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 Post subject: Painting a plastic case
PostPosted: Tue Feb 22, 2005 7:42 am 
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I have a simple black plastic computer case that is crying out for attention. So I've decided to give this rig a nice automotive paint finish. I am wondering if there is any special precautions that need to be taken when painting plastic? Or is this even possible?


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PostPosted: Tue Feb 22, 2005 8:56 am 
Monkey Federation (Top 10)*
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Location: In a cage, dumbass.
Check ou this thread.

http://www.maximumpc.com/forum/viewtopi ... 67&start=0

It will teach you more than you ever need to know about painting a case.


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PostPosted: Tue Feb 22, 2005 8:09 pm 
Boy in Black
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Nice thread, but the guy looks rednecky. I wouldn't trust him.

This is a nice thought, but lets break it down into pros and cons of sorts. If you want to pull this off, you'll need some info.

Painting plastic isn't really any different than painting metal; not in the basics anyway. The problem that arrises when doing so is that some sort of the mix reacts with the plastic and melts it. Ever pour gas into a styrofoam cup? Napalm. (boy, that'll lighten up the NSA's switchboard). Paint of any type uses pigment and a thinning agent. Pigment is just material, and the agent is a solvent. This solvent may, or may not screw up plastic depending on what it actually is. Reducer may not melt one plastic, but thinner may. And this even goes into more variables as you go from brand to brand.

The good thing is that many cars now have plastic (I will never ever type that sentence again!) ABS is widely used, and I've painted more than my fair share of plastic on cars with no effects at all. But a cheap plastic PC case by use cheap plastic. Makes sense to me. This stuff isn't resistant to anything particular. It's just plastic. But you could still do cheap plastic if you wanted to take some of these thoughts in mind.

What melts will harden again once cured. Even that melted styrofoam cup will harden again once the gas evaporates out. If you use very thin coats (and should anyway) of the base (color), then you'll keep the melting to a minimum. Once this layer is built up to a solid base, then it's not plastic anymore really...it's paint. You can then shoot the clear onto the paint, and as long as you don't cake it on, it won't bleed past the base and back into the plastic. Even rattle canning can get the same result.

Now all the bad stuff. Paint sticks to metal by getting into the microscopic pores of the surface. This is why prepping is preached so strongly. The job is only as good as the prep! So, if you sand, etch, tack, clean, etc...really well, then the paint will stick really well. I have no idea how to prep plastic. To get into the pores of the plastic, you'll have to melt it in theory. I guess that sounds like what would happen.

I've painted a cheap case with paint for R/C cars and thought it turned out very well. In the long run though, it's flaking off pretty easily. It never really bonded to anything but itself, making it's own layer. Once you break the bond between its own links, nothing else holds it onto the case; so it just falls off.

And with automotive paint, it comes in cans of raw material. How would you apply it? You could easily get into painting a $20 case with $200 worth of hardware and supplies. Krylon is starting to sound really good here. Even a cheap Airbrush kit or cheap gun ($50) still needs an air supply ($50). And the paint itself isn't cheap. These paints are mixed, and many don't like to mix anything smaller than a 1/2 quart, if that. It's hard for them to mix according to their ratio sheet, and it's hard for you to mix right with your mix cup. Then you get into the big can of $50 clearcoat, reducer, hardener (you can't buy this stuff in small quantities because it's for big cars)...it's getting out of line for a simple paintjob on something as small as a case.

For me, I have paint leftover from a lot of past jobs. I got this habit from my dad that had a wall of paint for me to play with growing up. I have no idea why he kept it, but he did...and still does. He's got paint going back to a job he may have done in the early 80's, and I'm sure it's junk by now, but he still has it. I do the same, so I have no problem with using some Orange left over, or some blue...whatever. But I still wouldn't do something from scratch with new material unless it was for profit or someone else paid for it. In the end, I'd have too much left over to do a couple cases.

My hopes is that soon I could do this for folks. Someone gives me a link to a case they want done, we hash out designs, I order and paint the thing and send it out. I need other things to happen in my life right now to get this right and in some form to make it work, so it's still on hold. But I'm trying to get a real shop together for bikes, and painting cases on the side would be a great little branch-off. This may get squashed, but still consider the plan in motion. I'm learning more about airbrushing so I could do some old-game-type theme for another member here...I'm set to lose a bit, so I'm prepping to pay up :D


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PostPosted: Tue Feb 22, 2005 9:42 pm 
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damn! true chumly style!


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PostPosted: Fri Feb 25, 2005 3:31 pm 
Boy in Black
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WhiteRabbit22 wrote:
damn! true chumly style!
Long, never to the point, random jaunts off the subject...that's Chum-style :D

I'm still reading and sucking in MPC's recent article. I just got it two days ago (always gets in my mailbox late), so the jury is still out there. But theirs turned out better than what I thought you could get with a rattlecan. The big issue I've had with the rattlecan is not the finish, but the adhesion.

I still have a dragon case (chieftec) that I had painted the insides with rattlecan. I spent good time on the prep and all that and used a good rattlecan brand (if that's not an oxymoron). The case has those removable drive bays and it still scratched right through when you put them in or pull them out. I also recently went through the whole thing for some really needed maintenance and an upcomming tutorial and I scratched the piss out of it moving the PS around. I still don't like rattlecan'ing because I just haven't found any that actually sticks worth a damn.

I'd find some really good primer if I were to do this again and may be why I haven't pulled this off very well. I used the same brand of primer so there wouldn't be any issues using different brands. But you can go and find some nice primer at AutoZone or whatever that should work too. May work better, may not.

As you know, I had to get a new job. They have a huge shop I can use! I also have to re-consider getting my own seperate shop again for some side profit. I did really well holding the company's large "items" in my own shop (kind of a cache for products going into their own shop) and if I can find the right insurance, will do so again. It'll pay for itself and I can follow through with my own plans as well. They don't mind my own projects in there, but once they see me trying to make a business, they'll crap their pants :D


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PostPosted: Fri Feb 25, 2005 7:54 pm 
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With the adhesion problem I found a few products at work that should help.

They all come in a rattlecan so here goes...

Starting with and adhesion promoter folloed by the primer the top uit off with a primer sealer. After that its just like you said, your just dealing with the paint and should be all good :)


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PostPosted: Sun Feb 27, 2005 3:16 pm 
Boy in Black
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That adhesion promoter is a good find! I had not used any prior to a few years ago. I just didn't see the use if I had prepped like I should.

Well, a couple years back I had to paint my Jeep (Hit a huge elk outside of Flagstaff) and decided to give it a shot. I love the stuff now. Even if I feel I don't need it, I shoot it on anyway. EVERYTHING gets a good shot of the stuff. The stuff I have used is pretty cheap, doesn't need mixing, and it just works good so I'll continue to use it. In places I had my doubts of the color sticking very long, it in fact stuck and is still there today (slick backsides of the grill and stuff like that).

I doubt rattlecan is any different. It should be just as good of an idea to use. Can't hurt IMO.


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