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Flouropolymer etching

I am trying to etch a PVDF pipe so I can get good adhesion with a fiberglass and epoxy coating. I have heard of a few methods but the most common I keep coming up with is a Sodium ammonia ⇦this on eBay or Amazon [affil links] solution. This means of etching is effective but slightly "browns" the pipe. I have a sample of pipe that was etched years ago and it seems to have a almost "powder like crackle finish" I would like to know if anyone has a means to duplicate this type of etch. Keep in mind this will end up being a pressure pipe application and I do not want to compromise the structural integrity of the line.

Rob Delaney
- Levittown, Pennsylvania, U.S.A.
2002

This is very old and well understood technology. The surface modification of fluoropolymer and copolymers in preparation for bonding or adhesion to other surfaces is accomplished in a variety of methods. Sodium ammonia is the oldest technology and provides the weakest bond strength. Sodium Napthalene provides approx. 25% greater bond strength.

Bill Scott
- Pittston, Pennsylvania, USA
2003