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Monday, November 12, 2012

Pin-hole-ing the Cowl

The last couple weeks I have been working on the cowl and the oil door.  Basically the cowl comes Pink and fairly smooth, but very porous as well.    If you just paint it, there are huge pinholes in your paint due to the lay of the fiberglass and honeycomb sections of the cowl.  There is no real easy way to fix this, but I do want to have some primer on the cowl to protect from UV and also want to remove the rough existing surface which can collect oil and dirt really easy between now and when it is painted.   So to avoid this I am working on the surface of the cowl.  Here is my process:

First sand the cowl to smoothen it out and open up any holes that might be covered..  Wash with dawn, then rub down with towel and after its dry use some acetone.   Then take some mixed epoxy and a squeegee, then pour the epoxy on the cowl and squeegee it around.   Getting it as thin as possible, while letting the epoxy fill the divots on the cowl.  In the end, the first time you do this used the most epoxy because it is basically absorbed into the cowl.   Before the epoxy has fully cured, i.e. is still tacky, I put another layer on..  This requires less epoxy, but is a bit harder because it is more difficult to tell where the epoxy is new vs. old.  Anyway, I got another layer on and let it dry.

Then couple days later I sanded it for 2 hours using 80 grit..   Then I used a bit of white rattle can primer to see how it was looking.   Pretty good, only some areas that were major holes still existed.   So I sanded away the primer, cleaned up the cowl like above and did the epoxy treatment again.  This time, it really went on smooth and a glossy finish of epoxy..   Two coats just like above and then sanded again with 80 for a couple hours.  Then went with 150 for an hour or so, then finally with some 220 for another hour.   Looks really smooth now and ready for Primer.  I don’t expect to see any pinholes but just a smooth primed surface.  I am going to use my PPG Two part epoxy white primer which will seal and protect until I get final paint.  Oh, then I need to do the lower cowl, since I have only been working on the upper half.   ;-)

Actually, I wanted to throw a photo in of the now finished upper cowl.  Looks like the additional work seems to have payed off.   No pin holes, and looks very smooth..   I will be happy flying around with this until I can get it professionally painted..

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