From: Lamar Davidge (lamar.davidge@airmail.net)
Date: Fri Apr 18 2003 - 20:52:23 EEST
I worked for Glyn during this time period. The thing that I saw that made
the biggest difference in good parts/ versus bad parts, was proper mold
design. You can have the best process in the world, but if you are pouring a
poorly designed mold, you will still get air entrapment.
Glyn, was also succesfully pouring, and getting parts into a pressure tank,
even when the resin had a pot-life of 60 seconds.
Lamar
Interesting thread to see on the RP list. Usually I see this on the APMM's
"MILE", (mail list). It is for members only but members have a wealth of
knowledge on this and other model making subjects.
In the late '90s I was shooting parts, up to several pounds, in 50 second
CIBA resins(now Vantico) and BJB materials, in custom reworked paint
pressure pots. We would directly meter-mix dispense the material into the
mold (using Ashby-Cross eqpt.) while under vacuum, and then reverse to
pressure as soon as the mold was filled. While I consider this more closely
resembling a black art form, if you were good at using the process, and
properly designing the molds, it worked beautifully. Parts could be
demolded in, say, 10-15 minutes. We also heated the materials prior to
dispensing, to lower viscosity and speed the process. If you had several
molds, the process was continuous, except for the need to keep the molds
cool enough.
Glyn
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