Ask the Expert Question-and-Answer Archive

by Ron Joseph

May, 2005

Applying PTFE

Q. We will be applying a PTFE fluorourethane coating to wind turbine blades as a protective coating. It applies like a slightly thicker polyurethane but is much slicker. It is a two part chemical thermoset. What is mixed for application must be used within four hours. It will be a continuous process. We like an airless HVLP system but aren't sure which is best for this industrial application.... which one(s) will hold up the best? Also, we would like to mix/blend several gallons a at a time. Any sage words of advice... on the who makes the best equipment for what we are going to do. Any other comments would also be appreciated.

A. The two companies you should look at are Graco and ITW-DeVilbiss. Both are leaders in the field. You might consider using plural component mixing equipment for which both comp anies can provide excellent products. There is no such thing as "airless HVLP", but I'm assuming you mean HVLP and both companien can help you on that too. If the coating has a viscosity that it too thick for HVLP then you might want to consider an air-assisted airless gun that is designed to deliver no more than 10 psig of compressed air to the horns of the spray gun cap. In that case you will be using an air-assisted gun that complies with the EPA requirements for HVLP. This is NOT an HVLP gun, but it meets the regulatory definition of HVLP.

Best wishes,

Ron Joseph