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.

Q: I have an application where I need pan head, insulating, high vacuum compatible, screw. It will also need to be usable at a service temperature up to 150C. Do I need a ceramic?

A: Though ceramics are excellent insulators, they are usually only used for high temperature applications, where polymers are not compatible. For example Alumina ceramic has a usable limit of 1650°C. Since this is a relatively low temperature, your best bet is a polymer like PEEK or PVDF screws. Depending on the strength, inertness and chemical resistance needed will determine which polymer PEEK or PVDF is best for your fasteners.

Q: I’m looking for a chemically resistant polymer that can withstand chlorine and chlorine dioxide as well as a decent amount of weight and tension (around 27 lbs of weigh). Can you suggest a material?

A: Of course it depends on the concentrations and temperatures you are operating at but generally speaking a very chemically resistant and strong polymer to consider would be PVDF or Kynar fasteners.   PVDF fasteners offers an ultimate tensile strength of 5000-8000 psi providing structural strength. This could also be improved with glass fiber by about 2x.  You will have to consider the diameter of your screw and the temperature of the applications to determine if PVDF is strong enough though