Can bondo be used as a balsa filler?

Yes. But it is very heavy compared to traditional filler. You would be better off going to you home improvement store or Wal-mart and get a small container of lightweight spackle. Or I use Elmer's wood filler. Both are much lighter than Bondo.</p>

Ken</p>

Bondo is better for fiberglass.

I just figured it would be a real good filler because (aside from the horrible smell) it goes on easy and sands super smooth, alot smoother than what I have used in regular wood filler. I am covering my plane with red fabric covering anyways, so would the red color of the bondo show through all that much? Do they make bondo in any color besides red?

On a Super Sportster 40 would the weight of bondo be all that significant with a .46 powering it? I have to buy the bondo for the wheel pants anyway and I hate to buy it just for that, I would really like to use it as a filler too instead of having to buy wood filler AND bondo.

If you want to use it then go ahead and use it. But it's going to add extra weight to your plane. Looking over your build you already have a lot of extra weight will all the extra epoxy and fillets your are using. While it may not seem like it all that weight adds up and adds up quick. Your result is going to be a heavy poorly flying plane. I'm not sure why you are adverse to the spackle. It's very cheap (around a buck or so if I remember correclty). </p>

Ken</p>

</p>

WHAT ARE YOU TALKING ABOUT!? Bondo has a great smell![sm=bananahead.gif]

Only a guy who's restored at least one car would say that!!!!!!

And before you ask, yes Ihave!!

Ken

Not that I purposely inhaled as much as I could, but I do like it. The metal canister markers always had a good smell too.

Now everyone's gonna think I huff CA too.[]

Good points made, I will be using spackle. What would the outcome be for the plane if I was to put a slightly bigger motor in than the .46?

It has nothing to with getting a "bigger engine". It's about building an airframe heavy. A heavy airframe has a lot of bad habits regardless of the engine you put on it. Weight increases the wing loading which means the plane has to fly faster to even stay in the air, which means you have to land faster to keep the plane from stalling as you slow down to land, which means the faster landings puts more stress on the airframe from the harder touchdowns as you land. This is just one example of what a heavy airframe does. And if you add a bigger engine you are just adding more weight to the formula which increases your wing loading even more. The list goes on and on. You really should be striving to save weight wherever you can when you build.</p>

Ken</p>

I wouldn't advise it. That will require better throttlecontrol than 'normal'.... especially down the glideslope.

...Wise decision to use Spackle as a balsa filler too.

Not to mention that the extra weight increases the stress on your airframe with every maneuver, and makes high speed stalls more common. There's no substitute for building light.

for filling directly on wood, this is one of the best I have used, Minwax StainableWood filler, when I use it for modeling, (I use it for work as well) I thin it ever so slightlywith a little water to loosen it up and make it a little more spreadable.

a photo of my latest project,my FockeWolf 190A8,the tail and wing fillets are filled with the Minwax filler.

after its dry the filler sands well and is very tough,its also light weight like the spackle but much more durable, and has a wood tone so it blends with the balsa color well.

as for Bondo type fillers I would have to agree with the posters that its needlessly heavy, and tougher than the surrounding wood areas wich can be troublesome when sanding it back.

a exellentpolyester filler for filling fiberglass, and glassed surfaces, like a fiberglass covered airplane is Evercoat body filler http://www.evercoat.com/productDetail.aspx?pID=33another material I use alot of for modeling and work, itsands smoother than regular bondo and is lighter for modeling.

I generally use it for doing the fine detail work after glassing my models,so there is minimum weight added.

you could also use a good automotive finish putty which will adhere and dry as hard as bondo but weighs almost nothing...and yes it smells good too.

heheh i agree

I used that light-weight spackle once... ONCE. I'll never use it again.

It melts under the heat of a covering iron [X(][:@][:'(]