In a powder plant we expected transfer rates of 70% or better from our
guns 80-85% was common). You will always have some powder that doesn't
adhere because each particle carries the charge differently. I would
highly recommend that you make a powder reclaim unit though. They can be
as simple as a plastic lined box for small parts to the huge downdraft
units with triple filtration that we had in the shop.
Now as to the transfer rate from a HF gun. It will be lower because it
doesn't use a real heavy charge and many times the ground side is not
very good. Oh and FYI if your attempting to coat tight interior corners
and are not getting powder in there, that is normal. It is Faradic
rejection due to the proximity of the negative charged pieces.

--
Steve W.
Life is not like a box of chocolates
it's more like a jar of jalapenos-
what you do today could burn your ass tomorrow!


"Noone special" wrote in message
oups.com...
I'd be interested in knowing the details of how you're planning to put
an internal blower in the gun.

While the HF gun is infinitely better than spray painting, it still
has
some things to be desired. I powdercoat mostly round tubing, and
seem
to get a substantial amount of overspray that doesn't adhere to the
tubing at moderately high flow rates. I'd guess my transfer
efficiency
under these settings is under 50%. At these high flow rates is when
I
also get occasional surging,

But since this is the only powdercoating equipment I've ever used, I
don't know what is reasonable to expect. If I am powdercoating, say,
1" round tubing, what would be a reasonable coverage rate (in linear
inches of tubing per minute) and transfer efficiency? As things stand
now, I'm getting a lot of dust settling on everything in my shop, and
am getting the parts together to build an air filtration unit.

-Jim




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