Light weight Bondo ---

[Christopher Crowe]

Is there a particularly light-weight brand of Bondo (or some other filler) that is low density, easy to sand...

They used to have a single-part product that was great in this respect.

Thanks,

Chris

[brownslane]

Chris, I mix microballoons with standard bondo. Works great!

For lightweight fairing compound I actually mix some super-light filler I bought from Mike Devins (at HRP) with epoxy resins and make my own. This stuff weighs about 3 oz per GALLON of volume. No foolin! The only complaint is that you have to be extremely circumspect about mixing it as it will blow everywhere....if a mouse farts...it will be everywhere. I actually mix it inside a clear plastic bag.

Another source that I use is a product called aeropoxy. Nice and light weight. Aircraft Spruce sells it. But it is about triple the cost of the mix-your-own stuff and no better. So I am just using up my supply.

Best, Tom

[Christopher Crowe]

Lemme get this right. Standard epoxy resin and micro-balloons for the REALLY light stuff (you know, the mouse-fart disturbable stuff)?

[Northwind]

OR use polyester resin with the micro balloons. That works well also.

[Daryl DeArman]

Here's a resonable option when compared to standard bondo:
http://www.aircraftspruce.com/catalo...s/superfil.php

[DSRDAVE]

If you use the micro balloons be sure and use some sort of protection against inhaling the micro balloons. They do get ALL over.

[brownslane]

Microballons are HEAVY compared to the stuff you can get from Mike Devins. His stuff is awesome!

I mix the stuff inside a clear plastic bag and wear a particle mask. When I am done I normally fire up the leaf blower and blast all the stuff out the door. You will find that the lighter stuff sands easier, is nice and smooth and is also lighter dust...so you will need a mask (ALWAYS) when sanding and use compressed air or the leaf blower often. I use compressed air on my clothes before I leave the shop and the leaf blower every couple of hours. It really works well.

And microballoons will mix with regular polyester resins, but the resin is MUCH harder than bondo...the slurry you will make with poly resin and microballoons will not be as nice to work with as bondo and microballoons. However, I use poly and microballoons as a "sticky mix" when applying the first layer of glass cloth to a plug. Often I will apply that first layer over top of all sorts of things, like plywood, chicken wire, or my most favourite; spray foam. You need the wetness of resin to wet out the cloth, while the addition of microballoons will make the slurry thick enough to adhere to vertical surfaces.

Best,

[Mike Devins]

Tom is correct on the handling of the expanded poly spheres that I sold him. You need to be really careful! A good option for the home builder is West Systems Microlite 410.

http://www.westsystem.com/ss/410-microlighthttp://

It is the same stuff only West does something to coat the spheres so they do not float around the room - Not Cheap, slightly heavier but not enough to count and for the amount that you would need it is a good choice.