How to Lifecast a Hand With Alginate

by AndrewW1977

68K46932

Intro: How to Lifecast a Hand With Alginate

Lifecasting is making a mold of a living body. In this Instructable I make a wax casting of my hand. The overall result was impressive. The detail captured was better than I expected, with the texture of the skin being realistically captured.

STEP 1: Materials and Tools

You will need the following materials and tools:

  • Alginate (I used dental grade)
  • Cold Water
  • Container (I used 2L pop bottle)
  • Stir Stick
  • Drill and Mixing Auger (optional but recommended)
  • Casting Material: wax, plaster, concrete, etc..

STEP 2: Alginate

What makes this whole process possible is something called alginate. It is commonly used in the dental industry to make impressions of teeth. Try to get the slowest setting alginate as my first attempt I had a batch that was quick setting and I was not able to mix it with water quick enough and I ended up with a poor cast. I purchased mine from the local dental supply but you can find it online at various places like Amazon.

STEP 3: Mix and Set


I did film the whole process so you can view it to see how it was done. I will try to document the written steps as well.

Follow the instructions for the alginate as each type can be different. For the type I am using, it is 1 litre of water per pound. I am using a drill and mixer to quickly mix the alginate. The colder the water the slower the alginate will set. If you are doing a large casting like I am, you want it to set slow. The stuff sets fast once mixed with water! I don't have any pics of the mixing but all I did was pour the alginate powder into the water and mix.

I mixed in a separate bucket and then poured into a 2 litre pop bottle that was a good size for my hand.

STEP 4: Making the Impression

I put my hand in the mixed alginate and tried to keep it from the sides of the bottle. The alginate I am using takes about 2 minutes to set so I had to work really fast. Keep your hand still until the alginate sets to a rubbery texture.

You can now remove your hand, it took some wiggling of the fingers but eventually my hand came free. it might seem like it won't come out but take your time and it will. Don't be too rough or you will tear the alginate.

STEP 5: Pouring the Mold

Get your casting material ready, I am using wax but you can use liquid stone, plaster, concrete etc...

I melted some tea lights for the wax and poured it into the alginate mold. I poured the wax into the mold then poured it out to establish a coating then filled the mold with wax and left it to cool. It will take a few hours with hot wax.

STEP 6: Remove Alginate From Casting

Once your object is set, in my case the wax was hardened. I then started removing the alginate, slowly and carefully, since the fingers of my casting could easily be broken. I used a utility knife to score and then peel the alginate. It took some time but I managed to get it out with out any damage. For the really stuck alginate in the creases of the hand, I used a mixture of baking soda and water (1/4 cup per litre water) and let the hand soak for a few hours. Then I used a toothbrush to scrub at the creases.

STEP 7: The Finished Wax Hand

The detailing captured by the alginate and wax of the hand is impressive. This would make a cool decorative object. Eventually I plan on using this positive wax hand and make a mold for lost wax casting.

25 Comments

sophialouise.ordinanza.ab 5 years ago

hi! thank you for the great tutorial! i just wanted to ask what kind of lubricant did you put on your hand for it not to stick to the alginate when making the impression? and how much do you put on the skin for it to be safely pulled out from the mold? :)

Msrollingstone 3 years ago

You don’t need a lubricant. As long as the alginate is mixed correctly, it will not stick to your skin.

ElishevaBD 4 years ago

What do you mean by "establish a coating"? Why not just pour the casting material in once and for all?

But mostly, will hot wax not ruin the mold? I'm thinking if melted crayons...

Aristarco 8 years ago

If only I could send the cast hands to a glove factory, I'd be the happiest man alive. No surgical or industrial glove fits my extraterrestrialesque hands. :(

Wonderful instructable!

macrumpton 6 years ago

Dip the wax hand into some latex and let it dry, then peel off your perfect fitting latex gloves.

AmiraC1 8 years ago

hi great tutorial , I'm going to try it soon ,may I ask , is it okay if I use liquid wax bought instead of melting the candles , there's is no difference for the final cast , right ?

Buck Chenny 8 years ago

Great Instructable and the vid is a bonus. The creamier you can get the alginate, the better. That's done by mixing it more and/or adding a little more water. Always a challenge as you can quickly run out of time. Use an air nozzle (using small puffs) to help separate the alginate from your final model as it will make a small gap of air to get rid of the suction when you try to remove your final cast. Do NOT use compressed air to separate your hand from the alginate as you run the risk of injury.

bobski_horner 8 years ago

Your correct about not using compressed air to separate your hand. I was told as an apprentice compressed air can get into any break of skin and cause an embolism straight to your heart and brain. A very slow and painfull way to die.

CarlS46 8 years ago

For clarification. Is it okay to use air from an air compressor, don't use compressed air from a can?

bobski_horner 8 years ago

as the saying goes "compressed air " in other words air contained under extreme pressure held in a suitable container that can bear the strain/stress of the compressed gas held within it.

On the subject of compressors the tank itself should be checked out yearly by ultrasound ,this is to check the thickness of the wall of the tank which gets thinner over time by internal corrosion. Failure to do this can make your insurance invalid if the tank did explode and harm somebody . Unlikely I admit, unless you have an old machine, but insurance companies will look for a way not to pay out for any damage or otherwise.

Kinnishian 8 years ago

No compressed air of any form is considered a risk.

Personally haven't done research and can't really believe it, but I've heard quite a few people say that.

Buck Chenny 8 years ago

You just need a few puffs to blow between your final cast and alginate. Whatever you got will probably work.

Callie Lea 8 years ago

Fascinating. Wonderful job. Wonderful video to accompany your instructable. You make it seem easy, although it is challenging to get it done correctly and cleaned up without messing up your hard work. Good luck on your next steps.

SusanH75 8 years ago

Totally cool. Olav has a good point though.

eLVirus88 8 years ago

Cool! The detail on that casting is phenomenal!

Do you think it would it be possible to get multiple casts out of an alginate mold?

Buck Chenny 8 years ago

Alginate dries quickly and is very delicate. You might be able to get more than one cast from an alginate mold. It can get easily distorted or torn when you remove your first cast. It starts to shrink as it loses water at room temperature and humidity. You would be better off using a silicone/rubber/latex material for multiple casts.

AndrewW1977 8 years ago

Don't think so unless it was a simple object, using some type of releasing agent would help and you have to do it in two parts. If you want to do multiple, I think a 2 part silicone is what prop makers use. The benefit of alginate is it is cheaper than silicone and was a quick way for me to give this a try.

gavinnn 8 years ago

Wax (or likely in your case, paraffin) fumes are very flammable and take little to ignite. Best to use good ventilation and a double boiler (a smaller pot with the candles inside a larger pot with water) when melting.

Olav AlexanderM 8 years ago

Make sure to file off the prints, so nobody uses it to frame you for some sort of international crime spree or login to your phone :-P

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