Tag: PVDF fasteners for corrosion resistance

PVDF Screws for HCl (hydrochloric acid)

Q: Am I right in understanding that polymer fasteners are  chemically resistant? I know they are not nearly as strong or temperature resistant as a metal, but our temperatures are ambient so would this work for me?

A: For HCl, you would want to consider PVDF polymer fasteners.  These are relatively strong polymers and very corrosion resistant.  They will be fine in the HCl environment, its just a matter if they are strong enough for your application. To be honest, I am not sure if they will be more economic than the C276. It will depend on the sizes you need.  Here is some info on PVDF:

https://www.extreme-bolt.com/pvdf-kynar-fasteners.html

PVDF Screws for Sulfuric Acid & Strength

Q: I’m looking for a polymer that can be exposed to low concentration of sulfuric acid. Which polymer do you recommend? I tried PTFE but they don’t seem to be as strong as I need.
A: PTFE and PFA fasteners offer the highest polymer corrosion resistance but the trade-off is lower strength. You may want to try PVDF fasteners. PVDF screws are slightly less corrosion resistant but hold up well in sulfuric acid and offer much higher strength than PTFE or PFA. PVDF is also usable to about 150°C (300°F)

PVDF Polymer Screws for High Strength Acid Resistance

Q: I have a laboratory applications that uses about 25% sulfuric acid at room temperature to 100F. I’d like to use a polymer rather than a metal if possible. I tried PTFE screws because I thought they were corrosion resistant, but they need to be replaced often because they can’t handle the work load. Is there another polymer I can use?
A: For a stronger polymer combined with corrosion resistance, you may want to consider PVDF screws. PVDF offers a good level of corrosion resistance and has a tensile strength around 2000-3000 PSI stronger than PTFE screws. PVDF screws are known for their balance of corrosion resistance and strength, where PTFE is best for corrosion resistance alone. PEEK screws could also be an option as they are 4-10x stronger than PTFE, but PEEK may weeken a bit with sulfuric acid at that temperature and concentration: