Re: Alginates


Bramblebush ForumsFAQ

Posted by bruce paul fink on December 06, 1999 at 19:24:41:

In Reply to: Alginates posted by John Odom on December 06, 1999 at 12:45:04:

Ho boy are you gonna have fun.

You can cast wax directly into a supported alginate mold but with some technical reservations.

First what is the size of the mold.

The alginate I have used needed a very fast and short term duration timed mix and if this is out dated material it will probably be even shorter. We are usually talking a mater of 3 to 6 minutes or less but it may be extended some by using a slightly greater percent proportion of water with it. This will also make it more fragile though and harder to later handle as a mold but it does help it take a better surface impression if flowing onto the forms.

All the kinds I have used could not be done in layers as they would not stick to each other so they had to have a one time mix/pour for each section.

Are you talking face impressions, or whole body casts?

I don't think I can help you on the whole body quatities here without getting into very precise and higher tech controlled proportions, mixers and fast distribution systems. When I have done body casts I used plaster bandages for the bulk of the areas and backed it with slight amounts of more plaster while only using the alginate for specific facial or other detailing (you said this was a class right).

I did do a very precise front body cast once this way for a lady in need of a full scale jello mold. This required it to be a food safe mold so the alginate had to be converted to an thin food safe plastic lining in a final plaster mold.

(It was one hell of a great ONE NITE ONLY POT LUCK GALLERY OPENING with hundreds in attendance. To get in everyone had to bring some item relating to food be it a painting, a sculpture, a movie, a dance or skit, costume or something that was really edible though it may not have looked like it. The entire show was also food related. Even had a huge roasted pig with full costumed players but we are getting off the point here.)

The wax can be poured into the alginate mold and either left to cool or slush cast but I think this will depend on the mold shape. I found that it was a one time pour use though... so in order to not loose the entire thing to any trials and errors I have used a plaster pour into it. Let that harden well and then discard the alginate mold. Wetting the plaster positive I then made a poured or brushed but thick wax mold off that. Then using the system of making waxes off of waxes to make more waxes I could use the plaster positive many times. Could also alter or recarve it and do variations from that, or vary the waxes and get a variety of different cast waxes from it.

Another use of this is to use the plaster positive for a green sand or kenset hardened sand mold and do some direct metal pouring into that.




Please let us know how this turns out John. There are quite a number of possible directions to go here.


For a more detailed description of the wax from wax for wax system go to the end of the chat on

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