PolyMaker ColorFabb Red varioShore TPU Filament - 1.75mm (0.70kg)

A prop foam sword is an ambiguous standard for comparison.

At the Colorfabb website, they actually claim an even lower, Shore hardness rating of 55A for Varioshore at its minimum density. I have corroborated this with my own testing, achieving 55A with prints at 230 - 240 deg C. For me, going higher than 240 deg C causes over-extrusion and excess dimensions on the printed part vs. drawing specs, and changes to the granularity of the foaming — all of which increase the stiffness of the printed part.

So, how soft is 55A? If you’ve poked around with those white, silicone rubber erasers for mechanical pencils — those are right about at 55A.

How “thick” the object is and how much infill is used will have significant impacts on the perceived stiffness and hardness of the object that is made from this material.

With the Varioshore TPU, I printed a 25mm diameter x 6mm high disk with a 3mm dia center hole at 240 deg C. This outputs high foaming with low density.

When I put the disk in a tub filled with water, it floated. When I pressed the disk to the bottom of the tub and let go, it floated right back to the top of the water.

It’s possible, when you have last eaten?

Any porous material (most printed filaments in general) shouldn't be considered safe for food contact without a food-safe sealant applied. TPU is hydrophilic, and will absorb atmospheric moisture over time. I haven't used this filament yet, but expect it to behave similarly. A food dehydrator or filament drier at 55 C works wonders to restore the print quality of filaments which have been exposed to atmosphere for long periods of time.

Pure TPU is inert enough to be food safe.

The “natural” color Varioshore does not appear to have any pigments added, and its foaming action is caused by the inclusion of sodium bicarbonate (baking soda) in the filament. Thus, there does not appear to be anything in the Varioshore compound that would cause a toxic food interaction.

The materials used in your extrusion path — such as brass components that have and can leach lead — and the porosity of the FDM print methods, however, all have downstream impacts on food safety regardless of the filament material.

While Varioshare is affirmed by Colorfabb to be safe for prolonged skin contact for items such as prosthetic apparatuses, helmet pads and insoles, I recall reading that they do not intend for the product to be used with food or anything internal to the body.