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Welcome to - Custom Source for the Hobby Caster!
Welcome to - Custom Source for the Hobby Caster!

Differences in Casting Products



Polyester Resin

Most new to casting like to start with Polyester Resin (PR) such Casting Craft, which is readily available in your local hobby store and can be purchased in small quantities. PR is also available online in larger quantities through manufacturers such as U.S. Composites. Polyester Resin does not require a pressure pot to create great looking colored pen blanks, and is the easiest to polish, but it smells very strong and can shrink away from other materials as it cures, so it takes some practice to get good at using it for pen blanks. We often times use it for clear casting HVAC metal foil tape, stamps, painted blanks, or other materials that have been glued with Mod Podge or other water-based adhesives. PR may come out of the mold sticky but can go into your shop oven on  a  low temp for a few minutes to dry it out. Polyester Resin casts well in any of our molds. 

Alumilite Clear (Clear Slow):

Another popular material more experienced casters like to use is a Urethane Resin called Alumilite Clear or Clear Slow. Urethane Resins have a shorter set up time than PR, so it requires experience with a pressure pot to reduce surface bubbling. Alumilite can be picky to mix, you have to be very precise in your A & B weight measurements (to the gram). It normally takes only a few minutes to set-up (7-12 minutes). We normally demold and turn a few hours after casting, which is a great turnaround for busy casters. offers a volume calculator to help determine how much resin is needed per mold dimensions.  We make many of our color swirls and hybrid blanks with these resins. We use Alumilite Clear with the weatherproof matte inkjet labels from on which we clear cast our label designs.  Urethane Resin casts well in any of our molds

West System, Liquid Diamonds Epoxy, Alumilite Epoxies, JB Royal:

In early 2017, we introduced the blue molds to meet the needs of Epoxy casters, who prefer to use resins by West Epoxy SystemLiquid DiamondsAlumilite's Amazing Clear Cast, Alumilite's Amazing Casting Resin, or JB Royal. We also have a line of HDPE molds that work well with epoxy resins. You can also cast Polyester Resin and Urethane Resin, so it's a better multi-purpose design for all types of resin casting.  We prefer Liquid Diamonds for casting thicker materials like our machine cut vinyl, decorative foils, and other holographic materials.  Nearly all epoxies require at minimum 24 hours cure time. We keep them in the pressure pot for that time, but not everyone uses pressure. Epoxy resin is the most difficult to polish to a shine, especially if not fully cured, so the key is patience. Some say it can take several days to fully cure before turning, so testing for your own epoxy is recommended. Note, not all epoxy resins are mixed with the same ratio.  Please read your choice product information prior to casting.

Mold Release

A Universal Mold Release such as Stoner helps to extend the normal 5 year shelf life of silicone molds. Alumilite Clear or Clear Slow is a Urethane Resin, so use the Stoner Urethane mold release. If you cast with Epoxy Resin, Stoner also makes a Thermoset mold release specific to epoxy resins. Using products not designed for your particular resin, such as oils or waxes, may affect the outside of your resin cast in an adverse manner. Stoner is the only brand we have found that formulates for the type of resin you plan on casting, which helps to produce better casts as well as save your mold wear.  

If you have any other questions, we are available most evenings and weekends to help. If you don't know what tube-in mold series to buy for your chosen pen kit, call or send us a message about which kit you are looking for help with casting.

Please visit our Casting Basics Guide for more information on casting topics.