[rv8r]

Hi there!
I just wonder if I should paint the cowl of my RV4 (new style with honeycomb) from the inside. The surface looks kinda odd, a lot of 'glasshairs' there. I guess that oil and dirt can soak into the cowl through that open surface. How did you manage that out there? Any suggestions?
Thanks a bunch and cheers from Germany

 

[robertahegy]

I coated the inside with that acetone/epoxy resin mix Van's recommends for prepping the outside of the cowl. I added some foil heat reflector to the bottom under the heat muff, Van's catalog stuff. Doing fine after three years.

Roberta

 

[Ironflight]

I used Aluminum....

Hi Dirk,

I started flying the Val with just a lousy spray-paint job on the inside of the cowl. I used a high-temperature white paint, and it did not give a hard or smooth surface. With the inevitable drips and drops of oil, I could see I was going to eventually have an unpleasant mess on my hands, so Purchased a couple yards of the sticky-back aluminum foil that Van's sells. In addition, I bought a roll of aluminum tape from Home Depot Aviation Supply, and went to work. I found that the first thing I had to do to get either types o foil to stick was really clean the surface using white gas (Coleman fuel). That got any remnants of grease off. Then I used the big sheets of foil where there were flat surface, and strips of tape when I had compound curves. You need to use a stiff plastic scraper (like you'd use for Bondo) to really press it on well and make it conform. It probably took about four or five hours all told, but now I have a surface which is smooth and impermeable to oil - easily wiped off.

In retrospect, I would recommend a good, hard and smooth paint finish or the aluminum foil treatment from the very start. It's easier to do while building than later on when you'd rather be flying.

Note - several folks have asked if I noticed a change in engine temps after the foil treatment, and the answer is "no". I only did my lower cowl for now - will do the upper some warm and rainy day (rained all day today, but to chilly to do good work in the hangar!).

Paul

 

[drakerv]

cowl paint

http://www.ppg.com/prc-desoto/pdf/hitempc.pdf
This is what we use on the race plane and my first rv 6 cowls.

 

[kentb]

Before applying Van's foil....

I used resin thined with aceton. About 50/50 mix and painted it all over the inside. This gives a real good seal as all the small hole get a good coating.

Then apply the foil where you think that you could have a heat problem.

Kent

 

[az_gila]

Color it white....

I coated the inside with that acetone/epoxy resin mix Van's recommends for prepping the outside of the cowl. I added some foil heat reflector to the bottom under the heat muff, Van's catalog stuff. Doing fine after three years.

Roberta

If you are going to use the thinned epoxy mentioned by Roberta, why not color it white?

Easy to do....

http://ecatalog.westmarine.com/0370.asp

My Tiger cowling was painted white on the inside during it's re-finish, and it makes stuff much easier to see, and helps spot very minor oil leaks quickly... The painter just used the same urethane as the rest of the plane.

Just don't do it like the Rolling Stones.... http://keno.org/stones_lyrics/paint_it_black.htm

gil in Tucson

 

[terrykohler]

Sand and seal the inside of both top and bottom using the resin acetone mix. Paint WHITE using a high temperature paint and the cover where necessarly using the foil tape (should be only where the exhaust pipes are in proximity to the glass). The white paint will make it very easy to spot oils leaks and soot. Also helps if your preflight includes only a peek inside the access door with a flashlight. Also makes it easier to find the odd hardware you may drop when working with the only the top off.

 

[cytoxin]

sand and paint

i will sand and paint mine with akzo. NOTHING GETS THROUGH THIS STUFF
i may then put the foil in a few choice spots.

 

[rv8r]

Thanks a bunch, folks ) Good to know to have people out there to ask for.

 

[DougBellSr]

painting inside of cowling

Dick
After fitting our cowling, I mixed a good batch (lots of it ) of epoxy and gave the inside a good coat with a 1 1/2" brush. It dried to a nice shine and after 100+ hrs. flight time, it still wipes clean easily, no sign of pealing like paint may do because of heat, chemicals etc.
Doug Sr.

 

[RV8N]

I highly recommend the paint to keep the oil out of the glass and the foil to keep the heat out.

One of my RV-8 buds didn't have the foil in in cowl. One day after flying we were checking the outside of the cowl for heat and noticed that part of the lower cowl (right where the exhaust ran) was very soft and could be pushed in. After removing the upper cowl, we saw that the heat had delaminated the inner f/g from the honeycomb material. The inner f/g had bubbled up to actually touch the exhaust. My friend had a local f/g guru cut out the damaged f/g and re-lay it. He then covered the entire inside of the lower cowl with the foil. He has never had another problem.

Before flying my -8, I installed the foil on my lower cowl (see, I'm not so dumb, I learn from others mistakes). About 3 weeks ago I took a local pilot for the $50k free ride and on the way back, I noticed a weird noise coming from my heat box. When I turned off the cabin heat it went away. Later I removed the cowl and found that one of my exhaust pipes had totally separated at the weld for the cross-over. Fortunately I had absolutely no damage to the cowl. I credit the foil for protecting the cowl.

Karl