Glassing wing center section

[Amir Neshati]

Will all due respect to your fantastic quality pipes, I humbly submit the
following:

The strongest lay-up in the case of the wing center section is to run as
much of
the glass fibers in the same direction as the balsa fibers, which is span
wise....
45 bias to the span/balsa grain is great for torsional strength, but that's
not what
we're after. The strongest will be to go to an 80/20 style fabric with 80%
of the
fibers running span wise and 20% cord....The  little 20% cloth cord wise
will be good
since no balsa or foam grain runs that way, but an all out uni will work
too...

The weakest direction of loading the bi-directional cloth in the center
section is the 45 bias.

Since there is balsa under our glass here, 60/40 may be hard to achieve for
most
with a bi-directional cloth, but with a uni, perhaps better can be achieved.

Have fun,
Amir





> It's quite important to cut glass on bias (0-45) then both warp and fill
> yarns will work. Strength wise, one layer of bias cut 4oz equals one layer
> of 0-90 cut 6oz. You will save weight and you will have smaller step. Also
> if you can, chose what's called balance weave cloth (warp and fill yarns
> have equal number of filaments). Do NOT use any kind of fast curing 5 or
30
> min epoxies. Use thin laminating resin preferably West System by Gougeon
> bros. It has been designed for laminating over the  wood in boat industry
> and it's user friendly. I'm glassing center section with only two layers
of
> bias cut 4oz cloth applied separately. First 2 inch wide over the joint.
Let
> it cure completely then lightly sand and make smooth transition on both
> sides to balsa. Apply 2nd layer over which will be wider than fuse by 1
inch
> on both sides and do the same. Ideally, your glassing job should consists
of
> 60% of glass cloth and 40% of resin by weight. You should see the weave,
if
> you can't you have way too much resin which will do nothing to strength.
> Laminate must be flexible otherwise when resin breaks so glass fibers
> inside. Paint small amount of resin on balsa first, then lay down cloth.
> Press it down with brush, wait till resin soak in then add some more. Be
> patient, don't rush.
>
> Ed Skorepa/EScomposites
> ----- Original Message -----
> From: "Jerry Wilson" <JWilsonJr at houston.rr.com>
> To: <discussion at nsrca.org>
> Sent: Monday, November 24, 2003 6:07 PM
> Subject: Glassing wing center section
>
>
> > I'm glassing the center section of my Elan.  Using 6 oz/yard K&B cloth
> > and 30 minute epoxy warmed with a heat gun on application.  The epoxy
> > brushes on well and when dry the weave of the cloth is noticeable.  In
> > other words the surface is not a smooth glasslike finish.  Is this OK or
> > do I need more epoxy applied for strength?
> >
> > Thanks,
> > Jerry Wilson
> > Katy,TX
> > NSRCA#3107
> > AMA#119585
> >
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