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Building Tips and technical articles. => Building techniques => Topic started by: Ron Varnas on August 17, 2006, 11:32:25 PM

Title: Balsa fuse sides "curl" after ply doublers dry??
Post by: Ron Varnas on August 17, 2006, 11:32:25 PM
I've an old problem that seems to re- appear :-[

A while back I glued a set of Ply doublers on the balsa fuze sides for a Gensis 35,
I used slow curing 24 hr epoxy, applied only a thin amount to both the doublers & the
balsa, weighted the assy's down with some alloy plates on a perfectly flat surface,
after they cured I inspected the job, nice flat assy............thats until a couple of weeks
later when I had another look at them and the balsa had "curled" along the length of
the doublers :-[.....why does this happen, moisture in the workshop?, should I have
"angled" the ply - grain to 30o?.. as in this case the grain on both the doublers and
fuze sides ran the same way.

Any tips or hints greatly appreciated
Title: Re: Balsa fuse sides "curl" after ply doublers dry??
Post by: Busby on August 18, 2006, 11:47:34 AM
The balsa had a higher moisture content than the ply
and after everything cured out the balsa shrank.
Are you keeping every thing in the same enviroment thru storage and building?
I have also had the same problem gluing the doublers on with a water based glue, ie thinned down Tightbond II.
Title: Re: Balsa fuse sides "curl" after ply doublers dry??
Post by: Ron Varnas on August 21, 2006, 07:22:36 AM
Right on the mark guy's :D

I took the sides indoors last week , placed them on a flat surface, and
now they have returned nice & flat ;D
need to really take care on the storage & climate of all woods in future