Subject: [harryproa] Re: Resin infusing honeycomb?
From: "Robert" <cateran1949@yahoo.co.uk>
Date: 12/25/2008, 2:48 AM
To: harryproa@yahoogroups.com.au
Reply-to:
harryproa@yahoogroups.com.au

From my understanding, preresined glass over Nidacore then bagged may
be a bit lighter than resin infusion. The underneath side should be
realtively easy to just resin on the table and then lay the honeycomb
on top. I worked out the extraweight of putting holes through
honeycomb and it added significant weight.
It may be possible to join panels using the method of joining balsa
panels in kit form. By routing a champher on the edges, the panels are
glued together using a clamp

Congratulations Rob an the Sydney Hobart kite work

--- In harryproa@yahoogroups.com.au, "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.
>
> George
> I am planning on sending off for samples of various core materials to
> evaluate. My first project with these will likeley be a 10' catamaran
> dinghy, but it is all in prepartion of building a 40-50' harryproa.
Can you
> give me some information on what thicknesses I should be looking at
for the
> different core materials. I am currently considering:
>
> core cell
> polycore
> nida-core
> airex foam (for the rounded hull bottoms)
>
> Also, what other core materials might be appropriate? I don't want
to deal
> with balsa, but other than that I am open to pretty much anything.
>
> Finally, what foam are you using for the bows? It looks like your
current
> process is to build flat panels for the hulls up to within about 1m
of the
> bows and then carve the compound shape out of solid faom. Am I
correct in
> that?
>
> Rob
> The 10 footer can be 6mm H80, the 50'ter will be 15 and 20mm H80.
Plain, no
> cuts, or scrim. You will need to perforate it by drilling 1mm holes at
> 100mm/4" centres through the stack of sheets. Apart
Divynicell/Termanto
> foam you have covered the options I would consider.
>
> I use high density polystyrene for the bows. Yellow Pages should
throw up
> half a dozen local suppliers. You can use any closed cell foam, but
> polystyrene is easy to glue and sand, light and cheap. The sides of the
> hull are flat panels up to 500mm/20" from the bow, below the
waterline foam
> goes back further, depending on how narrow the hulls are.
>
> George
>
> I apologize. I hit send too early. I am also curious about the
> fiberglass/carbon. Can I get away with just using fiberglass cloth
for the
> hulls? What weight is used on a Harry? How about a Visionarry?
>
> I have also noticed that there are sometimes 2 types of fabric
listed under
> cloth, "regular" cloth and "twill". Is either of them ok for use? Do
they
> both leave the same type of surface finish?
>
> I am also curious about pricing tradeoffs. From my very inadequate
sample of
> information, I am coming up with sq ft pricing that indicates that
the vast
> majority of materials cost is in the core material. For example,
based on
> the one infusion that I have seen done:
>
> 12mm core cell : $3.50/sq ft
> Vinylester resin: $1.25/sq ft
> Fiberglass 10oz: $0.55/sq ft
> Total: $5.30/sq ft
>
> But I saw some 12 oz carbon fiber twill on sale at Noah's for
$2.25/sq ft.
> While 4 times the price of the fiberglass, it only increases the total
> materials cost by $1.70/sq ft. Might it be worth just using carbon
fiber on
> the whole hull? Or maybe just on one side?
>
> I feel like I am askign alot of incredibly basic questions. There
must be a
> book or something out there that would help teach me the basics so I
would
> not have to pester people so much. Can someone recommend one to me
(purely
> in self defense <grin>) ?
>
> Rob
> Woven cloth is not used much these days as knitted cloth is
preferred. This
> is two layers of uni knitted together which keeps the fibres
straight and
> theoretically puts les strain on the resin. Harry has 400 gsm/12
oz, Vis
> 600 gsm/18 ounce.
>
> Regular cloth is one tow woven over one, under one. Twill is two
tows woven
> over two/under two. Twill looks hornier and the fibres have less
crimp, but
> it is hard to keep the edge s neat as it frays very easily.
>
> Core is the expensive part, which is why strip planking is (was in a
lot of
> places) lower cost. That is cheap carbon. Could use it on both
sides (not
> one) if the cost is affordable. Problem with infusing carbon is
that it is
> very difficult to tell the wet bits from the dry bits. I would test
with
> glass first.
>
> Your questions are not too basic. I certainly don't mind answering
them.
> There are a number of books which have some of the information in them.
> Google and the supplier's web suites are another good source.
>
> Regards,
>
> Rob
>
> Thanks,
>
> - Gardner Pomper
>
>
>
>
> On Thu, Dec 25, 2008 at 12:03 AM, Gardner Pomper <gardner@...>wrote:
>
> > Hi Rob,
> >
> > I thought you have recently been building with a honeycomb core.
Have you
> > been infusing that on just one side at a time, or is it different
enough
> > from nida core that you can do both sides at once?
> >
> > - Gardner
> >
> > On Tue, Dec 23, 2008 at 9:18 PM, Rob Denney <harryproa@...> wrote:
> >
> >> G'day,
> >>
> >> Glad it went well, George. Infusing Nida is tricky. I would not
drill
> >> holes in the core, you will use a fair bit of extra resin. George's
> >> suggestion would be better. The big problem is the edges.
Exposed edges
> >> could be tapered using a hot household iron, but joined edges
will be messy
> >> as you don't want a solid resin edge for weight, bending and stress
> >> reasons. A solution would be to taper them both at 45 and
overlap them.
> >> On big boats, you could leave a gap and join the inner and outer
skins.
> >> You could also bog the edges before infusing. None of these are
ideal.
> >> Unless there are labour/time considerations, i would lay it all
up wet and
> >> bag it. I would also talk to Nida and ask for their advice. It
is possible
> >> that a thicker layer of scrim would act as a transfer medium
> >>
> >> Funny story: I got a phone call yesterday from the guy that
bought the
> >> 420 sqm/450 sq' Outleader kite. He makes boating movies for a
living. He
> >> has chartered Brindabella (80' maxi) for Sydney Hobart, sold half
the crew
> >> positions ($10,000 each!) and because the forecast is for fresh
northerlies,
> >> wants to fly the kite in the race and film it for a future TV
show. Could I
> >> come over and show them how to work the kite?
> >>
> >> So, I leave here at 0005 on Boxing day, fly to Sydney, get to the
boat at
> >> 0900 and we cast off at 1100, race starts at 1300. A beat out of the
> >> harbour, then bear away, drop the main and hoist the kite. Next stop
> >> Hobart. A boat full of kite virgins, including the inevitable
few who think
> >> they know what they are doing and the world's biggest traction
kite. Add in
> >> the stress of the race, the on board cameras, a dozen media
helicopters,
> >> huge spectator fleet and we have the recipe for a flawless
display. ;-) I
> >> will let you know how it went when i get back.
> >>
> >> regards,
> >>
> >> Rob
> >>
> >>
> >>
> >>
> >> On Wed, Dec 24, 2008 at 12:31 AM, Gardner Pomper <gardner@...>wrote:
> >>
> >>> Hi,
> >>>
> >>> I got my first hands on demonstration of vacuum resin infusion from
> >>> George Kuck of this forum last weekend. Thanks George! He was
using core
> >>> cell and had drilled holes through to allow infusion of both
sides of the
> >>> panels. I an now looking to start trying some samples myself and
I wanted to
> >>> try out nidacore. My question is, can you still infuse both
sides at once on
> >>> honeycomb? I can't tell how big the cells are, but it would seem
to me that
> >>> drilling through might open a couple and you would end up with a
big block
> >>> of resin. Is that ok? I would think it would be a stress point.
> >>>
> >>> - Gardner
> >>> York, PA
> >>>
> >>>
> >>
> >
> >
>

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