Judy's Corner for Crafter's » mold making

Website Repaired

Administrator — Sat, 15 Jan 2011 04:43:20 +0000

For those who have ventured by recently, you probably noticed the site was broken. I have it up and running again and still working to set things right. I apologize for any inconvenience.

I also want to announce I finally finished one more instruction ebook. This one is the first in a series, following me through the creation of a silicone rubber mold for a human figure model. You’ll find links at the top of the page.

How to make Clay Molds or How to Make molds for Clay

Administrator — Sun, 29 Nov 2009 01:52:16 +0000

There is more to the mold world than just molds for ceramic slip or molds for resins or plaster products. Ever hear of slump molds?

A slump mold can be just about anything you can lay a thick slab of clay over, for make the inside form.

Take an empty 3# coffee can, set it on its top, cover it with a towel and you have a slump mold. You can also get fancy and make your own forms to use.

A simple example would be to pour mixed plaster into a bowl, creating a slump mold of the inside of the bowl. You can then use your new plaster form, to lay clay over, shape to the bowl form, then slip it off before it has time to shrink and you now have a bowl form.

One of my daughter’s favorites is to roll out clay then cut it into a square. Then she lays the clay over the bottom of a coffee can so that she can capture the flat bottom of her new creation and then form ruffles around the clay slab. You come out with a square bowl but with a rounded bottom (foot).

You can find all sorts of forms in your kitchen and use bowls turned upside down or using plaster, create your own slump mold, the form and size of the bowls.

Just remember that anytime you’re rolling out clay, to keep the thickness 3/8″ or so and even thickness throughout.

Have fun, coming up with new ideas to use as a slump mold.

Polymer Clay Molds

Administrator — Tue, 03 Nov 2009 02:51:22 +0000

I’ve been working with a man out of state, in designing and engineering a new concept in molds for polymer clay.

Just today, he began to introduce the new line. If you happen to enjoy working in polymer clay or if you’d like to learn how to create those gorgeous art dolls, here’s your chance.

These molds are not cheap. There’s a good reason for that. Each mold is separated into body parts. This first one to be offered online, is called ‘Gabriel’. He comes with a mold for the torso and head, 2 separate molds for the arms and 2 separate molds for the legs. Each arm or leg mold, also comes in 3 parts in order to make it easier to pull the clay after pressing.

These molds offer the novice more immediate results. Along with each mold, Gary (owner) offers his tutorials in the use of the molds as well as how-to make the armatures.

There has never been polymer molds quite like these. Next off the line, is the Taurus torso and legs to fit Gabriel, so that you can create the Taurus. A go-with set of goat legs can also be purchased.

There is also a set of molds for wings to fit Gabriel.

Next in line, which we haven’t yet designed, will be the female counterpart and a child, sized to go with Gabriel.

You’re going to love these molds. Regardless of how much natural talent you may have, with this mold line, you will create things like you’ve never imagined.

You can read more about this line at http://www.natureboyzart.com/
and if you visit soon, you’ll still be able to view the ebay listing.

Like I said, these are not cheap molds but you’ve never seen polymer clay molds like these.

Concept of Mold Making

Administrator — Mon, 19 Oct 2009 17:23:08 +0000

Sometimes, all it takes is the right frame of mind. Having the right concept, is half the battle.

What is a mold? A mold is the negative of your positive. If your fist is the final image and form, then your other hand wrapped around your fist would be the negative or mold.

Add to that concept, which materials are suited for which finished products. A rubber mold can turn out just about any finished material except ceramics. With ceramics, you are working with a clay mixture called ‘slip’ and slip requires a material that absorbs moisture, in order for it to form. So in the case of ceramic slip, your mold will be plaster.

Of all the materials you can make a mold from, only plasters will absorb and evenly, so that it’s possible to form a shell with clay.

Yes, it is possible to pour plaster into a plaster mold. In such a case, you have to watch for 2 things. One, a good separator inside your mold, to prevent added plaster from adhering. Two, undercuts.

Undercuts can be explained simply by imagining a ball within a ‘C’. If the ball fits snuggly against the inner walls of your ‘c’ then it can’t be removed through the opening. Or if you make a fist with one hand, and encircle it with the other, you can’t remove the fist without flexibility of the other hand. If your encircling hand is rigid, you can’t remove the fist. That explains an undercut.

Two hard, rigid forms must have clearance, in order to pull the inner form out of the outer form. So before you try plaster poured into a plaster mold (or any rigid mold), you need to carefully check that your poured form can be removed straight out of your mold. If not, other adjustments to your mold will have to be made. Such as cutting your mold and forming yet another parting line.

The most suitable mold materials for a variety of poured materials:
For any clay, including clay slip – plasters
For polymer clay – plastic, rubber or plaster
For paper mache’- plaster
For resins – rubber

You can find rubber compounds in both silicone and polyurethane. Polyurethane is your all around, multipurpose rubber.

Polyurethane also comes in what is called ‘wet’ or ‘dry’. Wet rubber constantly exudes a layer of oily substance, helping in later casting. The setback is that you can’t make repairs to your rubber mold by adding more. Once set, additional rubber will not adhere due to the oily surface.

Silicone is great for casting hydrostone. It’s very flexible and strong and captures high detail. It’s more expensive and requires that you have no sulfur present. Many of your oily modeling clays contain sulfur so you have to be careful which clays you use for your models and for sealing around your mold box.

Hopefully this information helps in your selections.

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Mixing Plasters

Administrator — Tue, 04 Aug 2009 00:54:26 +0000

Most everyone who comes here looking for plaster mixing directions, isn’t looking for the scientific answer. They want the quick answer. The one they can use in the kitchen. So I’m going to give you my never failing technique and I don’t weigh plaster or water.

I’m sure plaster manufacturers and dealers would see this an cringe. Sorry, can’t help that. And I’m sure you’ve read somewhere that all you have to do is add the plaster to water until it stands in a mound above the surface of the water. While that probably works, I’ll give you a workable technique that won’t fail you.

Take a small bucket about the size that would hold the amount of plaster you want. To fill the bucket to within about 3″ from the top, fill with water to about 1/2 for hydrastone and a little more for plasters.

Use something as a dipper to get your plaster. A coffee can, a plastic cup, whatever. It’s designated for the plaster. Begin taking cups or cans of plaster, one at a time and sprinkle it over the water, letting it fall down through the water. Keep doing this until the water looks all white and then just stop.

Nothing is going to happen until you disturb your plaster and water in the bucket. It’s the mixing action that starts the chemical reaction. Just let it sit there, undisturbed for 3 or 4 minutes then check it. If it looks like there’s about a 1/2 inch of water standing on top of your plaster, your ready to start mixing. If not, add enough more plaster and let it set again, until it appears to be 1/2″ of water standing.

If you don’t have a good high speed drill with a mixing blade, then I suggest you get ready for some heavy duty hand mixing. It’s the speed, the vigor and constant motion that starts the chemical reaction and the more speed and vigor, the stronger your plaster.

If your container is short enough for a hand held cake mixer to fit down into the plaster, with the blades about an inch off the bottom, then use that on high speed.

For pottery plaster or hydrocal, mix steadily for 3 minutes, let stand 3 minutes and pour. For hydrastone, mix 5 minutes steadily at the highest speed you can muster. When the 5 minutes are up, it’s ready to pour.

All plasters will begin to heat up during the set-up time. It’s then that the plaster is also expanding. It may feel hard already but as long as it’s hot, don’t pull your poured piece. Wait until it cools back down and begins to sweat. That’s when it should be pulled.

On cold winter nights, use that set-up time to set your piece under your feet, while still in the mold. It’s a great foot warmer.

If your plaster feels light weight and soft, you didn’t add enough plaster.

What is a Mold? What is a Master Block?

Administrator — Fri, 31 Jul 2009 23:13:04 +0000

Have you ever used cookie cutters with special little designs imprinted? You press the cutter down onto the dough and it leaves an exact opposite of the design you see in the cutter itself.
That’s actually a mold.

A mold is something you can use over and over to replicate a design, shape, form. Think of the mold as the negative that forms your positive.

A master block is actually the permanent positive for your mold. From the master block, you can make numerous molds and from the mold, you can replicate numerous positives in the finished form.

Place your hand down onto rolled out dough and make a print. Your hand is the positive-the print in the dough is your negative.

If you happen to want numerous copies of an original, you will need a mold. From the mold, you can make ‘repeats’.

If you also happen to need to know that you can make numerous molds, all exactly the same as the original mold, you will then need to freeze that design for all time, by making a master block of the original mold. In this way, you can continue to make the same exact mold, over and over for years. Thereby, freezing your design for all time.

Mold Making Materials

Administrator — Wed, 10 Jun 2009 16:59:05 +0000

There are so many ways to approach the subject of making molds, one almost has to be an expert on the materials available to make a decision.

For the most part, if you plan to make your finished product out of clay or clay slip, the material is pottery plaster.

Basically, you have 3 varieties of hardness. Pottery plaster, hydrocal and hydrostone.

Pottery plaster is the main stream for making ceramic molds. Of all the plasters, it’s the easiest to work with as it doesn’t run as fluid as the others. Easier to control leaks while making your mold.
If you’re able to find it in 50 or 100 pound bags, the name on the bag is #1 Pottery Plaster. If you don’t have access to the larger bags, you can find it in small quantities (although more expensive per pound) at the craft supply stores, under the name of Plaster of Paris.

I like working with Hydrocal (White Hydrocal) for ceramic molds for one reason only-it’s harder, just as absorbent and is more durable and longer lasting. People will tell you hydrocal is not suitable for ceramic molds. Let me tell you, I’ve had hundreds of satisfied customers, as well as using my own molds made of White Hydrocal.

Hydra-Stone or Hydrostone, is rock hard. The only time I’d consider this material for a mold is if I simply want finished pieces made of rubber. It is not absorbent. Hydrostone is most suitable as a finish product, like statuary.

When you want to make a finished product of a plaster material and it needs to be super sturdy and exposed to weather, something like stepping stones, there is yet another Hydra-Stone product called Hydra-Stone Super X. This is the cement material used in pavement. The only problem might be that it is a medium-dark gray.

In the middle is a variety of specialty plasters. One in particular, used strictly for figurines has a glass fiber in it.

Another specialty plaster is called Moulding Plaster. Don’t get this confused with pottery plaster. This Moulding plaster is strictly for finished pieces. Ultra-Cal, Tuf-Stone and Dry-Stone are the same. Not suitable for molds.

Good luck with all your mold making adventures and remember one thing from Judy – every mistake is a learning experience.

By the way, spilled plaster is no match for water. Don’t panic. If spilled on a concrete floor, it’s best to wait until it’s finished setting up. Then go after it with water splashed on it, and a flat edged tool. Just scrape it up. If it’s been spilled on carpet, add water and scoop it up as best you can. The portion that is left, that you can’t quite get to, will set up. If you’ve already added water to it, it has become diluted and weak. After it’s dry, you can come along with the vacuum and a stiff brush to help loosen it.

A rigid putty knife, about 3″ wide, is a helpful tool to keep handy. Especially when it comes to scraping up plaster from a smooth floor.

If you run into troubles, be sure to come back here and give me a holler. I’ll help.

Up coming Mold Making ebook on rubber molds

Administrator — Fri, 05 Dec 2008 07:11:25 +0000

I’ve finally remembered the camera while working on a mold project. As soon as I’m finished, I’ll start on the instruction book.

When writing the ceramic mold making ebook, I never imagined so many folks would be interested in making rubber molds. I’m finally getting around to writing about the rubber molds.

Once you know how to make molds for absolutely any casting material, there’s nothing you can’t reproduce.

I’ll keep everyone posted on the progress. If there are any other instruction materials, you’d like to see, just let me know.

I’m finally finished with the new ebook. Link http://judysbookshop.com/ceramics/e-book-downloads/