Quick building question

Steve Barlow stevebarlow at attbi.com
Wed May 7 15:44:11 AKDT 2003


Ok guys.  I did one side (bottom) thinned just a bit, and the other side
(top) with the epoxy strait (it's 30 min) and it spread just fine.  So the
question is this...Should I bother to rip the glass off the bottom side and
redo it, or just live with it?  I kinda figured that the bond we're looking
for here is for side load, so it may not be too big of an issue.

Thoughts?

Thanks again,
Steve

----- Original Message -----
From: "wgalligan" <wgalligan at cnbcom.net>
To: <discussion at nsrca.org>
Sent: Wednesday, May 07, 2003 5:18 PM
Subject: Re: Quick building question


> I'm with "U" PatternDUDE!!!!
> I have experienced the shrinking qualities of the epoxy in some fill areas
of a now departed airplane that was thinned with alcohol.   If it was
shrinking in a fill area imagine what would happen in a critical area like a
joint or in the glass seam... could it shrink enough to pull on the center
joint casueing problems... I dont know but I wouldnt want to find out.
> WG
>
>  Hey epoxy cutters,
> > This may be obvious, but I've seen some statements that can be
misleading.
> > When anything is added to epoxy, it either evaporates out or stays in
the
> > mix.  When you add alcohol or acetone to epoxy the mixture will be
thinner,
> > but these solvents will severely weaken the epoxy.  When we paint it on
balsa
> > (as in glassing wings) the solvent evaporates off, but if you use
thinned
> > epoxy on other applications (where the epoxy is inside a joint) the
solvent
> > molecules will be bound into the epoxy matrix and the result will be
weaker
> > epoxy.
> >
> > You can prove this by leaving the epoxy/alcohol mix 1/4 inch deep in
your
> > epoxy mixing cup.  When you come back the next day, it will be cured,but
> > rubbery.
> >
> > The best way to get thin epoxy is to start with a thin epoxy.  Don't
start
> > with thick epoxy, unless you don't care about strength.
> >
> > --Lance
> > > Use denatured alcohol (ethanol) to cut epoxy and be real careful how
much
> > > you use.  Usually a few drops will thin it down a lot, and adding it
will
> > > take the cure time from whatever it might have been to overnight or
longer.
> > > You can buy it at Walmart in 1 quart cans.
> > >
> > > Adding acetone may thin epoxy, but it will attack foam.  The only
thing I
> > > use it to thin is Aerogloss Dope.
> > >
> > > ----------
> > > From: Bill Mears <bill at mears.com>
> > > To: discussion at nsrca.org
> > > Subject: Re: Quick building question
> > > Date: Wed, May 7, 2003, 9:54 AM
> > >
> > >
> > > Can  acetone ne used to cut epoxy ?
> > >
> > > Terry Brox wrote:
> > > The view was certainly proof of that  LOL
> > > ----- Original Message -----
> > > From: "wgalligan" <wgalligan at cnbcom.net> <mailto:wgalligan at cnbcom.net>
> > > To: <discussion at nsrca.org> <mailto:discussion at nsrca.org>
> > > Sent: Wednesday, May 07, 2003 9:12 AM
> > > Subject: Re: Quick building question
> > >
> > >
> > >
> > > I think he os leaning more towards the "something" thing.
> > > WG
> > >
> > >  > Are you an epoxy expert or something?  LOL
> > >
> >
> > > BTW, Your new contest mate sure has a cute, um, shoe. LOL
> > >   ----- Original Message -----
> > >   From: Gray E Fowler
> > >   To: discussion at nsrca.org <mailto:discussion at nsrca.org>
> > >   Sent: Wednesday, May 07, 2003 8:41 AM
> > >   Subject: Re: Quick building question
> > >
> > >
> > >
> > >   Steve- Rubbing alcohol is a mixture of isopropyl and and water.
Water
> > >
> > > bad. Epoxy hate water.......Plus amines (the epoxy hardener) really do
>
> > >
> > > not dissolve well in isopropyl. You are better off with methanol or >
> > > denatured alcohol which is ethanol with a nasty taste killer so you >
won't
> > > drink untaxed alcohol.I do not know what epoxy you are using, but >
that
> > > center reinforcement is easy without cutting the viscosity. Bring > it
to my
> > > house I have lots of low viscosity resins.
> > >
> > >
> > >
> > >   Gray Fowler
> > >   Principal Chemical Engineer
> > >   Composites Engineering
> > >
> > >
> > >        "Steve Barlow" <stevebarlow at attbi.com>
<mailto:stevebarlow at attbi.com>
> > >         Sent by: discussion-request at nsrca.org
> > > <mailto:discussion-request at nsrca.org>
> >
> > >         05/06/2003 10:10 PM
> > >         Please respond to discussion
> > >
> > >
> > >                 To:        <discussion at nsrca.org>
> > > <mailto:discussion at nsrca.org>
> > >                 cc:
> > >                 Subject:        Quick building question
> > >
> > >
> > >
> > >   Guys,
> > >
> > >   I'm doing the fiberglass reinforcement over the balsa sheeting where
>
> > >
> > > the main wings are joined on a .60 size kit.  Can I use rubbing
alcohol > to
> > > cut the epoxy with to thin it just a bit?  Do you think that would >
cause
> > > me any problems?  It sure would make it easier.
> > >
> > >   Thanks,
> > >   Steve
> > >
> > >
> > >
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> > >
> > >
> > >
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> > > .
> > >
> > >
> > >
> > >
> >
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