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Vacuum versus centrifugal


#1

Kenneth Gastineau
gastin@mis.net

From: Jim Chambers pega@digital.net
To: orchid@ganoksin.com
Subject: Re: (Fwd) Orchid - member’s introduction
Date: Tuesday, October 01, 1996 1:15 PM

I would also like hear of your reasons for vacuum over Centrifugal… A
3
year beginner, never have used centrifugal, relizing that my techniques
may
not be the best, having tried lots of methods, having been told that
centrifugal is easier and provides more detail, AM CONSIDERING MOVING TO
CENTRIFUGAL AN AM CURRENTLY LOOKIN FOR A USED MACHINE… PLEASE TALK ME
OUT
OF IT BY YOUR KNOWLEDGE, EXPERIENCE, AND HINTS WITH TECHNIQUES!

Jim

At 03:21 PM 9/30/96 -0800, you wrote:

Jim,
As far as vacuum versus centrifugal I can’t really see a problem with
either one. A good caster can figure out how to cast well with both. Some
people say centrifugal casting produces better detail, but I have not seen
that to be the case. Detail is based on having good surfaces with no
porosity. This does not have as much to do with the method of casting as
with temperatures and cleanliness (in my opinion). I prefer vacuum casting
because I feel it is safer for larger flasks ( I plan to start using 6X9
flasks in the future and I cannot imagine slinging 6X9 flasks around the
room with over 1000 grams of molten metal with it.

One problem I can see with many of the vacuum casting systems on the market
is that most of them use small vacuum pumps, around 3 cfm. In my humble
opinion it is much better to use a larger pump, as I said earlier I use a
17 cfm. Sometimes these can be found used for a few hundred dollars. I
built my own casting chamber out of 9" steel pipe with a machined plate
welded to the top. I use a 1" pipe to connect it to the vacuum pump. If you
plan to retrofit an existing chamber to a larger pump you should plumb in a
larger line. Most casting chambers have pitifully small vacuum lines (it
is all you need with a tiny pump). When I hit the switch I immediately have
sufficient vacuum to cast.

You seem dissatisfied with vacuum casting, why? What kind of system do you
use? Do you use perforated flasks?

I still have my centrifugal casting system and may be interested in selling
it.

I am curious about what other subscribers think about vacuum versus
centrifuge.