Re: [GZG] Working with Balsa

The traditional material is "sanding sealer", usually a clear  
nitrocellulose varnish-like coating that serves two purposes: 1) To  
fill the grain. 2) To raise the "nap" of the wood surface and make it  
brittle and easy to sand smoothly without tearing.

You should be able to get it at any DIY/handyman/woodworking shop,  
although you might need to buy a litre or so. I used to be able to  
get it from model-shops in small tins back when I used to build balsa  
and tissue model aircraft, but I haven't been in one for years so I  
don't know what's available now.

However you only *really* need to use sanding sealer if you're going  
to apply a clear finish, which is unlikely if you're building model  
spacecraft. Assuming you're going to paint, any white acrylic  
undercoat will do. Apply a coat (no need for a spray, any brush or  
roller will do), let it dry *thoroughly*, and sand until the  
undercoat is only left in the grain. Repeat until the desired finish  
is achieved, and then apply a final coat and sand *lightly*.

If you are making your parts from flat sheets of balsa, you might  
want to consider doing your grain-filling and sanding on the entire  
sheet, *before* you cut out your parts. Consider also undercoating  
and sanding parts of the ship before assembly.

Best regards, Robert Bryett

On 08/09/2008, at 04:18 , emu2020@comcast.net wrote:

> Hello all, I am reaching out to the group for some help with using  
> balsa some custom ships I'm doing. I am having a problem in the  
> finishing because invariably there is a wood grain that shows  
> through the paint. Is there a way to effectively seal the finish  
> model that will allow me to give my completed models a smooth finish.

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