Microballoons

[Eric Page]

Maverick, what is the 3M product you mention you used vs. Hysol?

Since he's got a Series 5, it was probably Scotch-Weld (not sure which; there are several variants). That's what most of my 5 was put together with. It's amazing adhesive, but when they say "permanent," they mean it. Grinding/sanding is the only way I've been able to remove it. It laughs at solvents and heat.

[jrevens]

Maverick, what is the 3M product you mention you used vs. Hysol?

It’s surely 2216 B/A.. that’s what was used. It was (is?) used a lot in the aerospace industry. I never built a Kitfox with it, but used it on a lot on other aircraft. I still have a couple of tubes. It is more expensive than the Hysol 9460, and is mixed in a ratio of 3 to 2 by volume (I believe 7 to 5 by weight), A to B. It’s a very good adhesive.

[jrevens]

If you add enough microballoons to epoxy you can make something similar to Super-Fil. Light and sands very nicely. Flox-filled epoxy, not so nice to sand!

[taff]

It’s surely 2216 B/A.. that’s what was used. It was (is?) used a lot in the aerospace industry. I never built a Kitfox with it, but used it on a lot on other aircraft. I still have a couple of tubes. It is more expensive than the Hysol 9460, and is mixed in a ratio of 3 to 2 by volume (I believe 7 to 5 by weight), A to B. It’s a very good adhesive.

2216 B/A, that's what I used with building the Kitfox and also what I used many times on the Skybolt. Incredible adhesive!

This photo shows an aileron cove that has been glued to the aluminum trailing edge of the Skybolt.

[taff]

Another good additive for the epoxy resin is West System, Fairing Filler.
They (West System) suggest it for their own epoxy resin. Used to only fill areas. And real nice sanding qualifies.
It's not micro balloons but a very fine powder.

I also used it as an addition to T88 adhesive. T88 is probably the best epoxy adhesive there is for gluing wood together.

[Maverick]

Maverick, what is the 3M product you mention you used vs. Hysol?

It is the 2216 B/A mentioned by others. It is what was in series 5 kits. When I bought my project it was 23 years old and there was no glue so I bought it from Aircraft Spruce. I'd never ber heard of Hysol and since 3M is what I used to build my first KF5, I just went with what I was experienced using.

I built wooden wings on my vey first homebuilt. T88 was pretty new at the time and the EAA book on building with wood recommended FPL16. It was easy to work with but I don't see where it would ever be useful on a Kitfox unless you were going to build your own ribs from scratch.

[napierm]

I used it to make the tips of my Rudder/VS (speedster) and Elevator/HS look nicer, blended with the ribs. As you said, mix micro with Hysol. Kept adding balloons until it was more like a fluffy paste. Is pretty tough and weighs very little.

I agree with Eddie. They're also used as filler to make a light-weight, easy to sand mixture with epoxy or other resins. The fact is that they weaken the strength of a bonded joint. FWIW, I can see no reason to use them for bonding that piece to the fuselage tube because the tube is powder-coated and there is no direct contact between the dissimilar metals.