On 2 Aug 2003 at 22:37, jfarrelly5_at_comcast.net wrote: > What determines the weight of fiberglass cloth? Say 4 oz verses 6 The weight is per square yard. Five square yards of 4 oz will weigh 20 oz. > Why doesn't epoxy bond to older epoxy (say > 3 days old) unless it > has been lightly sanded first? You can bond newer epoxy to previous epoxy if the previous epoxy is not fully cured. The newer epoxy will develop cross-link bonds with the old. If it is fully cured, no cross-links can be formed. In that case, by sanding the surface, you create a larger surface area to bond with - no cross-linking, just surface adhesion. BTW - 3 days sounds too long. With the epoxies I've used, I wouldn't attempt to bond without sanding if it's over 1 day, preferably less.. > Why does slow cure epoxy create a stronger bond than 5 minute > epoxy? It isn't the time, it's the quality of the epoxy. 5 minute is usually cheap stuff. Mike *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************Received on Sun Aug 03 2003 - 09:07:09 PDT
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