The 3D Printer's Guide to Shore Hardness

Everything you need to know about choosing the right material hardness for your prints Stop Guessing. Start Printing Smarter. Ever printed a part that snapped when it should have bent — or felt like rubber when it needed to be rigid? The answer isn't your printer settings. It's Shore hardness. This guide breaks it all down so you can pick the right material every single time. What Is Shore Hardness? Shore hardness is a simple measurement of how hard or soft a material is. Instead of guessing whether something "feels flexible," Shore hardness gives you an actual number on a standardized scale — so you can make smarter material choices before you ever hit print. You'll see it on resin bottles, filament spools, and material spec sheets. Once you know how to read it, you'll never look at a material the same way again. The Two Scales You Need to Know There are two Shore scales that matter for 3D printing: Shore A — Flexible & Rubbery Shore A measures softer, more elastic materials. The lower the number, the more flexible the material. Think rubber bands, gaskets, and flexible grips. Shore D — Rigid & Hard Shore D measures harder, more rigid materials. This is the scale for solid plastics like PLA, PETG, and ABS — the stuff that holds its shape under pressure. Real World Examples Not sure where a number falls on the scale? Here's how common materials compare: Material Shore Rating Rubber band Shore 20A – 30A Car tire Shore 70A Hard hat Shore 80D TPU 85A filament Shore 85A PLA filament Shore D Shore Hardness for Resin Printing When shopping for resin, you'll notice Shore ratings on almost every bottle. Here's how to think about it: Low Shore A (20–50A) Very soft and flexible. Great for wearables, flexible props, and anything that needs to compress or deform without breaking. Mid Shore A (60–80A) The sweet spot for functional parts. Flexible enough to absorb impact, rigid enough to hold its shape. Perfect for joints, tires, and snap-fit parts. High Shore A / Shore D Rigid and strong. Best for miniatures, display pieces, mechanical components, and anything structural. Shore Hardness for FDM Filament Shore hardness isn't just a resin thing — your everyday filaments have Shore ratings too. Filament Shore Rating Best For PLA Shore D Miniatures, rigid structural parts PETG Shore D Durable rigid parts ABS Shore D Rigid mechanical parts TPU 95A Shore 95A Durable, semi-rigid flexible parts TPU 85A Shore 85A Soft, rubbery flexible parts The rule of thumb: if you need flex, you need Shore A. If you need rigidity, you need Shore D. Trying to print a flexible part in PLA is a fast way to end up with a broken part and a wasted print. Quick Cheat Sheet Goal Shore Range Feels like rubber Shore 20A – 50A Flexible but strong Shore 60A – 80A Fully rigid Shore D Download the Free Shore Hardness Cheat Sheet Get the printable reference card and keep it next to your printer. No more guessing — just grab the sheet and pick the right material every time. 👉 Download Free Cheat Sheet By downloading this model / guide, you consent to receive emails from MakerBuildIt.com, including updates, new content, and product announcements. You may unsubscribe at any time. Shore hardness is one of those things that seems complicated until it clicks — and once it does, it changes everything about how you choose materials. Whether you're printing in resin or FDM, flexible or rigid, the Shore scale is your roadmap to prints that don't just look great, but actually perform. Good prints look great. Great prints perform.