REFLECTOR:STRUCTURAL ADHESIVE

[reflector@tvbf.org]

Here's a spec sheet for one mix of 
Proset  http://www.prosetepoxy.com/125-226phys.htm  You may note that 
there's a significant change in some of the numbers for even a mild post cure.

Burt uses nothing but Proset at scaled.

Nat uses MGS http://www.mgs-online.com/ there's supposed to be an English 
section but I can't find it.

EZ Poxy is now made by Epoxical http://www.epoxi.com/main/home.asp they 
don't have a spec sheet on their web page.  Actually they don't talk about 
EZ Poxy much, they sell a lot more of their CPD line of laminating 
resin.  I've used a bunch (several 55 gal drums) and it's good stuff.  But 
I still like Proset better.  The adhesive - the gelled stuff from the gun - 
is absolutely wonderful for closing out blind ribs in strakes and wings.

Make sure you're comparing apples to apples.  There's a data sheet from 
PTM&W running around about Aeropoxy that has numbers an order of magnitude 
higher than these, it says it was done with 10 ply laminates.  I don't know 
what the standard is, but I know Aeropoxy isn't 10 times stiffer and 
stronger than anything else.



At 06:54 PM 5/6/03 -0600, you wrote:
>All of this sounds OK, sort of.
>
>But in the scientific world which we are trying to emulate its all 
>anecdotal, which means it ain't worth the paper its printed on.
>
>Where's the specs?  Where's the testing results.
>
>I know Rutan didn't recommend West but he states specifically that he only 
>recommends products that he has tested, and as far as I know he never 
>tested West for applicability.  Or maybe he did, but I haven't been 
>referred to any documents that support that.
>
>As far as I know Nat never did any testing of resins, he just followed 
>Rutan's lead, not a bad lead to follow.
>
>Here is a brief West Systems Properties page
>
>http://www.westsystem.com/webpages/userinfo/moreinfo/properties.htm
>
>I've seen one of these for EZPoxy but can't seem to find it.
>
>Anybody know of one online?
>
>Scott
>
>
>Alexander Balic wrote:
>>The resin provides the shear strength of the laminate - it is like the
>>difference between trying to bend a board (strong resin) and a telephone
>>book (weak resin) the difference in the telephone book is that there is no
>>shear strength between the pages (fibers).  But you only need just enough
>>resin to make maximum contact with the fibers, any more, and the fibers will
>>tend to float apart, causing more of the (much) weaker resin to be in shear,
>>by cross section, as well as making the lay-up unnecessarily heavy. so the
>>argument is correct, but to be able to stress a given laminate is
>>proportional to the shear strength of the resin, but once the resin starts
>>to fail, the laminate is done (de-lamination) so perhaps a stronger resin
>>could provide the same stiffness with less fibers, but I would say that the
>>only way to significantly change the stiffness is to go to a lower modulus
>>of elasticity (low E)  fiber like graphite, that has less stretch than the
>>glass.
>>-----Original Message-----
>>From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org]On
>>Behalf Of lawrence epstein
>>Sent: Tuesday, May 06, 2003 6:42 AM
>>To: reflector@tvbf.org
>>Subject: Re: REFLECTOR:STRUCTURAL ADHESIVE
>>
>>Is this accurate?  I was under the impression that a very small percentage
>>of the ultimate (load bearing) strength is from the resin.  "strength" is
>>derived from the fibers .  the resin merely keeps the fibers lined up?
>>Larry Epstein
>>173 FGE
>>
>>>I'm saying that for a laminate of the same strength or of the same
>>>stiffness you'd use fewer plies (and thus have less weight) with ProSet
>>>than with WEST.  (Note that they're both made by Gougeon)
>>
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