HOW OLD IS TOO OLD ?BALSA AND GLUE

A friend of mine gave me a Nobler that is completely framed up just needs covering and paint only problem its about 40-45 years old.Would it be worth the time to do so.Does this type wood get too old ,what about the glue any way to tell if it would hold up? All ideas will be appreciated

Leon Smith

leon99:+

Leon,

There is no reason that model shouldn't be finished. Balsa, like any other wood will rot, but since its all open you can quickly inspect it for such. Look for discolored areas, dark, grayish, brown. If you find areas like this, carefully poke the wood to see if its softer then the adjacent wood, if not, its fine. Carefully look it over with respect to the glue joints, a bit of CYA in accessable joints will help, if there are gaps use thick CYA. The most I've ever found to be wrong with old models is poor craftsmanship, bad fits and shakey control system installation. use a mirror to look down through the leadout holes at the terminations and bellcrank installation. If that isn't possible I'd strongly suggest some carefull sectioning out of the bottom center sheeting to get a good look and maybe get some epoxy applied to the crank floor if everything else looks good. If anything is soldered look it over well for cold joints and corrosion caused by years of flux residue. Also check the hinges, if they're fabric check them carefully for rot, if it was me, I'd automatically replace them. If they're pin hinges make sure they're all well glued in. Check the engine bearers and make sure they're securely installed, also check around the landing gear installation for sound structure and adequate gluing. When everything is secure go ahead and finish it.

Like Randy says I would check the major glue joints and if it looks good I think I would give the structure a coat of clear before I covered it.

About 17 years ago, I restored a Barnstormer that was built in the 1950's. It had been assembled using Ambroid glue. Some of the glue joints had turned glass hard with age. I cleaned them out with an exacto knife and reglued them with Ambroid. The new glue joints worked fine.

After flying the model for awhile, the old glue joints started disintegrating and failing due to brittleness.

Check and reglue all glue joints in high stress areas.

Dee has the handle on the potential problem with this model. If it is that old, it was built before epoxy and some of the newer glues. Most likely it was Ambroid or Testors cement (like Ambroid, only worse). These glues never stop shrinking and never stop drying. The end result is they dry and pull away from the wood they are supposed to be holding together.

I would check everything. If all the joints look perfectly good, then Chicken Little here just had you go through all that for nothing. On the other hand, I had a plane like that given to me once (fully covered, however). I proceeded to go out and fly it, only to have the belcrank mount pull loose and rip through the ribs one by one. Not a pretty sight. Inspecting the plane afterwards, I could just disassemble the parts piece by piece. The glue had dried out and no longer doing its job.

Hi leon,
Just what the rest have said! I still have my Smoothie from 1964. I did a "nose job" on it, completely oil soaked, and recovered it. While I was at it I checked every wood joint I could, and if any were coming loose, or looked suspect, I hit them with thin CYA. Replaced the cloth hinges, too. Flew better than before.
Good side of it is that the plane now HAS to be lighter after drying out for all these years!
Bill <><

After a while, Amberoid turns to dust. Ribs get dried out and really brittle and it is hard to keep from breaking them. And as the one gentleman said, hinges and silk covering get rotten and will come apart. In addition just due to storage, some aircraft develop warps from just the way they were stored, or maybe doped with Buterate dope. Old combat planes are the worst after being recommissioned, I guess due to the violent maneuvers and stresses those aircraft experience. Old braided leadouts are also prone to break as well. If you check and reglue there is no reason a 20 or 30 year old airplane won't fly fine and last.

Hothandle:)