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')
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@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.
>> >>>>
>> >>>>>
>> >>>>>
>> >>>
>> >>>
>> >>
>> >
>>
>
>