Glassing wing center section

[Edward Skorepa]

You're right! The strongest lay up would be with unidirectional cloth
running span wise. But that wasn't my point! If somebody wants to use
bi-directional cloth (most people do, it's widely available unlike uni) then
cloth needs to lay down on bias. Otherwise,  filaments laying cord wise
don't contribute to strength at all and are just waste and extra weight. As
I said before, TWO yarns on 45 are stronger (not optimal)  but much better
then ONE running span wise.
As for 60/40 ratio, it's achievable. I seal the wood first with sanding
sealer before glassing.

Enjoy your turkey.
Ed
P.S. thanks for nice comment about my pipes (check's in the mail)
----- Original Message -----
From: "Amir Neshati" <amirneshati at earthlink.net>
To: <discussion at nsrca.org>
Sent: Tuesday, November 25, 2003 2:29 PM
Subject: Re: Glassing wing center section


> 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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> > >
> > >
> >
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