Prep for powder coating?

I have a couple of 'bits' I want to get powder-coated. They were originally chrome, but the chrome is shot, there are a couple of scrapes and I'm going to do them in black. So: how do I prep them? Should I do a wet-sand (maybe around 600-800 grit) to take the shine off the chrome and give the coating something to "bite" into? I need to get rid of the pitting and surface irregularities caused by the deteriorated plating. Also, I have a scrape on one I'd like to fix beforehand. Ideas? I was thinking JB Weld...

 

I've done a bit of powder coating but nothing chrome yet. I would do some roughing of the surface to make sure you will get a good 'bite' from the powder. I know they make a speacial high temp bondo that could be used to fill any minor imperfections but I see no reason why JB wouldnt work as well as long as it can take the curing temp. I would 'test bake' a part with JB to see what it does first. Are you doing this yourself? If so, make sure the parts are squeaky clean and pre-bake and let cool the part before coating. Pre-baking will release any foreign particles that might otherwise gas out during curing and cause a bubble in your finish.

 

JB is supposed to be good to something like 1500 degrees, so I figured if I could get it to stick it might be the best bet. I plan to take them to a pro, haven't called them yet.

 

powder coating at least when I used to do it in a factory is drawn to the metal with electrical current to stick on the metal if you bondo, jb to thick where the current can't draw ans hold the powder it won't look good when done. Unless they have newer stuff out it has 10+ years since I was in a powder coat booth.

 

Conductivity would be the primary issue, I believe, and I don't know the conductive properties of JB Weld. I have heard that anything over the base metal you are coating is going to affect the finish. I always sandblast everything (or have the PC shop do it) to get an even, toothy surface for the PC to bond to.

Anther consideration is cost. The PC shops I've worked with (2) have a minimum price, based in part on the size of the piece (total sq. inches covered) as well as the number of pieces. They won't do anything for less than $135, I think, so I always try to get several pieces together first.

Finally, repairability- Once a piece is powder coated any repairs pretty much mean stripping and redoing. In the rock-crawling world, where things are regularly banged up, paint is often preferred as it's easier to sand and repaint than to strip the entire piece and recoat. On a bike I can see PC holding up very well, but if there is even a chance that it'll get chipped or scratched might it make more sense to paint?