Por-A-Kast TA is Synair's liquid urethane resin casting material, in a spreadable paste form. This casting system is ideal for use on vertical surfaces and as a back-up (Mother Mold) material. Por-A-Kast TA offers the same characteristics as the pourable Por-A-Kast products. It can be tooled, sanded, turned, ground, pigmented, stained, and filled to create an unlimited variety of colors, textures and effects.

We recommend Por-A-Kast TA as a permanent professional quality mother mold for our urethane rubbers and silicones to extend the life of your molds.

Synair's Por-A-Kast systems were designed specifically for ease of use. With their simple 1 to 1 mix ratio, and quick room temperature cure, these products are suitable for both the novice and those experienced in using casting resins. Por-A-Kast can be used for a variety of end products in the art, hobby, pattern, taxidermy, architectural, sculpture and industrial worlds.

Use in a well ventilated area, at temperatures above 65-70ºF. WARNING: MAY BE HARMFUL IF INHALED. MAY CAUSE SKIN AND EYE IRRITATION. The product in this container is isocyanate terminated. Prolonged exposure may cause irritation to the respiratory system resulting in breathlessness, chest discomfort and reduced pulmonary function. Repeated skin contact will produce irritation and sensitivity. Use only in a well ventilated area. Do not breathe or inhale vapors. Avoid contact with skin and eyes. Wear protective eye wear, oil resistant impermeable gloves and chemically protective clothing. CONTAINS: Methylene Bisphenyl Isocyanate (MBI) CAS#: 101-68-8

FIRST AID SKIN IRRITATION: stop immediately and wash affected area with soap and water. In the event of skin contact, remove product with isopropyl alcohol followed by soap and water. EYE CONTACT: flush eyes with cool water for 15 minutes. and seek immediate medical attention. INHALATION: remove to fresh air, seek immediate medical attention if necessary. INGESTION: If swallowed DO NOT INDUCE VOMITING-seek immediate medical attention.

Getting Started -SUPPLY LIST

SPATULA: metal or wooden.

THREE OR FOUR SMALL PLASTIC CONTAINERS (clean and dry): you will need four containers if fillers are used.

RELEASE AGENT

CASTING PRODUCTS

DECORATIVE OR WEIGHT ALTERING FILLERS: if being used.

RIGID OR FLEXIBLE MOLD

'MOTHER MOLD' SUPPORT MOLD APPLICATIONS:
Prepare the exterior of the flexible mold by first making sure that it is clean, dry, and has been allowed to fully cure according to the manufacturers recommendations (usually at least 24 hours). Coat the exterior of the rubber mold with an appropriate release agent. Paste wax, a paste wax slurry, petroleum jelly covered with a layer of plastic wrap or Synair's SynLube 531 can be used to create a barrier between the casting resin and the inner rubber mold.

If using paste wax, the wax can either be smoothed on by hand, or warmed and then brushed over the rubber mold. A paste wax slurry (made up of paste wax thinned with mineral spirits) is brushed over the surface of the mold. In both cases, be sure there is enough wax build up to provide an adequate barrier between the casting resin and the rubber inner mold, paying special attention to indentations and undercuts.

For a barrier of petroleum jelly and plastic wrap, apply a generous coating of petroleum jelly to the outside of the mold, making sure that the entire mold has been covered. Layer plastic wrap over the petroleum jelly to create an additional barrier before Por-A-Kast TA is applied.

Synlube 531 should be repeatedly sprayed onto the exterior of the rubber mold, with each application being allowed to dry thoroughly before re-application. There should be a visible build-up on the exterior of the mold before attempting to release Por-A-Kast TA from the inner molds surface.

Por-A-Kast TA is extremely aggressive, and WILL BOND TO THE EXTERIOR OF THE RUBBER MOLD; therefore, in each case, YOU MUST TEST THE EFFECTIVENESS OF THE RELEASE AGENT prior to your final application of Por-A-Kast TA.

MAKE SURE THAT THE CURATIVE AND PREPOLYMER ARE ROOM TEMPERATURE BEFORE BEGINNING YOUR PROJECT.

Por-A-Kast provides approximately 20-25 minutes for you to mix and apply the material before it begins to gel. Do not measure more material than you can use within that time period. If you have a large mold that requires more material than you can use in 20-25 minutes, you may apply Por-A-Kast TA more than once, but do so immediately.

NOTE: STIR THE CURATIVE COMPLETELY in a slow consistent figure 8 motion, being careful not to introduce air into the material.

MEASURE THE CURATIVE AND PREPOLYMER ACCURATELY an error of 3% may cause the material not to cure (you can measure by volume or by weight). If measuring by volume, dispense equal of amounts of curative(A) and prepolymer(B) into separate clean dry plastic containers.

The addition of filler can reduce the weight and cost of the system and double the resins volume. You may adjust the amount of filler to achieve different results in your castings or leave the filler out completely. NOTE: The addition of fillers will change the consistency and workability of Por-A-Kast TA. Be sure to run a small test batch to become familiar with these factors prior to your final pour.

If a filler is being used, add an equal amount to a third clean dry plastic container.

Add half of the measured filler to the curative(A) side, and half to the prepolymer(B) side. Thoroughly stir in a slow figure 8 motion.

Combine the curative and prepolymer into a new container stirring again in a figure 8 motion to avoid blending air into the material. Stir until the mixture becomes one homogeneous blend. For small amounts you can use a dry wood or metal spatula. For larger amounts use a jiffy mixer in a small hand drill.

 

Note: Before applying Por-A-Kast TA let the mixture rest 3-5 minutes, giving it time to thicken and change to a thixotropic state.

Apply Por-a-Kast TA with a brush or trowel in a thickness of ¼' to ¾'. The longer you allow the mixture to rest before applying, the thicker you can build your layers (8-10 minutes for layers up to ¾' thick). You may continue to build up layers of the material to achieve whatever thickness you desire. After the first layer sets up, you may then apply another. The two layers will chemically bond and not separate. If however you allow the layers to cure more than 24 hours, rough up the outer surface of the casting with a file or heavy sandpaper to insure that the subsequent layers will properly bond.

Por-A-Kast TA can be demolded in 16 hours. Allow 24 hours for the casting to cure completely.