Powder Coat -vs- Paint
by Chris S. (based on his experience)

Powder is really no different than paint, it just has a different
application. Depending which powder or paint you use, after the
application process you're left with either a modified epoxy or alkyd
film coating. Whether or not it was wet-applied and polymerized or
dry applied and "melted on" doesn't have much effect. If you compare
powder to spray-can, then that's apples to oranges. If you compare
powder to Imron, then they're about equal, assuming the highest level
of competency on the application.

Here are some of the negatives I have experienced with powder on MC
frames;

Poor adhesion-
The job is only as good as the prep. The frame must
be well blasted then pre-baked to flow out any oils and cook off what
doesn't come out. If you don't do this, the oil is going to come out
when you start the cure process and the powder/film isn't going to
stay long. The second adhesion issue is that unlike a high-
performance "paint" (wet process) powder doesn't "etch" to the
metal. Any good primer chemically bonds to the metal (etch) whereas
powder just melts over it. You'll see in marine applications where
the powdercoating is coming off of a piece in sheets- one hole and
creep can begin. This usually does not occur with an etching primer/
high performance spray finish.

Film thickness-
Powder masks metal issues as it is quite a bit
thicker than most paint systems. If I were building a race frame,
I'd want to see every weld and gusset. I've seen metal begin to
fatigue and be masked by powders elasticity. I want to know
immediately that a crack is starting, not at it's yield point.

Repair-
Powder doesn't field repair. At least not a repair you'd be
happy with. If you managed to re-apply dry powder to a damaged area,
it would be very unattractive as it goes on thick (20-40+ mils). You
could UV cure the spot but it would likely reflow the areas around
it. Not pretty.

The Faraday cage issue is really only seen in those $79 hobby guns.
It does occur in highly complex structures but any commercial
applicator isn't going to have a problem with a motorcycle frame.

Bottom line-
I think for a racing frame, powder has more drawbacks
than it has positives. For a show bike, it's durability isn't needed
and it's appearance isn't original-looking. You can get an
exceptionally durable finish with Imron or other high performance
systems.

This is important-
Don't ever try to spray Imron yourself, unless you
do it for a living. The stuff is about half a notch below plutonium
on the bad-for-you scale. I doubt you can even buy the original
Imron formulation in California and some other states. The have a
low VOC version, but it isn't nearly as good. It's not just
the "getting stoned breathing thinner fumes" stuff either. There's
some very toxic compounds in it.

I think there are some misconceptions here about powdercoat and
paint.
In short, there is no difference in the material. A chemist
could formulate either medium to do exactly the same things.
The only difference is method of application. Each method has its own
drawbacks. Powder is very production-friendly. The volatile organic
compounds (or the likelihood of those compounds being released into
the environment) are kept back at the plant with powder.
If I were in New York or California and needed to finish lawn chairs and I
wanted to put a lifetime warranty of the finish, powder would be my
only alternative. If I were in Texas (where they really don't look
too closely) I could paint all I wanted and spend much fewer dollars
to accomplish the same thing. The downside of powder is that it's
very capital-intensive to set up (exponentially if you want to do
large items.
You could paint Imron in your garage, your frame
probably won't fit into your kitchen oven to cure the powder).
Powder is also somewhat more difficult to control as far as
application thickness and it tends to pool or level in areas like
welds or corners.
The other advantage is the chemical etch that a good
metal primer adds- there's nothing that powdercoat can do (that I'm
aware of) that can match that bond.