Painting, done!

posted Aug 9, 2013, 11:44 AM by Andrew Stock
Hello Everybody!

Man... it's been a hell of a month. This is quite literally my first day off... in fact, my first 8 hours in a row off... since I got back from vacation in the middle of last month!  Work has been absolutely insane. But, I finally have a little time to myself... and where else would I spend it, but with updating everyone on my progress! 

As I eluded to last time, I was going to work quite a bit more on giving my remaining exterior pieces the mirror finish they deserve. These pieces were absolutely brutal to complete without screwing up. Took a very long time, especially the parts with perforation. I'll just jump right into the pictures and let you enjoy the outcome... not many words necessary! 

*phew* Nice to have all that done! 

Once all the exterior "clam shell" pieces were completed (the parts that make up the frame of the case) I went on to doing the doors. If you will recall, these doors had quite a bit of custom Dremel work done on them, making them an extremely difficult piece. Couple that with the fact that I wanted them to be absolutely flawless since they will be the 'star of the show' so to speak, and you end up with a heck of a lot of care and effort going into getting the finish just right.

I'll go through the exact process I followed, just in case anyone wants to duplicate my steps. Sharing knowledge about the build experience is what this log is all about, anyway! 

To give you an idea of where I start from, here's the piece after drying for a few weeks without any sanding or modification done:

You can see it's a literal "sea" of orange peel... everything is blurry like you are looking through security glass. It's probably a combination of my painting skills (or lack thereof! ) and my paint gun that produce this... I'm not really sure if you can get a paint job without this level of orange peel... but fortunately a bit of effort will clear it all up!

I start out with P1000 sandpaper from 3M. I pick up mine in the paint section of my local automotive shop... but I am sure you can find it elsewhere. They have a nice "kit" of sandpaper that has 1000, 1500, 2000, and 2500 all together for pretty cheap. I also have some rubber sanding blocks that have little flaps with spikes in them, so that you can tuck the sandpaper around the block and lock it in place. That makes sanding flat surfaces SO much easier than trying to evenly distribute the weight of your hand or anything like that. 

I also get a painters tray with a couple of cups of water, put a single dot of common dish soap in it, and stir it a little to distribute the soap. This helps the sanding block glide a bit better by reducing the surface tension of the water between the block and the surface of the material. I then throw all my sandpaper in there and let it soak for at least a good 15 minutes before using it, so that there isn't any dry paper left. 

Finally, I have a large bag of color-coded microfiber rags that I use so that I know what rags I used on each step of the process, and I can avoid using the wrong  rags with the wrong grit of sandpaper/polish, thus producing larger scratches than intended while cleaning off the surface to check that orange peel is gone. 

Now that all the setup is out of the way, I start by sanding in one direction (we'll say left to right) across the entire piece as much as possible. Sometimes I have to switch directions on detail pieces or corners, but the more you can stick to one direction, the easier it is later on. Every 20 or so passes on a spot, I will stop sanding, flush the area with water and dry it with a rag, and then check to see if all the orange peel is gone. This helps me ensure that I go no deeper through the clear coat than I have to, which will help make sure I don't go all the way through into the color coat by accident, since I am sanding this so many times!

Here's one of the case doors after the first pass with 1000. This part definitely takes the longest because you have to sand the entire surface until all of the orange peel is completely gone... leaving a hazy (but scratched up) clean surface. 

You can see, if you look very very closely in that slightly more white section in the center of the picture, there is a tiny extra deep pock-mark of orange peel. All that has to be gone, or it will be extremely obvious in the final finish! This first pass is also the most dangerous pass, because P1000 sandpaper has a lot of removal action... so if you grind on one place for too long, you'll go right through your clear coat and be back at square one! I've done it a few times... it's painful.  

You have to be extremely careful along edges and corners while using P1000 also. I would do no more than 10-15 passes when sanding "over the edge", as you remove way more material from edges than you do from surfaces. I use my fingers along the edges I am sanding to create a sort of "bumper" that will keep the sanding block from going off the edge of the surface, which keeps it from digging in too deep and removing too much material. The problem is, orange peel likes to hide at the edges... so I usually have to sand "along" the edge even if that isn't the direction I am sanding... and once I'm satisfied that I've sanded down the previous layer enough, I go over it a few more times in the correct direction to get everything uniform. 

After all the orange peel is gone, you switch to the next level of sandpaper (1500) and switch directions (up/down now). This pass also takes quite a bit of work, because P1000 leaves fairly deep grooves in your clear coat, requiring many passes to remove it all. You can see at the center/bottom edge of this shot where I haven't quite gotten rid of all the "side to side" scratches. Gotta get every single one!

These little groves along the edge of the case wall were a disaster waiting to happen, too... you can kinda see that the clear coat and paint is slightly risen compared to the rest of the surface... which is very easy to grind through by accident! Not to mention, every little ridge is like it's own corner... so the edge of this case panel was extremely hazardous to sand. I honestly expected to screw it up... but I got lucky!  Here we are, done with 1500. You can see the shine starting to show through!

Now on to 2000 grit, changing directions yet again! As the grit gets higher, it gets easier and less passes are required. I'd say that 1000 took as long as 1500, 2000, and 2500 combined. All you have to do is sand until the scratches from the previous direction are no longer visible, and then you are on to the next grit!

And finally... 2500 grit. For this level of grit, I switched from a rubber sanding block to a sponge. The reason I switched, was that I felt like it was a bit softer and less likely to cause deep grooves from trapped material or whatnot. I would flush off the piece much more often at this level, and try not to push down at all... just let the weight of the sponge do all the work, and use many many many light passes. 

Now that all the sanding is done... on to the rubbing compound. This stuff is almost like a soupy toothpaste, that has tiny bits of grit inside it. I would always use a particular color of microfiber cloth that I didn't use for anything else, because the grit gets caught in the cloth and you don't want to accidentally use it on a piece that you are polishing instead. I would lay a ribbon of compound onto a small area I was going to work on, maybe 6 inches x 6 inches, and use the cloth with my hand in it to "buff" in the opposite direction of the 2500 grit fairly hard... maybe 50 or so passes over each area, giving a fairly strong downward force to really work out the 2500 scratches. I didn't need to use a lot of rubbing compound because I went to the 2500 level with sandpaper. Previously , I was stopping at 2000, and it took a lot of rubbing compound. Once I had gone over an area with rubbing compound, I would use a cloth of the same color to wipe off the area and get rid of the extra residue. 

Looks pretty much done, right? Nope! Still have polishing to do! Unfortunately, the difference wasn't easily capturable by my camera... it's a very subtle nuance. But it's worth doing the polish layer afterward!

To polish the piece, I would use yet another color of cloth, another similar ribbon of polishing compound, and go in a swirling motion instead of an up/down or left/right. This makes it very obvious if there are any scratches left from either direction that need to be worked on. Sometimes, if I uncovered a rough patch, I would go back to rubbing compound and work on it a bit more to get rid of any residual scratches... especially on corners, where I was more careful with sanding. After polishing an area, I would get another cloth of the same color as my polishing cloth to clear/clean the area and validate that no scratches were visible anymore. 


Here's a quick before/after I took. The piece on the left is after clear coat without being modified at all. The piece on the right is after it's first polish pass letting it "rest" for a week. You can see a couple of scratches visible on the right piece, particularly in the bright areas. I noticed that if I let the piece sit for a few days/weeks after polishing, some "ghost scratches" would start to come back. I intend to go over the pieces one more time with rubbing compound and polishing compound to stamp those out. My guess is that the compound would get in the scratches making them disappear... but once the compound dried or got wiped off, it became visible again. I'm betting another pass will get rid of those! 

Anyway... now that all the months of painting are coming to a close... time to get back to the bench for the real fun stuff... reassembly! 

I started off by cutting some more custom-length M3 screws with my metric wire strippers. I needed about 8 of these to reassemble the bottom of the case and casters. The original screws wouldn't work anymore, as I added the bottom plate and acrylic piece (for a future feature!) to the stack, making them too short. I measured out the needed length, then cut each screw to be the same. 

Here we are, screwing the casters back on to the bottom plate:

Good! We're back on wheels again! 

Next, I put the other half of the clam shell back on, and assembled the drain plug through the whole business:

Alas, that's as far as I got! 

Hopefully some more time soon, as work starts to slow down again! Can't wait to get everything re-assembled so I can start to sleeve all my components! See you next time!