Materials

List of all materials from class

Casting and Molds:
Plastic: EasyFlo Clear (PolyTek) and SmoothCast300 (Smooth-On)
Resin: Envirotex Lite (craft store or Amazon)
Silicone Rubber: Oomoo 30 and Oomoo 25 (Smooth-On)
Polyurethane Rubber: Polytek 74-30 (PolyTek) and Vytaflex10 (Smooth-On)
Concrete: Kwikrete (hardware store)
Foam: Foam-It!5 (Smooth-On)
Chalk: Plaster of Paris and powdered tempura (craft store or Dick Blick)
Paper: paper scraps

Pigments:
SoStrong Pigments (Smooth-On)
Ignite florescent pigments (Smooth-On)
PolyColor pigments (Polytek)
Colores Resin colors


Additives and other:
Mann's Mold Release 200
Universal Mold Release (Smooth-On)
Ease Release 2831 (Smooth-On)
Stik-n-Seal (Amazon, hardware stores)


Websites:
PolyTek:  http://polytek.com/index.php
Smooth-On:  http://www.smooth-on.com/
Dick Blick: http://www.dickblick.com/

Chalk Casting

Lesson: Chalk Casting

·         Spray your mold with mold release.

·         Mix Plaster of Paris with water (4:3 ratio, or to the consistency of sour cream/greek yogurt)

·         Add any powdered color (powdered tempura is perfect for this, especially if you plan on using the chalk) and mix thoroughly

·         Pour into mold and tap gently against table to settle the plaster and bring any bubbles to the surface.

·         Let cure- 1-2 hour in the mold, then let sit undisturbed for another 4-6 hours before using.

·         After the plaster is set but still finishing curing, it will be cool to the touch. Once it stops being cool and goes to room temperature it is completely finished curing.

Let any remaining plaster cure and dispose of in the trash!!

Working with the castings:

·         You can embed objects into the chalk to be exposed as it wears away.

·         You can also imbed findings into the back of the chalk by placing them in after you cast and before the material cures. Any findings embedded this way should have a pin or rod that extends into the casting for stability and adhesion. Simply placing a pin back or jump ring on the surface is too fragile.

·         You can drill into the chalk- gently!

·         You can also carve the chalk using burs or wax tools.

·         Finish the chalk with gentle sanding- it wears away quickly!

Paper Casting

Lesson: Paper Casting

·         Tear your source paper into small pieces (approx. 1”) and soak in hot water to loosen the fibers.

·         Soak for at least 20min, longer for stiffer/thicker papers. You want the paper to feel like it will fall apart when you pick it up.

·         Place your soaked paper in the blender. Add a little water and blend.

·         If the paper isn’t blending well, add more water until you can get a puree.

o   Our blender is normal cooking size so you will make enough puree for several smaller pieces.

·         Once the paper is pulped completely- you shouldn’t have pieces of paper left, just mush- strain out most of the excess water.

·         You can place your pulp in a cheese cloth or fine mesh colander lined with coffee filters or paper towels if it is especially liquid.

·         You usually do not need to spray mold release for paper casting

·         Place some of the pulp into your mold.

·         Tap against the counter to settle the pulp.

·         Place a towel over the pulp and press down on it- compressing the pulp in the mold and wicking away the moisture.

·         Repeat until the mold is full and the pulp is tightly compressed.

o   If you are having trouble with the layers separating, either the pulp is too dry (add water) or not blended enough.

·         Let dry- depending on the thickness of the casting this can be anywhere from a couple hours to a day.

·         Demold and let sit for a couple hours. This makes sure that the areas deepest in the mold are cured as well.

Working with the castings:

·         You can’t do too much finishing work on the paper as it starts to fray and soften at the edges. If you do need to trim the casting, use an sharp Xacto or scissors to remove any flashing.

·         If you want more flexibility in your castings, mix in some Elmer’s glue or PVC glue (archival bookbinding glue) into the pulp.

·         You can (slowly and gently) drill the paper castings. The small nuts and bolts, tube rivets, and grommets are really good for connecting. You can use cord, chain or jump rings through the holes in the grommets or tube rivets. The protection of the metal around the hole helps to prevent fraying and the connection coming loose as the paper softens at the stress point.

·         For colors, it is best to use paper that is the color you want. Remember that since you are blending the paper, if you want multi-tone casting, blend the colors individually and mix together after straining the pulp.

Project 2

Project 2: Unexpected

For your second project, create a series of pieces that each have something unexpected or surprising in your use of the materials. Create 3 pieces.

Examples: Concrete is thought of as heavy- make a light concrete piece. Rubber is flexible, use it for something that needs rigidity like a spoon. Consider using multiple materials to achieve your goals. Foam is considered squishy and light- make it rigid and/or heavy.

Consider incorporating metal or other materials. Think about structure and visual appearance: How can you use those to create your surprise.

The unexpected quality must relate to the material but it can also relate to the subject matter of the piece. Think about a knife made of rubber or a weight made of foam, etc.

You must choose 3 different materials from the list below:

Foam

Rubber (polyurethane or silicone)

Concrete

Chalk

Paper

Plastic/Resin

Ideas/Designs: Due March 26

Project due beginning of class May 14 (final class)

Concrete Casting

Lesson: Concrete Casting

Concrete has a very thick consistency when casting- it is unsuitable for delicate thin pieces.

·         Spray your mold with mold release.

·         Scoop some concrete powder into a cup.

·         Add any additives such as vermiculite or sand- do not add more than 10-20% of the amount of concrete.

·         Add water slowly as you mix.

o   You want the mix to be as dry as possible and able to fill your mold. Think of ricotta cheese consistency. If the mix is too wet, add more concrete. Too dry, add more water.

·         Add any powdered color and mix well.

o   Concrete doesn’t color as deeply as the other materials. It will tint the concrete rather than truly coloring it.

o   For brighter colors you can purchase concrete stains that you pain over the surface after curing.

·         Spoon/pour the concrete into your mold.

·         Let cure for 4-6 hours then cover in plastic wrap.

·         Let cure for 1-2 days.

·         Demold and do any prelimanry wet sanding.

·         Wrap in damp paper towels and put in to a ziploc bag.

·         Keep the paper towel damp, and let cure for another 5-7 days.

·         Remove from damp paper towel and finish wet sanding.

·         Let surface dry.

Working with the castings:

Adding metal frames or armatures can increase the strength of the concrete.

Rather than drilling the concrete- consider embedding tubing in the casting. You can drill concrete but you need special bits and it is time consuming.

Foam Casting

Lesson: Foam Casting

·         Prepare your mold by brushing the mold release all over the surface(s) and let it dry. Make sure to brush around the opening you’ll be pouring into. Make sure to use the Ease Release 2831- the other mold releases will not work!!

·         The foam expands as it cures! The foam we are using expands 10:1. Check the bottle for this information as each foam expands differently.

·         Pour water into your mold to figure out the volume. Divide by 10, this is the total amount of foam you need. Divide by 2 to get the amount of Part A and Part B.

·         The polyurethane foam is quick curing, so work similar to the plastic. Pour part A, add any color, add Part B, mix and pour.

o   You can use any of the pure pigments for color (not the colores colors)

·         Tap the mold gently against the counter to help bring any bubbles to the surface.

·         Let cure. You can demold after 30min, but full cure takes 2 hours.

Safety: You must wear your respirator and gloves when working with this material. This can only be poured during class or hazmat open studio

The foam we are using (Smooth-On’s FOAM-iT! 5) is a relatively rigid foam, it does have some flex, but is not squishy flexible.

The foam surface is less porous when fully contained in the mold. If it rises out of the mold, it become a looser consistency.

Working with the castings:

·         You can drill and shape the foam with sandpapers and files. Make sure to clean your tools well before and after using them on foam.

·         Foam adheres to just about anything not treated with the 2831 mold release- this makes it very easy to attach foam castings to other surfaces or to each other with a little additional foam.

·         Test glues before using- some glues eat away the foam (cyanoacrylates do this). 

Casting Rubber

Lesson: Rubber Casting

For the casting process, rubber is very similar to the resins/plastics. We are using 1:1 ratio rubbers. The biggest differences are in cure time and type of rubber. Like types of rubbers will bond together- silicone rubber will bond to a silicone rubber mold. Polyurethane rubber will bond to a polyurethane rubber mold.

We have a silicone rubber and 2 polyurethane rubbers for casting.

Oomoo is a silicone rubber. We used it for mold making as well. Naturally it is an opaque lavender color when mixed and cured.

Vytaflex is a polyurethane rubber, pale peach color when mixed and cured- it has some translucency but is not clear. This is much more flexible rubber than our other polyurethane rubber.

Polytek 74 series is the other polyurethane rubber, also one we used for mold making. It is a clear light amber color when mixed and cured.

All rubbers can be colored with any of the pigments we used for the plastic. They can’t be colored using the colores pigments, or the ceramic paints- only the pure pigments.

Prepare your piece or mold.

If pouring rubber into a piece, make sure all finishing is done. This should be the last step.

If pouring into a mold, spray your mold with mold release. Make sure the release works with the type of rubber you are using! (read the label)

For delicate/thin castings:

The rubber is thicker than the resin and plastic. You may want to use a disposable syringe or eyedropper to inject the mold. This pushes the material in with greater force then simply pouring.

Thickening rubber for brush-on casting:

You can mix in some of the PolyFiber material to thicken the rubber, allowing it to just stay where you want it to when pouring, or to be able to brush on the material to create a hollow form. The PolyFiber does tint the rubber- making it a lighter shade and more opaque.

To Use:

Mix your rubber as directed. Add in PolyFiber a little at a time (half spoonful) and mix thoroughly. Add enough until the rubber resembles icing- it holds soft peaks.

Imbedding:

The rubber cures slower, but it is more viscous than the plastics. If the embedding material is light, pour a layer of rubber, lay the material in, and then complete the pour.

If the material is heavy and will sink through the rubber, you will need to do a multi-stage pour.

Connecting:

Rubber bonds to itself better that the plastic. In addition to the other connection methods, you can also connect castings by pouring a little extra material to connect them. Set your castings up on parchment or other non-stick surface at the correct distance. Block off the aarea/shape of the connection with plasticine, sculpey, or coated cardboard (i.e. anything that the rubber will not stick to). Pour, and let cure.