Most durable paint ever?

[bassmannate]

I'm about to start painting my first enclosure. I'm going with a steel electrical junction box. I'm going to hit the box itself with spray on bed liner. Does that need to be primed at all or can I just sand, clean and spray with bed liner?

The lid (on which I will mount the electronics) I'm going to hit it with a self-etching primer, a color coat, decals and then topped off with a clear coat. What is the absolute most durable paint out there (other than powder coating) that I can put on here in both silver and clear? I've searched the forums but I'm a little unclear as to what the consensus is about the toughest paint out there. I'm pretty careful with my stuff but I still like to have everything as tough as possible.

I had thought about having it powder coated but I would feel pretty silly walking in with a junction box lid and ask them to powder coat it for me. Not to mention I would still have to put a clear coat on after the decals anyway.

[alanlan]

the primer is the key (literally).

I used to have boxes painted at the Aerospace plant I worked at years ago, where they used to paint guided missile forebodies.  That stuff was pretty incredible, as it has to withstand years of corrosive salty water conditions without significant damage.

Wish I knew what it was, but one thing for sure was a grey primer undercoat.

I now work for a mixing desk manufacturer in the UK, and the stuff they use on panels is pretty bomb proof too.  I'll try to find out what it is but it is done by a sub-contractor.

Interestingly, we have recently moved away from paint finishes to custom designed Scotch self adhesive overlays on our latest product.  They are *really* tough but they can tend to lift at the edges so it's best if stuck in a very shallow recess.

[bassmannate]

That might be interesting if it's easily accessible. I guess I'm really confused about the stuff that you can access in automotive stores. Some people say that lacquer is toughest others say that acrylic is. What about using a two part epoxy for a clear coat? I've seen that mentioned and I can imagine that it's INCREDIBLY hard once cured. Are there any colored paints that epoxy would react badly with if I put one on the other? I'm not opposed to somewhat messy or waiting several days for it to cure up.

[nosamiam]

I know this isn't THE toughest stuff out there, but it's definitely a step above most other rattle can stuff... Appliance Epoxy. I get it at my local ACE hardware store. It comes in a spray can. No need for primer. It cures quickly and is very durable (but not bulletproof). It also seems to be pretty much "inert"; it doesn't react negatively with other types of paint. It's designed to work on stoves and such so it has to be able to stand up to the elements. The only drawback I've found so far is that it only comes in black, white, and beige. But if you find a design you like, ie. all black pedals with silver lettering or whatever, it's not really much of a drawback.

[bassmannate]

Thanks for the help! I think I know what you're talking about. I work at Best Buy and we have some of this stuff in the appliance department.

I did a bit (ok, a lot) of digging and decided I'm going to go with a self-etching primer followed by a silver acrylic and topped off with a two part epoxy clear coat. I think the epoxy should keep it hard enough to prevent chipping. Like I said, it's only going to be on the lid surface. The rest of the box will be coated in a few coats of bed liner.

[liquids]

I just did a two-part epoxy clear coat for the first time yesterday.  It is still curing a bit, but I can't say enough that it's awesome all around.  With a few tools and a little know-how, I found it the easiest box finish I've ever done, hands down.  Easier than painting, I dare say.  Definitely faster than waiting (read: hoping) for any rustoleum product to 'really' dry without issue.

You can get the pour-on epoxy clearcoat at select hardware stores and craft stores, but not just any store, in my experience.  I found "Envirotex" at the local Michael's craft store.  It can be ordered online too, but local will save you the spendy shipping costs if possible. "Easy Cast," "Crystal Sheen," and "Finish Perfect" are some other brands I found amongst others, though I've only tried the envirotex.  They're probably all very similar if not the same, Local Home Depot had something similar in the varnish area, but in a much larger quantity. Lowe's had nothing of the kind. Go figure.

One container of the stuff can cost about $10-$25 depending on size, but .5-1 oz or so is more than enough to do most pedals of normal size, so you can get over a dozen pedals out of even an 8 oz kit.  A little goes a long way.  It doubles as a straight up 30 minute epoxy, so it's a deal. It looks awesomely wet, and seems like it will make any box exponentially more durable to wear an tear, preserving any not-so-durable paint job below if the process is done properly.

PM myself, or better yet, m-theory, for more info about it, he is a wealth of information on the subject and will help beat the learning curve the first time you try it.  If you've worked with epoxy before, you'll be ahead of the game, but m-theory has the process down to a science for boxes in particular.  Your unlikely to try any other clearcoat again.  I'm actually considering stripping and re-doing every box I have now.  It's that good.

[m-theory]

Bullet proof finishes are a bit silly for guitar pedals, unless one is planning on leaving them parked in the driveway 24/7, 365 days/year.  Regardless of the materials used, you WILL get chips.  Sorry. 

Take a little walk around a tractor trailer the next time you see one parked somewhere, and tell me you don't find at least a few minor chips, no matter how new the truck appears to be.  Those trucks utilize the most durable finish products known...Catalyzed urethane and/or epoxy undercoats, urethane basecoats, and urethane clearcoats, yet they'll STILL get dinged by flying sand and stones.  Btw, these products are extremely costly and can be very dangerous to apply. 

The key isn't to eliminate chips, because that's an impossible goal.  The key is to maximize adhesion throughout, so that chips that occur remain minor, and don't develop into catastrophic delamination. 

To that end, it's worth noting that most electrical junction boxes that I've seen of are galvanized, and therefore require very specialized procedures and chemicals, in order to ensure proper adhesion.  Self-etching primers are NOT recommended as a bare metal substrate on gavlanized metal, by any paint company that I'm aware of.  I couldn't speak to the bedliner product without knowing what it is, and reading the associated data sheets. 

[bassmannate]

Bullet proof finishes are a bit silly for guitar pedals, unless one is planning on leaving them parked in the driveway 24/7, 365 days/year.  Regardless of the materials used, you WILL get chips.  Sorry. 

Take a little walk around a tractor trailer the next time you see one parked somewhere, and tell me you don't find at least a few minor chips, no matter how new the truck appears to be.  Those trucks utilize the most durable finish products known...Catalyzed urethane and/or epoxy undercoats, urethane basecoats, and urethane clearcoats, yet they'll STILL get dinged by flying sand and stones.  Btw, these products are extremely costly and can be very dangerous to apply. 

The key isn't to eliminate chips, because that's an impossible goal.  The key is to maximize adhesion throughout, so that chips that occur remain minor, and don't develop into catastrophic delamination. 

To that end, it's worth noting that most electrical junction boxes that I've seen of are galvanized, and therefore require very specialized procedures and chemicals, in order to ensure proper adhesion.  Self-etching primers are NOT recommended as a bare metal substrate on gavlanized metal, by any paint company that I'm aware of.  I couldn't speak to the bedliner product without knowing what it is, and reading the associated data sheets. 

I realize that I don't NEED a bullet proof finish. I would just really like it. I'm one of those people who HATE to have to do something twice because it gets messed up or damaged.

I'm looking to paint the box like mojotron (maybe I should contact him to see what he did?) did with these: http://www.diystompboxes.com/smfforum/index.php?topic=30980.0

What WOULD be the best substrate for galvanized steel then? I guess it never occurred to me that they were galvanized (You'd think that I would have noticed that the thing wasn't rusting or something)

Once again, the ONLY part that's going to take traditional paint is going to be the lid. The rest of the box will have bedliner sprayed onto it like mojotron did with his.

Edit: Duh, I just realized that I probably have one of the best resources for knowing how to paint metal. My father-in-law is an aircraft mechanic. He probably knows how to paint any metal surface known to man.

[Paul Marossy]

I like the powder coated/pre-painted  boxes from www.pedalpartsplus.com - they have pretty durable finishes on them.
I haven't heard about the appliance enamel before. I know it's very tough stuff, but I think the color selection is pretty limited...

[liquids]

You can get the pour-on epoxy clearcoat at select hardware stores and craft stores, but not just any store, in my experience.  I found "Envirotex" at the local Michael's craft store.  It can be ordered online too, but local will save you the spendy shipping costs if possible. "Easy Cast," "Crystal Sheen," and "Finish Perfect" are some other brands I found amongst others, though I've only tried the envirotex.  They're probably all very similar if not the same, Local Home Depot had something similar in the varnish area, but in a much larger quantity. Lowe's had nothing of the kind. Go figure.

I take this back....somewhat.  I gave the paint area a browse on a few recent visits to multiple Home Depots and Lowe's in other towns.  Seems that some do carry them, but it's a little spotty.  I've seen a few Home Depot stores carrying quart sizes of the same "Parks Super Glaze" made by Zinsser.  At one really new, huge Lowe's, they carried "Famowood Glaze Coat."  I can't speak for them, but they should all work about the same and are all clearly epoxy products for finishing woods, etc. 

As a side note, I've typically written off crafts stores as places to avoid carrying tones of things I despise  , but in addition to the Envirotex epoxy clear coat, Michael's seems to carry lots useful hobby supplies such as cans of testors spray paint, exact-o products, and other paint products I've liked so far.  They always have a coupon out for a good percentage off one item (40%-50% is not unheard of), it seems, so you can get the clear or some paint pretty cheap if you are a saavy shopper...

[Paul Marossy]

Actually, one of the best paint jobs I have done to this day was done with some Testors spray enamel. It seemed like it took forever to get fully cured, but it has been the most durable finish on anything I have done so far. In fact, I used it on my very first guitar pedal.

[bassmannate]

Cool. We've got a michaels near me. Maybe I'll keep an eye out for coupons.

Does anyone know if Testors is compatible with epoxy?

[liquids]

Cool. We've got a michaels near me. Maybe I'll keep an eye out for coupons.

Does anyone know if Testors is compatible with epoxy?

I did a coat of testors two (or was it three?) days ago, and that I did a "test coat" of rustoleum crystal clear enamel spray on the box's "lid" today to see if it would wrinkle, etc.  It took it just fine. Of course the coat of testors I did was, in effect, pretty thin since I dabbed it with a plastic bag for effect...so two or three days may be short--I don't know yet.  Patience is a good thing.  That being said, it didn't wrinkle, etc, but test for yourself given the variables...

You can do this epoxy clearcoat (which I will do next) over any paint, so long as it is fully dry AND will accept a 'recoat' as per the manufacturers instruction.  As a counterpoint, try painting, wait 2-4 hours (or 12 or even 24 with most paints) and spray a coat of even the same paint, and see what happens...wrinkle, wrinkle.  You have to read the cans for recoat times.  Sadly, though testors says almost nothing useful on the can.  Hence, I felt the need to test and experiment.  Three days air drying was enough for a light of testors to accept being 'painted' over.  Note that none of this involved heating, only air drying. 

So the testors will likewise accept an epoxy clear...any truly dry paint doesn't care, and neither does the epoxy.  Though, really, your best to be as patient as you can be with the epoxy, both in waiting to apply it after painting (3+ days) and while curing (2 days), to ensure both are truly dry before proceeding to the next steps. I guess I err on the side of caution, though...so YMMV.

But, so, in short, yes, you can epoxy over testors....

[Nitefly182]

I painted two coats of Testors candy green on a bare box about a week ago. Installed the footswitches last night and my wrench still left a couple small dents in the finish. The paint looks great but it sincerely takes about a month for those paints to actually cure. Maybe more.

[jacobyjd]

It's enamel! Bake it!

I'm going to give Testors a try I think--I'll be curious to see if it bakes as well as the enamel spray bombs I've been using.

[liquids]

What other enamels have you been baking successfully?  The rustoleum enamels I've used only take a day or two to air dry enough to recoat, but I've had issues when trying to bake the enamel the first time.  I had success with the rustoleum hammered and brush on polyurethane.  So many variables to know what the problem was....

But I thought rustoleum took a 'long time' to dry enough to recoat at 48+ hours....a week and the testors was still soft? Wow. I've seen a few here say the testor's takes a 'long time'...a long time is relative to the person waiting.  Two days is still pretty reasonable to me, but to me waiting over a week just ofr one coat is an unreasonable amount of time, unless the results are worth it.  Maybe we should start a new thread about testors spray enamel in particular...  Did you do a few light coats, or one/many big coat one that one that was still soft after a week?

I've realized I need a box exclusively for testing out primers, and paints, clears, baking, etc. I did this at first but had success right away, and stopped testing first.  Since then, I've had frustratingly mixed success with paints, and should get back to testing everything first. Besudes a little acetone and it all comes right off back to bare aluminum, especially if combined with a razor, sandpaper, and a 300 degree toaster!--gets any paint coat right off!     That much I've learned.   It would save me a lot of frustration and endlessly re-doing lids, hoping things wont get screwed up, and waiting on boxes I planned on being done by now...time to add a cheapo paint testing enclosure to my parts order list...

[jacobyjd]

I've been baking Krylon enamels, Rustoleum (I think), some fancy-pants brand I got at Lowe's (liked the color), and one Hammertone.

The oven I use is a REALLY old one (think 70's) with a temp control that goes down to about 170F. I usually bake at just under 200F if that helps.

It always gets a glass-smooth finish. I've had some chipping before, but only after heavy live use and banging around in my gear bag. Even then, the chips are tiny--no problems there. I don't really prime...I just sand with rough paper and wash with acetone, then spray and bake.

I usually bake each relatively thin coat for 30-45 mins.

[m-theory]

I've never once had any luck with baking.  I tried it a few times, had catastrophic failures that resulted complete stripping, and never went back to it.  It's pretty unnecessary anyway, imo.  I marvel at those who swear by it, but it just flat out did not work for me in any way, shape, or form, so I found ways to do this fairly quickly without that.  That said, however, I will add that, in every single instance in which I've had a failure of one sort or another, it's been essentially because I've gotten ahead of myself, and have tried to rush something along.  If you take nothing away from what else I say here, hold onto that thought.  You can NOT rush paint work and expect excellent results. 

As for paint products, this is one of the very few areas of discussion on this board in which I happen to be able to speak with great confidence, based upon a previous life in which I was a paint specialist in the auto refinish market.  There are a lot of misconceptions and confusion about paint in general, and I think I can help brush away some of that without getting too deeply into boring minutia.  Bear with me...this will almost certainly venture into tedious territory at some point...

First is a real nit-picky thing, but I see it a lot...non-catalyzed paints, which is any paint that has no hardening agent added to it, such as our beloved spray bombs, does NOT "cure."  "Cure" is the term given to the completion of the chemical reaction that occurs when an isocyanate hardener combines with the resins in a given paint formula (by that, I mean chemical composition, not color!) to literally create a molecular change with what was once a liquid product comprising of pigments, resins, and solvents into something not much unlike a hard plastic. 

What our paint does is "dry."  That refers to the evaporating of solvents in the product, to leave behind nothing but pigment and a hard version of the liquid resin that the product was built from.  Because our paints don't involve chemical hardeners, they can ALWAYS be "rewet," meaning that, in 100 years, you could soak a rag with thinner, lay it on your painted surface, and liquify that paint.  Want an easy way to strip a failed application?  Lacquer thinner on a rag. 

When we see a failure with these applications, it's USUALLY related to our hitting a previously coated substrate with another application of something, when that substrate is still "soft" underneath, and therefore susceptible to attack from fresh solvent.  This usually appears as wrinkling or "lifting," and the only way to really avoid it is to either recoat within and hour, or wait beyond the stated period on the can, often 7 days, for the vast majority of the solvents in the substrate to evaporate. 

For all of the talk about paint compatability, and there is something to be said for that, the fact is, as long as you're not pounding materials onto a substrate that's lying within that period after 1 hour and before the recommended recoat period of days, you can spray whatever over whatever.  I've never had a problem spraying lacquers over enamels or visa versa, as long as I'm not doing it when the substrate is vulnerable.  I wouldn't use that general rule of thumb in spraying cars, mind you, but we're not talking about cars here.  I also wouldn't spray a car with any non-catalyzed product, except self-etch or wash primer on the bare metal.  Every other layer should be catalyzed, for maximum adhesion and durability.

Here's a quick run-down on the three basic types of materials we encounter in spray bomb form, FWIW:

Lacquers - first developed long, long ago, as nitrocellulose material.  Not at all durable, generally dries VERY quickly and dull, and has to be buffed to shine.  Highly susceptible to solvent attack, as well as attacks from the elements, such as ultraviolet, gasoline, oil, farm chemicals, etc. 

Synthetic enamels (sometimes called "alkyd enamel") - This is pretty much all that Rustoleum has, as far as I know, although someone recently told me of a new line that they have that's claimed to be "fast drying."  One of the traits of this type of product is VERY slow dry times.  This stuff is VERY sticky, and stays wet for a LONG time.  At paint schools, it's often the product that produces the most impressive panels when students spray out, because it's very easy to get a terrific looking finish from it, because it flows out for so long, and tends to dry very smooth and glass-like.  This stuff is great for farm tractors and plows, because it's so darn sticky that you don't have to be real painstaking about the prep work.  Just wash the grease off and spray this crap on, and the ol' Massey is good for 2-3 years or so.  With a hardening agent, 5 years, probably.

Acrylic enamels - came about in the 60's, and were much favored over synthetics for the automotive market, because the dry time was significantly less.  The durability isn't that much different, although the slight edge would go to acrylic.  The real advantage was the dry time.  With significantly reduced dry times, an artist could mask off sections of a vehicle and paint multiple colors, for dramatic custom looks.  Nowadays, of course, basecoat/clearcoat systems make a mockery of those old school acrylic enamel dry times, but we don't deal in that world on these little boxes. 

The differences between these types of paint aren't due to anything more than brand name and solvent/resin recipie.  That's it.  The pigments are exactly the same, from one company to another, and from one paint type to another.  They ALL buy pigments from the same sources, for all of their paint lines.  The only exclusion is that some that contain lead are no longer allowed in all states, and even then, not in all paint systems.  What makes a lacquer a lacquer and an enamel an enamel is the type of resin and solvent used, and what makes one brand A and another brand B is nothing more than each companies specific recipie for those solvents and resins. 

For the sake of general knowledge, the most durable finish available today, in terms of "paint," would be a system that involves acid etching bare metal, either with what's called a "wash primer" or a "self-etching primer," following that with a catalyzed primer-surfacer, following that with a catalyzed primer-sealer, following that with a catalyzed base color coat, and finally, a catalyzed acrylic urethane clearcoat.  That's as good as it gets.  Again, it's not bullet-proof.  There's no such thing.  But, in terms of durability in the real world, the above-described "system" (and, it IS a system) is as close as you can get to it when applying colors. 

There.  Now you know more than you probably ever cared to about refinish products, but hopefully there's some tidbits there that you can put to use that will assist you in producing quality finishes on these boxes. 

[jacobyjd]

M--

You know your stuff

My mis-terminology aside, baking basically allows non-catalyzed paint to gas off more quickly than standard drying. From what I've seen, most people have trouble with baking because they're running at too high a heat. Lots of ovens don't go below the 250F-200F mark.

And no, you can't rush paint--but...for me, baking gets me there in a fraction of the time.

[bassmannate]

What about good adhesion to zinc galvanized steel though? Will I get good adhesion with just scuffing it up real good or should I use some sort of primer as a substrate for the paint? I guess that's my biggest question at the moment since I know that painting galvanized steel can cause problems. If just sanding the surface will give me good adhesion then great! That's one less can of something I have to buy since I already have sandpaper/emery cloth(did I mention I'm a cheapskate?) But if some sort of primer will do the job better then I would probably want to go that route. Seems that most of the self etching primers out there work best with steel and aluminum. No mention of zinc.