Fuel safe foam finish
05-07-2005, 04:11 PM
#1
Fuel safe foam finish
After building nothing but electric for 8 years other than a cox and kamdax that were already had fuel proof exteriors I have no idea what to do for a finish on a Skyhawk with a foam fusalage. Normally I just airbrush on whatever enamel I want onto the foam after I have covered it in lightweight spackle and sanded it smooth. On the inside I thinned epoxy with alchohol and brushed it on, a nice light fuel proof seal. But what for the outside? And of course weight is a huge factor.
05-07-2005, 11:06 PM
#2
RE: Fuel safe foam finish
Hi,
Just to be clear I guess generally when I think of "fuel proof" it is actually "oil proofness" that we are usually after.
I have found a waterbased polyurethane here in Japan that is very "fuel proof" to the 15%nitro I use- It is for wooden floors. I say fuel proof, I tested a bit when throughly (week old) dry by leaving both a puddle of oil from out of the muffler and a puddle of neat fuel. After an hour the polyurethane under the fuel was still hard and clear, and after 24hrs so was the oil. I didn`t think I`d ever find a water based polyurethane that was that good, but I just got lucky.
I have tried three different types of water based clear coats- the first was not at all fuel or oil proof, while the other stuff I used for my MiG is pretty oil proof and will tolerate a spill so long as it`s wiped up right away.
I think you want to look for polyurethane on the tin, but my advice would be to get a couple of test tins of different ones and try them to get a good one.
J.M
Just to be clear I guess generally when I think of "fuel proof" it is actually "oil proofness" that we are usually after.
I have found a waterbased polyurethane here in Japan that is very "fuel proof" to the 15%nitro I use- It is for wooden floors. I say fuel proof, I tested a bit when throughly (week old) dry by leaving both a puddle of oil from out of the muffler and a puddle of neat fuel. After an hour the polyurethane under the fuel was still hard and clear, and after 24hrs so was the oil. I didn`t think I`d ever find a water based polyurethane that was that good, but I just got lucky.
I have tried three different types of water based clear coats- the first was not at all fuel or oil proof, while the other stuff I used for my MiG is pretty oil proof and will tolerate a spill so long as it`s wiped up right away.
I think you want to look for polyurethane on the tin, but my advice would be to get a couple of test tins of different ones and try them to get a good one.
J.M
