Here you can read about and see some real-world examples of different applications for the Mold Rubbers provided by BITY Mold Supply.

Polytek 74 and 75 series mold rubbers are excellent for wet pour and dry tamp concrete. Polytek 74 and 75 series rubber materials are packaged as pourable mold compounds but they may thickened with polyfiber for multiple-layer brush-on mold applications.

Make it look great for a fraction of the cost.

What is Cold Cast Bronze? The Cold Cast metal process allows the artist to simulate the look of cast metal with a resin-bronze powder mix.

Why use the Cold Cast Bronze process? Props, decorations, and sculpture sometimes require a bronze look but must be resin-cast due to budget, weight, or time constraints.

Materials for Cold Cast Bronze:
• Equal parts A&B of EasyFlo 60 resin or Poly 1512 Clear
• Silicone mold (Urethane molds with proper release may also be used)
• Bronze Powder
• Pigment for Urethanes (Polycolor) Black or Brown
• Very fine steel wool
• Expanding urethane foam (3-5 lb density)

Step 1 Measure out equal parts (by volume) of parts A, B, and bronze powder.

Step 2 Stir bronze powder into part B of resin. Stir constantly to keep bronze powder from settling to the bottom of the mixing container.

Step 3 Add 3-5 drops of black or brown pigment to part B and continue stirring.

Step 4 Once the pigment and the bronze powder are well mixed into part B, begin stirring in part A. As soon as part A is added the pot life* begins.

Step 5 Application When pouring into an open, 1 sided relief mold: Use a disposable brush to spread the bronze powder mixture into the surface detail of the mold. Take care to avoid forming pools of resin in the low points of the mold. Continue brushing the mixture until it begins to gel. When pouring into a more complex mold: Pour the bronze/resin slurry into the mold and begin rotating the mold in all directions to allow the mixture to evenly coat the walls of the mold. Follow up with an additional batch of resin if necessary. Important: When adding additional resin do not delay. Waiting too long between layers of resin may result in a poor bond between layers of resin.

Step 6 Allow the resin coat to cure for several minutes. 1. If a heavy, metal feel is desired: Fill the inside of the hollow cast with unfilled resin or resin mixed with steel shot for added weight. 2. If a light-weight part is desired: Estimate the rough volume of the interior of the hollow cast. Mix parts A&B of Poly Foam R-5 rigid foam and pour into cavity. Work in several small batches to avoid overfilling (remember R-5 rigid foam expands roughly 10 times the original volume). R-5 Foam has a very short pot life* so mix fast (30-45 seconds) and pour. Rigid foam develops handling strength in 30 minutes at room temperature.

Step 7 Demold casting. Allow for at least 45 minutes after casting final resin coat to remove casting from the mold. Castings with very thin areas may require more time to fully cure. Casting will have a dull brown appearance.

Step 8 Trim flashing or bubbles from the cast and allow the cast to sit overnight. Buff the casting to a shine with fine steel wool.

*Pot life is the time that the mixed material remains fluid or workable before it begins to gel. In warm weather urethane resins may exhibit very short pot life while cold weather tends to retard it.

Polytek molding and casting materials offer some of the best options for Prototyping and product development. We are proud to carry Polytek's extensive line of high performance silicones and urethane casting resins.

Platinum Silicones
In addition to standard 10:1 ratio silicones (10A to 60A) we now have several high quality 1:1 mix ratio options that are low viscosity and easy to mix. Platsil^® 71-11 (10-15 shore A) is a new super low viscosity, soft, platinum silicone with incredible stretch and tear resistance. 71-11 is great for 1 piece molds or reproducing patterns with deep undercuts. 71-11 is also fast setting. 71-11 at room temperature gives the user 15-20 minutes pour time and a 40-hour demold.

71-20 (20 shore A) is quickly becoming one our most popular platinum silicones. Like 71-11 it is 1:1 mix ratio and also has a low mixed viscosity for easy pouring. Degassing is recommended. 71-20 also has a 15-20 minute pour time and a 4-hour demold. 71-20 is brushable with the addition of Plat-thix.

71-40 is our new translucent (actually hazy-clear) silicone. 71-40 cures overnight to a 40A durometer and is ideal for molds that need to be carefully cut open or vented. Degassing is recommended.

Casting Resins
Polytek 15 series
For high performance resins we recommend the Polytek 15 series. Resins such as 1512 have super high impact strength and the feel of thermoplastic resins.

15 series resins also offer maximum performance and flexibility through a various additives. Add 15F to foam 15-6 or 1510 resins to a density of your choice. Add 15X for accelerating cure (almost a cruel joke to us Texans).

Polytek also offers a selection of semi-rigid casting materials. Check out the 81 series urethanes and the new PT series for a variety of semi rigid casting options.

EasyFlo^® series
The EasyFlo^® series of resins is available for applications requiring super low viscosity urethane resins. EasyFlo^® 60, for example, pours like water and obtains amazing detail penetration. EasyFloª 60 is great for for bubble free castings without a pressure chamber.

EasyFlo^® 120 is a rotational casting resin with high impact strength. EasyFlo^® 120 is suitable for hand or machine rotational casting applications.

Poly fiber may also be added to 15 and EasyFlo^® series resins to create brushable plastics for casting applications or for impact resistant mothermolds. Add Poly fiber to slow setting resins such as 1510 or 1512 to create your own spreadable plastic paste.

Mitch has been building realistic dummies and other SPFX props for 17 years. Pictured is a rather crude early dummy, which attracted the attention of the Garland police and fire department. Bad Mitch.

Special Effects is by far our favorite subject. Where to start? BITY Mold Supply has volumes of technical advice and recommendations in this particular area and has aided some of the top Effects artists and prop builders in our area. BITY Productions has also been involved in TV and film production. A fair amount of our tech support knowledge comes directly from our personal SPFX experience.

Prop Building
Film props usually need to be light weight or flexible copies of their real world counterparts. Rigid foam, flexible foam and hard rubber casting materials are very popular with prop weapon builders. Weapon props such knives, guns, and other "metal" looking props are often cast in hard urethane rubbers such as 81-90. This allows the finished cast prop to be semi-rigid and relatively safe for use in action scenes. Casting with foam is used in scenic elements and large props that may need to come into contact with a performer. Pictured is a steak knife and its rubber duplicate. Metal powder pigments were brushed into the 71-20 silicone mold to create a metallic look.

This is a prop foam bat with the original. A piece of PVC pipe was embedded in the foam 3/4 the length of the bat. This allowed for the last 8-10 inches of the business end to be flexible and have plenty of "give" when striking a performer. Without the PVC support the foam bat would have been too floppy to appear realistic.

Silicone molding compounds such as 70, 71, and 73 series rubbers are all suitable for prop making. Fast setting silicones are preferable for applications requiring a mold and cast part in the same day. 71-11 and 71-20 are easy to use 1 to 1 ratio platinum silicones that may be demolded in 4 hours. Tin series silicones may be accelerated with TinSil fast catalyst. BITY Mold Supply offers keys (pictured) for additional registration of mother molds.

Gel-10 Platinum silicone makes excellent one-piece seamless molds. Gel-10 has incredible elongation and tear strength. The following photos show how Gel-10 mold was used to reproduce a rigid foam jug prop. Plaster Bandages were used to create a fast two-piece mother mold. The mold was made in about 1 hour and castings were made 45 minutes after demold.

Here is a one piece skull mold made using the same method.

Animatronic Skins and Underskull Materials
Platsil Gel-10 silicone is one of the versatile and best animatronic skin materials available. Gel-10 is a 1:1 ratio platinum silicone with a 6-minute pot life and a 30-minute demold. Use 71-73 retarder to extend working time. Add Platthix to create a brushable paste of varying viscosity. Smith's Deadener may be added to 200% to achieve a super soft, fleshy feel. Deadener eliminates the "snap" and rebound of silicones. Silicone fluid may also be added to Gel-10 to aid in degassing for pouring into large core molds.

Underskulls may be created using 1512 resin. 1512 may be thickened with Polyfiber for brushing into open molds. 1512 may also be bonded to Gel-10 silicone if poured or brushed against Gel-10 when less than 30 minutes old. Gel-10 may also be bonded to 1512 that is recently demolded and free of mold release. Pictured is a Gel-10 arm with a "deadened" core and a bendable armature to simulate the joint in the elbow.

Brushing or "sloshing" Gel-10 in to a mold will create super realistic body parts. Sloshing 1512 or Easy Flo120 behind the Gel-10 will create a hard bone-like understructure. Gel-10 may also pigmented and cast directly into alginate. Pictured is a Gel-10 skin brushed into a sealed plaster mold. Hair punches beautifully into Gel-10.

Gel-10 may be cast into some urethane molds but tests must be performed first. Some urethanes exude oil on the surface that may inhibit some Platinum silicones. Plaster molds must be sealed with Murphy's soap oil for casting.

Latex and F-5 foam Poly Latex is a great low cost skin material for use in mask making and foam props. Latex works best when use in a plaster mold. Latex is air drying and relies on the absorption properties of unsealed plaster to draw the moisture out of the curing latex. Latex skins are built up to a desired thickness by the dwell time of the casting. Latex is poured into a plaster mold to the brim. As the latex sits or dwells, a skin is formed where the liquid latex meets the plaster. The longer the latex sits in the mold the thicker the skin gets. Thick castings sometimes require a day or more dwell time.

F-5 flexible casting foam may be cast into the dry latex mask or prop prior to demolding. F-5 is also self-skinning and will form a skin when cast directly against a mold surface.

This dummy was made using a latex skin and a flexible urethane foam.

Releasing molds for F-5 foam F-5 may also be cast directly into a silicone, urethane, or plaster mold when the proper release is applied. Most silicone molds require little or no release. Urethane molds require Polycoat mold release. Plaster molds should be sealed with shellac and waxed. This plaster bandage mold was coated with paste wax.

F-5 foam may also be used to foam the interior of Gel-10 silicone props. F-5 will not bond to Gel-10 but fabric embedded into the inside Gel-10 surface will aid in locking the two materials together.

This dummy was made using a silicone skin. I foolishly tried to develop the pictures of said dummy at a major discount retailer (that will remain unnamed). Despite my assertion that these were FX related pictures there was a bevy of McKinney police officers awaiting my return to the 1 hour processing desk.

The irony of the situation was that this was a dummy of me! So the Police were convinced I had murdered my twin or maybe I was a really crafty time traveler. McKinney Police finally went away after I told them this was the best compliment I could receive for my handiwork. Bad Mitch.

If all this prop building fascinates you we recommend our Lifecasting 101 DVD. Lifecasting 101 demonstrates several lifecasting methods and , most importantly, shows how to make hollow wax positives for re-sculpting. Most of the dummies on this page were molded from re-sculpted wax heads. This process allows you to open the eyes of your sculpture and easily remove and re-sculpt defects.