When is an Electrostatic Spray Gun a Good Fit for my Coating Application
The primary benefit of electrostatic is its increased production while also reducing paint waste. Electrostatic can be up to 90% efficient in ideal environments. The caveat being “ideal environments”. Electrostatic utilizes electric current to charge paint particles allowing for them to attract to a target surface. This provides higher transfer efficiency as well as a wrapping effect where paint particles can actually go around a part being painted. However, this is under “ideal circumstances”.
What is meant by “ideal environments” is that the spray process is taking place in a clean, dry, routine, and well grounded environment. Will discuss each part of these fours parts electrostatic spraying in greater detail.
Clean – electrostatic requires that the part being painted have a clean surface free from contaminants. If the surface is not properly cleaned the charge on the paint will not properly attract to the part resulting in flawed transfer efficiency.
Dry – water is a source of grounding for electrostatic spraying ; which is why it is often difficult to properly get water based coatings to spray well electrostatically. They require special isolation stands for the paint pot along with a myriad of other tweaks. If your part is not dry electric charges will once again not experience the attraction to the part being painted eliminating the benefit of wrapping and improve transfer efficiency.
Routine – electrostatic spraying likes objects that lack many nooks or crannies. If a part has a lot of internal or external corners paint will attract to the portions of the part more than others and will result in a poor coating uniformity. This is due to an effect called the faraday cage effect. Additionally, electrostatic spraying requires operators understand the tool they use has a high degree of electricity. To safely work with electrostatic spray you need an operator who is able to understand the potential danger of the equipment they hold. They must ensure all objects are grounded so that a spark from the gun doesn’t jump and start a fire. They must strive to control paint consistency in regards to paint/solvent mixture, temperature, and humidity conditions. All these variables will allow the electrostatic gun to paint well while reducing risk of electrical spark. Electrostatic guns should also be maintenanced routinely. With a conventional or HVLP gun they are able to be rebuilt easier an electrostatic gun is more expensive at the outstart (it’s also way more efficient which allows for relatively quick payback). Additionally, the training curve is slightly higher with electrostatic spraying due to additional things to consider, electricity ect.
Well grounded – anything that is not grounded can be a source for a spark to jump creating a fire in the worst case scenario. Everything in the booth should be grounded to prevent any electrical arcing and ensure the coating is able to become charged electrically with ease.
If you consider these four variables you can determine whether electrostatic would be a good fit for your company. If you have a clean, routine, well grounded, dry environment that you know you will be able to maintain long term electrostatic may be the perfect solution for you.