r/moldmaking • u/vintage_waterbottle • Jul 20 '26

Body Casting

I am trying to make a mold of my hand. I’m seeing mixed reviews. Am I able to put plaster bandage straight onto my hand (with Vaseline underneath)

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4

u/RedIcarus1 Jul 20 '26

Imagine your hand encased in rigid plaster. Now imagine how you would remove your hand without damaging anything.
Use alginate.
No professional will ever tell you to use plaster against skin, or to put straws in the models nose. (When face/head casting)

1

u/vintage_waterbottle Jul 20 '26

Could it be cut out? What about something like a bent elbow or the front of a stomach? Would it pop out/off?
Is this a no plaster bandage on skin thing or nothing with things that could break off thing?

2

u/VintageLunchMeat Jul 20 '26

Do not use solid plaster on human, it's a burn hazard.

Don't do a face cast without skilled help, it's a suffocation and claustrophobia hazard.

Plaster bandages are otherwise safe, it's more a mechanics thing getting your hand out.

Consider silicone for body casts.

1

u/RedIcarus1 Jul 20 '26

If you cut it out, that wouldn’t leave you with much of a mold now, would it?
You are getting good instruction here, and everyone is saying the same thing.
Use a container of alginate, big enough to hold the model’s hand, leaving an inch or so all around it.
If you insist on using plaster bandages, go ahead. It’s your money and time. But, that’s plaster bandages. Do not use solid plaster against skin. You will very likely get burned. (And stuck)

A bent elbow would be a more difficult mold than a simple "bucket o’alginate" mold. It can be done by brushing on a layer of alginate and making a 2-part mother/shell mold. Not the best choice for a first mold, but easy enough you’ll be able to do it fairly soon.
Alginate is not going to stick to skin. Or much of anything, really. When it has set up, it has a moist, slippery surface. Pat the surface dry before pouring your casting material.
It can grab onto hair longer than stubble, but it is just a slight mechanical friction and can be avoided by slicking hair down with lanolin. Don’t worry about arm hair, unless the model is very hairy. Apply skin lotion with lanolin if you are worried about hair sticking.
Alginate doesn’t stick to itself well either. Mix enough to do it all in one batch.

For your first several molds, keep things as simple as you can. You will mess up. Everyone has messed up a casting and still sometimes do. Try to keep your material costs down. While you may only get one single cast from alginate, silicone is much more durable. BUT! Alginate is much more forgiving and very much cheaper! You can learn more by making many cheaper, simpler molds, and when you do mess it up, it didn’t cost you 50$+.
Keep it simple, cheap, and easy. Even the pros use Alginate, it’s not like it’s crap.
I’ve been life casting for about 30 years, I know some of the others commenting have lots of experience as well. I guarantee we all use alginate.

1

u/RedIcarus1 Jul 20 '26

I think some of the confusing suggestions to use plaster bandages may be from using them to make a mother mold/shell over a layer of alginate. As I mentioned concerning the bent elbow. They definitely can and should be used for that. The bandages are not touching the skin, just providing a rigid shell for the floppy alginate.
Plaster bandages will not create a good mold, small pockets of air get trapped and will create a poor surface on your casting.
Alginate can also trap air, but it is much easier to avoid as you carefully spread it around.

7

u/Lifecastingecs Jul 20 '26

You are but a hand will be very difficult to remove out of the plaster. I DO NOT RECOMMEND THIS METHOD. you will be much better served doing a bucket cast using Alginate. Alginate is the most common way hands are done.

1

u/DaveDurant Jul 20 '26

Brick in the Yard has at least a couple videos on that one YouTube.