Grit for Case Sanding?

[bbs lm-r]

I'm going to be painting the outer panels of an old case, but I need help figuring out what sandpaper grit to use for sanding before painting.

The panels are aluminum and the front is plastic. I was thinking i'd use like 50-60(?) grit before the first coat, and then a finer grit like 240(?) between coats. Is that ok?

Also, do I sand one last time before putting a clear coat?

 

[Arcygenical]

Oi. Do not sand with 60g sandpaper. ANYTHING below 200g and you'll mar the steel/aluminum surface, requiring many layers of primer.

Personally, using a circular motion, use 220g sand paper over the stock colouring (either anodization or paint) then hit it with a thin, then thicker, layer of self-etching primer. Sand with 400g after your thicker coat of primer.

Use an acrylic enamal paint (the Rustoleum/Tremclad Professional series) if you want a basic color, you won't need a clear coat. Sand every 2 full coats (you spray 2 light coats to get 1 full coat) AKA every 4 applications of paint.

I've never sanded before the clear coat with anything lower than 600g.

 

[aphasia]

I'm going to be painting the outer panels of an old case, but I need help figuring out what sandpaper grit to use for sanding before painting.

The panels are aluminium and the front is plastic. I was thinking i'd use like 50-60(?) grit before the first coat, and then a finer grit like 240(?) between coats. Is that ok?

Also, do I sand one last time before putting a clear coat?

with respect to Arcygenical reply to the OP's original post, save your time, pain & your lungs, get a pro to strip the paint off your Al case. A professional paint stripper will drop your case in a chemical bath that will cleanly remove every spec of paint plus etch it in preparation for a primer coat.

When i did my case mod (TT mozart rebuild - in mod sub forum. Typing this on a phone otherwise i'd provide the link), i had my whole case stripped in this manner. It was a perfect job with no deep scratches on the surface. Just virgin aluminium. Cost me about 20-30bucks all up. Took it to the powdercoaters after that. That cost a bit more, round $100 tho it was a big case (double-wide tower case).

If u don't mind all the sanding, priming, painting bullshit then the poster above has excellent advice. Personally i hate doing that stuff. Plus powdercoating does give a much cleaner/durable finish due to baking process.

Edit: Back at PC. link to my case that went thru chemical bath then powdercoated...
http://hardforum.com/showthread.php?t=1621835&page=5
didn't see the bit about the plastic facia. obviously can't get that powercoated, still have to do that by hand.

 

[bonnev659]

from what I read I agree with Arcygenical below. Also I know I am not talent enough so I would most likely do what aphasia said with powdercoating.

Oi. Do not sand with 60g sandpaper. ANYTHING below 200g and you'll mar the steel/aluminum surface, requiring many layers of primer.

Personally, using a circular motion, use 220g sand paper over the stock colouring (either anodization or paint) then hit it with a thin, then thicker, layer of self-etching primer. Sand with 400g after your thicker coat of primer.

Use an acrylic enamal paint (the Rustoleum/Tremclad Professional series) if you want a basic color, you won't need a clear coat. Sand every 2 full coats (you spray 2 light coats to get 1 full coat) AKA every 4 applications of paint.

I've never sanded before the clear coat with anything lower than 600g.