Question 1

How do I make a press mold to recycle scrap plastic?

Accepted Answer

Upload your STL and Meshcast generates a 3-part compression mold: a cavity body, a base lid and a plunger. Print them in a rigid, heat-tolerant filament like PETG, melt a measured wad of scrap plastic, place it in the cavity, press the plunger hard, let it cool, then push the part out through the ejector hole.

Question 2

What plastic and how much do I need?

Accepted Answer

Use clean scrap of one plastic type (e.g. failed PLA prints). The tool computes the cavity volume and shows the grams needed - PLA is about 1.24 g/cm³. Weigh a little extra; excess squeezes out of the overflow gap by design so the cavity fills fully.

Question 3

Is melting plastic at home safe?

Accepted Answer

Hot melted plastic burns and gives off fumes. Always work in a well-ventilated area, wear heat-resistant gloves and a respirator/mask, and use a heat-resistant surface. Never overheat plastic to the point of smoking.

Question 4

What shapes work best?

Accepted Answer

Flat, solid, low-relief objects - coins, hearts, keychain charms - work best in this first version. The molded part comes out with a flat top face (single-sided relief), so two-sided pieces, deep undercuts and thin hollow shapes are not suitable. Shaped 3D objects (dice, tops) are coming in a later update.

Recycled Plastic Press Mold Generator — compression mold maker