On 9/28/2013 1:13 PM, Erik Friesen wrote: > Did a vacuum pour test. Complete failure as far as I am concerned. The > small amount of air introduced in the connection, as well as the small > amount of air in the mix becomes an instant mini volcano. > > One option that could work for me is a double pour. Does polyurethane > water tight seal on "cold" joints?
In my experience, urethanes bond to themselves extremely well, as long as nothing is allowed to contaminate the surfaces you want to bond. I've had incomplete castings that I've "topped off" and the join is invisible - when all goes well. Sometimes the mold doesn't fit quite exactly back onto the casting and resin flows over one or both sides of it. Goes in the trash. Also some times the join is visible, trash too. Most of what I do is clear or colored transparent resin for non-stressed parts so appearance is most important. For your pump housing it's probably not a good idea to try salvaging an incomplete casting for anything but testing. If you want to deliberately do partial castings, that's another can-o-resin. For example you could machine away parts of the housing and mill slots into the edges to get more bonding area, then cast clear into the cut out sections for a 'cutaway' demonstration model that can be used with fluid flowing through it. Just be sure to pressure test *before* doing a demo for people you want to buy the thing! 'Sides that, having a bi-color product ups the "Oooooo!" factor to make your technical prowess look even better. ------------------------------------------------------------------------------ October Webinars: Code for Performance Free Intel webinars can help you accelerate application performance. Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most from the latest Intel processors and coprocessors. See abstracts and register > http://pubads.g.doubleclick.net/gampad/clk?id=60133471&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
