cure for about 72 hours before applying the color coat. I think it must be something reacting to the new paint. I will try to upload the pics so maybe someone will recognize the problem.
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Old Jun 15, 2014, 06:56 AM
Raptor90
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Finally, some pics! Hope someone can figure it out.
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Old Jun 15, 2014, 07:16 AM
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Sorry if I missed it but is this a new fuse or a repaint? Was the fuse gelcoated? Any filler where the blotching is? When dry, are the blotchy areas hard or softer than the other painted areas?

Looks like the topcoat is soaking through the primer or into the fuse itself. I've had this happen on different types of surfaces myself especially on new fiberglass that I found wasn't mixed properly before using or where filler was to smooth out imperfections. Most frustrating! I would reccommend sanding most or all of it off and using a sealer underneath before topcoating. The more topcoat you apply to try to fix this may only cause more problems.

Good Luck!
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Old Jun 15, 2014, 12:33 PM
Raptor90
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United States, FL, Fort Myers
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Originally Posted by SteveSw View Post
Sorry if I missed it but is this a new fuse or a repaint? Was the fuse gelcoated? Any filler where the blotching is? When dry, are the blotchy areas hard or softer than the other painted areas?

Looks like the topcoat is soaking through the primer or into the fuse itself. I've had this happen on different types of surfaces myself especially on new fiberglass that I found wasn't mixed properly before using or where filler was to smooth out imperfections. Most frustrating! I would reccommend sanding most or all of it off and using a sealer underneath before topcoating. The more topcoat you apply to try to fix this may only cause more problems.

Good Luck!
This is a repair and re-paint. I am quite sure that it was painted in the mold. There was some filler used in a couple of places where the repairs were made but it is dulling in places where the original finish was not disturbed except for final sanding before an initial coat of primer/sealer. After that was sanded smooth the final coat of regular primer was applied and then the color coats.
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Old Jun 15, 2014, 03:46 PM
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Did you use a surface prep solution prior to spraying the primer/sealer. Something like a wax, grease, and silicon remover?

If the model was painted in the mold, then the paint surface was probably contaminated with mold release, and wax.

A wash with a surface prep solution before working on the model, and just before spraying the sealer/primer coat, would remove those contaminants. Sanding will only spread the contaminants, it won't remove them.
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Old Jun 15, 2014, 04:49 PM
Raptor90
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United States, FL, Fort Myers
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Originally Posted by Ken Barnes View Post
Did you use a surface prep solution prior to spraying the primer/sealer. Something like a wax, grease, and silicon remover?

If the model was painted in the mold, then the paint surface was probably contaminated with mold release, and wax.

A wash with a surface prep solution before working on the model, and just before spraying the sealer/primer coat, would remove those contaminants. Sanding will only spread the contaminants, it won't remove them.
Due to a heavy workload i spent months glassing the repairs and filling/sanding until i thought it was ready for paint. I guess i got anxious and never even thought about cleaning the surface. The vertical stab was not damaged and was only lightly sanded so i figured it couldn't be anything i applied that caused it to dull. It actually looks as bad or worse than the rest of the fuse. It looks like you may have answered my question. I am still wrestling with a heavy workload so it appears that i will either need to spend many more weeks sanding back down to the original surface or send it to a professional like i should have done in the first place. This is not an inexpensive jet and i wish i had done that anyway. Thanks for all of the advice. I do appreciate the help from all of you. Hopefully someone else has learned something from this.
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Old Jun 15, 2014, 05:46 PM
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If you decide to strip it, take a look at paint remover.

Make sure that you thoroughly clean the model afterwards, though.
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Old Jun 15, 2014, 06:44 PM
Raptor90
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At this point i will most likely just give it to a pro but if i do decide to try it again i will certainly consider using a remover if i can be sure it will not harm the fuse.
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Old Jun 16, 2014, 11:12 AM
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Most chemical strippers aren't "safe" for fiberglass, in other words it will harm the fiberglass. Somewhere in the instructions it will say not to use the stripper on a list of items, and one of them will be fiberglass.

Some chemical strippers are formulated to be safe when used on fiberglass, after all someone wanting to strip their Corvette, wouldn't want the body to dissolve, along with the paint. These strippers will usually state that they are safe, or compatible, with fiberglass, where it is easily seen.

Your problem is that most newer fiberglass model aircraft fuselages, aren't actually fiberglass. They are epoxyglass. Instead of using a Polyester Resin, and glass fiber, they use Epoxy Resin, and glass fiber.

Just because the chemical stripper says it is compatible with fiberglass, doesn't mean it will not harm your fuselage. Check with the strippers manufacturer before purchase, and ask if it is safe to use on Epoxy Resins.
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