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Creating Latex Puppet Hands

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So - I got asked to make puppets for a company in NYC. It seemed like the perfect excuse to try new things... like casting in latex. So, I've never cast anything before in my life - but I'll lead you through the process that I tried and that has mostly worked out for me.

Also check out Creating Latex Puppet Heads which discusses a three part mold process.


Creating Latex Puppet Hands
The Two Part Mold

1. Using a non-baked clay (I used oil clay [link] , you could probably use sculpey types with no problem) create your - in this case - hands. I created mine on a welding rod up the center (similar to the strength of a coat hanger) - you need something like this so that you can hold the object level to do the initial pour of plaster, it could be something inserted later into the top and the bottom but because of the small size I just sculpted on the rod.

2. While sculpting determine where your seam points will be. In the case of the hands it was 1/2 way through the hand laterally - so there will be a seam along all the fingers, and on the outside of the thumbs and pinkies to the bottom of the forearms. Beware undercuts. With undercuts you will need a multi piece mold.

3. I created a box out of foam core and tape. The sizing needs to be at least an inch on all sides and between objects. The tape I used was gaffer's tape but if you have duct tape I'm sure that would work also - or, you can seal by coming back and laying in some oil clay for a better bond. I had no leaks with this version. I picked a 1/2 way point and skewered the rods through the foam core - make sure that the hands were level with where you want your seam lines. The bottom of the sculpt - the end of the forearms - gets pushed right up to the side of the box creating an entrance for pouring the latex in later. And make sure that the box itself is level (since you'll be pouring in a liquid)

4. Mattering on the clay you have used you may need to use a release agent - and you're definitely going to need one between the two layers of plaster when making the mold. For plaster, the best release agent is potter's soap or green soap [link] . Don't use Vaseline since you need the plaster to be porous and absorb water. Oil clay doesn't need a release agent with plaster but the welding rods do. With a paintbrush or similar implement spread a thin layer over the surfaces that will come in contact with the plaster. Make sure it's not too thick as it will inhibit any details you may have.

5. I figured the amount of plaster that I was going to need for the mold. Water to plaster ratio is 100:70 and it has been proved that a quart of water and 2 pounds 14 ounces of plaster fills 80 cubic inches. So - L x W x H = area in cubic inches. Divide that by 80 to discover how many quarts of water you need. Each quart of water needs 2 pounds 14 ounces of plaster for a consistency of 70. Of course this is just the box, NOT including the loss of where your sculpted part is... so it's actually more. OR - you can just buy a bunch of plaster, not care about the loss and start hucking it in a bucket with some water... see 7. below.

6. I used gypsum #1 moulding plaster [link] - it's not the best for strength over time and use... but it worked great in this case. Plaster is used because in order to cure the latex, water needs to be drawn out. Ultracal 30 is the hardest and most resistant - but doesn't absorb water. Hydrostone is the strongest for this type of procedure, but more costly.

7. You can exactly measure (with the formula above) and weight out all plaster and water needed - or you can use the island method which is more fun... and seems to have worked out just fine. [link]
Start out with a bucket and the plaster. Put warm water into the bucket in around the amount that you need for the pour. Sift the plaster into the water – DO NOT STIR – and continue to sift plaster in until small islands of plaster begin forming in the water and remain there after a few moments time. Let sit for around a minute and begin mixing, making sure that you’re not getting a lot of air into the mix and mix for around a minute or three. Just remember, either way you go, always sift the plaster into the water.

8. Once the plaster is mixed and ready to pour, slowly begin pouring into the bottom of the box. Just a reminder - make sure that the surface you are working on is level. I shimmed the box a bit just to make sure that it was covering evenly. Once at the 1/2 point, stop. If the pour or the initial level of the clay piece is not level, you can always let it set up and pour in the rest that is needed after. Word of advice be careful of air bubbles in the plaster mixing and in the pouring.

9. Plaster sets via a chemical reaction, and gets quite hot. You can test where it is in the process of this and once it's coming back down in temperature again you could pour the top half - but I let mine set over night. Before it was fully set I poked some dents into the surface to work as keys when lining up the halves for casting. Once set, I placed wedges of oil clay on the three sides, these will be used later when opening the mold. Over all of this, spread a layer of green soap to act as a barrier and release agent for the two halves of plaster.

10. Mix up another batch of plaster and pour in on. Once again be careful of air pockets, pour evenly and slowly. If there are details that you're worried may not fill, mix up a smaller batch of plaster and brush it on first, then do the second larger pour. Let set.

11. Once set, dismantle the box surrounding the plaster and gently pry with a flathead screw driver in the oil clay wedge locations. Open, and remove the oil clay sculpture. Ta-Da!! You now have a mold. There is a little clean up necessary, getting clay out of the molding area and such. Mattering the area a light rub down with sand paper maybe useful. Also, you can clean the plaster mold with 3M Citrus cleaner.

12. Once cleaned, place the mold into an oven at 200 degrees for 3 to 6 hours mattering on the thickness. This will take out extra water in the plaster. This should be done with the two halves of the mold together incase of warping.

13. Once out of the oven and cooled, strap the two halves together - large rubber bands, bungee cords... and fill the seams on the outside with oil clay for an added seal - especially pay extra attention to where the rods left holes in the base. Stand on end in a container large enough to catch all runoff.

14. The latex I used was L200 casting latex mixed with #64 Filler for strength in a ration of 1:3. [link] Mix together the latex and the filler let sit a few minutes to get all air out. Pour latex into the opening at the top of the mold. Let sit about an hour. Continue to top off the latex as needed. After an hour, pour off the excess and let sit overnight.

15. Gently open the mold - using the wedges again. Be careful not to tear the casting inside as it will still be damp. If the item is large and has a larger hollow cavity inside blow some talc powder in to keep the side from bonding to each other as you remove it from the mold. Remove and let dry in front of a fan for 3 to 4 days. After a few hours it will be workable enough to trim some of the flashing... and will be hard enough in a few days to sand or dremmel.

And with that you have puppet hands. So - definitely read up on this if you're going to be trying it...
The Prop Builder's Molding & Casting Handbook by Thurston James is great [link]

I also learned a lot from the pics on the puppet museum site:
[link]
- in the puppet workshop area.

All supplies for this project were bought at:
The Compleat Sculptor, Inc.
90 Vandam Street
New York, NY 10013
[link]
They are absolutely amazing, have pretty much everything and are extremely helpful and nice. If you have questions about a project, they will try their best to lead you to the supplies you need.

Pictures:
Basic walk through pictures of the process.
Also, you'll see the failed hand attempt. That was caused by not paying enough attention to the 1/2 way line in the fingers and they got stuck in one side of the mold... I was hoping that the latex may have been soft enough to allow a little give when coming out of the mold... I was wrong!!! But, I went back and carved out the places that it had gotten stuck and recast. There is a lot more flashing between the fingers, but that was easy enough to trim. It was definitely disheartening, but didn’t cause a stop to the progress!!! Definitely keep trying and don’t give up!!

------------------------------------------------
oracletheatreinc@oracletheatreinc.com
[link]

sculpturalmyth@yahoo.com
[link]
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© 2006 - 2024 shalonpalmer
Comments8
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Girl-q's avatar
You give a very detailed description of the process. and the illustrations are cool. Thank you!