Elliott Equipment Corporation

We get many inquiries asking for electrostatic spray guns and most of the time the caller is looking for a recommendation on whether it should be an air spray or air assisted airless electrostatic gun. For this post we will focus on liguid electrostatic spray guns; not powder spray guns.

I start out by asking a number of questions to help me make a recommendation. 

• What is the part you are painting? Size, Geometry, Complexity?
• What is it made out of? Metal, Plastic, Wood?
• What is your finish quality criteria? "Class A" Automotive?, Industrial? Just trying to cover the imperfections?
• What is most important? Finish Quality? Speed? Transfer Efficiency and Paint saving?
• Are the parts conveyorized or  too large for a spray booth?
• Are you trying to finish on site or outdoors?
• Is the coating solvent or waterbased?
• How much is the coating per gallon.? How much do you use a day, week, month, year?
• Really still want to use an air spray gun but the environmental inspector says it has to be electrostatic?

The answer to these questions will help me make a recommendation on the best spray technology for their application. One size definitely does not fit all when it comes to electrostatics. 

Then I try to clear up some misconceptions about the nature of spraying paint electrostatically. I can tell you the number of folks who have the idea that (1) electrostatics will completely eliminate overspray or (2) somehow "bond" the paint to the substrate better. Neither of these truisms is true.

(1) Depending on the technology chosen and the answer to; the questions above we might reach transfer efficiencies in the 40%-75% range. (Actually there is a gun used to refinish metal furniture onsite that will achieve efficiencies in the 90% range; but that is a topic for another post and not pertinent to our discussion here) Even with those transfer efficiency ranges, you can see that these guns will still produce overspray. Given; however; that conventional air spray or even air asisted airless or HVLP guns will have efficiencies in the 20-30% range these are significant improvements that we are talking about and these paint savings and productivity increases can easily pay for the cost of one of these guns in a short period of time. from then on the savings go directly to the bottom line.

(HVLP guns with a transfer efficiency of 20-30%? What about the 65% you always hear about? Check back in the near future for a post with straight talk on the real transfer efficiency of an HVLP gun.)

(2) While it is true that paint; as it is sprayed will be electrostatically attracted to the substrate; once the negatively charged paint is deposited on the part; the electrostatic charge is disipated and the paint sticks or "bonds" to the part in the same manner as if it had been painted conventionally.