Du Pont resin growing thicker

From: aaroflex (aaroflex@aaroflex.com)
Date: Fri Jul 16 1999 - 04:51:17 EEST

Dear Du Pont resin users,

The Du Pont resin has a great affinity for water. Originally AAROFLEX
staff maintained a humidity level of 80% in the vat area of the Solid
Imager , but this is very difficult to do unless you install some good
equipment. AAROFLEX discontinued that effort and then occasionally
misted the vat with distilled water, then mix well from the bottom of
the vat. Of course, one will fail to do this on a routine bases when in
a hurry to fabricate parts and the resin begins to thicken. I know it
is difficult to justify a new vat of resin if you are not using the
machine every day and the resin is thicker. Therefore this becomes a
problem that has been mentioned from time to time. Then on desperate
measures the staff would simply pour into the vat some distilled water
after a run, then mix well from the bottom and the let it set over the
weekend so that the water would be assimilated well into the liquid
resin. Up to two percent addition of distilled water into a thick vat
of resin may be possible. This is not a recommend procedure, but using
a thick resin is not a normal procedure either. Too much water may
cause microscopic bubbles if you are running the power too high for the
proper cure. Trash in the bottom of the vat does not cause any
significant thickening of the resin as claimed. Why do you have trash in
the bottom of the vat anyway? Two containers of resin were set back for
over a year. One container of resin was open to the air and the second
container of resin was closed with partially cured parts in the resin.
The open clean resin became thicker and the closed contaminated resin
was not thicker.

AAROFLEX, Inc. is a distributor for both DuPont/DSM and RPC resins.

Yours for what ever it is worth.

Albert C. Young, Jr., P.E.

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