Tag: polymers

Non-metal fastener for hydrochloric acid

Q: I’m building some lab equipment what will be housing hydrochloric acid. I need a non-metal fastener that is corrosion resistant . Can you make a recommendation?

A: In terms of a material that is not metallic and can handle hydrochloric acid, I would suggest either PTFE or PVDF. PTFE is virtually inert to most acids, as well as bases. If you laboratory is working on anything organic, it is bio-inert and will not leach into or contaminate sensitive scientific material. PVDF is also a good choice, as it offers similar resistance as PVDF to harsh chemicals, but with increased mechanical strength.

Why ceramic bolts don’t have yield strength

Q: I was looking at your site and noticed that the ceramics don’t have a yield strength. What does that mean?
A:  Metals and plastic have yield strengths because they start to stretch before breaking… the point where they start stretching is the “yield point” and the stress at that point is termed the “yield strength”.
Ceramics on the other hand are very, very stiff.  They stretch very little and will break catastrophically.  Therefore, since there is no reasonable amount of stretch in the material, they are not given yield strengths.