Submitted by LH on 9/6/99. ( ) 208.233.40.102
Got a project coming up that requires some castmaking of tracks. I've never used alginate before and am curious as to whether it forms a permanent cast that will stand up over time. Can anyone provide me the info I need? Thanks in advance.
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This response submitted by G.B. on 9/6/99. ( ) 205.188.208.9
Alginate is a good molding medium for a guick, usually one pull mold. Alginate is mixed with water and will start shrinking very soon after cured. It is also fairly fragile and I can almost never get more than one pull from the mold. If I where molding an animal track I would use molding plaster. If you are concerned with the mold breaking you could pour a thin splash coat of the plaster in the track after this starts to set pour a thicker mix over the first but work in some burlap for strength. The plaster will need to dry for about 10 days or so and then should be sealed with thinned shellac (2 coats). Add a release agent to the mold and pour your part. this mold will last a long time. For a permanent mold that is easily packed into the outdoors this would be my choice LH. Good luck.
This response submitted by Jim Tucker on 9/6/99. ( bigjims@wilkshire.net ) 206.68.132.250
Alginate is a dental impression material that picks up good detail when used to make temporary molds for death masks and even artificial noses etc. It is not a casting material. It is very soft and fragile when it sets up and will eventually deteriorate. When casting animal tracks plaster remains the best choice.
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