Here are the items I use. More readily available for me than Silmar or Alumilite.
From top left.
Bathroom cup and popsicle stick to mix the resin.
Blue painters tape seal the bottom of the PVC mold. Easier to find than corks and no cutting off plastic gloves or saran wrap to seal the corked end. All around better.
Extra Dixie cup for excess resin. Used to make bottle stopper blanks. Next to that is PVC for larger blanks also made from excess.
Water and guerrilla glue for gluing tubes into acrylic
PVC pipe molds. Cut shorter than standard pen blank length to eliminate waste. Sized for slimline. No issues yet of it not making a long enough blank for other pens.
Castin craft from either Michael's or that other place.but not hobby lobby because they're too expensive comparatively. The hardener should come with the can but depends on the store. Hobby lobby cans here do not have the hardener with the can. A local place here in Charleston that caters to artists and craftsman, aptly named Artist and Craftsman also sells Castin Craft for a ridiculous price. But they do have 1gallon cans but its $100 for it.
Powder pigment to color the resin. PearlEx is my choice. The artist place here carries their full line and a little goes a very long way. Check around for a shop that caters specifically to the artists in your area. The one I have here is the best I've ever seen. Amazing place.
Hammer,6" extension and 12mm socket. This fits the pvc mold perfectly for knocking out the blanks when they've cured. Mold release is not needed for pvc. A few taps on the bottom and the blanks pop out. Easy.
Not shown is spray paint for tubes and back painted the resin. I get Valspar from Lowes that closest matches the base color of whatever color pen I'm making. That's used on the tube. I use Apple Barrel acrylic paint and a q-tip to back paint the blank. Again, getting a color that closest matches the base color or dominate color of the blank.