Most durable paint ever?

[jrem]

$0.99 WalMart paint bombs, bake in a toaster oven, low heat for a long time (I have the values around somewhere, I think 220f for an hour or so).  Works great.  Several coats and you have a rock solid enclosure.   Sure, they ding up, but so do old MXR pedals.  Don't cook food in the oven, though.

[liquids]

This thread inspired me to give baking another shot. Especially with the testors.  I used a thermometer to discover that my oven is around 190 F at the lowest setting...no wonder I was having issues with peeling, etc.

Manipulating the oven door about as much as possible without it turning off, still on the lowest setting, yielded temps around 150.  I tested a few thing like that on a spare box lid or two that I will strip later, and surprisingly there were no real issues, then. 

It seems best to bake it after the final coat, as baking (cooling, and re-coating) tended to put rustoleum past that "1 hour window," meaning it wrinkled when I re-coated after baking while still technically within it's "1 hour window."  Testors seemed to firm right up, and this morning it was dry to the touch and fairly resistant to hitting it to see just how dry it was, even with a thick coat and only a half hour in said oven. 

Likewise, it seems best to try and let it air dry some before you bake it rather than put it right in.  I really like the testors can I have thus far, so that's probably all I'll use it for, but this gives me less worry about wait times and means I'll buy more testors for sure. The testor's comes off very thick (apply carefully and lightly if possible!) and dries fairly even.   I also like how it smells.  I'm careful and paint outdoors, but am sensitive to this stuff, so I still have a bit of a paint headache this moring

Anyhow, since I don't mind waiting 48 hours for rustoleum to be able to accept another coat on top, and air drying seems more predictable in that regard, I'll probably not bake rustoleum stuff that much, if at all.  The can is always more reliable than the variables of judging 'is it dry enough?' via heating. I think the main variable is toaster ovens--they're clearly not all the same from what I've read here, and so probably not build to be all that well 'regulated'  for air temp especially below 200.  Their heating coils are pretty close to the boxes when it comes down to it, so in some ways it's more like 'broiling' than baking, if you will....     YMMV. 

[m-theory]

What about good adhesion to zinc galvanized steel though?

There's only one method that paint manufacturers would stand behind, and that's the method that they've published to specifically address galvanized steel.  In short, although all will be similar and will begin with a thorough cleaning following by acid wash/scrub, the details will be slightly different for each paint maker.  Therefore, it's impossible for anyone to tell you one set of steps that will work for all paints. 

What I would do with galvanized metal on a pedal would probably be to sand it good with 180g, then 320g, prime it with Rustoleum automobile primer/surfacer, let that dry, sand w/600g paper, apply color. 

Beyond that, I'd probably take it to a neighborhood body shop (probably not the hoity toity "A" shop, since they're too busy painting cars to fiddle with something like this...look for the smaller shops for this type of thing), show it to the owner and explain what you're trying to accomplish.  It's entirely possible that he'll not only acid wash and prep the substrate for you, but he'd also prime, sand, paint, and clear it for you if you wanted, probably for not that much money.  The bigger "A" shops don't lift a finger without billing you for it...that's how they got to be "A" shops. 

But, the smaller, "mom and pop" type shops are much more laid back, and much more likely to take something like this on, because they get a kick out of doing things out of the ordinary.  Not that they'll want to do it for nothing, and don't expect that (although it MIGHT happen, if you get along well with the guy right off the bat), but they may well be will to barter or do the work very cheaply, in exchange for a nice 8x10 photo of the finished work or something.  Perhaps, they've got a nephew that plays guitar, and you could offer to build one for him in exchange.  Worst case scenario, you pay the man what he wants to do the work. 

Again though, I'd probably not go this far with a pedal, but that's just me.  I'd not be using galvanized boxes for pedals, either! 

With regard to baking, I tried temps ranging from 175 to 200, and varied the times widely as well.  I never saw a finish come out of the oven fully dry.  They were ALWAYS soft underneath, and highly susceptible to solvent attack on recoat.  My theory is that the surface heat very quickly skins over the film surface and traps solvents underneath. 

If a guy had access to short wave infrared, you could dry from the inside out at the same time as from the outside in.  The more traditional way to resolve this, and the way that body shops address it in a booth, is to have rapid air flow, to draw out the solvents as the heat is applied.  Locking the box in a nearly airtight oven isn't a very efficient way to remove solvents. 

The thing is, since I'm using a clear that takes 25-30 hours to set up well enough to handle, what difference does it make whether or not I can shave 10 minutes off my painting time?  I can be completely through with primer, sanding, and color coat in a little over an hour the way it is.  I never saw significant time savings with baking, and certainly not the savings that would justify the hassles I encountered with it.  Good to see that it works for some, but it sure didn't for me. 

[bassmannate]

Awsome. Sounds good. I'm assuming that when you say automotive primer, you're referring to an automotive primer that is NOT self-etching? I know you mentioned fairly early on that the self-etch stuff tends to react poorly with zinc.

Edit: One more thing. I'm assuming also that mineral spirits will be just fine for cleaning. I have a TON of this stuff laying around from previous projects and would hate to see it go to waste.

[m-theory]

It's not that self etch primers react poorly with galvanized, but rather that it's not the only step that's recommended for the bare metal.  As I recall, and this is going back 11 years now so it may have changed, and I may be off a bit, the process for the company that I represented called for a very specific type of acid wash (there's more than one type of chemical used for bare metal etching), followed by very specific cleaning technique, and THEN the self etch primer or an epoxy.  Bottom line is that galvanized is a real beeatch to get adhesion to, and for a vehicle, adhesion is the #1 factor, from bare metal up. 

Rustoleum has a primer that they have labeled "automotive primer," or something along that line.  It's still an alkyd enamel, just like the rest of their products, so it's not as if it's something high tech and spectacular, and Lord knows I'm not pimping for that company...I generally hate their line, truth be told.  But, I've found that this particular primer does provide excellent adhesion to the cast aluminum that most of us work with on these pedals.  I've got a box that I use to "road test" circuits that I like, to see if they'll work as well on stage as they do in the basement.  It's an old box that no longer had any purpose, so I stripped the paint and hit it with a couple coats of the Rustoleum primer.  It literally gets thrown around, and has for the past couple of years, yet it shows nothing but a few chips here and there.  Not a hint of peeling anywhere, and not a hint of any of the minor chips becoming more severe.  That's what you're looking for in a primer, so I saw no need to argue with it at that point.  Beyond that, the stuff dries fairly smooth and wet sands to a glass-like smoothness that's very favorable as a substrate for color coats. 

FWIW, I was using an aerosol self etch primer for a while, until I finally broke down and bought a quart of the acid.  I suspect I'll probably go back to the spray bomb stuff rather than shovel out another $35 or so for another quart of the acid when it's gone.  The reason I bought that was because I was having some serious adhesion issues on a DD build that I was doing at the time, and I was at my wit's end.  I suspect that there was some sort of release agent within the pores of the metal that was leeching out and causing delamination.  At any rate, I stripped the failure to bare metal with 80g and applied the acid, then primed and painted, and never had the delam on it again.  I've been using it since, but it's overkill for most situations.  For whatever reason, that DD box and another one that I had similar problems with, were the only times I've encountered a truly problematic situation with regard to adhesion on the hammond-type boxes. 

Although I've never actually done this, I would venture to guess, based upon what I have tried, that if a person used nothing but either a self etch aerosol or the Rustoleum automotive stuff and color, you'd be fine and dandy on MOST of the hammond-type boxes (my two DD problem children except, of course).  Galvanized is a whole other story, though. 

[mojotron]

Bullet proof finishes are a bit silly for guitar pedals...

....maybe I should contact him to see what he did?...

Back then I was uinng minwax poly and Future floor finish - I think the Future did not look as good as the poly, but held up better as it's not a hard finish - it bends...

These days I just use a sharpie and no paint

[mojotron]