How to Shape Polyurethane Foam

By Jeremy Cato
Foam like this can be cut and shaped.

Polyurethane foam is the soft, bouncy foam found in most furniture cushions and mattress toppers. It is well-known for its ability to be modeled into a nearly endless number of shapes and cut to any size. It can also be used in a variety of crafts, from costume making to homemade gifts. Shaping polyurethane foam is not too difficult and can yield very impressive results. There are several approaches you might want to consider.

Preparation

Find a large, ventilated workspace and clear away any furniture of large items that could get in the way. Consider working outside if you cannot find a suitable workspace.

Cover the area with the plastic tarp, making sure to cover the entire floor and all valuable items. Shaping polyurethane can produce a lot of dust and waste.

Put on the gloves, goggles and face mask. Cutting foam produces a lot of fine dust and debris that can irritate skin and eyes.

Scissors Method — 2D Shape

Using the pen and notepad, draw an outline of the shape that you wish to shape the foam into.

Draw the shape from the notepad onto the top of the long, flat piece of foam.

Cut the shape out of the foam by compressing the foam as you slowly cut. When you use this method, the shape should have very few rough edges.

Electric Knife Method — 3D Shape

Using the pen and notepad, draw an outline of the shape that you wish to cut the foam into. For the three-dimensional shape, you must make six drawings of the shape — one for all six sides of the foam block. The drawings should represent the shape as it would be seen from the left side, right side, front, back, top and bottom.

Draw the shape from the notepad onto the corresponding sides of the foam block. Make sure that the drawings are the same size for each side.

Cut the foam with the electric knife. Do not cut into the image on either side, but simply cut away the foam around the images.

Continue to slowly pare down the foam until you achieve the desired shape.

Hot Wire Method — 3D Shape

Using the pen and notepad, draw an outline of the shape in the same manner as Section 3, one image for all six sides of the foam block — left side, right side, front, back, top and bottom.

Draw the shape from the notepad onto the corresponding sides of the foam block. Make sure that the drawings are the same size for each side.

Cut the foam with the hot wire device. Just as with the electric knife method, making sure not to cut into the image on either side, but simply cut away the foam around the images. Be extra careful when working with the hot wire.

Carve the foam with the hot wire device until you achieve the desired shape.

Tip

These directions can be used to carve foam shapes for a Halloween costume, a Thanksgiving centerpiece or whatever else you can imagine.

Warning

Be very careful when handling a hot wire cutter, as the tool can reach extremely high temperatures. Cutting the foam with a hot wire can also produce gases that some people may be more sensitive to than others, so the mask and gloves should be worn at all times.

About the Author

Jeremy Cato is a writer from Atlanta who graduated with Phi Beta Kappa honors and an English degree from Morehouse College. An avid artist and hobbyist, he began professionally writing in 2011, specializing in crafts-related articles for various websites.