KR> Glass cloth shelf life

[smwood]

The glass in fiberglass cloth does not have a shelf life.  The glass is 
inorganic.  The sizing coating on the glass strands is an organic compound 
and has a definite shelf life.
I use to teach this fiber glass stuff for the EAA Sport Air Workshops and 
still do at AirVenture.

Sid Wood
Tri-gear KR-2 N6242
Mechanicsville, MD, USA

---
> Sid said  - Fiber glass cloth has a sizing coating on each strand to help
> the epoxy
> resin to bond to the glass. The shelf life for most fiber glass sizing is
> five years. After that time the wetting out with the resin becomes more
> difficult and will result in a weaker structure. The older the cloth the
> worse the situation will be.
>
> I posted this question to the group some time ago and was told that there 
> is
> no end shelf life on fiber glass cloth. Would someone in the industry, (If
> there is someone in the group), please check in and clear this up.
>
> Patrick Driscoll
> Saint Paul, MN
> patrick36 at usfamily.net
> www.pensbypat.com
> If you can read this, Thank a teacher
> If you are reading this in English, thank a veteran
>
> 

KR> Glass cloth shelf life

[brian.kraut at eamanufacturing.com]

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KR> Glass cloth shelf life

[Patrick Driscoll]

Sid said  - Fiber glass cloth has a sizing coating on each strand to help 
the epoxy
resin to bond to the glass. The shelf life for most fiber glass sizing is
five years. After that time the wetting out with the resin becomes more
difficult and will result in a weaker structure. The older the cloth the
worse the situation will be.

I posted this question to the group some time ago and was told that there is 
no end shelf life on fiber glass cloth. Would someone in the industry, (If 
there is someone in the group), please check in and clear this up.

Patrick Driscoll
Saint Paul, MN
patrick36 at usfamily.net
www.pensbypat.com
If you can read this, Thank a teacher
If you are reading this in English, thank a veteran 

KR> Glass cloth shelf life

[Jeff Scott]

It is true that the sizing on the fiberglass cloth does deteriorate with age 
and the sizing is on the cloth to help the cloth wet out with resin. ?But, it 
will still wet out and produce the same strength composite structure as there 
is no shelf life for glass fibers. ?However, old cloth with degraded sizing 
will not wet out as readily, so it is easier to make a structure that isn't 
fully wet out. Or you may end up using more resin while attempting to get the 
cloth to wet out, making for a heavier structure. ?

If you don't have a lot of experience with glass, you really need for things to 
go right as you'll make enough mistakes without having the cloth fight you. 
?Much of the glass I am using for my modifications is quite old (purchased in 
2005). ?I can see the difference in that it takes more effort to get it to wet 
out thoroughly, but it does still work just fine and once wet out, the glass 
fibers bonded together with the resins should be the same strength as when the 
materials were new.

-Jeff Scott
Los Alamos, NM

> - Original Message -
> From: smwood
> Sent: 03/26/13 04:04 PM
> To: krnet at list.krnet.org
> Subject: Re: KR> Glass cloth shelf life
> 
> Fiber glass cloth has a sizing coating on each strand to help the epoxy 
> resin to bond to the glass. The shelf life for most fiber glass sizing is 
> five years. After that time the wetting out with the resin becomes more 
> difficult and will result in a weaker structure. The older the cloth the 
> worse the situation will be.
> 
> Sid Wood
> Tri-gear KR-2 N6242
> Mechanicsville, MD, USA
>