Making Plastic Worm Molds
By Frank Manuele (a.k.a. "SenkoSam")
It's quite easy once you get started. The equipment is very cheap, the rewards are considerable and you can copy most lures, even grubs!|
The following method is for one- and two-part molds. Flat-sided baits of a one-part mold work, but may not appeal to the eye in some styles or have the same action as a totally rounded lure. The Senko or other jerk worm is the easiest to duplicate and catch fish immediately (one or two part). To get started though, a simple one-part mold is fine for many forms that will catch fish.
- Flexible container (soft-aluminum baking pan which can be used over and over, usually three-for-a-buck at Wal-Mart® or dollar store; margarine tub (cut down); Hungry Man TV dinner plastic tray, etc.)
- Tablespoon to add plaster to cold water .
- Water (to mix plaster, clean brushes); and a separate container of cold water to cool the new lures fast and see the drop rate or action, if salted.
- Popsicle® sticks to put into the plaster as future alignment guides for two-part molds and to stir plaster.
- Thin aluminum foil for easier separation of new two-part molds.
- Vaseline® for upright Popsicle® sticks and for releasing the two mold halves or any mold from its container.
- Lure to be copied (tip: start with a jerk worm - Senko type).
- Sealer - any plaster/wall board, water soluble sealer such as Valspar® gloss glaze (superior in many respects to Mod-Podge® craft glue, which peels off after 10 pours.)
- Cheap brushes to apply sealer to the cavity and to apply worm oil for a glossy finish. It also acts as a worm release.
- Plaster (i.e. at Lowes®, 25lb of DAP® cost $7.00!) (Don't waste money at a craft store. DAP® is DAP®.) (Wal-Mart® also carries a tub of plaster, but your cost/lb. is high.)
- Small chunks of old plastic or liquid plastisol. (melted plastic can be reused, but care must be taken not to overheat or seer! Burnt plastic will become hard and black and the smoke and fumes can choke you!)
- Non water-soluble worm oil (i.e. Fish Formula®, Mega Strike®, Baitmate®) as a cavity coating to produce a glossy sheen, to aid in worm release and to store plastics when in a plastic bag. *note: water must never get into hot plastic. It will cause uncontrollable foaming, bubbling, spitting and hot steam!
- Optional: Ziploc® sandwich or freezer bags to store creations or unused plastic (by color) to be remelted and used again (note: glitter may dissolve the second time around and more needs to be added; colors may fade, get darker or turn drab, which may be overcome by adding a few drops of dye.)
- Plastic softener - a must for soft, Senko-type worms because salt hardens a bait when used in a large enough amount to add weight.
- Plastic or plastisol.
- Microwave, stove or stove top burner.
- Pyrex® measuring cup (for microwave) or small metal pans (for stove top) to melt and pour plastic)
For the bottom (or first half)
- Add a little cold water to mold container.
- Add heaping tablespoons of plaster and stir well with stick, (but use the spoon only to add dry plaster). The plaster should have the consistency of cake batter, have no bubbles and should be at least 3/4" high (a little less for one-sided molds or thin baits). Wait until it will support the weight of a plastic form (a few minutes.) Once plaster becomes too firm for the form, junk it and start over.
- Add lure to the plaster. Make sure it doesn't float too shallow. When making a two-part mold, the form should only submerge to half it's thickness. One-part molds require that the form is pushed down so its top surface is flush to the plaster surface.
- For a two-part mold, take two inches of Popsicle® stick and shove down into the mushy plaster, but away from the cavity. This will act as a guide to assemble the two parts, exact surface-to-surface, when pouring.
- After the mold hardens and dries, remove the form and, for-one part molds, coat the cavity and upper surface with sealer.
Time to make the next half
- Take small strips of aluminum foil and smooth onto a small part of the surface of the bottom half and tuck into the corners of at least two sides of the container. This serves as a border between the two halves and greatly aids in separating them.
- Leaving the forms in the lower half, grease up the plaster/aluminum foil surface and Popsicle® stick with Vaseline®. Coating the form with worm oil may give a smoother upper cavity surface.
- In a separate container, mix up enough plaster to add another 3/4" of plaster over the bottom half.
- Pour and then wait until the top half is dry and hard (25-45 minutes).
- Pop the mold from the aluminum or other container.
- Use a thin, wide flathead screwdriver to separate the two halves a little at a time by inserting and twisting. Go around the mold a little at a time. The parts will pop apart, with the lower half holding the guide-alignment stick(s). The aluminum foil only serves as a guiding boundary and can be removed.
Finishing the mold
- Remove the form(s)
- Enlarge the pour hole, to prevent air pockets when pouring by taking a steak knife and carve a funnel-shaped pour-hole into both halves (semicircles).
- After the mold dries completely, apply sealer and coat the cavities, surface, and pouring hole. Note: Devcon® 2-ton epoxy is the best sealer. Make sure to get any excess out of the cavities with a fine brush or it will blunt the details.
Pouring for the first time:
Take a small Pyrex® cup and melt some new or old plastic in a microwave for 15- to 30-second intervals, until it has a thin maple syrup consistency. Stir with metal only to insure no globs are in the plastic. Pour into the cavity or down the pour hole. For two-part molds, slant the mold to prevent an air pocket. (If using a one-part mold, pour evenly until a slight hump forms. Hot plastic contracts once it cools and the one side will be concave.)
Note: I brush Fish Formula® (oil) into the cavities just before pouring to get a glossier surface and to add scent to the molten plastic. You can also sprinkle glitter in one cavity, before pouring, to affix it to the surface of the hot plastic. I do this for Kalin® grub tails for added flash.
Note: Adding salt is fine as long as it's ground to a powder. Grain salt settles fast and may not evenly distribute. Salt is used mostly for added weight. I use a cheap coffee grinder.
Note: The mold may need to be recoated if the sealer wears off, but usually not for months with Valspar® gloss or a good sealer. Valspar® is water soluble and cleans up easy.