Return-Path: Received: from dub-img-3.compuserve.com ([149.174.206.133]) by truman.olsusa.com (Post.Office MTA v3.1.2 release (PO203-101c) ID# 0-44819U2500L250S0) with ESMTP id AAA15069 for ; Thu, 10 Dec 1998 20:17:03 -0500 Received: (from root@localhost) by dub-img-3.compuserve.com (8.8.6/8.8.6/2.17) id UAA22724 for lancair.list@olsusa.com; Thu, 10 Dec 1998 20:17:27 -0500 (EST) Date: Thu, 10 Dec 1998 20:13:22 -0500 From: Marvin Kaye <74740.231@compuserve.com> Subject: Jeffco and Ratio tolerances Sender: Marvin Kaye <74740.231@compuserve.com> To: Lancair Mail List Message-ID: <199812102017_MC2-6330-950E@compuserve.com> X-Mailing-List: lancair.list@olsusa.com Mime-Version: 1.0 <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> << Lancair Builders' Mail List >> <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> >> Posted for Guy Buchanan Subject: Jeffco and Ratio tolerances Pine, If you can't get a reply from Jeffco (619-576-9900), I have some basic information. The Jeffco's "Lancair" system uses its 3102 hardener, which is listed as an aliphatic mannich base hardener. In general aliphatic hardeners are cross-linking and rely on a "stoichiometric" mixing ration. Thus, if you supply only 78% of the hardener required, you will cure only 78% of the available resin. This sounds worse than it is, because a gross estimate of E/epoxy bidirectional laminate properties indicates that the bulk properties go as follows: Modulus ~ -5% (4.44 Msi to 4.23 Msi) First ply failure ~ -9% (18.4 ksi to 16.7 ksi) Ultimate ~ -3% (72.5 ksi to 70 ksi) Please note that compression properties are notoriously sensitive to resin stiffness, and my software does not recognize that fact so you could end up with greater reductions in compression strengths than those noted above. Respectfully, Guy Buchanan Buchanan & Newcomer ******************************** NEW EMAIL ADDRESS: bnn@abac.com ********************************