Subject: Re: [harryproa] Re: Resin infusing honeycomb?
From: "Rob Denney" <harryproa@gmail.com>
Date: 1/7/2009, 2:07 AM
To: harryproa@yahoogroups.com.au
Reply-to:
harryproa@yahoogroups.com.au

G'day,

Robert,
The bog is applied to hand laid glass after it has gelled. Not to
vacc'ed laminates. Wetting out on a flat surface then transferring
the wet cloth to the job is possible (carefully with double bias,
which 'stretches'), but with flat panels it is easier to do it on the
job.

Gardner,
> 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?

No. Flip it and glass the Polycore, bend it and glass the foam.
>
> 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?

Can use a stringer, but lighter and neater is an edge radius. Derek
Kelsall has a free dvd on KSS which should include edge radii.
Strongly advise you and any other potential builders to get a copy.
>
> 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?

Generally speaking 12 ounce carbon will replace 24 ounce glass.
Stiffer, lighter, 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?

Honeycomb bends a lot, but is prone to kinking, so do it slowly. Foam
in curved areas is an alternative.
>
> 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?

Same weight as foam, otherwise true, but there are edge issues.
>
> 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.

Phone them with a price enquiry for a couple of 100 sq m for your
80'ter. This gets there attention and gives you a bargaining chip
later on. Make sure you get the person's name and ask for him when
you chase it up 4 days after you ask. Polycore Aus and Nidaplast are
similar, but there are a bunch of inferior products out there.
Rapscallion is importing the Polycore Aus product into the USA, so ask
kim for a sample.

regards,

Rob
>
> Thanks,
>
> - Gardner
>
> --- In harryproa@yahoogroups.com.au, "Rob Denney" <harryproa@...>
>
> 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@...> wrote:
>> > 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@...> wrote:
>> >> 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@...>wrote:
>> >>
>> >>> 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.
>> >>>>
>> >>>>>
>> >>>>>
>> >>>
>> >>>
>> >>
>> >
>>
>
>

__._,_.___
Recent Activity
Visit Your Group
Yahoo!7 360°

Start a blog

Public or private-

it's your choice.

Y!7 Toolbar

Get it Free!

easy 1-click access

to your groups.

Yahoo!7 Groups

Start a group

in 3 easy steps.

Connect with others.

.

__,_._,___