|Tubing & Hose Buying Tips
#11: Hardness and Softness
It can be challenging to make sure you’ve covered all the bases during the tubing and hose selection process. Have you considered all the elements involved with the application? Temperatures, chemicals, pressures, flexibility needs? In Tubing & Hose Buying Tips we’ll address common selection factors, one at a time, in each issue of extrusions.
How soft or hard should your application’s tubing or hose be? Tubing hardness is measured as its durometer, and different scales, namely Shore A, Shore D, and Rockwell R, are commonly used for plastic and rubber materials. The lower the scale number, the softer and more flexible the material will be.
For instance, silicone tubing is a very soft, flexible product. A typical hardness rating for it is Shore A50. Polyurethane tubing is not as soft as silicone and can measure between Shore A70 and A95. Harder materials such as nylon and polyethylene are normally measured on the Shore D scale, and actual ratings vary widely due to different material formulations (for example, high density polyethylene and linear low density polyethylene). Others like polypropylene use the Rockwell R scale.
Flexibility and softnessor hardnessrequirements differ greatly between applications, so the needs for your particular job must be carefully considered. Typically, softer tubing materials are more flexible, and some may be a bit tacky. Harder products normally offer less friction and can easily glide across the surface of other items. Also, the type of fittings that are needed to make connections changes depending on tubing hardness, as does the necessity for clamps.
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#10: Moisture Related Factors
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