Pin Hole Process

[DanH]

It doesn't matter which brand of epoxy you use. Pick based on which one sands easiest.

No problem starting over if you sand off all the high-build.

Shell the inside of the cowl just like the outside, then shoot it with a single stage 2-part white paint.

[axlr8r]

as a practice project prior to moving to the outside.
I used advice found in this thread and others as a guide and found all the information helpful.
First, I sanded out the rough spots and sharp edges and scuffed sanded all of the rest. Then I cleaned the inside thouroughly w/ soap and water and gave it a final cleaning w/ acetone. After that, I mixed the epoxy w/o diluting it and brushed it all over the inside. I then used a squegee to work it into any low spots. I was surprised at the amount of epoxy I was able to remove and work out of the cowling by the squegee process. Overall, I think it was a good learning experience that will help me w/ the exterior of the cowling. I plan to scuff sand the interior, prime and topcoat. Have not figured out what color yet.
My friend has a -6 w/ no finish on the inside of his cowling. It looks like oil had permeated the fiberglass weave - he can never get it clean and it always looks messy.
Steve

[DanH]

Good for you Steve.

You'll like it sealed and painted some light color inside...leaks show instantly, it is easy to keep clean, reflective heat barrier foil sticks really well, and it improves lighting if you like to peek in the oil door and up the outlet for preflight.

[scard]

Ommmmmmm.... Ommmmmm.... Read, review, try, fail, fix, (back to VAF) read some more, try again. I'm closing in on it . The clear candy shell is key, and those epoxy squeegee coats as thin as humanly possible it seems. This pass at the re-read, I need to go dig up a foam roller to see about dealing with the squeegee lines at application time, instead of spending 'extra' time wet sanding. Thanks Dan!

[fatherson]

Originally Posted by scard

Ommmmmmm.... Ommmmmm....

No kidding, Scott! Who needs meditation when you've got VAF threads?!? :-)

--
Stephen

[DanH]

Scott, I'm slow sometimes....I just realized you've been talking about wet sanding the epoxy shell pinhole coats. You should be able to sand dry, in the 120~180 grit range. If it's clogging the paper, you may have amine blush or it's not fully cured. Both are avoided by making the shop warmer and humidity lower.

"Non-sanding primer" (like PPG DPLF) has to be wet sanded, because it is sorta gummy no matter what. Luckily you don't have to sand it unless you let it cure more than a week before topcoat.

High build primer-sealers (like K36 or K38) can be block-sanded wet or dry. I like to block with 320 wet, but I'd do it dry in February

Following the squeegee with a nappy roller is just a trick to eliminate ridges and lines. The resulting orange peel surface is a nice sanding guide so you don't sand through. I've not tried a foam roller. I've been buying the cheapest nappy ones and chopping them to a 3" length on the bandsaw.

[scard]

Thanks Dan.
Another piece of genius from "the Horton": Yesterday, I was ready to shoot a little K36 but it was actually sleeting and snowing outside, if you can believe that! I have a little spray booth setup in my shop with an exhaust fan out a window. I have dedicated central a/c and heat, so I heated up the shop to about 77deg and engaged the Horton: I opened the attic door for air inlet (just outside the booth), and cranked up the exhaust fan. It worked GREAT! My total heat loss was about 5deg over about 20min. Simply amazing.
After the shoot session with parts moved inside to dry, I needed to fully flush the shop so I opened my usual direct fresh air source with the same exhaust and lost 15deg in 3min.

[jjet]

Try using Evercoat Polyester Glazing Compound. A glass airplane builder assist guy turned me on to this stuff, it works great.

jjet

[CharlieWaffles]

This thread has been a god-send. I am just finishing up my canopy interior (with Aerosport Overhead Console). The lessons and tricks here have been beyond in-valuable. My donation to VAF was worth this thread alone. I have never worked with fiberglass before and I would have been lost with out it.