Drilling over powder coat

[richtersand]

Hi all, I just pulled all the aluminum off of the chassis. My current plan is to PC all of the panels. At this point in the build, it strikes me that it would be easiest to drop all the panels at the powder coater and have him do everything at once. But the panels aren't drilled yet. Will it be an issue to drill into powder coated panels? I imagine it's better to drill and then powder coat, but the rivet heads will cover any messiness from the drilling so I think it'll be okay. What am I missing?

THANKS!!

[GoDadGo]

For what it is worth, I drilled and fitted before painting my pans prior to installation.

Then I shot clear over the rivet heads after the installation was completed.

For the record, I WISH I would have powder coated the pans instead.

https://thefactoryfiveforum.com/album.php?albumid=977&attachmentid=51775

[fletch]

You’ll be fine either way. Doing the powder coating later will allow you to cover up any mistakes, but drilling after PC is perfectly fine too. This is one of those decisions that can go either way IMO. Good luck!

[JohnK]

In general you should be fine, but there were several tight spots where the spinning chuck of the drill scuffed up an adjacent aluminum panel as I was drilling. If the panel had been powder coated, it would have marked up the PC pretty good. If you're careful and put down some blue painters tape to protect as needed, you should be OK.

[chmhasy]

FYI when you are drilling, the scrap chips that come off the drill can wrap around the drill and scratch your PC. The top of the rivet will not cover it. the scratch will be outside that perimeter.
Don't ask how I know.

You have a few hundred, if not a thousands holes that you need to drill

1. drill and fit all your panels using Cleco's. note: fit means trimming panel to fit correctly on frame. so yes we want to dill into the frame at this stage.
2, clean the debur panels
3, send out to be Powder coated
4, carefully rivet panels to frame

[rich grsc]

Always fit and drill your panels first. Some panels may need to be tweaked to fit the best, and I can guarantee that the drill will slip at least once and skip across a panel.

[OSU Cowboy]

Powder coating after drilling all of the panels will add a small thickness of the PC material in the hole diameter itself - which will be a pain when you try inserting rivets into the aluminum panel holes.

Probably worse - powder coating after drilling the panels almost guarantees that your panels won't line up with the previously drilled holes. Why? For the same reason as above ... the pc thickness will add up across the panels to the point that you will be
drilling some new holes or at minimum hogging out existing ones in order to get the rivets inserted.

Recommend you ask yourself why powder coating "all panels" is necessary. Most will be covered up by some combination of dampener / insulation / carpet anyway. I did have those panels that would show powdercoated ... most of those are seen in the engine bay.

Hope this helps.

[chmhasy]

If you are worried about re drilling for PC thickness first drill using a #30 or #29 drill instead of a 1/8" drill.

[Blue Viking]

Powder coating after drilling all of the panels will add a small thickness of the PC material in the hole diameter itself - which will be a pain when you try inserting rivets into the aluminum panel holes.

Probably worse - powder coating after drilling the panels almost guarantees that your panels won't line up with the previously drilled holes. Why? For the same reason as above ... the pc thickness will add up across the panels to the point that you will be
drilling some new holes or at minimum hogging out existing ones in order to get the rivets inserted.

Recommend you ask yourself why powder coating "all panels" is necessary. Most will be covered up by some combination of dampener / insulation / carpet anyway. I did have those panels that would show powdercoated ... most of those are seen in the engine bay.

Hope this helps.

I had no such issues. Had to freshen up a few of the holes to fit the rivet, but for the most part it was no problem. I did not experience any panels that were not in the prefixed position after powder coat either. I would drill and fit everything before powder again if I were building another car in the future.

[Al_C]

Clearly there are a lot of opinions on this topic! I chose to powder coat before drilling. I also chose to powder coat only those panels that you actually see. As stated above, you really don't need to do all of them because many will be covered in one way or another. I also agree that a #30 bit is a good idea. A sharp center punch is also a good idea for marking drill locations.

[edwardb]

I'm with Rich and some others on this one. Highly recommend fitting and drilling before powder coat. You will need to tweak a few bends, made some minor adjustments here and there, clearance for welds occasionally, etc. No point in doing that and risking damaging the powder coat. Plus it's way easier to mark away with a Sharpie or whatever when laying out the holes, locating the underlying frame members, etc. The added thickness of the powder coat will not adversely affect the fit as long as you get all the overlaps the same. Yes, you'll probably have to chase the powder coat out of some/all holes. With your #10 or #30 bit as appropriate. Fast and easy step. Regardless of the finish used, get them fitted and drilled first. I just don't see the point of working with them any more than necessary once finished.

[richtersand]

Thanks everybody, this is a really helpful discussion. I think I'm sold on drilling/fitting now vs. after PC. At this point, it makes sense to me to fit and drill ALL the panels so I can get it all in one PC run. But this deviates from the manual and not the way I see most guys here doing it. Thoughts on fitting/drilling everything NOW vs over the course of the build?

And yes, I think you guys are right on PCing only the panels that are visible after the build is complete. In addition to engine compartment and footboxes, it looks like the floor panels are also visible from the bottom of the car. What else should I PC??

Thanks again.

[edwardb]

Thanks everybody, this is a really helpful discussion. I think I'm sold on drilling/fitting now vs. after PC. At this point, it makes sense to me to fit and drill ALL the panels so I can get it all in one PC run. But this deviates from the manual and not the way I see most guys here doing it. Thoughts on fitting/drilling everything NOW vs over the course of the build?

And yes, I think you guys are right on PCing only the panels that are visible after the build is complete. In addition to engine compartment and footboxes, it looks like the floor panels are also visible from the bottom of the car. What else should I PC??

Thanks again.

Based on quite a few years of watching, and multiple builds myself, fitting and drilling before finishing the panels is the most common and almost always highly recommended. So you're not exactly going against the grain doing it that way. The Factory Five does mention it, saying do the panels in advance so you're not waiting for them. I guess, but with a little planning no reason you have to wait. Get them all fitted and drilled, off to finish, and you'll have plenty to do with suspensions, brake lines, fuel lines, etc. while they're getting done. As far as what panels to finish, that depends on your definition of "visible." Some say this means only the engine compartment. That's probably the common response. But if you don't want to see bare aluminum anywhere (my preference), meaning also in the wheel wells (pretty visible) and underneath, there are only a few parts that don't have at least one side showing somewhere. Cockpit outer sides and the sill pieces right above them get buried. As I recall, that's about it for the Roadster. For most shops, the fewer batches you have the better it will be for cost. You don't want to be taking them piecemeal. I generally do a Roadster in two large batches. So I'd recommend getting as many as you plan to finish ready at the same time. As best you can.

[Hacksaw84]

And yes, I think you guys are right on PCing only the panels that are visible after the build is complete. In addition to engine compartment and footboxes, it looks like the floor panels are also visible from the bottom of the car. What else should I PC??

Thanks again.[/QUOTE]

To answer your second question. I did just the engine bay panels and the footboxes plus a few random parts/brackets. My dash is also powder coated. My thought was any part that would probably be seen (not crawling up under the car with a flashlight) or a steel part that would rust (and I didn't already POR15 it). I took my parts to the PC shop in two batches. Slightly less efficient and maybe a couple bucks more but it helped me keep making progress. I too did most of the fitting before PC, but have had plenty of post PC drilling/cutting etc. I wouldn't overthink it too much.

[FLPBFoot]

And yes, I think you guys are right on PCing only the panels that are visible after the build is complete. In addition to engine compartment and footboxes, it looks like the floor panels are also visible from the bottom of the car. What else should I PC??

Thanks again.

Something to consider: The floor panels under the car will see rocks and other road gunk. I chose to coat those with the truck bed liner I used on the inside of the body. Also the outsides of the trunk area and the back of the passenger compartment. I think this will also help with the solid feel of the floor and passenger compartment. No rock ding sounds, etc.

Steve

[richtersand]

Thanks again for all of the input. I ordered #30 drill bits and I am cranking away on the panels.