Return-Path: Received: from pop3.olsusa.com ([63.150.212.2] verified) by logan.com (CommuniGate Pro SMTP 3.5b2) with ESMTP id 830445 for rob@logan.com; Tue, 17 Jul 2001 02:05:17 -0400 Received: from spdmgaad.compuserve.com ([149.174.206.137]) by pop3.olsusa.com (Post.Office MTA v3.5.3 release 223 ID# 0-71175U5500L550S0V35) with ESMTP id com for ; Tue, 17 Jul 2001 01:52:57 -0400 Received: (from mailgate@localhost) by spdmgaad.compuserve.com (8.9.3/8.9.3/SUN-1.9) id BAA17733 for lancair.list@olsusa.com; Tue, 17 Jul 2001 01:59:35 -0400 (EDT) Date: Tue, 17 Jul 2001 01:56:09 -0400 From: Marvin Kaye <74740.231@compuserve.com> Subject: Re: Sticky Pump hardner color Sender: Marvin Kaye <74740.231@compuserve.com> To: "lancair.list@olsusa.com" Message-ID: <200107170158_MC3-D97E-8072@compuserve.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Mailing-List: lancair.list@olsusa.com Reply-To: lancair.list@olsusa.com <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> << Lancair Builders' Mail List >> <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> >> >> my Jefco hardner gets darker and darker over time in its unopened plastic container. << Bill, et al, The Jefco hardener starts out a very light amber color and changes only slightly in the plastic container. I have one unopened catalyst container in my shop that is only slightly deeper amber than it started out after 4 years. The color that Bill (Maddox) was talking about is a very deep red, almost mahogany shade that the catalyst takes on after only a very short time in the original Michael Engineering dispenser. I, too, have had discussions with the folks at Jefco about this color change and was told the same thing, that it would have no effect on the characteristics of the epoxy after it was cured. Bill's concern (and mine as well) is that there have been no longevity tests done with the resin system with the hardener in that particular changed condition, and so we don't really know what's going to happen after 5 or 10 or more years. Maybe Jefco is 100% correct in their position, and if that's the case then we're worrying about nothing. But if they're wrong we could be in for some undesirable surprises. Anyway, the dramatic color change is obviously a result of some reaction that is taking place inside the dispenser tub, and is caused by the check valve assembly. You can test this by putting fresh catalyst into a CLEAN dispenser tub and let it sit for a few weeks without pumping.... if you look at the catalyst during that time you'll see a cloud of deeper color that slowly forms around that check ball. If you leave it sit, the reaction spreads through the entire contents of the tub and eventually the entire batch of catalyst turns that dark red/brown color. To make a long story short, thanks to Bill's and others' discussions with the folks at Michael Engineering, they have come up with a check valve for the cat side that is made of a different material which doesn't discolor (ie, react with) the material. Bill has been testing the prototype valve for the past month with the pump in a controlled 80 degree environment and the material is the same light amber color, with no evidence of discoloration having occurred during that time. Hopefully they (Michael Engrg) will let us know when they've frozen the new design, the cost of the replacement valve assembly and when they'll have production versions ready for shipment. I, for one, will feel much better about my resin system knowing that the only reactions that are occurring are those that I initiate when I mix the resin and hardener together prior to doing my layups. I suspect you might feel the same. I hope that this clarifies this situation. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> LML website: http://www.olsusa.com/mkaye/maillist.html LML Builders' Bookstore: http://www.buildersbooks.com/lancair Please send your photos and drawings to marvkaye@olsusa.com. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>