# Sealing foam & balsa for sanding & strength.



## srspicer (Oct 14, 2007)

Hello All,

I usually post in Model forum under sci-fi.

I have been commissioned to build a large scale static dislplay of a modern tanker -type ship. The model, HO scale, will be about 6 feet long, 7" tall and 12" wide. It has to be light and sturdy! 

The bow has been carved from dense foam. I intend to make the flat bottom and verticle sides from balsa and foam core board. An odd combination, but very sturdy!
What I would like to do is to then cover the structure with thin tissue or similar material and a resin or epoxy of some kind. I hope to give it strength and a sandable surface that can then be colored and decorated.

Your suggestions would be greatly appreciated!!
Regards,

Scott


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## crazy mike (Aug 26, 1999)

Epoxy and foam core board, good.
Resin and foam core board, BAD, very bad.


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## Twmaster (Aug 11, 2008)

Try a very light fiberglass (like 1/2 ounce) and water based Minwax polyurethane. I use this on my foam planes. I think you'll like it.

--
Mike N


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## Mike Clark (Apr 28, 2007)

I have flown Nitro airplanes for years and we seal Balsa the same way you could seal the foam. Make sure the foam has received a good finish sanding and blow ALL dust from model or you suffer from pimples. 

Take the longest cure two part epoxy, Devcon, HobbyPoxy or whatever. After mixing both A&B together, thin it down to the consistancy of paint. "Denatured alchol". 
NOTE> make sure that you do a test strip with the alchol thinner first but I don't expect any problems.

Then apply the mixture to the hull with a out of date creditcard. Then spread the mixture out thin, the thicknwess should be about three to four mills thick. This will give you a slick hull. The finish will be tough and repairable with very little effort.

Now paint away.


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## coreybarnes8 (Aug 24, 2008)

*Hovering C-57D SciFi Cruiser*



srspicer said:


> Hello All,
> 
> I usually post in Model forum under sci-fi.
> 
> ...



Hi Scott,

I feel you are on the right track. How will the display be mounted for veiwing?

Nice ideas on the structure and stability. The right angle "I-Beam" construction technique can be formadible. Nice ideas on combining materials. I am contemplating many of the same issues in my current design.

Perhaps you could consider microfiber fiberglass mess, or even something as simple as women's nylon hoisery, over laid with a neutral expoxy resin. It would be lightweight, durable, flexible, and have a fine sandable finish if applied with apropriate thickness. I would suggest fine multiple layers of resin prior to finishing.

Would you be receptive to being a consultant in my design and adventure? I hope to hear from you. Best of luck in your commission.

Best Regards,
Bob in Mansfield


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