Subject: Re: [harryproa] Wrapped Foam Plank infusion
From: "Chris Purkiss chrispurkiss@bigpond.com [harryproa]" <harryproa@yahoogroups.com.au>
Date: 7/6/2018, 7:56 PM
To: harryproa@yahoogroups.com.au
Reply-to:
harryproa@yahoogroups.com.au

 

If you are wrapping the foam strips 360 degrees in glass then a problem might be getting the glass to go around the corners and leave you with square surfaces to but together.Might be hard to keep to fair.


Try a couple of curved strips to test your method.

Chris Purkiss
M. 0428755749

On 7 Jul 2018, at 2:05 am, Björn bjornmail@gmail.com [harryproa] <harryproa@yahoogroups.com.au> wrote:

 

I think it's a good idea. I've been thinking about it as well. But it's a lot of manual work, and maybe this stiffness isn't needed. Well, at least not with a normal skin thickness or core material. I guess that with this method you could have a super thin skin, and maybe also the lowest grade XPS core. The "webbing" will have twice the skin thickness or more, depending on how the glass is wrapped around the "planks", so will be strong enough for the shear load even without a core, probably.

A similar method would be to make cuts in the foam at regular intervals, and push glass through these cuts. Lets say  cuts of 5-10cm/2-4" at 5-10cm intervals, or so.But I'm not sure if the shear load in the core is so high that these cuts needs to be reinforced with glass. Maybe the epoxy is enough? And if you make more cuts in different directions across the foam, lets say a 60° angle, then we are back to "my" idea of a honeycomb pattern in the foam. =)

On Fri, Jul 6, 2018 at 5:10 PM, StoneTool owly@ttc-cmc.net [harryproa] <harryproa@yahoogroups.com.au> wrote:
 

    In looking at construction possibilities, I keep coming to a rather
unique method..... or at least it looks unique to me. That is to slice
the foam into planks say 15 - 20 cm wide.   Wrap the individual planks
with fabric on the bias or with triax, sticking it to the planks using
spray adhesive.    Then do the infusion layup, laying fabric down, then
the planks, all pushed tightly together, then the interior fabric.  
Then infuse.

    This of course is more work, but has multiple advantages,
especially where foams like XPS are being used.   The interface between
the planks will be a solid glass rib of two plies, and this will make a
stiffener / stringer.  The ribs will also facilitate infusion, creating
a flow path between the surfaces. But most important, they produce a
solid glass longitudinal shear web at each joint, reducing concerns
about core separation from the surface plies.   The challenge for me at
least is the fact that the edge where the hull side meets the bottom is
going to be curved, as is the top edge.... but it's all doable, just
challenging.

H.W.


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Posted by: Chris Purkiss <chrispurkiss@bigpond.com>
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