Re: Vacuum Pump

From: Michael Tsenter (
Date: Tue Aug 10 1999 - 18:00:19 EEST

Dear M.C. Moolman:

You may want to visit our web site and take a look at our turn-key
vacuum casting & polyurethane injection system. The CAMATTINI Protomix
System is used to de-air silicone, and then inject fast-setting
polyurethane materials under vacuum.

We use a 1.2 HP vacuum pump (our chamber is an eliptical dome with
dimensions of 38" x 24" x 17") and we normally de-air silicone in a
plastic bucket for about 10-20 minutes under full vacuum while the pump
is running. We then cast the silicone into the mold box, and then
de-air the silicone again for 30-45 minutes (depending on the pot-life
of silicone). The mold is then cured overnight (to minimize shrinkage),
or in the oven for faster cycle time.

We have not had any problems using Wacker Elastosil M4640 or other
platinum based silicones produced by GE or Shin-Etsu.

Michael Tsenter

CAMATTINI - North America
a division of NEST Technologies, Inc.
3849 Ridgemoor Drive
Studio City, CA 91604 USA
Tel:	818-761-6500
Fax:	818-761-6116
web site:

M.C. MOOLMAN wrote: > > Dear List, > > I am busy putting together a low cost vacuum chamber to de-air RTV > silicon. > At present I am using Wacker Elastosil M4640 transparent RTV. It is > extremely tacky and with the vacuum pump I am using now, I have > difficulty releasing the bubbles from the RTV. > Can anybody give me a pressure rating of a vacuum pump that I will > need to de-air most RTV's? > > Thanks > > M.C.Moolman > Freeplay Engineering > Cape Town > South Africa


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