How to Make Soft Plastic Lure Molds? Best Guide 2022

Feb 14, 2022

How to make soft plastic lure molds? Before building any artificial in plastic resin, we will have to worry about building around it to be reproduced, a two-part mold.

There are two main construction methodologies

The original to be reproduced could be an already existing artificial on the market or a new subject built by us, perhaps using balsa wood.


How to make soft plastic lure molds?

I use 3- or 4-mm plywood for the longer sides and 10 mm plywood for the two shorter sides. In this way we will be able to reuse them, without having to redo them every time.

We take our original, fix it or stick to it at both ends (head and tail), two steel wires. We can keep it raised halfway inside the plywood box.

Obviously, to do this, it will be necessary to make two cuts in the shorter sides of the box with the jigsaw up to approximately half height. How to make soft plastic lure molds? This operation will serve to create a small space (7/8 mm.) We will then pour the expensive silicone rubber. The remaining space of the box will be entirely occupied by the much cheaper plaster.

Method A: create a cylindrical or conical housing

Now we need to create a cylindrical or conical housing. This starts from the head of our lure and reaches the end of the mold. It will be good to use to pour the silicone rubber into the cavity left free by the plasticine.

Use a piece of nylon on the piece of marble

We then place the wooden box, with all its contents, on a work surface (I use a piece of marble) to prevent any spillage. How to make soft plastic lure molds? This keeps the empty part upwards. I recommend placing a piece of nylon on the piece of marble so that it can then be removed easily.

Quickly mix gypsum with water, in sufficient quantity to fill it, taking care to make a very liquid amalgam. It can easily fill every gap. The plaster sets in about fifteen minutes. We will have to act quickly, helping ourselves by cutting a small trowel to fill every smallest hole.

After about ten minutes, when the plaster has set, we will take a wooden (or marble) ruler. How to make soft plastic lure molds? With sharp edges about twenty centimeters long and, scraping slowly. We remove the excess plaster, above the box, leveling the surface until the sides of the wood emerge.

Now, we will allow the plaster to dry perfectly, for at least two or three days. It dries, small cracks form around the sides of the wooden walls and the plaster takes its natural white color.


Overturn plaster and begin to remove the plasticine

Now some space has formed again, the space necessary for the second plaster casting.

Before carrying out it, however, it will be necessary to sprinkle the surface of the dried plaster with a veil of detaching wax. We gently open the wooden box, and separate the two parts of plaster.

How to make soft plastic lure molds? Remove the plasticine

We have thus built two overlapping parts, two gypsum shells. This overlap will form the rigid reinforcement of our mold. Now we will sprinkle the artificial cleaned from the plasticine with a layer of release wax. We will prepare for the pouring of the silicone rubber for molds.

Join the two plaster parts with the help of ropes or rubber bands

We carefully close each slot with plasticine, with gummed paper or pieces of nylon. So as not to let the liquid rubber come out and we straighten the mold joined in plaster. How to make soft plastic lure molds? It holds the tube or the plastic cone, in order to facilitate the insertion of the liquid silicone rubber.

We catalyze rubber:

We will have to mix it for a long time with the tip of a large screwdriver, together with the necessary amount of catalyst.

The one I use requires 10% (ten percent) of catalyst and solidifies in 24 - 36 hours depending on the external temperature. For a mold of a medium / large size minnows, we will need 100 grams of silicone rubber and 10 grams of catalyst.

Pour the liquid through the plastic tube

How to make soft plastic lure molds? Now we can pour the liquid and catalyzed silicone rubber, through the plastic tube, until all the empty space around the lure and the tube itself are filled. But be careful to slowly pour the rubber, with the help of a small jug with spout, so as to let the silicone rubber flow slowly into the mold, in order to allow the air to flow towards the other, leaving the place to the rubber.

In this way the rubber will fill exactly the amount of space between the plaster and the original, allowing us to obtain a perfect mold.

How to make soft plastic lure molds? Rubber that manages to reproduce

Once the rubber has poured, the mold will be kept facing upwards, for the entire time necessary for its definitive solidification.

Now we can open our plaster mold, freeing it from the windings, we cut delicately with the blade of a sharp cutter, laterally the rubber, near the head, for about two / three centimeters on each side, in order to allow the original to extract.

Then we will continue the cutting operation, always following the contours of the plaster molds.

How to make soft plastic lure molds? Now we will detach the two parts of the mold; it is a very exciting moment, the moment of truth, because it is right now that we discover whether the steps of our upstream work have been correctly carried out.

Accommodate the plastic resin and the lure assembly

Having removed the original wood and cut the silicone rubber in two parts, one realizes with pleasure that the mold is finished, ready to accommodate the plastic resin and the lure assembly and to produce hundreds of baits ... super captivating.

At the end of the operation we will find two gypsum shells integrated with two parts of silicone; together they will form the mold to reproduce our lures.

Now the two-part mold is really finished

After drying, with a sharp cutter it will divide into two parts and the mold will be ready for use. How to make soft plastic lure molds? The same procedure will have to adopt if we have to reproduce Jigs or spinner bait heads and any other small parts.

In this case we will have to use inert sinking fillers (marble powder). It is to mix with the plastic resin. Moreover, it is to ensure that these details do not float, but rather cause the artificial for which they are intended to sink. We must be able to obtain at least 1 kg of silicone rubber for elastic molds and the relative catalyst.