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Balsa wood filler?

Old 01-26-2004, 02:23 PM
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Default Balsa wood filler?


I am finished my Extra 300S, took me a month to build, now its time to do some dent-filling (before covering)... lots of those in the wing LE and the sheeting on the wing... What is the best kind to use that will sand easy?


Old 01-26-2004, 02:31 PM
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Default RE: Balsa wood filler?

If they are fairly good sized dents apply water and follow with a warm covering iron. If it's just hangar rash mix up some Elmer's white glue and some baby powder to a paintable consistency and apply - sand, apply - sand, apply - sand until you achieve the finish you want. After that you can cover or paint. You Xtra is probably all planked so I assume you will paint. Paint with whatever you want as long as you fuelproof. The baby powder is by no means fuelproof so it must be covered or painted but it sure makes a good filler.
Old 01-26-2004, 03:06 PM
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Default RE: Balsa wood filler?

I ran the damn sander into the sheeting on the wing near the fuse, its a dent the size of a pencil, and 4" long or so... Several more bumps on
it.. BTW its GP Extra .40...
Old 01-26-2004, 03:24 PM
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Default RE: Balsa wood filler?

I use Autobody filler and spot putty for small dents. Be sure to get the "lite" variety of filler. Easy to use and sands very well.

Mark Shuman
Old 01-26-2004, 03:34 PM
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Default RE: Balsa wood filler?

I've always found that spackle does a good job. Cheap and light, it is also easy to sand and apply.
Old 01-26-2004, 03:38 PM
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Default RE: Balsa wood filler?

Go get some red devil spackle. It is really light, sands just like the balsa and is very easy to use. If you put something on harder than the wood and have to sand, then you sand the wood faster and make a bigger problem. This stuff is a really good filler. I don't use anything else.
Old 01-26-2004, 03:42 PM
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Default RE: Balsa wood filler?

Go to the lumber yard, Menard's, Lowes, etc. and look for "Red Devil" brand "One Time" light weight spackle. It is about 1/10 the wt. of ordinary spackling compound and extremely easy to sand.
If you are using covering, (MonoCote/UltraCote), you may want to put on a little BalsaRite. If you can, avoid putting your iron Directly on the filled area.
I've used this stuff on everything from trainers up to and including our 40%ers.
Good Luck,
Old 01-26-2004, 06:16 PM
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Default RE: Balsa wood filler?

I have used those lite spackles, but I don't like them. They are too soft, and they can melt under a covering iron. I use Elmer's wood filler. You can get it anywhere, and it's very easy to use and sand.
Old 01-23-2020, 05:29 AM
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As an experiment, yesterday I mixed cornstarch powder in with 15 minute epoxy to create a puddy. Applied the mixture in a gouge I made in a piece of balsa wood and spread it to conform to surface of the undamaged balsa. It spread well, adhered well and was able to sand it smooth the next day. Will give that a go on my plane which has several minor non structural dings before covering it.
Old 03-24-2020, 04:49 PM
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I've owned an auto body shop for 20 years, currently doing furniture restoration and built models of all types most of my life.

The most useful "putty" I ever saw for filling dents, nicks, filling seams, shaping contous, etc. is called Spot-Lite by Evercoat (you can Google it). It's white in color and becomes light blue or a pinkish color depending on which color hardener is mixed in. There is no difference in the hardener except color.

The putty comes in a can and has a creamy consistency that's just the slightest bit thicker than peanut butter.

A small amount of hardener MUST be added and thoroughly mixed in until there is no sign of any straight white color in the putty. You then have less than 5 minutes to apply the putty to the surface before it begins to harden. After 10 minutes it's fully ready to sand.

Now for the best part: Using a sanding block, this stuff is as easy to sand as balsa and blends with the surrounding wood or any other material beautifully! At the same time it never clogs the sandpaper like many other fillers will and because it sands so well, there is no tendency for the sandpaper to chew up adjacent balsa and cause depressions.

This material is generically known as polyester spot/glaze putty and there are other manufacturers that produce their own versions of the product, but having tried others, I must say this one is best!!!

The marketing of this product is aimed primarily toward the auto body repair industry, but it's also commonly used in all sorts of industries where there is design, fabrication, prototyping, etc., but this is not a hobby product so don't expect find it where you get your hobby supplies.

The best way i can describe this stuff is that it works like spackle, but it adheres to the surface much better and it's waterproof so you can wet sand it.
Old 03-27-2020, 02:08 PM
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Have been using brown microballons and 24 hour epoxy mixed together for decades ! Nothing beats it!

Old 04-02-2020, 03:58 PM
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you have several choices, many of them already suggested. I would say it depends on the material you want to correct:
Wood: lightweight spackle. If it is a hole you can use a piece of napkin with CA on the inside of the hole and then spackle it.
Composites: automotive 2 component filler, finest grade, I use from R&G.

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