Always one for ingenuity, Eric Strebel puts his industrial design expertise to good use even with the simplest of tasks. This time, he’s been commissioned to produce 120 cast parts from a single solid master part. Seeing how costly it is to make solid parts, Strebel decides to take matters into his own hands and by using a specialized mold of his own design.

Here’s how he did it:

YouTube video

Using a reusable mold box, Strebel glues the master part and registration markers onto the bottom before submerging them under a mixture of green silicone. Once the silicone has cured, he removes the mold by disassembling the box.

To hollow out the mold, he lays down some sheet clay on a surface. After flattening it to a thickness of about 10mm, he cuts out the clay pieces and places them into the mold; taking care not to overlap the clay.

Taking his clay-filled mold, Strebel then clears out some room in his fridge and places it right beside his easy-cook lasagna. You don’t really need to buy lasagna to complete this part, but it helps Strebel’s viewers know he’s a connoisseur of only the finest frozen Italian foods.

Once the mold is hard and the lasagna is eaten, he scrapes the top of the mold before rubbing on some lacquer thinner to smoothen the whole thing out.

Placing the mold back into a mold box, he fills the hollowed-out portion with silicone and waits for it to dry.

He then adds some sticks to the sides of the mold which, once the second part of the mold is finished, will serve as weeping channels where resin can freely flow without messing the hollow casts. Strebel finishes the mold by covering the base with a second layer of silicone.

After the mold has dried, he pops the second blue mold out from the green one and removes the sheet clay between them. He finishes it off by continuing the weep cuts which were started by the previously placed sticks.

The blue part serves as the final mold which Strebel uses for the hundred or so hollow casts. He pours the resin into the mold and uses a syringe to top it off.

Considering how much cheaper this is than making a hundred solid parts, Strebel delivers some pretty awesome casts at a fraction of the cost. As always, you can find more of his design know-how over on his YouTube channel.


Carlos wrestles gators, and by gators, we mean words. He also loves good design, good books, and good coffee.