John German wrote:
>
> To any investment casters out there,
>
> Does anyone know of a material that can be used for patterns or samples
> that is very runny (like water), that sets up in a very quick time, has
> very little if any shrink, and has a low ash content so it can be burned
> out of an investment mold? We have tried several kinds of wax, and has
> been working fine, however in order to get the wax to a very runny state,
> we must heat it up considerably, which causes the wax to loose some of its
> properties. We want a material that will be able to pick up very fine detail.
>
> thanks in advance,
>
> John
>
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> For more information about the rp-ml, see http://ltk.hut.fi/rp-ml/
John
1) Usually the problems you mentioned are solved by pressure injection
of the semi-melted wax into a hard
mold/die. Are you pouring your wax into a soft mold (RTV)?
2) In the early days of investment casting mercury was sometimes used
with chilled molds and treeing. The
advantages were the lack of expansion during the phase change and
"melt-out" was really "pour-out" at room
temperatures. The disadvantage is, of course, the mercury positioning
problem.
3) I don't have a reference on it but some work is being done using
water as the pattern matter with the
problems of chilling and aqueous slurries. Also, sometimes its
difficult to get an MDS for the material.
4) You might contact the people at the wax supply houses such as J.F.
McCaughin Co. in Rosemead Ca.
(800) 573-3000, or others.
good luck
martin
For more information about the rp-ml, see http://ltk.hut.fi/rp-ml/
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