Durometer Hardness Scale: A Complete Guide

If you're making a product, you absolutely have to know if your material is going to be squishy like a gummy bear or hard as a hockey puck. We believe getting this one property right is make-or-break for a product's performance and reliability.

This is where the durometer hardness scale saves the day. We're here to provide a straightforward rundown on the durometer scale, show you how to interpret a durometer hardness chart effectively, and help you select the right material for your project.

What is a Durometer Scale?

Essentially, the durometer scale comes from a specialized tool that uses a specific indenter to see how much a material resists being poked. It's a standardized way to quantify a material's push-back against a set force. 

The number you get, from 0 to 100, tells the story. A low number indicates the material is soft and compliant. A high number signifies it's tough and unyielding. Getting a firm grip on what is durometer rating means you can confidently compare different polymers and plastics and know precisely what you are working with.

Related article: What is Durometer? All You Need to Know

Durometer Hardness Scale

Here’s the deal: there isn't just one single durometer hardness scale. For pretty much any job you'll ever have, you're really only going to bump into two main players: Shore A and Shore D. 

From our perspective, if you have a solid handle on these two, you can address the vast majority of material hardness questions.

• Shore A Scale: This is your go-to for all the soft, flexible stuff. We're talking about materials that need to give a little, like the rubber O-rings that form a perfect seal or the comfy grip on a power tool.

• Shore D Scale: When you need to measure the tough guys—the hard plastics and unforgiving rubbers—this is the scale you'll use. Think of a construction hard hat that needs to take a beating or the wheel on a shopping cart that has to roll over all sorts of junk.

Related article: Shore Hardness vs. Durometer: Complete Explanation

To put this into perspective, we've put together this durometer hardness chart as a handy reference, so you can see how these numbers relate to common items.

Choosing Your Instrument: Analog vs. Digital

Once you know the scale, you need the right instrument for the job. The choice between an analog durometer and a digital durometer is based on your specific operational needs. 

In our view, there isn't one "best" option, only the best fit for a given application. The analog durometer is a highly reliable workhorse, perfect for quick quality checks in the field or on the production line where portability is key. 

However, for laboratory work where precision and documentation are paramount, we find the clear readings and data output of a digital durometer to be indispensable.

Related article: How to Use a Durometer in a Few Easy Steps

Factors That Can Influence Durometer Readings

To get repeatable and trustworthy results, consistency is everything. We have often seen how simple environmental variables can affect readings, which is why following a standard procedure is so important for quality control.

• Temperature: Trying to test a piece of rubber when it's freezing cold is a waste of time. It's going to seem way harder than it actually is. You have to let your material just sit and get used to a normal room temperature first.

• Thickness: This is a big one we see people get wrong all the time. If your sample is paper-thin, the durometer is just going to feel the hard tabletop underneath it. You need a piece with some decent body, at least 6 mm, to get a real reading.

• Press Time: Don't just jab it and pull back. How long you press on the material actually makes a difference. You’ve got to be consistent with your timing for every single test if you want numbers that mean anything.

Your Qualitest Durometer Solution

At the end of the day, the durometer hardness scale is your secret weapon for making sure your materials are truly up to snuff. We believe that when you know how to read a durometer hardness chart and pick the right tool, you're setting your whole project up for a big win.

At Qualitest, we are passionate about providing effective testing solutions. 

We understand that different applications have different requirements, which is why we offer a full range of high-quality, cost-effective instruments. Whether you need the durable reliability of an analog durometer for field use or the high accuracy of a digital durometer for your QA lab, we have the right tool. 

Contact us today. We would be glad to discuss your specific application and help you select the instrument that fits your needs perfectly.

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