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-   -   Cowl painting question (https://vansairforce.net/community/showthread.php?t=158253)

Charles in SC 03-01-2018 11:55 AM

Cowl painting question
 
I have the fiberglass parts about ready to paint. This paint is just to protect the material until I have 40 hours flown off and can take the plane to get a real paint job. I have read that the final paint shop will probably remove whatever paint I apply to get through the 40 hours. What are some paint s that I should consider? I was thinking Stewart System rather than a 2 part epoxy because it would be easier to sand off. Any input will be appreciated.
Thanks in advance!

bkervaski 03-01-2018 12:12 PM

Any minor flying damage to the fiberglass would be trivial to repair vs removing all that paint. I say leave it as-is and fly it like you stole .. er .. built it! :D

az_gila 03-01-2018 12:24 PM

Quote:

Originally Posted by bkervaski (Post 1243054)
Any minor flying damage to the fiberglass would be trivial to repair vs removing all that paint. I say leave it as-is and fly it like you stole .. er .. built it! :D

Maybe, but I would be more concerned about oil/grease soaking into the fiberglass surface than minor damage.

Check with your painter but two local guys told me to use a two-part epoxy and they will sand it (maybe all off, maybe just scuff it) before they painted.

Any non-epoxy primer would probably give a more porous and absorbent surface.

YellowJacket RV9 03-01-2018 12:25 PM

Flew for two years with Stewart ekoprime only on the fiberglass. Plane is finally at paint shop now, and it was all easily removed.

Chris

Raymo 03-01-2018 01:52 PM

I painted the inside with a two part primer and covered it with reflective heat shield from Vans - to protect from oil/fuel. The exterior is still bare after 150 hours and a little over a year.

Carl Froehlich 03-01-2018 02:02 PM

Don?t forget fiberglass and ultraviolet light do not mix well. Put something on it.

This is what I do for flying before final paint:
- Prep all fiberglass to fill pinholes per the Van?s instruction.
- White two part epoxy primer on the inside of the cowl (e.g. PPG DP48LF). Two coats. Do this before first engine start.
- Van?s stick on aluminum heat shield on the inside of the cowl in the obvious places (check for discolor after the first few flights and add as needed).
- One coat of PPG epoxy primer on outside of the cowl and all fiberglass.
- One coat PPG single stage paint in your choice of color on top of the primer. I find a medium blue goes well with the rest of the plane in bare aluminum.

Reasons:
- Anything you can do to prep the glass will be appreciated by your painter (especially if that painter is you). He might even drop the price a little as he?ll see the PITA fiberglass prep is well started. The primer and top coat paint will also give the paint guy material to block sand - that will only improve the final product.
- Even though you plan on painting right after the flight test program, odds are you will be flying like this for some time. The simple extra step of adding a coat of color on the fiberglass will make it look worlds better.

Carl

lr172 03-01-2018 02:56 PM

Quote:

Originally Posted by az_gila (Post 1243055)
Maybe, but I would be more concerned about oil/grease soaking into the fiberglass surface than minor damage.

Check with your painter but two local guys told me to use a two-part epoxy and they will sand it (maybe all off, maybe just scuff it) before they painted.

Any non-epoxy primer would probably give a more porous and absorbent surface.

+1

Most non-two part (i.e. catalyzed) paint will be porous and won't help with liquid contaminant intrusion of the fiberglass. Go to the local paint store and get a lower cost epoxy primer and spray two coats on.

Also, some airborne contaminants can be just as much of a problem for paint adhesion as oil.

Larry

az_gila 03-01-2018 04:25 PM

Quote:

Originally Posted by Carl Froehlich (Post 1243074)
Don?t forget fiberglass and ultraviolet light do not mix well. Put something on it.

This is what I do for flying before final paint:
- Prep all fiberglass to fill pinholes per the Van?s instruction.
- White two part epoxy primer on the inside of the cowl (e.g. PPG DP48LF). Two coats. Do this before first engine start.
- Van?s stick on aluminum heat shield on the inside of the cowl in the obvious places (check for discolor after the first few flights and add as needed).
- One coat of PPG epoxy primer on outside of the cowl and all fiberglass.
- One coat PPG single stage paint in your choice of color on top of the primer. I find a medium blue goes well with the rest of the plane in bare aluminum.

...........

Carl

Exactly what I did, except for the last step of a color coat.

I thought the flat white primer look in the glass parts was OK. :)

I used Kirker epoxy primer in white and painted both the inside and outside of the cowl as you did -

https://www.autobodytoolmart.com/kir...r-p-12620.aspx

RV10Pilot 03-01-2018 05:16 PM

Southern Polyurathanes SPI
 
Consider using Southern Polyurathanes (SPI) epoxy primer. I have been very happy with the product and there customer support is first class. https://www.southernpolyurethanes.com

sblack 03-02-2018 10:11 AM

Quote:

Originally Posted by Carl Froehlich (Post 1243074)
Don?t forget fiberglass and ultraviolet light do not mix well. Put something on it.


Carl

Just to be a picky PITA, it is not the fiberglass that breaks down, it is the epoxy resin that holds it together. I would use any good 2 part acrylic urethane primer. It is high quality, compatible with any paint, sticks like crazy, cures quickly and it will seal and protect the cowling. Being catalized it will be impervious to most things - thinners etc. They make it high build so you can fill the weave and other imperfections.


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