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  #1  
Old 03-14-2015, 08:37 PM
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carrollcw carrollcw is offline
 
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Default How to prep your cowling for paint

So, I need to prepare my cowling for paint. I have tried the vans recommended method of mixing epoxy resin with acetone, but that is not working for me. Just gums up the sand paper. I have heard there is a good product to apply to the cowl to get a uniform finish, but cannot figure out what it is. Recommendations?
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Old 03-14-2015, 08:41 PM
Kyle Boatright Kyle Boatright is offline
 
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You might look into Smooth Prime, which is water based acd can be rolled on, then sanded.
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Old 03-14-2015, 08:59 PM
BobTurner BobTurner is offline
 
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Adding micro to the epoxy mix will make it easier to sand.
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Old 03-14-2015, 08:59 PM
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There is no one step process for filling the pinholes. I mixed up thick epoxy and micro slurry and squeegeed it into the pinholes with a single edge razor blade. Sand and repeat. Then I used the UV Smoothprime sprayed on several coats and sanded smooth. Repeat as needed.
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Old 03-14-2015, 09:05 PM
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carrollcw carrollcw is offline
 
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Does smooth prime really need to dry for 3 weeks prior to prime and paint?!?!?! Any other options?
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Old 03-14-2015, 10:43 PM
denbobp denbobp is offline
 
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Default Cowling prep

when I was at a recent EAA meet a fellow giving a demo mixes wallboard paste and water into a glue consistency then squeegees it on. After that he sands and only dry wipes off the dust from sanding, primes over that and repeats if needed. The sanding dust stays in the pinholes and becomes hard when covered by primer. That's how I'm going to do mine when I get that far.
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Old 03-15-2015, 05:05 AM
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MikeyDale MikeyDale is offline
 
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I had better luck wet sanding the epoxy skim coats......My main gear fairings had pinholes galore after shooting one coat of Stewart Systems Eko Prime. As an experiment, I dipped my plastic spreader in Eko Prime and then spread it on the fiberglass and worked it in back and forth in the holes. I eventually got all the holes filled in but there were some stubborn ones that I had to keep going back and forth over. The nice part about using primer like this is you can see the holes open back up if you don't get them filled. You can also sand in about an hour as opposed to waiting till the next day.

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Old 03-15-2015, 07:31 AM
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rleffler rleffler is offline
 
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I used smooth prime on my pants. Yes, yo do need to wait three weeks for any outgassing to stop. While doing my pants, I read danh's recommendation. I used epoxy, not diluted. Just make sure to get it as thin as possible. I did three coats. As long as you keep the epoxy thin, sanding isn't too bad. Results were m ugh nicer and quicker to obtain than using the smooth prime.
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Old 03-15-2015, 08:37 AM
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DanH DanH is offline
 
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Quote:
Originally Posted by carrollcw View Post
So, I need to prepare my cowling for paint. I have tried the vans recommended method of mixing epoxy resin with acetone, but that is not working for me. Just gums up the sand paper.
At some risk of insulting the inhabitants of the Mother Ship, thinning epoxies at random with anything is really dumb....Russian roulette with chemistry.

Do some reading at the producer tech level. There are base epoxy resins thinned (by the original producer) with acetone, MEK, toulene, xylene, and other solvents. The solvents were not selected by spinning a bottle.

There are base epoxy resins that contain no solvents at all, and the producer did not intend that any be used....viscosity is adjusted by controlling the molecular weight of the finished product.

If you want a low-viscosity epoxy, just buy it. I've used lots of System Three Clear Coat, but there are others; just look at the viscosity spec.
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Old 03-15-2015, 10:05 AM
harleyl harleyl is offline
 
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Many years ago I used to do a lot of Corvette repair and restoration and we used a product called Featherfill to block the waves out of the fiberglass. It also worked very well for the everpresent pinholes. Could be described as a sprayable polyester filler (read bondo). Can be blocked with 80 grit or finer and can be topcoated with any quality primers. Haven't finished my cowling yet but I will try it when the time comes. Maybe someone on the forum has tried it on their epoxy parts and can give a report.
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