How To Make Plastic Sheet Molds

Get the right mold material.

How to make plastic sheet molds. The example here is the outside of a mold but it can work inside too. The first thing you need to have for creating a plastic part is a mold. On the first day prepare your template object and work space. Cover a flat area with plastic trash bags to avoid mess and spray the plastic with a mold release agent.

Layer the sheets on top of eachother. Build a molding box a frame that holds the mold in place that is bigger than the size of your template object. The mold is a female replica of your original part. The plastic i have melted so far has set a bit too rigid for casting anything with undercuts.

You need to create your mold with a material called rtv room temperature vulcanizing slicone rubber. Each sheet should be 6 inches longer than the mold. Remove the excess water by squeezing the sheets over the bowl. Dip the sheets in bowl filled with room temperature water for 1 second.

Recycling plastic for making the molds for the concrete would make good use of what would otherwise be pollution. Once your part is formed it has to be shaped. Lay the sheets over the mold and up the retaining walls. Cool plastic is hard plastic.

As you ll need to put the plastic sheet into the oven this is your size limitation. The best part of rtv is it comes in the form of liquid until you add the required catalyst. Have a mold ready to use. I want to make molds for pouring concrete into.

Releasing the mold from the plastic before it fully cools within 2 3 minutes of forming is also a good idea. Measure the inside of your oven.