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Well-Known Member
Apr 8, 2004
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Ok I know there are about a million ways to seal your balsa, basswood etc. But what do you guys use to seal your stuff?

this is sealing before painting im refering to.

I know Ca works...but does it repel the paint? I would think that the paint would need to be able to either adhere or absorb into the paint in some way.

Also what kinds of primers and paints do you use?
Where do you get your stuff from?

I know lots of questions but someone has gotta ask :D
For balsa fins, I laminate with paper and seal the remaining exposed edges with CA. It doesn't repel paint.

For larger areas like nose cones), I've had good luck with lightweight spackling compound thinned a bit with water. Ultra easy to sand. Lot's of guys say Elmer's Fill 'n Finish is best, but none of my local hardware stores carries it.

I never use any solvent based sealers anymore. Too stinky, too long to dry, etc...

For a final smoothing, I use a sandable primer.
filling balsa ... I still use the stinky olde-tyme "model airplane dope" fillers because I can't get Fill-n-Finish around here, I have had poor results with white glue (straight and thinned), and yellow glue, and CA glue. lightweight spackle didn't work so well either - either gummy or crumbly, didn't stick. besides, the smell of the solvents takes me back to when I was a kid and built stuff with my dad...
I've had great luck with Elmer's Fill and Finish - I get mine at Fred Meyer, but I've seen it at Target and Wal-Mart also. As far as I can tell, it's essentially wood spackle. The key is to thin it with a few drops of water so you can paint it on with a brush. Then, it sands really easily and shapes pretty well (although it is a little brittle) and paint sticks great.

Recently I've been using Plasti-Kote primer and Krylon paints. Seems like color selection is a little limited with the Krylon, but it is a lot cheaper and easier to apply than Testors or other "hobby shop" paints.

When I have die cut fins in a sheet. I use the Fill N Finish (aka carpenters finishing wood filler) before I remove the fins from the sheet.

I spread it on the whole sheet (both sides) with a bondo spatula and then sand smooth and flat before removing the fins from the sheet. I think it saves time and is easier. then you just need to address leading and trailing edges.

Well, now that we are on the subject...

I note that many of you use Fill N' Finish thinned with water to seal your fins, but what is the magic formula? Some say a "few drops", other stuff I read says "2/3 Fill N'Finish to 1/3 water." I know the goal is to get it to the point where it can be brushed on, but my experiments are always too thick or way too runny.

So dudes, share the magic, please. I'm tired of sanding sealer fumes, even though I wear a mask and use the stuff outdoors. Also the Aero Gloss sealer is getting expensive, and I would rather spend this money on fun stuff, like kits and parts and engines and, well, you get the idea...

Just Finished: Quest Big Betty
Needing Finishing: Semroc Astro 1, Fliskits Rhino
On the Bench: Semroc Swift
Originally posted by cls

filling balsa ... I still use the stinky olde-tyme "model airplane dope" fillers because I can't get Fill-n-Finish around here

I was using a dope filler too until I found Minwax Polycrilic. It's a water based product, doesn't stink, and you can clean up your brushes with soap and water.

It requires several coats, much like the dope, but I got a small can and added a couple tablespoons of taclum powder to it and it fills a little better.

The surface of the balsa seems harder to me and in an article in Model Airplane News they claimed it was just as hard as balsa soaked in CA.

The best description I have heard for the Fill N Finish is to get it like thick pancake batter.

What I do is make a pool in the center of the tub and dribble water drops in there and mix some around until it's the consistancy I want. Then dip it up on the finger and spread it around. If I'm filling a whole sheet I can leave it a little thicker and spread it into the balsa with a bondo spatula.

Hope that Helps

I don't measure it so I don't know if this will be very helpful, but my guess in a 1/3:2/3 ratio would be WAY too wet.

I take a scoop of the Fill-n-Finish (size depends on how much filling I have to do), take it to the sink and turn the water on so it is just dripping andget it wet. Mix well, make wetter if necessary. Be aware that it does get sloppy VERY fast so add the water in tiny bits at a time and mix mix mix.