Having just re-entered the hobby after a 40 year hiatus, I'm noticing that times have changed.  After an hour or two of fruitless internet searching, it appears that the old Aero Gloss sanding sealer is essentially extinct, having been killed off by the arguably necessary crackdown on VOCs.  From what I've been able to glean from internet reviews, the water-based replacements (clear acrylic with baby powder filler?) leave a good bit to be desired, particularly in terms of not penetrating and hardening soft balsa like the old acetone and toluene laced butyrate sealers. 

So... any ideas as far as a suitable replacement?  I've re-finished a few old wood cased tube radios with shellac.  The thought occurs that it's got some similarly desirable properties- it soaks into the wood, adds (insect shell based) hardeners to the wood, and leaves a smooth, sandable finish.  Has anyone tried shellac (with or without talc filler) as a sanding sealer substitute, or any other concoctions that work better than the water-based ersatz sealer?

Thanks

I use acrylic wax with talc powder to mixed results on balsa. Lately it has been rial and error.

Lou

Not sure how it would mix with acrylic paint but Durham's water putty has a talc consistency and fills holes nicely - probably stronger than just talc.  Durham's is available at most hardware stores and Amazon $4.00   I work in basswood and seal all my models with automotive sandable spray primer exclusively, sanding between coats.

Interesting idea.  Since both are water based, I wouldn't anticipate compatibility issues.  And Durham's does indeed set up rock hard.  I think this combination would leave a smooth, hard finish.  Still interested in finding something that would soak into the balsa and harden it.
Thanks!

Hi SpaceMouse

A couple of approaches come to mind. The first one is shellac. It dries hard, soaks into the wood well and should be able to handle adding talc. It is fast drying. I use it as a sealer on all my models to seal in pitch. Shellac is a great primer for oil and acrylics. It also dries quickly. I normally dilute the first and second coats with alcohol to promote absorption. But it can be used undiluted if required. It comes in clear, orange and Zinser makes a white.

You could also consider an oil based urethane varnish with talc. As with shellac, I dilute the first couple of coats with thinner. However, urethane takes longer to dry than shellac and is initially softer than shellac. You should also be able to add talc to thicken up to fill the pores of the balsa similar to shellac.

If I had to choose between the two options, I'd go for shellac since it's drying time and hardness are closer to the older sealers than urethane.

-ken

I've been using a lacquer-based sanding sealing, to which I add more talc.  But it's possible that lacquer may not be available where you live (I live in the US).

I have a small bottle of clear nail polish (the lacquer type) that I added talc to and use with the built-in brush to seal very small parts. 

I have also used CA adhesive to harden sharp edges (like carved inlets where the edges are very thin). I mostly work in basswood.

Garet

Great suggestions, thanks!

I have used lacquer based sealer to good effect when I was building balsa flying models but suddenly found that this is no longer stocked in the hardware stores I frequent. Water base products are widely available. Lacquer product can't be mailed but I imagine with lots of money it can probaly be sent by courrier. My budget precludes that option.

Lou

Brodak still sells dope and lacquer based sanding sealers. http://brodak.com/finishing-products/dope/sanding-sealer-4-oz.html
I believe that they buy from Randolph's and repackage it.

A few posts below oceaneer99 mentioned clear nail polish. What is nitrate dope made from?  Basically it's nitrocellulose (gun cotton) desolved in acetone. What is nail polish made from? Nitrocellulose desolved in acetone. Aircraft grade nitrate dope has some additional  plasticizers added.

I purchased a bottle of clear (.5oz) for a couple dollars from the local drugstore make up isle. I simply applied it straight from the bottle using the included brush. Dries fast for additional  coats and seals the wood perfectly! It sands well as I expected.

Solid coloured nail polish works as well it. Primer over top can be sanded until the color shows helps evaluate the surface for defects.

Regards Fraser

I have been meaning to try the chrome nail polish, but I keep forgetting to pick up a bottle.

Lou