Fosshape® is a unique kind of felt-like Thermoplastic used in sewing, millenary, and costume design. It was originally designed for hat-making as a glue-less alternative for Buckram. When exposed to high temperatures using an iron, steamer, or heat-gun, this soft, pliable fabric can be formed and shaped into gravity defying lightweight shapes that maintain their shape even after crushing. Perfect for cosplay and costuming applications.

It is a non-woven, non-fraying, felt/batting like material that can be cut and sewn like regular fabrics. Fosshape® can be sewn to itself or can be sewn as interfacing to provide a hidden, gravity defying stiffener. It can also be shaped into stand-alone structures or sculptural pieces.

How to Use: Fosshape® comes in soft, flexible sheets cut by the yard, but becomes stiffer and more rigid the more heat is applied to it. However, too much concentrated heat will cause melting and holes.

When applying heat Fosshape® will stiffen and hold the shape it has been formed into. Once formed it will retain its shape even when flattened or squished.

Fosshape® can either be formed freehand or shaped over an object like a mannequin, dome, square, ect.

For a slower, subtler, more controlled shaping we suggest using a steamer. Gradual heating allows for more control over the stiffness of the fabric. For more angled, gravity defying, extreme shapes, carefully heating with a heat-gun will yield better results.

What makes Fosshape® particularly useful in cosplay and costuming is its incredible ability to regain its shape after being compressed. A witch's hat, hip cage, or any other costume/ prop piece made of Fosshape® can be squished into a suitcase and should pop back with minimal deforming.

Molded Fosshape® will lose its shape with repeated deformation, but can be re-shaped with additional heat/steam.

Fosshape® is only available in white and black, but can be dyed using synthetic dyes.  


We sell Fosshape® in three sizes:

Fosshape 300®: Versatile and lightweight, the thinnest of the 3 sizes most similar to felt. For lighter weight needs, recommend for use as interfacing.

Sold in white. Click Here To View


Fosshape 400®: A blend between Fosshape 300 and Fosshape 600 for medium weight projects or lining.

Sold in Black. Click Here To View


Fosshape 600®: The strongest, thickest and most durable of the three. Fosshape 600 is for heavy weight and structural applications, and is commonly used by museums and historical societies to make custom mannequins.

Sold in White. Click Here To View