Questions about spray painting?

[uJalled]

Hey, so it's summer now and a good season to work outdoors, so I decided to kick off with something I've never tried before- painting a keyboard case. To be honest, it's pretty nerve wracking, just because I run the risk of messing up my Filco TKL  . There are all sorts of threads on painting, but everything seems to say something different. Some people say a primer is necessary, others say no primer is necessary with Krylon Fusion, some say vinyl dyes are the best, some say sanding with only 400 grit is okay, while others say I have to use 400, 600 and 1000 grit. So many ways to mess up, it makes my head spin. For anyone that has done this in the past, can you share some tips and advice on spray painting a Filco? Also, if anyone has found a good spray painting thread, that would also be awesome.

Thanks!

[Leslieann]

I'm no expert (at all), but I can tell you that 600 and above is for working the paint after to remove orange peel, not prepping.

Plastic really needs special paint, my advice would be use whatever the can recommends.

Dye can work, but to really get it done right, but often the part needs to be boiled to get good penetration. This would warp a Filco. They can also turn out splotchy. Paint you can always sand off redo it.

[uJalled]

I'm no expert (at all), but I can tell you that 600 and above is for working the paint after to remove orange peel, not prepping.

Plastic really needs special paint, my advice would be use whatever the can recommends.

Dye can work, but to really get it done right, but often the part needs to be boiled to get good penetration. This would warp a Filco. They can also turn out splotchy. Paint you can always sand off redo it.

Thanks so much for the reply! This is pretty helpful. I was about to go ahead to use the vinyl because it's what everyone says can just be sprayed over the casing without sanding or prep, but I had no idea about boiling. Plus I know that vinyl dyes are nasty stuff to breathe in

[fohat.digs]

Most threads about "dye" around here are talking about boiling PBT keys in RIT dye to get exciting colors.

You are not going to boil a case, anyway. There are things like the Dupli-Color (bought at Auto Stores) that are more like stain in that they penetrate and don't build up a film. With those, you will not use a primer, but they are better going from light to dark than vice versa.

[Photoelectric]

Some oil enamel is mixed to adhere to plastic.  Rust-oleum has a lot of paint like that (such as Painter's Touch line), but I was also able to use their Stops Rust line, and it adheres super well too without any primer.  I have a can of plastic primer, but so far, it's been superfluous with many paints.  Instead of the primer, I sometimes use a thin base coat oil enamel that's formulated to stick to plastic and then other enamels on top.

Never mix different kinds of paint without researching what they are and testing them together.  The more obvious no would be mixing acrylic paint over oil paint (but I think you can do oil over acrylic.  Still wouldn't advise mixing).  I always do a test of my painting plan on a piece of scrap metal or plastic to see how long it will take to dry, how thin paint layers need to be, how the colors will turn out if I add more or less clear coat, etc.

You don't need to sand to prepare your surface if it's already sufficiently smooth and free of other paint that could interact with your paint, as any noticeable imperfections can come through after painting (if they are fine enough, multiple layers of paint + clear coat + sanding / polishing after can cover them up).  Just painted a Filco Camo myself, and the Camo print was very tough and durable, and did not require sanding.  CM QFR has some sort of a rubberized coating--that I would mostly sand off.

You should make sure to clean the surface really well prior to painting.  No oils, no soap residue, NO WATER DROPLETS anywhere.  If you use oil, don't use alcohol to clean any of the coats--it will dissolve and discolor the paint.  Just use mild liquid soap and lukewarm water, wipe really well, and dry thoroughly.  Maybe some high content rubbing alcohol on bare surface and wipe / dry really well.

Sandpaper... Something like 200-grit will easily sand off chunks of your Filco case, like the tabs that hold the top and bottom case parts together.  600-grit is much finer and will do well for fine sanding, rounding edges and such.  Once you've painted and used multiple  layers of clear coat, I would not use anything under 1000-grit.  2000-grit wet-sanding is as low as I personally go.  Wet sanding enamel clear coat will help remove the orange-peel surface that you will get after painting, but will make the surface look dull.  To further polish, you can get a rubbing compound from a car supply shop and follow with a polishing compound.  I use these:



The amount of clear coat and sanding / polishing depends on how you want the end result to look.  Personally, I find some amount of "orange peel" looks interesting with metallic paints, giving them texture and a more rough metallic finish.  If I do flat paints, I use  more clear coat and sand it really smooth, to be as car-like as possible (easier said than done).  And a word of caution: don't start any of the sanding / polishing until at least a day or two after you've painted.  Some paints take forever to dry.  Always test a tiny area with your fingertip / nail before doing anything.

And finally, everything I said here refers to oil-based enamels, which I prefer.  I don't like any Krylon products I've used due to most resulting in uneven finishes or other issues, but maybe I've just been unlucky.  Krylon Fusion for plastics is not made to work safely with all plastics and when I tried it on an optical drive cover (probably ABS), it actually melted the plastic where it interfaced with the paint.  I could scrape it off with my nails a few days later.  There may well be other good paints--look for reviews.

Here's a good thread that might be helpful if you choose oil-based enamels:
http://www.overclock.net/t/382840/guide-painting-patterns-with-spraypaint

[uJalled]

Some oil enamel is mixed to adhere to plastic.  Rust-oleum has a lot of paint like that (such as Painter's Touch line), but I was also able to use their Stops Rust line, and it adheres super well too without any primer.  I have a can of plastic primer, but so far, it's been superfluous with many paints.  Instead of the primer, I sometimes use a thin base coat oil enamel that's formulated to stick to plastic and then other enamels on top.

Never mix different kinds of paint without researching what they are and testing them together.  The more obvious no would be mixing acrylic paint over oil paint (but I think you can do oil over acrylic.  Still wouldn't advise mixing).  I always do a test of my painting plan on a piece of scrap metal or plastic to see how long it will take to dry, how thin paint layers need to be, how the colors will turn out if I add more or less clear coat, etc.

You don't need to sand to prepare your surface if it's already sufficiently smooth and free of other paint that could interact with your paint, as any noticeable imperfections can come through after painting (if they are fine enough, multiple layers of paint + clear coat + sanding / polishing after can cover them up).  Just painted a Filco Camo myself, and the Camo print was very tough and durable, and did not require sanding.  CM QFR has some sort of a rubberized coating--that I would mostly sand off.

You should make sure to clean the surface really well prior to painting.  No oils, no soap residue, NO WATER DROPLETS anywhere.  If you use oil, don't use alcohol to clean any of the coats--it will dissolve and discolor the paint.  Just use mild liquid soap and lukewarm water, wipe really well, and dry thoroughly.  Maybe some high content rubbing alcohol on bare surface and wipe / dry really well.

Sandpaper... Something like 200-grit will easily sand off chunks of your Filco case, like the tabs that hold the top and bottom case parts together.  600-grit is much finer and will do well for fine sanding, rounding edges and such.  Once you've painted and used multiple  layers of clear coat, I would not use anything under 1000-grit.  2000-grit wet-sanding is as low as I personally go.  Wet sanding enamel clear coat will help remove the orange-peel surface that you will get after painting, but will make the surface look dull.  To further polish, you can get a rubbing compound from a car supply shop and follow with a polishing compound.  I use these:

Show Image

The amount of clear coat and sanding / polishing depends on how you want the end result to look.  Personally, I find some amount of "orange peel" looks interesting with metallic paints, giving them texture and a more rough metallic finish.  If I do flat paints, I use  more clear coat and sand it really smooth, to be as car-like as possible (easier said than done).  And a word of caution: don't start any of the sanding / polishing until at least a day or two after you've painted.  Some paints take forever to dry.  Always test a tiny area with your fingertip / nail before doing anything.

And finally, everything I said here refers to oil-based enamels, which I prefer.  I don't like any Krylon products I've used due to most resulting in uneven finishes or other issues, but maybe I've just been unlucky.  Krylon Fusion for plastics is not made to work safely with all plastics and when I tried it on an optical drive cover (probably ABS), it actually melted the plastic where it interfaced with the paint.  I could scrape it off with my nails a few days later.  There may well be other good paints--look for reviews.

Here's a good thread that might be helpful if you choose oil-based enamels:
http://www.overclock.net/t/382840/guide-painting-patterns-with-spraypaint

Thanks for the reply! I picked up two cans of Rustoleum, one of Ultracover Painter's Touch, and one of a glossy Clear finish from the Home Depot (it was pretty cheap, around 4 dollars a can). I'm going for a more car like finish, so since my Majestouch 2 has a rough texture to it, what sandpaper should I use to sand it down and make it smooth?

[Photoelectric]

Yeah, Home Depot is awesome for having a large selection for cheap.  Is the clear coat you got an "enamel" or a "lacquer"?  Make sure you got the "enamel" which is oil-based, to go over Painter's Touch, which is also oil-based.  I found that Painter's Touch clear coat does not like for you to take a 24-hour+ break between the base coat and clear coat and can wrinkle the base coat if you wait that long.  I even waited 48 hours at one point, and it still wrinkled.  So if you have that one, best to do everything at once.

Do you have something like AutoZone or Advance Auto Parts next to you?  They have a large selection of fine sand paper to choose from.  I would use something like 600-grit to smooth out the surface.  You don't need any finer. 

I posted here, talking about how to remove the Filco logo from the top cover, which is all I'd paint on a black Filco for starters.  Use some painter's tape to tape over the inner parts (you'll need to do some folding, and get the thinnest tape available.  This is basically so that the surfaces that will be flush with the bottom tray don't get painted.  Like the surfaces where the locking tabs are.  Everything else won't make a difference if you paint over it.

Look at the guide I listed in my previous post and go by that--it's a good one.  Start with a very fine layer of paint and wait a minute.  Then do a slightly more even layer of paint, and wait a couple minutes.  Another semi-thin layer of paint, and wait 2-3 min.  Make sure to never overspray, which will result in drying problems and finish issues that will be very difficult to correct.  Better to wait a bit and do another thin coat.  Best to spray outside so you can see how even the paint coat comes out, and to avoid breathing all the fumes.  When you're done with the base coats, do a very fine mist of clear enamel.  Wait a minute and do a very slightly heavier coat.  Then wait a few min and do one-two more slightly heavier coats.  Basically don't spray new coats until your current one is dry to light touch).  If it looks shiny and wet still, don't touch or spray more.  Once you're done, leave it to dry for 24 hours to do any polishing or trying on or anything that could ruin the paint before it's fully dry and can still move around.

And finally, if you do decide to sand the clear coat later and use 2000-grit sandpaper wet, keep in mind that even though it feels super silky, it does still sand   If you go over any bent surfaces / corners, use a very light touch, as those will be much easier to sand vs. flat surfaces.  I'd avoid oversanding corners as much as possible and focus on flat surfaces instead with small flat pieces of 2000-grit paper.  You may not notice right away, but even with 2000-grit you can eat through the clear-coat around corners if you are not careful.

[Leslieann]

Another thing about paints made for plastic is that they include a flex agent. Normal paint will crack if the plastic is flexed too much.

[Photoelectric]

That is true.  Though oil enamels allow a fair amount of flex as well.  And a keyboard is not going to be flexed enough to crack the enamel.

[uJalled]

This is the kind of finish I bought, not so sure whether it is enamel

http://www.amazon.com/Rust-Oleum-249117-Painters-Multi-Purpose-12-Ounce/dp/B002BWOS5I/ref=sr_1_1?ie=UTF8&qid=1371427572&sr=8-1&keywords=rustoleum+clear+coat+enamel

[Photoelectric]

That's oil enamel.  The Painter's Touch line is all oil enamel.

[SpAmRaY]

That's oil enamel.  The Painter's Touch line is all oil enamel.

Is that a recommended paint for cases?

[Photoelectric]

Not necessarily.  I only know oil-based enamels since that's what I've had best luck with.  I don't have access to Montana paints, for example, and Krylon has been crappy for me for various projects (non-computer related too).  Krylon and DupliColor are owned by Sherwin williams, and I didn't like their paints either, but a lot of DupliColor stuff is quite good.

The reason I go with Rust-Oleum a lot is because it's easy to get good color selection at Home Depot and car supply shops, it's cheap, and it's pretty cheap at HD.  Painter's Touch is REALLY smooth when painting.  The nozzle sprays smoothly, the paint comes out looking very even, I really like it a lot.  In comparison, I got a can of Krylon enamel in brown, and it was all splotchy and too uneven after many coats.  Painter's Touch is made to stick to plastic as well.  The only thing touchy about Painter's Touch is using clear coat over it--I would do it right away.  For many enamel paints, you can wait 24 or 48 hours to let the base coat dry and then use clear coat.  With Painter's Touch, the clear coat has been wrinkling for me if I don't spray right away.

I'm no expert, just sharing my personal experience and paints I've had best results with and have greater room for error.  If you have a color in mind and would like to try oil enamel, let me know, and I'll try to give some tips about products and combinations.  There are some very cool paints to use and combine, such as DupliColor Metal Specks (fine glitter metallics) and MetalCast (transparent tinted coating to tint a surface or make a gradient), color changing paints like Rust-Oleum Color Shift or DupliColor Mirage. 

I would like to try PlastiDip at some point.  Been watching videos and looking at photos of results, and there are some very cool things one can do with those paints.  Like copper metallizer over brown or black, or making carbon fiber design, etc.

[SpAmRaY]

So is the paint linked above what you use?


Any tips for starting over if something gets screwed up? Is striping an option?

[Photoelectric]

I've used mostly Painter's Touch on 2 computer cases personally.  It comes in non-metallic colors.  Gloss or Satin don't matter, as it's all about sanding/polishing afterwards.  You can still get satin texture and coat it with a clear gloss, and it will end up glossy.

For my keyboard cases, I used metallic paints, because I decided I wanted some sparkle on them.  First got a thin layer of Rust-Oleum Stops Rust in "Black Night Metallic" over bare plastic as a "primer", then I did multiple layers of DupliColor Silver Metal Spec (fine silver metallic flake spray, kind of glittery), and then coated with an iridescent clear coatt (DupliColor).  The copper-toned cases I did were with Rust-Oleum Universal line ("Aged Copper")--that one is primer+paint in one.  I LOVE the colors, but it's very difficult to work with.  It takes FOREVER to dry.  It's the first paint I've used where I can still shift the paint slightly 24 hours after painting.  I learned on my mistakes with the first case I used it on, and the second case I left alone for 24 hours before I even touched it much, let alone polish.  If you use any paints from that line, be sure to wait few minutes before coats, and if you clear coat, wait like 10 min before clear-coating.  And don't touch the case for a day or two as it dries.

So from personal experience, in terms of ease of use and more foolproof results:

* Rust-Oleum Painter's Touch (adheres to lots of surfaces, even plastic, as advertised on the bottles and tested by me)
* DupliColor Metal Specks metallic colors--use over a layer of paint, like Rust-Oleum Painter's Touch, as the metal specks don't adhere well to bare plastic.  Multiple layers of this stuff = awesome sparkly surface.  Comes in many colors.
* Rust-Oleum Stops Rust in "Black Night Metallic"--kind of a gunmetal-black with silver sparkle.  Very nice, goes on evenly and looks great.  I've tried "Copper" from that line too, but it makes kind of an unevenly colored finish.  You can see from its cap what the finish is like (not as finely swirled though)
* Rust-Oleum Automotive Clear Gloss enamel - great standard clear coat over any oil enamel.
* Dupli-Color Clear Effex - iridescent clear coat.  Don't use too many coats.  Adds very fine iridescent metal sparkle over any paint.  Enhances metallic colors and used on flat colors, it gives a very fine shimmer, only visible when direct light hits it (otherwise you can't tell it's there).  This is optional, and it does make the base coat look a bit lighter and more milky with multiple coats.

As with everything: spray-test first on something disposable before you use it on your case.  You may decide you don't like the combination you had in mind at first after you see it materialize.  Or you may decide you don't like a lot of clear gloss over your flat paint and just want a small amount.  Or maybe you just want satin non-glossy clear coat for protection and no gloss finish.