This is a process of heating your parts at elevated temperatures to achieve faster cures and/or maximizing physical properties.  The Technical Data Sheet (TDS) will make recommendations depending on your cast material.

This is the amount of time you have to pour your casting material once A&B components have been mixed. At a certain point, the material will thicken and cease to flow well through your mold. Our work times are based on 100 grams of mixed material. Keep in mind, the more material you mix, the material will react more, and work time will decrease.

Demold time is the point a material is cured enough to be removed from your mold and the part will not distort or be damaged cosmetically. BJB determines our demold times with a cast part that is typically 1/8” (3.175mm) thick.

Using an example mix ratio of 100/60:  100 Parts A to 60 Parts B.  If you pour 250 grams of A, multiply 250 grams times .60 (60%) to get the B amount needed (150 grams) for 400 grams total A&B combined.  If you know you need 400 grams total A&B combined for your cast part, divide 400 by 1.60 (160% = 100%A + 60%B) to get 250 grams.  This is the A (100%) amount.  The balance between 250g A & 400g Total A&B (400g-250g = 150g) is the B amount: 150 grams.

Using a pressure chamber is not required in many applications. However, you may find using one in situations may help alleviate problematic part configurations. Even if the cast material has been vacuum degassed, material flow through a mold may create bubbles through turbulation or voids in the detail. Pressure casting shrinks small bubbles and pushes casting material into voids. We recommend using 40 – 60 PSI and ensure the material has sufficiently cured before releasing the pressure.

Using a pressure chamber is not required in many applications. However, you may find using one in certain situations may help alleviate problematic part configurations. Even if the cast material has been vacuum degassed, material flow through a mold may create bubbles through turbulation or voids in the detail. Pressure casting shrinks small bubbles and pushed casting material into void areas. We recommend using 40-60 PSI and ensure the material has sufficiently cured before releasing the pressure.

Shelf life can vary and will depend on a few factors. Here are some handling tips that will help you get the longest shelf life possible. 1) Avoid over-exposing open containers to ambient air. Replace lid or cap quickly after dispensing desired amount. 2) Purge open containers with dry nitrogen or dry air like our Gust Air Purge before re-sealing. 3) Clean the opening of the container before re-sealing. 4) Store materials between a temperature of 65F-80F. Typically, materials used in dry climates will have a longer shelf life than those used in high humidity conditions. Check the material’s Technical Data Sheet for the rated shelf life of that product.

We recommend purging the material container with dry nitrogen or a dry air source, such as our GUST product, before closing for storage, and closing the container lid promptly after dispensing material to minimize moisture exposure.

Pigments are typically used to produce opaque colored parts, while dyes are used with translucent or clear materials to achieve translucent coloration, the terms “pigments” and “dyes” are often used interchangeably, so it’s helpful to understand the differences between them.

We recommend staying below 2% PBW to the total weight of A and B components when possible. Exceeding this amount is not uncommon; however, you may see a reduction in physical properties like heat resistance or tear strength in your material.

No, the FR certification will be lost if any chemical changes or additives are introduced; BJB offers approved color options listed on the UL Yellow Card, so be sure to review those before assuming additional colorants are allowed.

This is most likely a sign of chemical freezing, as some of our products can chemically freeze at temperatures as high as 65°F, we recommend slightly cracking the lid to avoid pressure buildup and gently heating the material to around 120°F (40–50°C), stirring occasionally to ensure even warming and prevent scorching, and once the material has returned to room temperature, it should be ready to use as normal.

We do not offer mold-making or part-casting services, as we do not want to compete with our clients.

Our Water Clear series performs best in outdoor applications, offering superior resistance to moisture and UV exposure, is highly color stable, and is available in both flexible and rigid options.

For polyurethane parts that won’t be painted or glued, we recommend E236 Urethane Release. For parts that need to be painted or glued, we recommend E302 Rocket Release.  For epoxies, paste wax like our Partall High Temp system.  On new molds, typically 4-6 coats (buff on and off between coats) and 1-2 coats on seasoned molds.  RF-5215 PVA release film is often sprayed over the wax on new molds to ensure good release.  For foams, our Challenge 95 and a light spray of E302 works great.  For silicone to silicone release, Zip ME-301S is recommended.

For most cast polyurethane parts, you should see around 25-50 parts per mold. Geometry of the part, type of casting material used, and type of mold release used, will play a role in mold life.

For a rectangular silicone mold, add a ¾” border around the widest points of the pattern area to form a support wall. This is sufficient for most parts.  Multiply Length x Width x Height of the box to get the volume in cubic inches.  Use this number and divide by the Cubic Inches Per Pound value found on your BJB material’s Technical Data Sheet.

We use common container sizes in our packaging process.  However, this does not refer to the volume of material in each kit.  The kit size simply refers to the packaging used (Quart, gallon, 5-gal, etc).  The Tech Data Sheets list the individual component weights of A & B so you can calculate the kit size needed for your project. The amount of material is calculated by the ratio of the product. For example, TC-890FR has a mix ratio of 70/100. This means a gallon kit will contain 5.6lbs of A and 8lbs of B.

While it has no effect on the physical properties, many materials can vary in shade of color from batch to batch. This depends on the raw ingredients we receive from our suppliers. You may also see a change in shade from when you first received it after it’s been on the shelf for some time. This is typically caused by oxidation and is most commonly seen in urethane formulations.

Not really an FAQ, but we do our best to hire well qualified, non-commissioned employees with extensive backgrounds in this field to help our clients with their projects.