I swear that everytime I get an answer, it brings up more questions
<grin>.
Ok, so what I am hearing is that one reasonable way to build one of
these boats might be to use a 4' strip of Airex R63 for the keel
(assuming a 2' waterline beam) and lay that out flat with honeycomb
(polycore or nidacore) on either side and lay fiberglass on top, wet
that out with a sqeegee and then vacuum bag the whole thing to insure
a good foam/fiberglass bond (the scrim on the honeycomb wil bond
without the vacuum). That takes care of one side. Then flip it over
and wet layup the foam part. After that cures, bend it up and vacuum
bag the interior side of the airex. Am I good so far?
Next question is about attaching the roof to the hull. If the core is
only 15mm (roughly), there isn't much to attach to. Do I go back to
the old stringer method? Do I attach the stringers along with the
fiberglass when the core is still on the table? Or do I just put
thickened epoxy on the core edge and settle the roof on top and then
lay fiberglas tape over the edge and fillet the interior joint?
What about fabrics? I know I ran across a good price on 12 oz carbon
twill. Carbon is stronger than fiberglass, so can I just substitute
12 oz carbon in place of 24 oz fiberglass? What about 6 oz carbon?
That will make the boat lighter, but will it be as strong?
How much will the honeycomb bend? The airex seems a good bet for the
high curvature of the keel, but there is also reasonable curvature in
the bunk roofs. Should I just use airex wherever there is "noticable"
curvature?
>From the discussions, it seems like the honeycombs are now the
preferred core material, except perhaps below the waterline and in
areas of high curvature. The reasons for this are 1) light weight, 2)
good adhesion to the laminate, 3) low cost. Is all that true?
I have been trying to get samples from the various manufacturers, but
the only one who has replied in the past 2 weeks has been core cell.
I probably should not have sent the requests over teh holidays. For
polycore, it is the "Polycore Australia" company that I should be
going to, isn't it? I thought there was some discussion about there
being 2 companies that produce polycore and that one was definitely
inferior.
Thanks,
- Gardner
--- In harryproa@yahoogrou
wrote:
>
> G'day,
>
> Infusion fills every crevice in the core, and is particularly heavy
> when used with slit core on curved surfaces, which is where 95% of
> infusion is done. Check the claims, they usually specify lighter
than
> hand layup.
>
> I wet out curved surfaces with a foam roller and a squeegee. If it
is
> flat, pour the resin on and move it round with the squeegee,
removing
> all excess. For big jobs, use a wet out machine, but for a table
> sized job the clean up time makes this a poor choice unless you have
> another job to do at the same time.
>
> Bog is low density filler. With peel ply the weave is filled with
> straight resin, specific gravity 1.1. Bogging it fills the weave
with
> bog, sg about 0.3. It is also much cheaper. I would not use bog
> where critical secondary laminating is required, but on the exterior
> it works a treat.
>
> regards,
> Rob
>
> On Tue, Jan 6, 2009 at 7:14 PM, Gardner Pomper <gardner@...
> > All the info I have seen on infusion claims to be lighter than
vacuum
> > bagging. Interesting to know that isn't true in practice.
> >
> > How do you wet out the fabric when you bag it? Just lay it down
and
> > apply resin with a brush? Or do you have some sort of wet out
machine
> > that works on 50" wide rolls?
> >
> > Finally, what is bog? I had gotten the impression it was a low
density
> > filler, but now you are referring to it as an alternative to peel
ply.
> >
> > Thanks
> > Gardner
> >
> > On 1/5/09, Rob Denney <harryproa@.
> >> G'day,
> >>
> >> Infusion done perfectly is the same weight as vacuuming, but
perfect is
> >> pretty hard to achieve, so it is invariably heavier.
> >>
> >> Infusion is a very neat process, but takes a lot of setting up
and wastes
> >> more than I like. The bigger the job or the fewer the workers
available,
> >> the
> >> more it appeals.
> >>
> >> Punish yourself by cleaning resin off immediately you get it on
you and
> >> you
> >> will soon develop clean work habits.
> >>
> >> The only reason I bag a polycore laminate is to get a table
finish. It is
> >> probably quicker to hand lay it and apply a layer of bog (or
peel ply)
> >> when
> >> it is green to fill the weave. With foam, the bond between the
core and
> >> the
> >> cloth is pretty poor, so vacuuming is preferred.
> >>
> >> None of which is a deal breaker, go with whatever you are
happiest with.
> >>
> >> regards,
> >>
> >> rob
> >>
> >>
> >>
> >> On Mon, Jan 5, 2009 at 10:28 PM, Gardner Pomper
> >> <gardner@...
> >>
> >>> Rob,
> >>>
> >>> I am curious why you have a preference for vacuum bagging over
infusion.
> >>> I
> >>> know whenever I get within a foot of epoxy, it gets all over
me. The
> >>> infusion seemed really neat, and no more effort than vacuum
bagging. What
> >>> am
> >>> I missing?
> >>>
> >>> - Gardner
> >>>
> >>> On Thu, Dec 25, 2008 at 1:25 AM, Rob Denney <harryproa@.
wrote:
> >>>
> >>>> I am building with Polyore, under vacuum, but not infusing
(too much
> >>>> hassle for small panels). If it was not for the desire to get
a mould
> >>>> finish on the outside, I would not have bothered bagging it. I
would
> >>>> not
> >>>> infuse Polycore or Nida for the reasons stated earlier, and
would not
> >>>> infuse
> >>>> foam unless there were time constraints. The 15m lee hull will
be built
> >>>> in
> >>>> one panel, 7m x 15m, hand laid and vac bagged, not infused.
> >>>>
> >>>>>
> >>>>>
> >>>
> >>>
> >>
> >
>
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