Hi,

I have just finished reading the thread of Mark Novack on the pattern forum and I have got a question.
Whenever he uses epoxy he mixes this with microballoons. I have never used this before and wonder what it's good for?
Also, who produces this?

Thanks in advance.

Microballoons are tiny glass spheres added to lighten epoxy when used to make fillets. Looks like powdered confectioners sugar. Must be used carefully as it is not a good idea to inhale glass in any form. A safer additive that some use is cornstarch.

Dave Segal

Microballoons are just that. Incredibly tiny little bubbles of a lightweight material that are added to epoxy or other glues as filler.

The way I usually use them is for creating a Fillet between say, the horizontal stab and the fuselage.

You mix epoxy, add microballoons to get a fairly thick consistency, spread it into, onto the joint and shape it.

Once cured it sands much more easily than straight epoxy, and you haven't added much weight to the tail of your plane.

Dennis-

Microballoons come in two flavors, glass and a form of plastic that is brown in color. Both work well but the brown is harder to cover without the dark showing thru the covering or paint.

Thanks for all the replies.

Does this mean that using microballoons influences the strength of the epoxy or doesn't that make a difference?

THX

Micro balloons are intended to take up space with minimum weight, not to add strength.

The second part of your question, as yet unanswered, is source.

Many years ago I bought a 42 gram bottle from Prather. Still working on that supply.

That doesn't sound like much, but the density is so low that 42 grams is almost a pint in volume.

Bill.

You also have to be careful in the amount of balloons you add. They will make the epoxy cure alot faster, less work time. I use Hobbico brand.

The West Systems Epoxy products have a light weight filler which appears to be mostly the phenolic plastic brown microballons and are very good at maintaining some strength but lightening the mix significantly.
They may be harder to cover up but Ihave found them much easier to sand than the glass spheres.

Thanks guys

Dave brown Products makes the phenolic plastic brown microballoons

Top Flite makes a white Microballoon Filler