Technical question ?


MARROW SUN

Active Hunter
Many factors contribute to the life of your molds. If your casting with polyester your mold will last longer than urethane. Urethane kicks off considerably more heat and is much harder on your molds, you will notice discoloration very early when using urathane, this is your mold absorbing chemicals and breaking down. You can prolong the life of your molds by using mold releases as well you can clean your molds using acetone.
On top all these factors the type and quality of silicone is important.
 

MandoMan

Active Hunter
Not to steal your thread, FettTheHunter, but what if I were to use plaster for the mold? Would that be a really stupid thing to do? I'm just asking because I've seen your work, MarrowSun, and I really admire it.
 

MARROW SUN

Active Hunter
Well with plaster molds your master must be totaly colvered in some sort of release agent otherwise the plaster will stick to it. Doing this you may lose some detail. Also Plaster is heavy and fragile making it difficult to work with in my opinion. Lastly, depending on what you plan to cast it better not have any undercuts otherwise the mold will end up locked into the casting and you will have to physically break your mold to get the copy out.
 

FettTheHunter

Active Hunter
MARROW SUN said:
Many factors contribute to the life of your molds. If your casting with polyester your mold will last longer than urethane. Urethane kicks off considerably more heat and is much harder on your molds, you will notice discoloration very early when using urathane, this is your mold absorbing chemicals and breaking down. You can prolong the life of your molds by using mold releases as well you can clean your molds using acetone.
On top all these factors the type and quality of silicone is important.

I'll be using a sillicone rubber mold with a plaster surround, amd casting in fibre glass, will I be able to get six helmets out of it ?

Thanks for sharing your knowledge (y)

Metal molds ?
 
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