Powder paint question

You will get quite a bit of over spray with that style gun because they don't generate a lot of static charge to pull in the powder.

recover some of the powder?) (or is that worth the effort?)

You can EASILY build one out of clean cardboard or smooth wood. I built mine out of light sheet steel.

None as long as you start with a clean reclaim box. You just knock the loose powder back into the container. Keep any crud out.

gets on the piece? (I'm sure technique matters but "generally"). thanks

Powder is great stuff IF you understand what it is. Unlike liquid paints you can re-use any powder as long as you don't contaminate it with different colors or crud. It is actually nothing more than a finely ground thermo set material. As for how much goes on the part? You only need to cover the part with enough that it flows out and coats completely. make SURE that any spots you don't want painted (threads, precision holes, ???) are masked or plugged. You can remove the plugs before you bake the part if you can do it without disturbing the rest of the coating. Drill and mask holes before coating because drilling after coating can be a problem if you slip.

pect with this?

recover some of the powder?) (or is that worth the effort?)

tage gets on the piece? =A0(I'm sure technique matters but "generally"). = =A0thanks

The motorhome factory that I worked at used powder coating on their trim parts, the booth that they did it in had a sloped bottom so any overage could be removed and reused. At one time, the bag house reclaim was reused, too, but that was before my time. Apparently it clogged the guns up, so they just put it in a drum to be sent back to the manufacturer for recycle. As far as wastage, more went on the parts than was removed by the bag house or fell on the floor. They usually went through a drum a week and if they had 10-15 pounds of recycle, I'd be surprised.

The cure is the key, though. You need to heat up the part slow enough to fuse the powder onto the part, not just fuse the surface. They had a big oven with a U-shaped conveyor to run the parts through, slow heat-up, slow cool down, took about 20 minutes from start to finish. When properly done, a nickel wouldn't remove any finish when an edge of it was rubbed on the surface, a swipe with an MEK-soaked Kimwipe didn't remove any finish and the part could be bent double without the finish flaking off.

Because it's done with high voltage static attraction, if you've got any sharp edges on your parts, they'll get extra buildup. It doesn't work too well for closed internal spaces for that reason, either. Don't expect to use it on close-toleranced moving parts and keep those tolerances.

If you expect to use it on automotive body parts that are steel and exposed to salt spray, you might want a rethink. The coating lasts a looong time, but once the steel starts to rust because the coating finally got penetrated, it'll go fast. There's no such thing as touchup with it, either, you have to strip the whole coating, remediate the rust and recoat. We had a big tank with water-covered methylene chloride stripper to redo the oopsies at the plant. Took most of a day soaking just to get it to the point where it would come off in strips. The residue had to be drummed and shipped to the dump as toxic waste, too.

Stan

great -- thanks. going to try it out today for 1st time. so damn humid out, thought I'd do it in the basement. need to build a smooth mdf board box first -- that should be a good surface for recollecting the powder, I would think.