Glassing wing center section

[Nat Penton]

Amir , if my memory serves correctly (and it generally does not ) Ed is
correct in that using a bi-directional cloth the tensile strength  is X in a
warp direction and 2x .707 X in the 45 degree direction.
----- Original Message ----- 
From: "Amir Neshati" <amirneshati at earthlink.net>
To: <discussion at nsrca.org>
Sent: Wednesday, November 26, 2003 3:30 AM
Subject: Re: Glassing wing center section


> Ed,
>
> Even when using a balanced bi-directional cloth, it is still strongest in
> the
> 0-90 direction. This way, either the warp or fill will be perfectly lined
up
> with the span, which is still stronger than both warp and fill in a 45
bias.
>
> The one yarn of cloth in the correct orientation (span wise) will be
> stronger
> than both yarns in the wrong direction (0-45)....
>
> by the way, I accept PayPal...could have saved ya a stamp ;-)..You did
> put the stamp on 0-90, right?
>
> Happy holidays,
> Amir
>
>
>
>
>
>
>
> > 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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