Re: Slow E-Z poxy or alternative?

Robert Cringely

Vinylesters don’t like to stick to epoxies, that’s for sure, so I’ll offer another option. I have an all-aluminum Davis DA-2A that is the only one ever built with wing tanks. Alas the original builder didn’t know about Pro-Seal or chose not to use it so the tanks have always leaked a bit. And as you can imagine any bit is too many bits in this case. What to do?

We sloshed the tanks with Eastwood Gas Tank Sealer, specifically the type for gas with ethanol just in case. That was a year ago. The plane hasn’t yet flown because we’re doing a new panel, but the tanks are deliberately full and haven’t leaked a drop in that time. We used two gallons and by the time it all dried we’d lost less than a gallon of capacity. 

It’s just a thought…


On Wed, Apr 13, 2022 at 7:07 PM Mike Bergen <dmbergen@...> wrote:
Sanjay, sorry for the delay in response as the last two weeks were eaten up by preps and attendance at Sun N Fun as Richard and I volunteer at the composite workshop all week and bring a lot of stuff for demos.

Epoxies are just not the best solution for fuel tanks if there is alcohol involved. Richard Kaczmarek has had great success in splashing the inside with Rhino 9700. Very hard to splash the entire inside of a Quickie fuel tank as it is not easy to toss it around. ;-)

What I have done with the inside of my Q200 tank is use Nexus veil with Derakane 470 vinyl ester resin during construction. This is the same approach that is used in fuel storage tanks. But the only way to get the vinyl ester to adhere to the bottom of the epoxy fuselage is to wet the tank area with wet epoxy, kinda wipe it so as not too wet and sprinkle cotton flox over the entire area. The next day you vacuum the loose flox leaving fibers standing on end to provide the tooth needed for the vinyl ester and Nexus to grab, otherwise the adhesion is too poor between the two different resins. This is due to the amines in the epoxy that frustrate the cure on the vinyl ester.

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