Introduction: How to Cast a Face in Plaster

Picture of How to Cast a Face in Plaster

Making castings of things is a lot of fun, and casting a face is fun PLUS all the weirdness of having something looking like you lying around, hard, cold, and unmoving. Creepy! On a recent Build Day we cast Bilal's and Josh's faces, and this Instructable explains how.

There are 3 general body molding techniques: pat-on, dip-into, and pour-around. They're pretty self-explanatory. For a face you need to use the pat-on method, which is more annoying but allows you to make the all-important nostril holes.

Step 1: Prepare Your Work Area

Picture of Prepare Your Work Area
You're going to make a mess. Know this and prepare in advance. Lay down a drop cloth if you have one, or ensure that all nearby porous surfaces are covered with plastic or newspaper. Gather all your materials together as it will be difficult to get, say, another bucket when your hands are covered in alginate.

You will need:

  • alginate, the stuff dentists use to cast your teeth. There are a couple different brands, we used Dermagel brand from Douglas & Sturgess.
  • three measuring cups of at least one quart capacity: one for the alginate, one for the plaster powder, and one for the water (don't get any of these materials mixed together at all until you are ready to use them)
  • a bucket to mix the alginate in
  • some plaster-impregnated cheesecloth, again from Douglas & Sturgess
  • a couple of bowls for water, one for each helper
  • two measuring cup
  • a big bucket to mix the plaster in
  • something to mix the powdered plaster with; a power drill mixer attachment is ideal but a metal whisk will do
  • paper towels
  • something to rest the mold in while you pour; a cardboard box with a towel or some packing material in it works well
  • a brave volunteer! wearing an old t-shirt that can get tossed out afterwards (the castee will get very gloopy but the casters won't usually ruin their clothing)

Before getting started, cut some of the plaster-impregnated cheesecloth into strips, about an inch or two wide and three or four inches long. You need about 2-3 times as many as are in the picture. Also cut some much smaller pieces, an inch or two by a quarter inch, to use in the nostril area.

Step 2: Prepare Your Castee

Picture of Prepare Your Castee

Make sure your castee is OK to discard the shirt they are wearing, as it will get alginate all over it and that is very difficult or impossible to get out.

Have your castee sit comfortably in a chair that is metal or plastic, or covered with a dropcloth. They'll need to keep relatively still for around half an hour to 45 minutes. In my internet research I always saw people rubbing vaseline on eyebrows and around the edges of the hair, but I find that this does not help very much in preventing the alginate from sticking to the hair, and it darkens the plaster cast in spots if you don't get it all off the alginate before pouring. I call this optional.

Step 3: Mix the Alginate

Picture of Mix the Alginate
Measure your alginate and water. You'll need about 350 ml each of alginate powder and water. The proportions should be close to 1-1 but err on the side of a little more alginate if you have to. Once you have measured your alginate powder, put your hands in it and fluff it up, breaking up any lumps you can find. This helps it mix better.

Pour the water into the mixing bowl or bucket first, then the alginate powder. Mixing is best done with the hands, a power mixer or whisk doesn't get the lumps very well. Squeeze lumps between your fingers to get them out. Mix as quickly as you can; when the water and alginate touch, the clock has started. You have approximately ten minutes to get the alginate on your castee's face.

We found that a good setup was to have the castee hold the bowl of alginate mix, and one helper would stand on each side.

Mix it like this:


Step 4: Gloop the Face

Picture of Gloop the Face

Slop some gloop on the castee's face. It will try to fall off. Push it back up. Obviously, be very careful around the nose area, both to avoid covering the nostrils and to make sure the bottom of the nose is covered as well as possible in the alginate.

Rub the alginate well into the eye cavities and eyebrows. Try not to leave any air bubbles between the face and the alginate. This is difficult as there is no way to tell by feel if there are air bubbles; your best bet is just to push the alginate around a lot. The eyes and eyebrows are the worst culprits for air bubbles. Little bubbles can be filled in after the mold is complete, but the skin texture will be lost so you want to do as little fixing as possible.

Push the gloop as close to the hairline as you can, especially at the center front. Also carry it well down onto the neck. It will try to fall into the castee's ears, as well; this isn't dangerous as it won't go into the ear canal without being pushed, but it makes a lot of people twitchy so prevent this if you can.

A good breakdown of responsibility between the two gloopers was to have one focus on the nose and eyes, and the other just slop the gloop everywhere else and keep picking it back up as it fell down.

Finally, remember that you have limited time, and that it is better despite everything to get the whole face covered even if it's a little uneven, than to get a perfect nose and eyes and have it set up before you can do the rest. You'll have a tiny amount of warning when it's going to set up, the consistency starts to get more cottage-cheesy, at which point you have between 30 and 60 seconds left.

Step 5: Plaster the Alginate

Picture of Plaster the Alginate

If you didn't cut up any plaster strips before you started, you can do it now - your castee will just have to spend a little more time underneath.

Each helper should have a shallow bowl with a bit of water in it. Take a plaster strip, dunk it in the water, squeeze out any excess, and lay it on the alginate. Cover all the alginate with strips of plaster, until you can't see any alginate blue through it. Three layers is a good amount.

Use smaller strips to cover the nose area. You want to support the alginate as much as possible while still leaving nostril holes for the castee to breathe. Try to push the plaster strips into the crannies of the alginate as much as possible, especially around the nose. You'll have to fill in the nostril holes later and having the plaster close to the alginate is very helpful.

The plaster takes about 15 minutes to set, during which it gets slightly warm and, of course, dries out. You'll be able to tell it's done by feeling its dampness and trying gently to flex it around the edges.

Step 6: Remove the Mold

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Carefully ease your fingers around the edges of the alginate. There will be some hair stuck in it (this is inevitable). You can tear or cut the alginate if it's too far past the hairline, or if it's only a little, pull it gently out. Once the edges are free have the castee blow out through their mouth and the mold should come right off. If the castee has facial hair you will have to do a bit more work in this area.

Place the mold somewhere it will be supported underneath, so you can pour into it. A medium sized box with some packing material works well; a scrunched up towel does too. Don't turn the mold over or try to remove it from the plaster, it may be hard to get it back in. You can look at it more thoroughly after you've done the casting.

The alginate face mold looks just like one of those convex/concave optical illusions. At the right angle, with the right light, it's hard to see it as a negative image, even in real life. In a photo it's nearly impossible.

Step 7: Patch the Holes

Picture of Patch the Holes

Working from the outside, use a couple more small plaster strips to fill in the nostril holes. Do this from underneath so the mold doesn't have to turn upside down.

Once that's set, mix up a little more alginate (a teaspoon or less, really you need very little) and patch the inside. Cover the plaster that will now be showing through the nostrils - if your alginate is not too loose, you can build this area up a little to be more nostril-y and undercut.

You can also patch any areas where you had bubbles underneath, or where the alginate tore, or was a little too thin. The new set of alginate won't stick all that well to the set alginate, so it's not suitable for very large patches. But small patches work just fine and are much less noticable on the finished casting than blobs of plaster sticking out into an air bubble.

Step 8: Mix the Casting Plaster

Picture of Mix the Casting Plaster
Read the directions on your plaster to find the correct proportions of water. There's a fair amount of leeway here; more water makes a thinner slurry that takes a bit longer to set, but pours more cleanly and has fewer bubbles.

Estimate the amount of plaster you'll need by eye. The plaster sets much slower than the alginate, so if you don't have enough, there will be time to mix up a bit more. (You can even pour more plaster over cured plaster, although the color won't match exactly and you'll see a line.)

Again it is powder and water, but this time mix the water into the powder. Use a large bucket where you're unlikely to spill. If you have a power drill mixing attachment that works great, otherwise mix vigorously with a paint stirrer or other hefty stick. Scrape the sides, bottom, and corners frequently.
Here's what the mixing looks like:


(I unfortunately did not track the proportions we mixed, but I believe it was about 300 ml of plaster with about 150 ml of water.)

Step 9: Pour the Cast

Picture of Pour the Cast
Set up your mold somewhere stable - the floor is good, especially if your bucket o' plaster is large. Slow & steady is the key here. The plaster takes half an hour or so to set so there is no rush, and the slower you go the less chance you have of leaving air bubbles on the face.

Here's what it looks like:



When you've got it filled up, shake it gently to break loose any air bubbles you might have at the bottom. It doesn't matter if there are some bubbles in the middle, but any at the lower surface - the face itself - will be Unsightly. Tap tap tap!


Step 10: Demold

Picture of Demold

Now, you wait. The plaster should cure in thirty minutes or so, depending on how thin you mixed it. It will heat up noticably while curing. There is actually a chemical reaction going on that solidifies it, it's not just drying out. Once you can see it's no longer liquid, touch the back periodically to feel the temperature. When it's gotten warm and then cooled down to room temperature again, it's safe to take it out of the mold.

Pretty freaky, huh?

Step 11: Cleanup

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Extra mixed alginate or plaster is not really usable so be careful to mix as close to the exact amount as you can. Cleanup is pretty simple if you managed not to get any alginate or plaster into anything porous. Both substances will break or peel off the plastic buckets, most metal, etc.

Plaster is a bit harder to deal with in, for example, the mixing bucket - it's best to rinse it out before it sets. But don't pour it down a drain for it to set there... pour it into a plastic bag and let it cure, then discard the excess water and toss the bag in the trash. You will also want to rinse the mixing stick if it's not a throwaway.

For small splashes - and for any alginate cleanup - it's much easier to wait until it sets, than to try to clean up the wet mess. Alginate peels easily off skin once it has set, and plaster is only slightly more difficult.

Comments

AnneliseS4 (author)2017-06-20

A tip for anyone looking for a stronger and more durable plaster cast:
I learned how to make plaster casts in Italy and we would pour in our plaster a little bit at a time and move it around the mold for an even coating. We would swish the plaster around till it no longer moved (not fully dry, just not viscous) and then add more. After we had built up about half an inch to an inch of plaster we would make little nests out of hemp fibers and start adding them in to the plaster layers. The fibers add tons of strength to the plaster, you can get them easily by taking apart hemp rope bought at craft stores. The last thing we would do is ensure the plaster had a concave back to it so there was not so much tension and brittle-ness, plus it allowed space to carve away for a nail or other device to support it when hanging. Using the fibers is REALLY important if you would like to chisel or carve the plaster at all after it's dry because without the strength they add you risk the entire mold cracking

HectorT13 (author)2016-05-18

So we did this wrong and the plaster has set on my face mustaches and beard !!! How do I get it off ! It hurts to peel it's too stuck

KerryK14 (author)HectorT132016-05-31

Seen you wrote this comment although it was 13 days ago, They really should have mentioned applying vaseline thickly to facial hair such as mustaches, eyebrows, eyelashes etc!

PCPkillz (author)2008-09-27

Thank you so much for posting this. I've been wondering how to do this for the last 2 years, as I wanted to do a "family portrait" for my mother, who has been blind since long before I was born. She will absolutely love this.

DawnS60 (author)PCPkillz2016-02-05

This post is so awesome. (My son is blind)

wow that is smart

mwwdesign (author)PCPkillz2008-09-28

Brilliant idea

GeneM2 (author)2015-03-17

I also saw a rubber coating you could put on in layers to make your body mold but I don't know what its called or how much it coasts can any one help

jesseeking (author)2014-11-27

I am an artist and at VA TECH we sculpted one another in one class. We could not use electrical helps but I hope to go by these instructions and sculpt as my hands are not as strong. Your instructions sound great. I'd forgotten some steps. As artists, we looked at one another and sculpted the bust from clay over a T and filled paper. Then many of used the plaster, let it harden, chiseled the mold and poured the plastercine in--I just forgot the steps. Wish I'd used terrecota and burned in a kiln. Can you help me with the steps? It will make the process easier, much easier by using the electical tools although I still want to do the sculpture from scratch rather than placing over the face. Thank you so much for your wonderful explanations.

GnowledgedGnome (author)2014-11-15

Is the mold broken when you remove the plaster or does it stay intact? If it doesn't stay intact is the plaster bust pretty durable?

rachel (author)GnowledgedGnome2014-11-25

Alginate is not the strongest of mold materials, but with care you are likely to be able to make several castings from one mold. These have to be done right away though, as the alginate will dry out and start to crumble. The plaster casting is quite durable although if dropped from a height it will break :)

GnowledgedGnome (author)rachel2014-11-25

Thank you.

lisa.dukes.391 (author)2014-10-23

Very nice instructable! You can make the nostril thing a bit less scary for the castee by using short pieces of straws in their nostrils so they can breathe more easily and so you don't accidently get alginate up them.

rachel (author)lisa.dukes.3912014-11-25

I've been advised by professionals not to put straws in people's nostrils due to the risk of cutting them. As another commenter put it below,

"The reason why you do not put straws in any orifices you are going to mold is because when you apply the alginate or mold material gravity takes over and tends to drag the straws out pf place. When this happens the model cannot breath and when panic sets in the mold maker trys to force the straws back in place. This is when things tend to get bloody. Rule of thumb do not insert things into your models ever!!!!"

fxguy2000 (author)2013-02-10

I have read your instructable and I agree with some of what is being said but I have to disagree with leaving your hair not covered by a bald cap. alginate is not a forgiving substance and neither is plaster. when alginate forms around hair it tends to not want to let go. anyone who wants to try this process please get a bald cap and mask off your hair line or else you run the risk of having a halo effect until your hair grows back. I have been perfecting my craft for over 13 years and I do know what I am talking about! thank god you didn't tell people to put straws up their nose while the process is being done? that is another big no no that could get your model hurt seriously. please take every precaution needed shortcuts in this business can get people hurt or worse!

Vasline is a good release agent to use to keep plaster from sticking to things. Last year I started making molds in college for my sculpture class and that's something we used. Of course, you have to apply generously, but in the end the mold just pops right off.

It is a good release agent for sculptures if you are careful to apply the layers uniform. The issue that i was refering to was the application of a head cast. While putting vaseline on your eyebrows and facial hair is fine applying it to your hair runs the risk of your mold bonding to part or all of your hair. This is not a risk i would like to endanger my models with. You will never get a do over with that person if they have to shave their head! The safe way is glueing a bald cap to their head using prosaide and covering that with vaseline. The mold doesnt stick to anything and everybody is happy. I really cringe when people suggest using straws up the nose so the person can breathe or trying to cut corners when it comes to the safety of the model. It is paramount that people doing this need to understand many things can happen if it is rushed mostly bad things! Please take your time doing it the right way and be aware if you are the lead person doing the mold that you are responsible for two things. The mold coming out properly and the safety of your model. That means doing things by the book when doing a head mold.

The Rambler (author)fxguy20002014-07-28

Question for you: What woud be the reasoning behind not using straws? I ask because I am genuinely curious. They seem logical to me and without having seen your comment I would probably have used them so I'm glad I read it. I'm just curious as to the reasoning ehind the warning.

fxguy2000 (author)The Rambler2014-07-30

The reason why you do not put straws in any orifices you are going to mold is because when you apply the alginate or mold material gravity takes over and tends to drag the straws out pf place. When this happens the model cannot breath and when panic sets in the mold maker trys to force the straws back in place. This is when things tend to get bloody. Rule of thumb do not insert things into your models ever!!!! Ruins you as a serious mold maker and endangers your models. Doing a face mold get the model to take a deep breath and exhale through their nose to make breathing holes. It is safer and you will have repeat models for the future. It is only professional courtesy not to hurt or kill your models? Now you go have fun and be safe. Love to see what you make in the future

The Rambler (author)fxguy20002014-07-31

Ah, that makes a lot of sense. Haha, yeah I would say not hurting or killing your models is a pretty good business practice. After I commented I also saw another person say that things in your nose can itch and cause you to sneeze, ruining the mold, so all things considered they definitely appear to be a bad idea. Thanks for answering my question. I realized after posting it that your comment was from a year ago.

efarrow2 (author)fxguy20002014-03-10

I saw another set of instructions on this site who did use straws I kindly told them to not do this and explained why those in the industry dislike them. I am in no way as experienced as you, I am just a student of make-up. We have not always gone for a bald cap though, we have often used Clingfilm.

fxguy2000 (author)efarrow22014-03-12

It is perfecty ok to use a rubber or plastic film just to cover the persons hair. I hope that I didnt come off as a know it all but I get concerned when people see how to do things one way and pick up others bad habits. This cripples you when you are trying to learn a very fun and speacialized craft. I encourage you to keep learning and dont ever take my advice as discouraging. I hope to continue seeing your work and nice job on the lifecasts to you and your team. If you ever want to talk shop add me on face book my name is glen simon from antigonish. Hope to hear from you soon. ;)

WeiG (author)fxguy20002014-06-09

Hello! I'm a master student in the Uni Heidelberg. May I ask you some questions about this? Currently we are trying to make a human head mold of latex, to mimic the skin characteristics. So our idea is also first to make a alginate negative form like this, and then "brush" inside the alginate form with liquid latex. But one of our question is, how to make the final latex layer in a certain thickness like skin, which is 2 to 3 mm. Thank you in advance, Mr. Simon!

The Rambler (author)2014-07-28

Very cool. This might come in handy for me very soon. Did you dress like Chell (from Portal) on purpose? Haha

efarrow2 (author)2014-03-10

Pouring can leave air bubbles in your cast. It is much better to start by a scooping action, little by little, and then you can push the plaster gently into the recesses before pouring more into the negative cast. I would apply vaseline (Stuart Bray uses Nivea) on any exposed hairs including the beard to be careful.

Bitsi (author)2008-09-28

I had one of these done for me somewhat differently at an arts fair (oh, about 30+ years ago). Here are some distinctions that that craftsman made -- 1) positioned me prone on my back on a table. 2) did the vaseline bit on my hairline and face. 3)inserted straws in my nostrils so that I was assured that I would not suffocate 4) poured simple plaster of paris over my entire face (causing a moment of panic when it covered my mouth and nose) and removed it when it got warm 5) used a cardboard frame around my face to keep the plaster out of my hair and ears. The resulting plaster mold lasted a good 20 years and was used often to make halloween masks and wall sculptures. :-)

efarrow2 (author)Bitsi2014-03-10

Seriously plaster heats up drastically and tightens this is not recommended and is never practiced within the industry by a respected professional.

dcarroll3 (author)Bitsi2011-07-07

With respect - if anybody is reading, please do not follow this advice.

Plaster has a rapid chemical reaction when it sets, heating up - Chemical burns to your face are not fun. It's what Alginate was designed for.

See the BBC link above for good reasons why you shouldn't use plaster for this job.

MoRoToRiUm (author)2008-09-28

Back when I did a series of clay faces as a concentration piece, I skipped a bunch of steps. Lets just say it involves straws up my nose, Vaseline, and plaster straight onto the face. Worked just as good, but faster (for those even more daring :-).

efarrow2 (author)MoRoToRiUm2014-03-10

Seriously misguided and dangerous. As a student in make-up, we do not even like plaster bandage touching any of the skin. Markp.com and dcarroll3 are right.

Markp.com (author)MoRoToRiUm2009-12-06

Putting plaster direct on your face is one of the most stupid things you can do!

As mentioned in the article, it heats up drastically! See this BBC article about a poor girl who lost most of fingers when using plaster direct on to skin!

http://news.bbc.co.uk/1/hi/education/6485481.stm

You're much braver than I am! I'll only let alginate touch my face.

spaceanimal (author)2014-02-28

what's a good substitute for alginate?

KDS4444 (author)2013-05-09

Some questions: If you did not use vaseline on the one fellow's beard, how did you get the casting off his face? Next, does alginate not stick to plaster? Or does it work like a rubber mold? Next: is the alginate mold destroyed once used? Next: does alginate make a "truer" casting than plaster would have? In other words, tell me about the magic of alginate. I have never used it and am very curious.

rachel (author)KDS44442013-05-14

As I recall, I peeled the alginate off his beard slowly and carefully. It was a fairly dense and tight beard and maybe we got lucky - see fxguy2000's comment just below for a different view on alginate + hair.

Alginate doesn't stick to plaster at all, it doesn't stick to much. It's kinda jello-y when set up, and wet feeling. It's not as strong (thus the plaster "mother" mold) but is otherwise much like rubber, but it's much easier on the skin than plaster directly. You can usually make a couple castings from one alginate mold but it will degrade fairly quickly and I wouldn't count on more than a few uses before it starts tearing apart. If you have undercuts at all, you will probably only get one casting as those will almost certainly tear when you take the casting out. It's a bit more fine-grained than plaster, so the mold is slightly finer, but not significant. The reason to use it, in my mind, is that it's easier for the model to deal with as it doesn't get hot or hard on their face like plaster directly does.

iongets (author)2013-05-13

I only made plaster molds by pressing the face into fine damp sand in a box, then pressing the sand around it with my hands ( need to be able to hole your breath for 30 sec or so) withdrawing the face carefully- there may be a few sand crumbles that fall inside but can be removed if you careful otherwise just flatten them out with a fine art brush. Then slowly pour in your plaster of paris . It has a pretty good look to it when it hardens.

Lorddrake (author)2011-07-20

how much alginate was required to make the casts? Trying to figure out what size container i would need for the casts that I want to do.

SelkeyMoonbeam (author)Lorddrake2012-08-09

A 1-lb jar from Douglas and Sturgess was good to make a couple of casts with some trial and error. I'm actually in the process of writing up my own version of this 'ible.

thomasready (author)2012-01-25

You got to be kidding us you really want people to burn, I once tried this to make a mode of my Woodie damn that hurt. Woodie never been the sane!!! just saying.

antboy (author)2010-05-14

Hey, how about a light dusting of baby-powder/chalk/powdered-sugar during step 2? Why just the eyebrows anyway? GREASE IT UP I SAY! Your whole face. There would be no "dark 'spots'" ; it would be evenly-contaminated by the vaseline or whatever...
Also, how can we make a food-safe mold for buntcakes and jellO so we can eat our own faces? There are silicone pans at the pampered chef...

stringstretcher (author)antboy2011-07-20

You can, in fact purchase silicone mould making materials that are approved for use in the food industry. That would allow you to eat your face. Check at www.smooth-on.com for their selection of materials.

timdomul (author)2009-10-25

there are something you can do better, like drop the plaster over the water instead of the water over the plaster, and mix it up with your hands like you mixed the alginate and you will have less bubbles, and if you put some food wrapper plastic around the forehead will protect the person's hair from the plaster and alginate.

Great job!!

vicsouders (author)2008-10-03

Not bad, one suggestion though. During step number nine embed some thick gauge wire into the plaster to form a handle to assist with de-molding. I generally use coat-hanger, about 16 inches long and folded in half, bent to form a loop with large nut twisted onto each end (as an extra precaution to prevent the wire from pulling out of the plaster). By doing this the plaster positive usually comes out of the alginate negative cleaner and I’m often able to pour two plaster positives from the same negative. Enjoy!

rachel (author)vicsouders2008-10-03

That's a great idea, I'll use it next casting I do.

the_keiser (author)2008-10-02

best and most detailed how to of life casting I've seen, that you don't have to pay for ;) great work. I'm a caster too and this post is great. love it. keep it up.

Kiteman (author)2008-09-27

It looks like Josh found the whole thing more relaxing that Bilal.

T3h_Muffinator (author)Kiteman2008-09-28

Hehehe - I don't know about that. You should have been there ;)

My hair was tied up in ways I didn't know it could be tied up. The hair ohhhh, the hair.

lamedust (author)Kiteman2008-09-27

I had been trying to do the one eyebrow up face... Failed though ; P

The Mad Pancake (author)2008-09-27

could this be used to make masks like from mission impossible 3?

Theoretically you should be able to use the plastered bust as a sort of cast for a latex mask. That could be interesting for Halloween parties. You and your date swap faces for a day. :-)

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