You can refrigerate the material to increase shelf life. I spent 25 years building circuit boards including multilayer boards with "B-Stage" epoxy coated e-glass. Refrigeration with desiccation would allow the epoxy to survive for up to one year. If you are talking glass cloth only, you should see up to 3 years. If handled properly, you may be able to hold it longer at temperatures around 0OF with proper humidity control. Keep in mind that this is not readily conducive to household refrigerators. Your best bet is to "buy fresh". If you have the money the glass can be tested for usability, but most of us don't have the bucks to do that.
While the shelf life of the sizing may be five years, that assumes a relatively stable environment regarding humidity and temperature. If it was kept in someone's garage, barn, basement, etc., you don't know what you are getting. This is probably not the best place to go cheap. kind of like resin systems; this is the envelope you are flying in. best is better. Mark W. N952MW (res.) -----Original Message----- From: KRnet [mailto:krnet-bounces at list.krnet.org] On Behalf Of smwood Sent: Tuesday, March 26, 2013 5:05 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 ---------------------------------------------------------------- > I have searched the archives with no luck so I would like to post the > following question to the group. > Is there a way to determine the weight of fiber glass cloth based on > the thickness of the material ? > > I have recently been given some cloth by a former boatbuilder but am > uncertain to the weight (oz../sg.yd.) His widow just wanted it gone so > I was happy to help her in that regard. > > Both compare favorably to the sample picture in the Wicks listing for > KR cloth. in that both batches seem to be BID( woven at right angles). > One has 18 threads per inch and is .008" thick. > The other is 15 threads per inch and is .013" thick. > Can anyone confirm that either is suitable for use on the KR? > Other than cutting out a sq. yd. and weighing it is there a way to > determine what I have ? > I hate to cut it up if I can determine what it is by other means. > > Also, does anyone have an approximate count as to how many yards of > cloth is needed to complete a KR ? > > Thanks, > > -- > Jim L. > e.flyer1"at"cox.net > Virginia Beach VA > _______________________________________________ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org please see other KRnet info at http://www.krnet.org/info.html see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options
