Re-coating blemished powdercoats...

[fleetfeather]

Hi all,

So, I happen to have a powdercoated aluminium case in my possession, which I'd like to get re-coated. I've never gone down the path of manufacturing before, so I was hoping to get some clarification from the community before I approach a shop to do it for me.

1. The blemishes in the panels appear to be caused by some rubbing of metal screws on the coated surface. As such, there's a slight amount of 'depth' to the blemishes. The blemishes aren't deep enough to expose the bare aluminium below, so there shouldn't be any issues with uniformity of the new coat, right?

2. Since I can't obtain the colour code for the existing powdercoating job, I was going to go with an entirely fresh coat for the case (rather than trying to match blemished panels with unblemished panels). Will the existing coat need to be stripped first, or can new coating be placed over the old? I'm mostly worried about panel fitment and/or countersunk screw clearance with two layers of powder.

2. I've stripped the case of all the front panel connectors as well as the various screws and stand-offs. Should the screws and stand-offs remain in the case to ensure the holes don't get clogged by the coating?

3. Is there anything I'm overlooking with this process?

Bonus question: If I wanted to do something a bit different, would it be possible to get the existing powdercoating removed (perhap via media blasting?), and get the entire case anodized or clear-coated instead? If so, how would be best to go about this process - I imagine I'd have to get a few different parties involved?


Thanks for reading!

 

[Josh | NFC]

Howdy!

Sucks that your case got scratched, but you sound like a good owner taking care of your PC case, which I respect. I have some thoughts...

1. Depending on the type of powder, you might actually be able to buff these out as good as new. The depth is no big deal and wouldn't show up like it would with wet paints if you were to recoat it.

2. Yes, you can totally shoot over old powder. You don't necessarily want to do this depending on the lightness/finish/texture you are going for, but you can shoot powder over powder. You are correct to worry about panel fitment with even one thick layer of powder. More than likely in this situation the PC guys would sand your panel smooth (not totally strip it) and shoot over it.

3. In my experience you don't need to cover any holes, which saves money. Your screws will retap the powder no problem.

4. You asked a bunch of great questions. Really powdercoating is weird and different chemicals, metal, grounding, gun setting, and temperature not to mention the powder mix can mess up. I think its unpredictability is why it's not more popular. But that isn't your problem, it's the people you take it to. Just make sure they do it right before you pay them!

5. Professional anodizing, like for a PC case, is going to require alot of chemicals and a special setup that you are unlikely to find at a normal paint shop. Even the S4 MINI is really too big to hobby anodize. But yeah, you would need to have your panels blasted totally before you did this. Clear coating the panels is no big deal, but I would want to polish or swirl or something to make the panels look interesting before clearcoating. You could even do a powdercoat clear.

 

[fleetfeather]

Josh!

Thank you for your reply and expertise, that's some really helpful info there

What sort of powder is conducive to buffing? Should I be looking for anything in particular to determine this?

I might just try to get the shop to sand it and re-coat the whole thing (providing buffering can't / doesn't do the job). Given your experience with PCing for special editions of your own case, would you recommend any particular brands and colour codes that you were happy with in the past?

I was thinking of getting the shop to coat some raw aluminium expansion slot covers first, to get an idea of the finishes I could expect (keeping in mind that coating over a sanded-but-coated case will look slightly different). I'm mainly worried that the PC company will try and push some sort of tacky gloss finish suitable for cheap bicycle frames or something... partly because some guy or gal at a powdercoating shop might not understand the hobby we all enjoy and the pride we try to put into things.

Given some other designers' experiences with anodizing, I'm assuming anodizing is more prone to problems with finish than powdercoating, right?

Thanks again!

 

[mimoto]

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[defensecoater]

Hey. Good questions. You might be able to find your answers here, read here

 

[Josh | NFC]

Josh!

Thank you for your reply and expertise, that's some really helpful info there

What sort of powder is conducive to buffing? Should I be looking for anything in particular to determine this?

I might just try to get the shop to sand it and re-coat the whole thing (providing buffering can't / doesn't do the job). Given your experience with PCing for special editions of your own case, would you recommend any particular brands and colour codes that you were happy with in the past?

I was thinking of getting the shop to coat some raw aluminium expansion slot covers first, to get an idea of the finishes I could expect (keeping in mind that coating over a sanded-but-coated case will look slightly different). I'm mainly worried that the PC company will try and push some sort of tacky gloss finish suitable for cheap bicycle frames or something... partly because some guy or gal at a powdercoating shop might not understand the hobby we all enjoy and the pride we try to put into things.

Given some other designers' experiences with anodizing, I'm assuming anodizing is more prone to problems with finish than powdercoating, right?

Thanks again!

Your concerns about the quality of PC are what I have found to be true. Most shops look at this as an industrial solution. I would be very clear with them up front you are looking for show-quality, and they can charge you appropriately for it.

As for anodizing, I should be more clear: you are VERY unlikely to find a place that can do a perfect anodize and dye for you are expecting. Professional parts are done in the thousands and they need to be of the same size. If you do get them anodized, you might not get a perfectly even dye. I don't know what you have in your area, but this is a specialty thing. Just wanted to explain further anodizing/dying a big flat part perfectly evenly isn't as simple as painting.

Peace