A Western Renaissance

Pouring Equipment and Materials

In the early years, most pourers used hot plates and ladles to pour plastics. A small saucepan was heated and a dye added to the mix. Once the plastic reached melting temperature, it was ladled into the open-cavity mold.

In the mid 1970s, Lee Precision started making pouring pots specifically for plastic. The pots are similar to those used to make leadhead jigs and bullet weights, but run at much lower temperatures. These pots offer far better control of the plastic—in temperature control and control of the pouring stream, important in producing fine baits.

Until the 1990s, pots and ladles were the mainstay of pouring equipment. That was until Gregg Stump, originator of the Robo Worm, automated the process. Using computer-aided robotics, Stump developed a process that requires only heating plastic, mixing colors, and pulling the baits from the molds. The pouring is done completely by robotics.

Materials for pouring plastic begin with the polyvinyl chloride plastic. Before heating, the plastic is in a “monomer emulsion state” that looks like milk. Upon heating to about 340°F, the vinyl chloride in the mix reacts to form long chains of molecules (it polymerizes). In the polymerized form, the plastic becomes clear. After complete reaction of the plastic, dyes made specifically for this type of plastic can be added. Or glitter can be used for baits with more flash.

The single-sided molds used for hand pouring are made of acrylic and RTV silicon. RTV silicon has been accepted as the standard, due to its long life, ability to withstand high temperatures, and resistance to breakage. Some larger manufacturers use molds machined of aluminum, a costly avenue for the do-it-your-selfer.

Pouring

Plastic from either a bottom-loading pot, like those Lee Precision makes, or from a ladle, is poured into the mold so a slight bulge appears in the plastic above the cavity. This ensures that as the plastic cools and sets, the bottom of the worm doesn’t become concave. By slightly overfilling, the worm has a bottom that is slightly rounded.

For two- or three-color baits, at least two pots of plastic are needed. Fill the mold halfway with the first color and then finish with the second color. Make sure that when pouring two- or three-color baits that the plastic from the first pour is still molten when pouring the second color. If not, the two colors will not laminate together and may fall apart.

Mixing Colors

Unless the home pourer wants clear baits, he must add color. Dyes used must be specifically for PVC, as food coloring or other dyes result in disaster. Plastic dyes can be purchased from any company that sells pouring materials. All pourers who take their business seriously log each color formula they come up with to be able to repeat a color. Also, many colors on the market today are a combination of two or more colors.

Mixing colors can take place either before or after the plastic is heated. When first developing a color, though, mix the coloring a little at a time into the hot plastic. This allows for pouring a sample bait to test its coloration.

Once a pourer becomes efficient at mixing colors, there’s no bait on the market that cannot be color matched. In over 20 years of pouring, I’ve only had two colors that have stumped me. Just keep good notes, and you’re on your way.