How to Easily Mold Acrylic Plastic Sheets

This article will teach you a super easy way to form acrylic plastic sheets without cracking, splintering, or destroying the sheet. Note that this is not on the level of mixing and pouring a fluid for intricate forms. Instead, this is for taking an existing plastic sheet and cutting and bending it to a form. You'll need cold weather gloves, strong scissors, your mold and an oven.

Steps

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    Measure the inside of your oven. As you'll need to put the plastic sheet into the oven, this is your size limitation.
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    Have a mold ready to use. The example here is the outside of a mold, but it can work inside, too.
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    Make adjustments appropriate to the specifications of your project. The only major variable that can affect the forming process is the thickness of the plastic sheet. This article uses a sheet about 1/4" thick, so all times are about 10 to 15 minutes per step. For thicker sheets, it will take longer, and for thinner sheets, it will take less time. Modify the timing as necessary.
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    Measure the size of the of the overall piece you need. Make sure the sheet is just big enough for the form. Use a plastic cutting knife to cut the sheet down to the general overall size.
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    Mark the shape with a black felt tip pen. This should include any interior cutouts, corners, etc.
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    Place the plastic sheet on a cookie sheet and place in an oven set to 250 F. Wait about 10 minutes for it to warm fully. When it's ready you'll find it flexible when you try to pick it up.
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    Put on your gloves when you work with the plastic. It's hot and will burn you if you're not careful.
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    The first step is to cut any curves, corners, cutouts, etc. using the heavy shears or scissors. You'll have about 2 minutes before it cools and hardens too much to cut. If it gets too hard, put it back in the oven to warm up again.
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    Once it's cut to form, place back into the oven and raise the temperature to no more than 275 F. At 300 F. it will begin to stick to the cookie sheet. Above that temperature it can melt and/or begin to bubble.
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    Pull the plastic out and quickly press onto or into the mold that's ready. use your fingers and firm pressure to press into any corners, fold, bends, etc. Continue to hold and press into shape until it begins to harden.
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    Quickly dunk into cold water to cool and set the piece.
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    If there is a mistake, reheat and start over again.
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    Final check. If there are a few curves or bends that need correcting, you can turn on a burner on low to pass the piece back and forth over to SLOWLY heat it up for localized bends.

Tips

  • If the area to bend is on an outer curve or bend, or if you want to create a tighter corner, try using a frying pan on LOW heat to hold the plastic area to bend. Once heated it will bend easily.
  • The reason this works is because acrylic plastic actually melts at 405 F. I haven't tried, but someone else can try, to actually melt plastic waste pieces to see if they will join and pour or flow into tighter molds.

Warnings

  • Don't heat to more than 300 F. or you will begin to create bubbles in the plastic.
  • Make sure you use heat (cold) resistant gloves. They will still get hot as you work.

Article Info

Categories: Sculpting