powder coating?

[Handyfarmer]

my understanding is powder coating is a plastic coating instead of a "paint",
and I know a lot of machine and live stock manufacturers are using it now for durability on there equipment.


first i have never powder coated before.
my understanding is one hooks up a static charge to the item sprays a plastic power on the item and then cooks it in an over to melt it on the surface of the item, at about 380 to 400F for about 15 mins,

is that correct?

ok I was able to pick up about 60 sheets of galvanized roofing about 20 feet long for $2 each, (yes used, in very good shape) plan on using on the shop and possible the house,

first this would be done before the tin was put on the roof,

considering painting it and the the thought popped in my head to "powder coat" for a longer lasting job,

to my understanding the oven would be my biggest problem,

my thought was something I could feed it in to on a slow conveyor belt chain and that section would be in the oven for say 15 mins at suggested temp,
possibly using a infrared shop gas heater that is over 3 foot long (have two of them if needed) , gear motor and some wheels (steel if needed to roll the tin on

would it work?

 

[Justind97]

Powder coating is done with a current attached to the metal. The powder is sprayed like a paint gun and then it gets cooked at 350 for 45mins or so.

This is not something that you can just do on your own, especially with roofing sheets.

 

[Old Man Roger]

Gaco makes a silicone coating that would work better than powder coating. You roll it on with a brush after the roofing material is installed, that way you are sealing the screws too. I suspect powder coating would lift, because the roofing material is so flexible. Plus you would have to screw through the powder coating.
https://www.google.com/url?sa=t&rct...oof-coating/&usg=AOvVaw37PoBnYcp3ykPjfX9qWusj

 

[laser3kw]

Powder coating is done with a static electric charge attached to the metal.

fixed it
one thing about powder coat on items exposed to the elements is it seems to flake off. Usually, a small disruption in the surface, air pocket, nick or defect allows moisture under it and the metal surface starts to rust. The powder coat then flakes off exposing more metal and more rust.
If you have galvanized, you may not have a worry.

 

[Handyfarmer]

Thank you for the words of wisdom.

 

[CJ7VFR]

fixed it
one thing about powder coat on items exposed to the elements is it seems to flake off. Usually, a small disruption in the surface, air pocket, nick or defect allows moisture under it and the metal surface starts to rust. The powder coat then flakes off exposing more metal and more rust....

This has been my experience with everything that I have ever purchased that was powder coated.

I bought powder coated step-up (Nerf) bars for my Jeep because everyone said how tough powder coating was, and how much better it was than paint for items that see hard use, and that it does not chip as easily as regular paint.

But within 3 months the powder coating on front part of the bars, that is facing the front wheels, had developed a few small chips. In no time at all the rust formed under the coating and huge flakes of coating peeled right off exposing so much rust underneath that there were actually holes starting to eat thru the metal.

I bought a small dump cart 3 years ago to pull behind my lawn tractor for doing chores around the outside of the house. It was completely powder coated from the frame to the hitch part, as well as the sides and bed of the cart.

And I never left the cart out in the rain or exposed to water or moisture. I stored it in my shed after every time I used it. But now it has so many areas where the powder coating has flaked off, and the metal underneath is starting to rust, that my project for this winter is to strip off all the powder coating, fix the rust, and prime and paint the entire cart.

Just about every tool I have that has powder coating on it also has spots where the coating has peeled off and the metal underneath is starting to rust.

I don't know if it is just me, or what, but I hate powder coated stuff. Not a single item that I have that is powder coated, and actually gets used for it's intended purpose, has had the coating last, or has held up to even the slightest use.

And these are all products from cheap to expensive in cost, and from all different manufactures.

Jim

 

[MrSurly]

This has been my experience with everything that I have ever purchased that was powder coated. <hear, hear!>

I bought powder coat
<snip> because everyone said
<snip> how much better it was than paint

<snip> huge flakes of coating peeled right off
<snip> the powder coating has flaked off
<snip>I don't know if it is just me <It's NOT!!>

I 100% agree.





Jim

I don't know why, I have never applied it, claim no expertise about it, but the ballyhoo that I've heard about how awesome the stuff is falls on deaf ears for me.
Mfr's would claim *It's Powder-Coated!! It will last like forever! *
I guess I haven't seen enough side-by-side comparisons and maybe its just because powder coat fails in such a particular way... but it sure seems to me that it ain't what it's 'talked up to be'.
Look at lawnmower decks. Those John Deere Lawn tractors that are everywhere... I've seen examples of those with powder coat flaking *in front of the Lowes*

Sorry, I've been wanting to rant about the stuff for a while...

 

[Old Man Roger]

I don't know why, I have never applied it, claim no expertise about it, but the ballyhoo that I've heard about how awesome the stuff is falls on deaf ears for me.
Mfr's would claim *It's Powder-Coated!! It will last like forever! *
I guess I haven't seen enough side-by-side comparisons and maybe its just because powder coat fails in such a particular way... but it sure seems to me that it ain't what it's 'talked up to be'.
Look at lawnmower decks. Those John Deere Lawn tractors that are everywhere... I've seen examples of those with powder coat flaking *in front of the Lowes*

Sorry, I've been wanting to rant about the stuff for a while...

Back in the day the stuff was amazing. I've had some 80's Honda street bikes that looked like new. Sometimes the old saying ''They don't make it like they used to'' really is true.

 

[CJ7VFR]

...Sorry, I've been wanting to rant about the stuff for a while...

Me too.

I have never seen for myself anything that was powder coated where the coating lasted very long. It might last a few months maybe. But never years, and never, ever on a product that sees any type of actual usage.

My small dump cart that I bought actually had the powder coating start to flake off in huge pieces on the underside of the dump bed just a month after I bought it! The underside never saw anything hit it, or scrape it, or anything like the actual inside of the bed. I figured that the inside of the bed, or the sides, would start to flake first, but it didn't.

I have metal things that were properly prepared, cleaned, primed and painted that are outside all year long, in all kinds of weather conditions from rain to snow, to heat and cold, and years later they still look good and the paint is not peeling off.

I could not even imagine what these things would look like if they had been powder coated and the coating got a small bubble or chip in it and the rust started to form under the coating.

Does anyone have an example of a metal tool or vehicle frame, or something that has been powder coated, that has been used in all types of weather conditions, that is still holding up and is not all flaked up and rusted? I would love to see that so I might change my mind about powder coating.

Jim

 

[Old Man Roger]

Now that I think about it, I've had a bunch of Honda products from the 80's that held up great. I've had a few Honda odyssey dune buggies and a few Honda 50's that looked like new. Somethings changed with the newer stuff though.

 

[Jinks]

I doubt a "roll-through" oven would work. For something that large you would need a large oven, but they aren't all that hard to find. The ornamental welding shop that fabricated my porch rails has one. Some of those sections were 12.5 ft. long. They did some HUGE gates for a mcmansion down the street that were too big for even their oven, so they borrowed a bigger one in the next town north of us.

Having a local shop do the coating for you might be more than you want to spend, but it's worth looking into...........

 

[Old Man Roger]

Would it even stick to something galvanized?

 

[OldNeons]

You can powder coat galvanized, but you can likely buy new roof tin for what you'll have in this by the time you mess around coating it, and you'll likely never duplicate a factory finish like what comes on new roofing. I'd use it on the roof as is (galvanized), or find another use for it and get new roofing.

 

[matt_i]

My take is the manufacturer of new roof tin has a megabuck investment in their paint product and process, a staff of technical people dedicated to improving it. I see 50 year warranties offered with new metal roofs, so its not a fly-by-night thing. If you can duplicate that level of performance in your own shop then its time to put out a sign and start shipping product!

That roof tin could be used somewhere, but personally I don't want to mess with roofs any more than I have to. I want to do the best job that I can so I can actively plan around getting the most of the 30+ year time window. But to get there imo one needs the best materials to start with.

 

[maxpat82]

most powdercoater will sandblast the material to garantee a good adhesion of the powdercoat.

I doubt it will ever worth it on roofing sheet.


20' oven isn'T an issue...my uncle have one that he powdercoat car frame and such.

 

[d19h]

Powder coating is similar to paint in that it's all in the prep work. Powder coat can be very durable when the surface is prepared correctly or it'll flake off in 10 minutes just like paint. I would think that purchasing roof panels from a company would be a better option. Whether you choose paint or powder coat, if the manufacturer stands behind their product with a warranty/guarantee, if it's good, it'll last.

 

[StingRay]

If you have a substrate that corrodes or degrades and you manage to perforate the coating and moisture gets under, no matter the coating, it will fail eventually. Heavier coatings like powder will trap stuff under it until it comes off in chunks. If you have corrosion inhibiting coatings where they have galvanic protection as a part of the chemical mix then your survivability is better. Galvanic coatings like zinc and aluminum protect even when breached but then the coating is sacrificial. Certain epoxies and the like have some galvanic properties. Powdercoatings are generally epoxies and polyesters and some hybrids. Essentially the same chemistry as paints. They apply differently but are subject to many of paints limitations. How you prep for paint or powder matters. The best prep will have a conversion process as the beginning that leaves behind iron phosphate or even better zinc phosphate. It will act like a really thin galvanizing and give the surface very good adhesion properties.

With powder it should be cleaned, blasted, baked and phosphated. It can actually have a high zinc primer powder coating as a first coat that will enhance corrosion resistance. lastly a properly cured top coat powder.

Any very sharp corners on parts should be softened prior to coating or the coating will fail at the sharp edge. Likewise ALL surfaces and edges to be coated need to be blasted, sanded, tumbled or abraded in some manner to provide a suitable profile to adhere to. On laser cut parts shiny edges often get missed and are the first place to fail.

 

[ForceFed70]

Agreed, it would be cheaper to buy new roofing sheets.

For large items, many use infra-red heaters to heat the item hot enough to melt the powder. You could use this approach for roofing panels but it would be a very time consuming task.

 

[readhead]

Manufacturers brag about powder coating their products but it really is about EPA requirements. There aren't nearly the hoops to jump through as there are with wet paint and the solvents that go with it.

 

[isb cornbinder]

Manufacturers brag about powder coating their products but it really is about EPA requirements. There aren't nearly the hoops to jump through as there are with wet paint and the solvents that go with it.

good man. You have that so right. The company I worked for had powder coated components that were exposed to road rash. The coating failed like regular paint. Regular paint can be repaired, powder paint, not so much. The problem we had was moisture getting under the powder/plastic coat and rusting the steel through in a surprisingly short time. For powder coat to last it take much more clean surface preparation. If you neglect the super clean surface preparation, the coating will fail and fall off in flakes.
The plastic coating has the ability to retain moisture, just like a ZIP-LOC bag. We experienced rust through of 5/16" plate in as few as 30 months.
The only place that I used powder coating was on the cast grill parts for my 1940 Ford. these cast zinc parts are notorious for off-gassing and lifting the chrome plating and leaving pitting.
I bought new cast grill parts and headlight bezels from Bob
Drake Reproductions. I glass-beaded the chrome off and detailed the parts. I got the parts primer powder coated so I could have these parts painted to match the body colour. I had the power coater heat cycle the parts about 6 times, over a work day to de-gas the castings, then apply the power primer in the last batch.
This worked out really well, for me.

 

[CudaChick1968]

"... The powder ... gets cooked at 350 for 45mins or so. ..."
​

This is why the internet can be dangerous. If you really don't know, don't type. Someone will believe it, and that's how rumors get started.

As with pretty much any industry, most commercially available items you purchase that were powder coated by a manufacturer are VASTLY inferior to a job that was properly done.

d19h up there stated it perfectly: Prep is EVERYTHING, and if it isn't done right (or, in some cases, at all) the finish will fail sooner rather than later. The powder that flaked off in sheets as oft-repeated above to reveal rusty / corroded metal underneath is sadly the norm instead of the exception. It occurs because the powder finish was applied over a dirty, oily (CNC / machine / etc.), raw and/or UNBLASTED substrate. The powder needs "tooth" to adhere to the metal and effectively bond with it rather than ride on top of it.

My most recent example is this factory coated aFe air box. Check this thing out -- https://afepower.com/afe-power-51-10661-magnum-force-stage-1-pro-dry-s-cold-air-intake-system

With an MSRP of almost five hundred dollars (!!!!!), this is what you get after just a few years under the hood not even exposed to the elements (please excuse my awful cell pics -- it's a POS phone lol):








Look closely at the last shot and you'll notice the shiny area revealed when I lifted the big flake. This alone shows the metal was never blasted, and probably wasn't very clean either, before it was powdered and cured most likely on a conveyor assembly line such as that mentioned by the O.P. about the roof panels.

Anyway, the whole point of my post is to ask that you not judge and convict the entire industry based on the flakes falling off of your 6 month old welding cart. Powder coating really IS beneficial to wet paint in several ways (environmental especially), but the job has to be done right.

If you think it's expensive hiring a professional, just wait til you hire an amateur.

I hope @mziggy will see this thread and jump in with some feedback on his air box now. He mentioned it will likely outlast the truck.

 

[laser3kw]

Thanks for the incite Cudachick.
I worked part time at a small shop that manufactured go karts. They did powder coating and I got to see first hand how they prepped the karts. It went something like this:
welded frames came to a wash bay where they were de-greased and dried.
Then they were prepped with a acid wash to produce the "tooth" you spoke. Metal with the factory skin just will not take right.
Then they are dried again, in the oven on low.
Then they are painted, where after they were baked.
All that work did give an exceptional nice finish that held up well to the bumps and bruises of racing or yard kart abuse. Didn't really ever here ay complaint about the finish peeling or rust.
But other stuff I see, no so much. The picture she shared are typical of what most people experience with "powder coating" sadly.

 

[Mziggy16]

Leanna is spot on. Powder coating is AMAZING when done correctly. I can't emphasize the "when done correctly" enough.

I familiarized myself with powder coating last year when I was refinishing a childhood Tonka truck for my son. The first truck I did got the primer and rattle can treatment. Looked amazing day one. But after 6 months of wear it was pretty chipped and just not the quality I had hoped for.

So...I did some research and was enthusiastically pointed to powder coating. Easy, right? Wrong. I went through TONS of failure before Leanna was so kind to help me understand how important prep work is. Long story short, I have 3 more Tonkas that are now 8 months into getting beat up by a 2 year old and they still look like new.

BUT, when it came to my personal car (air intake shroud), I didn't even hesitate - time for a pro. The stuff Leanna does, and any true professional powder coater does, is far superior to a coat of regular paint. The difference between just a decent powder job and an expert is oceans apart. It's all in the prep work. Anybody who tries to shortcut it will end up with a sub-par finish and, eventually, flaky paint - it'll look good enough to buy, but you'll pay later.

If you have something that you want to truly last send it to a pro. I'm a highly satisfied customer of Leanna's and I would enthusiastically recommend you send her anything you want done perfectly.