Roger:

This is really useful information! I have always wanted to know the best way to thin epoxy.

 Just to be clear,  both the epoxy and the hardener are
separately thinned before the two are mixed together. The ratio of the epoxy or hardener to acetone is one part epoxy/hardener to 10 parts acetone - or do I have that backwards?

Thanks for this!


Graham Stewart
Agile 76

On Tue, Nov 7, 2023 at 11:03 AM ROGER PIHLAJA <roger_pihlaja at msn.com> wrote:

> Hi Peter,
>
> At one point in my career at the Dow Chemical Co, I was chief engineer at
> a plant where we made C fiber insulation for the, then new, C-17 cargo
> plane.  As I recall, a 10%wt solution of epoxy in acetone was thin enough
> to spray with a conventional paint sprayer.  The thinned epoxy/acetone
> solution would flow by capillary action along the fibers and tended to
> gather at the fiber/fiber intersections.  Here, the acetone would
> evaporate.  When the epoxy kicked off, it bound the fibers together.  I
> would use the West System 209 extra slow hardener and 105 resin.  Mix up
> the resin/acetone & hardener/acetone separately and then mix them
> together.  At 75 degrees F, this will give you ~45 minutes of pot life and
> ~24 hours to fully cure.  This will be plenty of time for the acetone to
> evaporate and diffuse away.  Until the epoxy kicks off, the mixture will be
> thin enough to inject with a hypodermic syringe.  But, you could also just
> brush it over the crack and let it be drawn in by capillary action.  The
> thinned epoxy will also soak into the wood along the crack.  So, there will
> be very little squeeze out.  This will greatly strengthen the repair.  Once
> you have the crack filled, clamp the piece to force the crack faces
> together and clean up any squeeze out with a cloth damp with acetone.  You
> will end up with a solid epoxy/wood composite that will last so long,
> you’ll be able to pass it down to your grandchildren.
>
> Roger Pihlaja
> S/V Dynamic Equilibrium
>
> Sent from my iPhone
>
> > On Nov 7, 2023, at 10:16 AM, Mark Whipple <mark at whipplefamily.com>
> wrote:
> >
> > I just repaired a delaminated tiller I got from Stan. I used epoxy and
> > syringes made for use with epoxy. The epoxy I use is from a company in FL
> > called RAKA and is pretty low viscosity - thinner than West as I recall.
> >
> > I laid down some wax paper (epoxy doesn't stick to it) and put the tiller
> > on its side - after digging out as much of the gaps as possible. After
> > mixing the epoxy I used the syringe to direct the epoxy into the gap. I
> > clamped the tiller to close the gap. I think I probably used unthickened
> > epoxy first to coat the surfaces and then added some silica to thicken it
> > and put some of that in the gap as well.
> >
> > There were a number of gaps in this tiller and I also drilled out and
> > filled several holes, so it took a few days to get it all done, but it
> > looks pretty good now. I may drive some screws in from the bottom of the
> > tiller to further reinforce where the cracks were.
> >
> > Mark
> >
> > Boston, MA
> > 2000 R22 *When and If*
> >
> >> On Tue, Nov 7, 2023 at 10:00 AM peter beckerman via Rhodes22-list <
> >> rhodes22-list at rhodes22.org> wrote:
> >>
> >> Hi All,   My tiller handle has some delamination to the point that you
> can
> >> see light through a gap in the wood.  I want to glue it back together
> and
> >> then revarnish it.  I'm wondering if anyone has any good techniques for
> >> getting glue into the gap.  I was thinking of trying to thin some glue
> and
> >> injecting in with a small needle, but it needs to be pretty thin to
> force
> >> it through such a tiny lumen.  Anyone know of a better approach?  Any
> word
> >> glue that can be made pretty thin?
> >> Thanks,   Peter
> >>
>