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Electrostatic painting rusted steel

We have been awarded a contract to rework 14,000 steel reels used for shipping plastic pipe. These look like 8' diameter wagon wheels made from 1 1/4" square tubing. These parts have been laying out in the weather and are evenly coated with a solid layer of rust. The surface is completely rusted, but not to the point it is flaking off or pitting. My customer wants them painted blue, but they don't care about the quality of the paint job. These are disposable packaging and anything looks better than rusted. We bought a second hand Nordson electrostatic wet paint system. When we paint clean, bare steel, it works great. When we paint the rusted parts, it is no different than a cheap spray paint gun. We are grinding a clean spot to attach the ground strap. I suspect that the layer of rust is acting as an insulator, preventing the electrostatic attraction from affecting the paint, but I do not know this for a fact.

By accident, we discovered that if the steel was wet (this is Georgia and it always rains) the electrostatic attraction is the same for the rusted steel as the bare steel. The paint did not adhere, but it was strongly attracted to the wet steel. Does anyone know of a way to increase the static attraction for rusted steel? It is not practical to remove the rust or do any elaborate pre-treatment, but might be practical to spray the parts with a solvent or some other liquid. Any help would be welcome!

J. Mark Runnels, PE
- Augusta, Georgia, USA
2003

It may be a bit late to answer this question, but I'll give it a shot.

Why is it not practical to remove the rust? A soak in a mild acid would do the trick with little to no effort on your part. If you don't want to use acids, or if you don't have access to them, something as simple as lemon juice can do the trick. Do a search in the archives on rust removal and a lot of fairly simple methods will pop up.

Good luck,

Jim Gorsich
Compton, California, USA
2003

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2004

I once knew a cop in Detroit who had a side job - painting. He was contracted to paint thousands of feet of twisted wrought-iron fencing that enclosed a cemetery. Being a cop, he did not have the financial resources to purchase a ⇦this on eBay or Amazon [affil links] . His solution? Heavy rubber rubber gloves ⇦this on eBay or Amazon [affil links] over which he wore sheepskin car-washing mitts. He just dipped his hands (lightly) into the paint, grabbed the top of a fence picket in each hand and just slid his hands down to the bottom, and repeated - several thousand times.

Randy Shereda
Handyman specializing in electrical and steel fabrication - Las Vegas, Nevada, USA!

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Been electrostatic painting for 14 years with a Ramsburg #2 gun with the rust problem you have try wiping it down or soaking in MEK / methyl ethyl ketone. IT FLASH DRIES IN SECONDS.

James Barr
- Louisville, Kentucky
2006