To start off with you need a few things. Some you might have at home like the electric whisk, if you donít have one of these a battery operated or mains drill, with a bent bit of wire in the chuck works fine as a mixer for mixing it up.
The materials you will need to buy, and while most hardware shops sell plaster of paris the alginate is normally bought online as local shops unless you are really lucky donít sell it. I use dental quality alginate for two reasons. One its minty J and second being dental grade, its ok to use a normal household mixer without having to convince the rest of the household itís safe. Donít go to the local dentist and ask if they sell it, as they come up with some weird crap and make out its like gold dust and they can sell you some, but for ten times what it can be bought for online. You also need something to put you hand in, and for this I use a coke bottle with the top cut off. Last off a two litre plastic jug, again something most folk have in the kitchen.
With those sorted you are ready to start.
So its not that often I get asked to make body parts, but it is something people tend to ask for around Halloween for their party gimmick bits. A chopped off hand or foot placed strategically in the garden or hand pinned to the back of the loo door is a good one, especially if the loo faces the door. Girl goes in and sits down, then see the hand and shrieks. For some reason even though itís a Halloween party the hidden or severed limb gag always get a shriek.
So to make them as the film guys make them does cost an arm and a leg pardon the pun, but you can do it quite cheaply, especially if itís a one time thing.
The first thing to do is make the hand mould in alginate. This requires two jugs, or a jug and container to hold the water. For runny alginate, suitable for moulding your hand well, you mix it two parts of water to one part alginate powder. If you make it any thicker than this, it won't run and fill the mould properly and you will get a mould with lots of trapped air in it, ruining the cast.
Now one thing to point out is this sets in minutes, so get everything ready before you mix them together, once mixed its too late if you forgot anything.
Now onto the mixing. This is much better of there are two of you, but as many things I do, I find when I need a chum to help none are around, so while two people makes this much easier, I will go with the doing on your own tutorial to cover all corners.
So if you are using a mixer with slow start this is ideal, as you can start the water churning then tip in the alginate, and mix it as you go. Try to avoid tipping it all in at once, as this actually takes longer to mix in than a bit at a time.
Once itís all in and getting mixed together turn the whisk up to full and give it a good mixing together. This is a fast and vigorous but quick mix, as the longer you spend mixing, the less time you have till it sets.
If there are two of you, the hand to be moulded needs to be held in the plastic bottle, while the second person pours in the mixed alginate in, but if youíre on your own, itís easier to pour the alginate in first, and then place your hand in it. If you try to hold your hand and pour, you tend to get in a muddle, with the holding your hand still while pouring and you canít scrap the jug out to get all the alginate, so some is wasted. Donít worry if there is a bit of unmixed alginate left, as most times some gets stuck round the jug and only drops out when you scrap it clean.
This is where you need to be patent. Alginate only takes around three or four minutes, five at most to set, but it seems like ages and ages.
Its imperative you keep your hand as still, and as tempting as it may seem to wiggle your fingers, DON'T. While its runny slight movement is fine, but once it starts to set, any movement more than a slight tremble, will result in the alginate tearing or your enlarge the area around the part of your hand you move.
While it won't seem like much, even the smallest tear or enlarged area in the mould will show up on the finished cast.
Once the alginate has set, and to test for this poke the top of it with your other hand, its time to get your hand out.
This is not as straightforward as it may seem. Your hand is vacuum held in the alginate, so pulling it straight out will ruin the mould.
You need to gently wiggle your fingers and hand till you can feel the alginate come away, and build on this till your whole hand is free. You can easily feel if something is still stuck, so donít pull your hand out till it all feels loose around it. Itís very easy at this stage to just pull your hand out as there is only a bit still stuck, but if this rips away, everything is wasted.
My advice be over cautious and really make sure your hand if free before pulling it out.
Next its time to make up the plaster and fill the mould. How much it holds is a guess, so I tend to make to little too start with and just keep adding some more till its full. You can go the wasteful route and make up loads then throw the access away, itís up to you.
Before you start make sure you have everything you need, including two jugs, one to mix in and one for water, and a whisk of some kind.
I have some old electric whisker prong bits which work fine in an electric drill, or if her indoors is out nick her cooking one. (Try not to get caught, as they take offense at you borrowing their cooking gadgets for some reason ;)
Mix up the plaster so it is sort of thick custard consistency. To runny and plaster is not as strong, too thick and you will get lots of trapped air.
I find pouring it in a bit at a time and giving it a good shake helps get all the air out. Plaster sets fairly slowly, so no great hurry here.
Pour a bit into the bottom to cover all the fingers, then shake and gently tap on the table, to make all the air rise. When you are happy with that, pour a bit more in and repeat till the mould is full.
Then leave to set which depending on the plaster used, to how long it takes.
I leave over night, then remove the alginate and leave the hand on a shelf for around a week to fully harden.
So the finished in this case hand. Depending how what position you held your hand in the alginate to how it looks when done.
There might be some surface bobbles which were air bubbles, and these can be gently scarped off with a blunt knife.
If you want to use it as a severed limb, just hack at the stump with a large bladed knife, and this tends to do the job.
As for painting I base coat it first with matt varnish to seal it, as plaster is very porous, then apply the skin tones.
Use your own hand as a guide, and when painted one of the easiest ways to give it that dead grey look is to apply cement powder with a large brush. I have an old blusher brush which is huge with really soft bristles.
Apply and dust till it looks good to you.
If you don't have cement powder, dry brush light grey paint, or borrow some of her makeup.