Making an Alginate Mold for Mask Making

[PlanetAlexander]

Heya RPF, I've got a project I'm working on with a mask in which I want to be able to cast a final copy from resin. The mask is made from foam clay and PLA plastic from 3D prints, and I'm going to seal it all in flexbond and wet-sand it smooth.

I don't really have time to learn hands-on using silicone for making molds, so I'm hoping to make a one-time mold from alginate, then use that to make a resin cast. Hopefully later, after the main project is done I can then make a mold from silicone.

Just wondering if anyone has any tips on making a mold of a mask from alginate? I've read/watched heaps on things on making silicone molds for a variety of purposes (including masks), but I don't know how much of that will translate to alginate. Do I still need to do a single print layer and then bulk up the mold? How long does alginate last before deforming/decaying?

Cheers!

 

[ChickenHaunt]

Urethane resins don't play well with water, which the alginate mold is largely composed of, so not recommended. You can do plaster/stone in alginate very well. Generally you want to do the entire alginate build up in one go, as it doesn't stick to itself (without help) once it sets up. Remember an alginate mold is really only good for one casting. You want to keep it hydrated in the time before you make your casting, as it starts shrinking from water loss very quickly.

 

[benhs1898]

I recommend just doing silicone. It’s honestly easier than alginate because you aren’t worried about the degradation of the inner mold while you create the mother mold.

 

[PlanetAlexander]

Thanks for the respones guys! I guess alginate is just not at all the way to go. I will have to dish out on some proper silicone - luckily I've got a couple of things I can cast and not just the mask for what may be a one-off. Any suggestions on a good silicone to start to learn with? I'll be ordering off an Australian site like Barnes or Lumin's Workshop.

Also, is there any other way to make a jacket mould then from fibreglass, maybe with plaster? I've actually never used the stuff and I'd rather not have to learn in the short time I have left.

 

[yodakiller1138]

Plaster bandages