Letter 11023

Effect of Paint Resistivity on Electrostatic Transfer Efficiency  

 

I'm looking for any "Hard Data" that shows impact of paint resistivity on electrostatic transfer efficiency - particularly with bell spray. I don't seem to be getting any data from bell suppliers.

Gerald Goodell
E. I. DuPont - Troy, MI, USA


 

What is impact of lesser or higher paint resistivity than specified range ,affects transfer efficiency, finish,wrap-a-round effect on the surface to be painted using electrostatic hand gun?

Satyajit Vasant Pandit
- Pune, Maharashtra, India


 

The paint resistivity is not a main factor in efficiency. But rather the charge to mass that you achieve on the droplets after or during atomization. If you use a water soluable coating and isolate so that the extreme conductivity does not cause high current flow to ground you can achieve high effieciency. More important is how you handle the following.
1. Current to ground.
a. The current reduces the voltage, which lowers the charge to mass ratio achievable. following.
2. The conductive charge, or contact with the charged tool. following.
3. The ion field, generated off the edge of the tool, sharper is better for ion field. following.
4. The droplet distribution, the largest most uniform droplets which provide the desired film formation will achieve the best charge to mass and have the best attraction to the field. following.
5. The field generated to the workpiece, proper distance ect. following.
6. The lowest droplet velocity which achieves the desired film formation. following.
Also critical are the conditions of the booth air flow.

Anthony Brajdich
- Lapeer, MI


May 25, 2007

If you have a paint that is adjusted to the range of resistance of the electrostatic pistol but still does not give the desired transfer to the metal, are any solvent o resin or any type of additive that improves that conduction?

Diana Gutierrez
R&D - Antioquia, Colombia


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