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cowling interior finishing....

cropdusterdave

Well Known Member
So I thought it'd be fairly important to fill the weave and work out pinholes on the inside of my cowling to prevent oil nastiness later on. (pink cowling)
I'm on my 4th day of working on just the top half and there'd still be alot of work to be done to make it all nice and smooth. Just wondering how indepth I should get with this. The area by the spinner is by far the worst as the rest is fairly straightforward. My arms are killing me.......
 
I learned (probably here on VAF) to use leftover epoxy from other jobs on the inside of the cowl. It was a good place to use it up.

Afterwards, apply adhesive foil and then epoxy the edges to keep oil out from under the foil.
 
Roughened with 80 grit, cleaned, coated with epoxy, applied heat shields with pliobond, epoxied edges. No need to make it pretty.
 
This is very simple. Sand the inside of the cowling just enough to open up any holes and clean it out before the next step. (I blew mine out and then wiped it clean.) Then mix some epoxy resin 50/50 with acetone. That will make it VERY runny. Then get a three inch high nap paint roller and roll the stuff on. Let it set for a day before adding the next coat. Give it four coats and you are ready for the head shield.

Don?t worry about mixing the epoxy, the idea is to thin it so it fills in any holes. You don?t care about the strength of it.
After that has set (It will take a long time, but it will harden.), us a wallpaper seam roller to push the heat shield in place. This will help smooth the heat shield and make sure it adheres to the inside of the cowl.

Don?t be afraid to cut the head shield to fit your cowl.

Here are a couple of pictures:
IMG_1209.JPG

IMG_1212.JPG
 
What is the best way to do determine which areas of the cowl interior need a heat shield? In my case, the io540 for the rv10. Not much info in the plans on this subject.
 
What I did for my O-360 is probably overkill but one nice thing about covering most of the bottom cowl is that it is easy to clean.

If you want to save a few dollars on that insulation, put the bottom cowl on and mark where the pipes are and then give them, say, for inches on either side. That should be more than enough, IMHO.
 
What is the best way to do determine which areas of the cowl interior need a heat shield?



Shoot rattle can white primer on the inside and go fly for couple hours. Then decowl and check for brown spots. Place reflective material on them. :)
 
Mark,

I initially went from hinge line down 12" X 24" fore-aft centered on exhaust pipes. After a few test flights two brown spots appeared in lower cowl horizontal area, so I went back and put another 6" on each side. The ones from ACS with adhesive did not hold well in a few areas and contacted my exhaust pipe. Melted aluminum foil but did not burn through fiberglass fabric. I went back with pliobond adhesive from ACS and they seem to be holding good. I wanted some heat protection up near horizontal hinge line in case of an exhaust flange or pipe crack.
 
....put the bottom cowl on and mark where the pipes are and then give them, say, four inches on either side. That should be more than enough, IMHO.

This a bit more than 4" wide, but same idea. Sealed, painted with epoxy primer and two-part single stage. Vans self-adhesive aluminum foil heat shield over fiberfrax strips.

Cowl%20Insulation1.jpg


Cowl%20Insulation2.jpg
 
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Don?t worry about mixing the epoxy, the idea is to thin it so it fills in any holes. You don?t care about the strength of it.

Revisiting this subject as I am about there. Are you saying not to use hardner? Just mix the resin and acetone 50/50? Or is it resin&hardner mixed 50/50 with acetone?
 
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