This is a step-by-step of how I custom painted my nintendo 64 for no money
Step 1: Open 'er Up!
In order to get a clean paint job and avoid gumming up the works, you'll want to remove the plastic shell from the n64 in order to paint it.
the first obstacle here is the screws on the bottom. there are six of them, and they require a certain type of screwdriver. It's called a 4.5 mm gamebit and it works for n64 and gamecube (picture included). If you plan on taking apart a lot of nintendo consoles, I think it's a good investment but if you are like me and hesitant to purchase things off the internet for one time use only, don't fear! there is another way and it involves a bic pen (those clear plastic ones work best- again, pic included). here's what you do. unplug the n64 and remove the game cartridge and the jumper pack. flip it over, belly up. remove the ink and cap from the bic pen. you can use either end of the pen for this next step but I found the butt end was more durable. hold the end of the plastic pen tube over a flame to soften the plastic. you don't want the plastic to get drippy, but it should be fairly soft. Then jam the soft end down onto one of the screws and hold it until it dries. VOILA! a cheap gamebit screwdriver! the only problem is that these wear out quickly and they are A LOT harder to make once the screws are already out so I would recommend making one new one for each screw you remove, that way you will be sure to have plenty when you go to put the screws back in. ( this way you will only need 3 pens because you can use both ends)
Step 2: Take 'er Apart (sort Of)
now it's time to remove the shell. note beforehand that I wasn't brave or adventurous enough to paint the bottom half, but I think all you'd have to do is take the machinery out, which is held on by a few philips head screws.
anyway- once you have removed all the screws (don't lose 'em!) and the two front feet, flip the n64 back over and lift the top off. I chose to paint mine because it had sharpie doodles all over it and I decided it was time to move on and grow up. in order to remove the top you will need to remove the jumper pack first.
Step 3: Dismantle (part 2)
before you paint the shell you will want to remove the moving parts so that they don't jam up with paint. the jumper pack cover comes off easily, and the power and reset buttons, if you look, are held in by little teeth. push these teeth together and then push down and the button should pop out. the last bit to remove is the flap where the cartridge goes in. this is held in by small philips head screws and is easy to take apart. If you aren't mechanically inclined, be sure to remember how everything went together so you can reassemble it later.
Step 4: Paint It
now it's time to paint it. shake the spray paint well and do this in a well ventilated area. keep the paint about a foot or so away from the plastic to ensure a smooth, even coat without drips. I used masking tape to cover the n64 logo on the front of the panel, and you might also want to put tape over the sides of the buttons and in the spots where the buttons go. This will ensure that the buttons still push and slide smoothly. be sure to use paint that is well suited to smooth plastic. I used what I had lying around which was a white bare metal primer and a purple anti-rust enamel. the bare metal primer worked really well and the anti-rust enamel took longer to dry, and was a little grippy when finished. If you are purchasing paint for this project, I would suggest asking your local hardware store employee what paints are best for smooth plastic. In the second photo you'll notice I threw in a controller too. these are easy to take apart as they are only held together by philips head screws. I painted the shell, the directional pad, and the L,R, and Z trigger buttons. give the paint plenty of time to dry. If the weather is nice, start in the morning and let it dry all day, just to be safe.
Step 5: And Back Together Again!
now that it's dry, you can screw it all back together! make sure all the parts and pieces still fit and move like they should, so that you can do any last minute sanding/ lubing. I also took advantage of the open n64 to clean it out with a compressed gas duster. I was just testing the waters with this instructable, since I'd never seen step-by-step instructions on how to do this. but I plugged it in and played with it and it works like a charm. I think the colors I chose make it look like the classic gameboy, but know that It doesn't harm your console (try removing and painting the bottom too, if you feel up to it) and feel free to go nuts with the paint job! if you do try it, post a photo and let me see your awesome paint jobs (I'm sure they'll beat mine). have fun!