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Old Oct 17, 2015, 06:38 PM
Jim.Thompson is online now
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Gurit M80 foam.

Has anyone used this density Gurit foam? It is available in a range of densities, this is the second lowest on available. I was sent a sample of some of this years ago and have only now found a possible use for it.
It seems that is used a lot for boat construction as a laminate core material.
If I can obtain some 3 mm thick sheets (and get it delivered here to where I live) I will try some as a core material for a laminate sandwich for skins for both very thick airfoil wings and for box section fuselage construction.
This material will bend and hold it's new shape with a bit of heat from a heat gun.
The planned method for the wings, is to laminate the skin "shells" and build in a shear web and a few ribs to keep the airfoil shape over the span.
This kind of construction is used in some of the CARF Models, but I could not find the pictures again on the website this morning. The core material that they used is not specified.

Jim.
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Old Nov 10, 2015, 10:57 PM
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deleted... see below by John McGinnis
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Old Nov 10, 2015, 11:08 PM
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I have made very extensive use of Gurit Corecell M60 and M80 in both giant scale RC and full scale aircraft construction. It is perhaps the toughest, strongest foam available when used as a core, but M80 is a bit heavy (3x Dow blue foam density). It doesn't seem like an economical choice for any flat foamie work, and it can crack where EPP might crush but stay intact. (This assumes much higher loading, however. It would make one tough model if used as you described.)

I generally CNC machine 'solid cores' to shape, then laminate over them with carbon fiber or fiberglass. For comparison, here are some numbers from a test comparing A500, a similar SAN chemistry(Corecell) product from Gurit, to a styrofoam sandwich core of the same dimensions and total weight. M80 and A500 are close in properties, and although M80 is very slightly cheaper and heavier, I like it better.

A 2" thick test core of the Gurit A500 Corecell product, without lamination, failed at 232 lbs transverse load, with 5/8" of deflection in a 9" span.

In contrast, an EPS core, epoxy/fiberglass laminate (1 layer of 9oz, 8 harness satin weave on each side of the foam) of the same test dimensions failed at approximately 172 lbs, at the same deflection. Both weighed roughly the same (3.2 oz vs 3.4 oz respectively) as tested.

I built winglets for a 33% Synergy model using M80 with a carbon fiber skin. The only word that describes the result, in terms of overkill strength and stiffness, is "ridiculous." It's just ridiculous. Way too expensive, though, for ordinary work.

I'm sorry that I won't be able to respond to this post for any follow-ups as there is simply no time available. I hope I've been thorough enough to help.
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Old Nov 11, 2015, 12:34 AM
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I've just done a job using the 80 kilo stuff , so have got a whole bunch of offcuts , if there was a easy way to slice the foam from 20mm to 1 - 11/2mm I'd be laughing :-)

3mm is going to be very heavy ? And probably stupidly strong ?

I've used it as an intensifier in my mini quads and it sure makes a difference
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Old Nov 11, 2015, 04:40 AM
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Quote:
Originally Posted by mcsquared View Post
................................ Way too expensive, though, for ordinary work.
I came to the same conclusion.
Quote:
I'm sorry that I won't be able to respond to this post for any follow-ups as there is simply no time available. I hope I've been thorough enough to help.........
Thanks for the reply. It is good information for sure.

Quote:
Originally Posted by Blackrat View Post
I've just done a job using the 80 kilo stuff , so have got a whole bunch of offcuts , if there was a easy way to slice the foam from 20mm to 1 - 11/2mm I'd be laughing :-)

3mm is going to be very heavy ? And probably stupidly strong ?
.................................................. ............
Yes, if I was to use it, I would find a source of thinner material or a method for slicing the 3 mm into two 1.5mm or thinner slices.
See above, too expensive etc...........
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