(Not Another) Enclosure Finishing Thread

[Ginsly]

I've read through many threads about finishing enclosures, but info is all over the map and I was still left with some questions. I really should have just gotten pre-painted boxes from Tayda, but all I have are bare aluminum enclosures. Some of them are more "finished" than others. Some things I've been considering:

- Buffing them to a smoother, shinier aluminum surface as a "finish", not just prep for spray paint (but that too). Wet sanding? A few different grits?

- I'm a print maker, and plan to try a simple screen print on the box top at some point too. I typically use Acrylic inks. I could always screen a layer of clear Acrylic medium on top of the screened artwork, but it would likely still be susceptible to scratching. Since they aren't enamel-based I'll need to put a clear coat on top - the recs are all over the place, some saying that auto sprays are the way to go. What kind of clear coat is best?

- I have some random spray paints that were given to me. This is one I considered using to coat some in black: https://www.montanacolors.com/en/productos/graffiti-fine-arts-hardcore-paint-aerosol/. A few others are Montana's "94" series: https://www.montanacolors.com/en/productos/mtn-94-aerosol-spray-paint/. Seems like these are usable? I take it I should wet-sand bare enclosures before applying paint, but would I need primer? I'd finish them with a clear coat, and again, hopefully someone has a good all-around rec for that!

- Hammertone Paint. I like the look, and many say it's easy to use (possibly no sanding/primer?). This is likely how I'd finish most of these enclosures, and I'd love a specific brand recommendation (Rust Oleum?), and any pointers if you've done this.

- I don't have a booth for any spraying, so it would be outside. Chicago varies a LOT temp-wise. With any of these sprays (clear coat, paint, hammertone) I feel like there must be off-label temp/humidity considerations for a better outcome on aluminum. Same thing for overall technique (mist coats/waiting periods/proximity/etc) - what worked best for you?

I'd really appreciate any input, thanks all!!

 

[Bricksnbeatles]

I would definitely recommend using something more durable than acrylic for screen printing. Enamel/epoxy inks are great on bare metal— I know the cleanup can be a pain but it’s probably worth it.
@steviejr92 what have you been using for your screen prints?

 

[hamerfan]

I use an alu primer (2 times with polishing the surface with very fine steel wool) every time except hammer tone and clear coat on alu. The laters are only polished before spraying.

 

[Ginsly]

I would definitely recommend using something more durable than acrylic for screen printing. Enamel/epoxy inks are great on bare metal— I know the cleanup can be a pain but it’s probably worth it.
@steviejr92 what have you been using for your screen prints?

I had the feeling this would be the case... So Acrylic is a bad idea even with a clear coat over it?

I use an alu primer (2 times with polishing the surface with very fine steel wool) every time except hammer tone and clear coat on alu. The laters are only polished before spraying.

Gotcha, thanks! Would love to know what specific aluminum primer, hammertone, clear coat, and polish you like.

 

[cdwillis]

I don't mess with enamel. It never really cures or dries in my experience. You can get decent acrylic lacquer from O'Reillys or Autozone if you want to use spray cans. I've used hammertone paint on a few enclosures. I can't remember which brand, but I can find the can later. It takes a little longer to cure than the can says. I had a klon/kliche that I used copperish brown hammertone paint on and ended up with a thumb print on the side of the enclosure even after waiting two days. It probably depends a lot on the humidity and temperature and how thick you sprayed it. Hammertone needs one thick coat to really get the hammered look vs a few thin coats layered on top of each other over time.

 

[Ginsly]

You can get decent acrylic lacquer from O'Reillys or Autozone

Would this still require some sort of clear coat? If so, what would you recommend - just a clear version of the same acrylic automotive lacquer?

 

[jwin615]

I'll add, you don't want to wet sand for a painted enclosure. You want to use a rougher grit(200/400) and scuff it. Just a couple of minutes total. No need to overwork it. It's going to look ugly but that gives the paint more to "grab" and will end with a more durable coat. If going for a fine/smooth finish, I prefer auto paints and clear coats. Duplicolor is the main dog here in the states. Their 4K clear coat is pretty resilient. they also have some cool color shift and flex rattle cans.
If you want a showroom floor finish, lightly wet sand with the highest grit you can find before clear coat and do a fine buffing after. I would advise watching a few YT vids on painting cars if you want to go that route.
If not using auto paint, I go for an enameled paint. Al self etching primer is the way to go if using primer.

I say all this to add, I've gone away from showroom floor type coats as something always goes wrong. A thumb print, dust, a thin spot. Good enough is good enough.

Also, get some 3 inchish screws with the same taper as the enclosure (6/32?) to use as standoffs and to keep the treads clean as well.

 

[jwin615]

Enamels seem to do better when heat cured btw. And make sure you clean your tips, especially on your clear coats.

 

[Ginsly]

I'll add, you don't want to wet sand for a painted enclosure.

Good to know! So you don't use primer with auto paint? I wonder if I'd need that for those Montana paints I linked to...

I'll check out Duplicolor for sure. Lots of people just recommend Rust Oleum clear coat, but not sure how it lasts.

Enamels seem to do better when heat cured btw. And make sure you clean your tips, especially on your clear coats.

Outside of a heat gun, I don't think I have what it takes to start messing with any heat curing. Probably don't wanna pop these in the oven!

When cleaning tips, I assume you mean the spray valve on the paints?

 

[Harry Klippton]

I don't consider myself to be a spray paint person, but I guess I've used a lot of different spray paints for finishing. I've had success with various paints by waiting for perfect weather with low humidity and long dry times, sometimes up to a week. all my spraying is done outside. I always heat my cans before spraying and spray them upside down when I'm done to clear the nozzle

Here's a mic body I painted with enamel

A pedal enclosure with Montana cans and a crackle finish

A steel enclosure with Rust-Oleum

I did a couple guitar refinish jobs with nitro spray cans too but they aren't documented on here

 

[cdwillis]

The paint I mentioned from O'Reillys is Dupli-Color Perfect Match. They have clear coat and a bunch of different colors to match up with difference car manufacturers:

https://www.oreillyauto.com/detail/c/perfect-match/dupli-color-perfect-match-8-ounce-clear-touch-up-paint/dpl1/bcl0125?q=automotive+paint&pos=2

The clear coat will make it pop. I've never messed with it on pedal enclosures, just a couple guitar projects where I painted the body. They didn't come out like factory bling, but not bad at all for a DIY job. I usually just get powdercoated enclosures from Tayda now.

This is the Hammertone paint I was talking about:

Robot or human?

 

[Ginsly]

I don't consider myself to be a spray paint person, but I guess I've used a lot of different spray paints for finishing. I've had success with various paints by waiting for perfect weather with low humidity and long dry times, sometimes up to a week. all my spraying is done outside. I always heat my cans before spraying and spray them upside down when I'm done to clear the nozzle

Great info, thanks much. Looks like you've used Montana paints before too! I see no reason why the "94" type I have wouldn't also work like the crackle you used. You heat the cans? I have to assume this is something done very conservatively- yikes!

The paint I mentioned from O'Reillys is Dupli-Color Perfect Match.

Excellent! I've seen that exact Hammertone paint mentioned, too. I think that's the one people seem to use without sanding/priming iirc...?

 

[cdwillis]

On my first enclosure I didn't sand at all and on the next one I sanded with 300 grit I think and I couldn't tell any difference. Don't hesitate to give it a nice heavy coat without going heavy enough that you get runs. It makes the hammer effect more prominent I think.

 

[jwin615]

Just set the cans in the sun or in some hot tap water. It thins a little bit.
I cure them in my oven. Note, they are dry for a couple days already. Pre heat to 200F, bake for 10 minutes and turn the oven off. Leave for an hour ish. It seems to help the enamel harden faster. Otherwise, enamel takes weeks to fully cure.

 

[jwin615]

On my first enclosure I didn't sand at all and on the next one I sanded with 300 grit I think and I couldn't tell any difference. Don't hesitate to give it a nice heavy coat without going heavy enough that you get runs. It makes the hammer effect more prominent I think.

I think the sanding is just an adhesion thing. Probably more important is good cleaning.
I just use a palm cander and do a quick stuff, then wipe. 60-90 seconds all in.
Then a quick thin coat of primer. Again. Just there for adhesion. Ready to paint in 10-15 minutes.

I doubt the hardcore paint needs primer, as most don't *need* it on solid surfaces. Again, just adhesion. *May* help avoid chipping but won't look any different.

 

[Alan W]

Aluminum is very difficult to get good paint adhesion on. In my shop we basically spray automotive lacquers, but for aluminum we always use an etching primer. This was the only primer that passed a “rub a piece of masking tape in it and pull” test. I think you can get self etching primers in spray cans, but I don’t know. We were using a DuPont product, in their Variprime line.

Yes to getting the surface really clean. We typically use soap and water, and then acetone. Fine sanding to increase surface grab would help if you don’t have an etching primer, but even 220 should help with that; and I’d recommend always sanding with a decent amount of water.

Dupli-color was one of the few spray cans brands that worked well, most if the time. We did very little can spraying in my shop, but when I taught, students often used spray cans, and typically had worse luck with Montana than most other brands, with Krylon and Duplicate-color being the most successful.

its REALLY important with spray can paints to make sure that every layer is from whoever the manufacturer you’re using’s same product line of finishes, otherwise you may get incompatibilities (like the paint never hardening, etc., that can sometimes take a few days to show up. If you’re mixing brands of primer and color, and possibly top coat, I’d really recommend spraying some samples (aluminum foil even) and waiting to see if there’s any problems. Having to scrape bad finishes off anything is a really unpleasant job.

edited to clarify, see bold

 

[steviejr92]

I would definitely recommend using something more durable than acrylic for screen printing. Enamel/epoxy inks are great on bare metal— I know the cleanup can be a pain but it’s probably worth it.
@steviejr92 what have you been using for your screen prints?

I use one shot paint for my graphics, printing on bare enclosures as well as powder coated ones works very well!

 

[Erik S]

Lots of good suggestions above for getting the best possible results.

Another rewarding path might be to just do a bad job and be happy with it. I personally like the look of a crappy/ failed DIY spray job.

Hammer tone is cool, but is tough to get consistent results from.

Scotchbrite pads are my favorite for polishing aluminum.

I don’t paint colors, but I do clear coat all my enclosures to lock down the posca pen lettering. I’ve had good results with whatever they have at the auto parts store, but this is the one I’ve been using lately. They claim it’s good for direct to metal.

https://www.amazon.com/KBS-Coatings-8114-Diamond-Aerosol/dp/B06XR7SYF7/ref=mp_s_a_1_2?crid=WJG7GQCFORYL&dib=eyJ2IjoiMSJ9.X9C2VHD2otXKoHrJdfXFHrUsYzAH_D46sWlPe8wlIJJ69U2vTzxsxzXxo4tdbDuKIqtbwM0-ZxXitfo4rb9HJyXhqyPM847VGq8eattJtlkzyjcxBYVk5W9KpK-V9yBPZ30hXFKrsjFssk8EJaFobPumA9-DYsLUeEf4HbePbML2FX4nrXj1IeZo96al5z43p4gXDMZoA0YScbv6gHRDLg.F0wjMrf1rxDkr0a4lA_d-WiPLHIM1mdrsU5TYqHvtH4&dib_tag=se&keywords=clear+coat+diamond&qid=1725148356&sprefix=clear+coat+diamond%2Caps%2C162&sr=8-2

All I do for prep is a wipe down with alcohol, and then I only handle them with gloves until they’re painted to avoid fingerprint problems.

My favorite painting tip is these wire stands. I forget who I copied them from, but they’re great.