Powder Coating Aluminum Panels

[hrosenthal]

I'm planning to powder coat my aluminum panels. I've read that it's best to drill all the holes before powder coating. Is there a good reason for this? I'd prefer sending all the panels out for powder coating as the first step after I remove the panels from the frame, then following the steps in the assembly manual and drilling as I install. I though masking tape would be enough to prevent any scratching.

[trichardson]

The best reason is that you'll need to trace any hidden tubing onto your aluminum panels so that you'll know where to drill rivet holes. If you want to powder coat your panels before drilling, you'll have to mark them after they're powder coated so now you have to clean the marker lines off your pretty aluminum after drilling. Unless you're really careful, you'll scratch the powder coated surface with some of the aluminum dust from drilling. The second best reason if that you might walk a drill bit or scuff the powder coating finish when you're drilling them (or trimming them to fit). Powder coating after drilling will hide those blemishes. The third best reason is that the powder coating guys will need to drill a hole in the panel to hang it. If you've already drilled it they'll use one of your holes. If not, they'll drill their own. Murphy's law says they'll drill it in the worst possible place. The last reason I could think of is that you'll have to find a way to store all of that finished aluminum without scuffing it. I'm PCing mine in small batches. It costs a little more that way but when I put mine in they're fresh. Finally, I seem to modify everything as I go. I'm building a coupe but I've butchered my trunk panels with battery covers, access panels and now a spare tire rack. With all of that cutting, sanding and drilling if I had PCed first I'd have to blast the pieces and rePC them now.

[MPTech]

I plan to mock up most of my go-kart build, then send the panels for PCing.
During my build I've been careful not to scratch them, but it still happens and I'm glad I didn't PC them yet!
I've also made several modifications and re-bent and re-cut existing panels, so I'm glad I'm not working with final versions yet.

[hrosenthal]

That makes sense. Thanks.

[COBRA_DUDE]

The powedercoaters also like the pre-drilled rivet holes as it gives them something to hang the panels from during the powder coating process.

[Tom Mauldin]

Not to mention, you may have to trim some of the panels or adjust the bends a bit.

[snakebit31]

I powder coated my panels after drilling. Some of the panels were coated on one side only, if the other side would not be seen. There have been a few places that I have drilled or cut with shears after PC'ing. In some of those areas, the powder coat has chipped around the holes.