Glassing wing center section

[Amir Neshati]

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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> >
>
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