Hi
Just made some metal porch railings, most of which will be on a covered porch, but one piece will be exposed to the weather. We had them powder coated but I’m wondering if the finish would last longer if we put something else over that? Marine varnish? What (if anything) is suitable?
Thanks
smithy
Replies
I can't imagine much being more durable than the powdercoat if it's done right. There is clear coat for powdercoating...would give a "wear layer" of sorts.
PJ
Everything will be okay in the end. If it's not okay, it's not the end.
You said it, "...if it's done right." I have seen too many manufactured items that are powdercoated such that there are microscopic pinholes through which corrosion rapidly grows, eventually pushing off the entire coating. The problem is that as a consumer it is impossible to easily determine if a powdercoat job is any good...until it is too late.Bill
What actually is powder coating? - Anybody? I always assumed it was a glaze like material that was baked on - but never really thought about it that much...
Powdercoating is dry particles of coating material that are made to cling to the object so coated by electrostatic charge. The object with powder all over it is then baked to fuse the particles into a continuous coating. Dust that falls off in the application chamber is collected for reuse.The process is a beautiful one because there is no waste, no solvents are used, and the static cling works to ensure an even, complete coating.My guess about the bad jobs is that the object is not baked long enough or hot enough to effect complete fusion of the powder. It comes out of the oven looking good to the eye, but has microscopic pores through which corrosion starts. Careful spray painting works better than incompletely fused powdercoat.Bill
Thanks Bill.
The track record of powdercoating is so bad that a lot of companies advertise that their product is primed & painted and not powdercoated.
I have never seen anything with a powdercoat paint job last in the elements.
Look at powdercoated truck racks, tool boxes, snowplows, etc. etc. The powdercoat is peeling off in layers every place there is a weld. This is a process that was started to comply with environmental regulations, not to insure long term durability of the product.
All it takes is a little surface contamination or a few pinholes and you can watch your paint job peel off.
It works well if you are meticulous with prep and material. However, this is not the real world!
I'm glad I'm not the only one to see that the Emperor's new clothes are peeling off!In fairness, I have had an aluminum Weatherguard cross-bed toolbox on my truck for several years now. The clear powdercoat has only failed where it has been abraded off. I live by the sea, so aluminum can get gnarly in a hurry.My steel lumber rack advertised that it was wet-painted, just as you mentioned. It was seen as a desirable selling point by the dealer for the reason you outlined. The paint is failing miserably and I need to do something before the rust gets too bad. The paint failed where no contact with ropes or loads occurs. Wished I'd spent the dough on a stainless steel rack - type 316.I purchased both the rack and the toolbox on the same day at the same store. The moral of the tale is that workmanship always matters, no matter the process.Bill
Bill, I too put Weatherguard steel racks and steel boxes on my new truck. That was in 1995. The boxes were total rusted out junk in three years, with the powder coat peeling off in sheets. Weatherguard actually offered to completely replace the boxes, but I knew the same thing would happen again.
The racks were rusted badly at every weld. I took them off,sandblasted them, repainted with epoxy primer and two coats of good equipment paint, and they are on that truck today looking like the day I painted them. I would definitely go with stainless steel the next time!
I replaced the boxes with Weatherguard aluminum boxes (3 of them) and had a powdercoat failure in one spot at a weld. I called Weatherguard and asked them how to fix this, since it was about a year out of warranty. They sent me a brand new complete box lid at no charge. Now that is what I call standing behind your product.
Powdercoat on a new snowplow is a joke. It looks good for a few months and then the problem starts. In two years, you have a rusted out mess. I know many people who buy these plows out of the factory before they are powdercoated and spray them themselves with a good primer/enamel.
My experience has been 180 degrees of what you have been reporting. If powdercoating is actually applied correctly it takes a he11 of a lot to get it to fail.
In the past when I was working as an engineer I have saw a lot of companies try to claim they were using powdercoating when it actually ended up being just paint.
A dozen years ago or so I had my boat trailer sandblasted and then powdercoated by a company who wanted me to start using their services and it still looks great. Sure there are a couple of chips in the finish but unlike a painted finish corrosion doesn't get a foothold and start bubbling the paint off.
Surface preparation is everything, it has to be clean. When you painted your racks you didn't cut corners and the paint stayed on and so would of the powdercoating.
I have heard more horror stories about painted products than powdercoated ones. My old boss used to tell me stories about GM's primer and how he could just about just guarantee that the paint would peel on certain vehicles that were primed before breaks and painted after.
If I bought a product with the powdercoat peeling I would be more concerned on what other quality issued they have going on.
I agree that powder coat paint on a properly prepared surface works fine. The problem is that for products like I mentioned, there is always a certain amount of surface contamination ( rust is the main culprit) or areas (welds) where it is almost impossible to apply the coating properly, and this leads to failure.
This is the nature of that kind of business. They cannot afford to be meticulous about surface prep and unfortunately, powder coating requires just that.
I am not saying that powdercoating isn't tough, I am saying that the way industry uses it today is nothing more than decoration to get the product out of the factory.
As for GM and their paint jobs, I cannot believe that they weren't sued by a million truck owners. That gray primer with the blue paint was just horrible. The response from GM was that there was nothing they could do because the warranty period was over.
You will see that most of the top name manufacturers of trailers now advertise that their products are primed/painted in multi step processes rather than using powdercoating.
Can't think of anything more durable than the powder coat.
Anything you can paint on is going to require sanding to make it stick, sounds like marching backward to me.
Joe H
Powdercoating is generally the most durable finish. Can't imagine a benefit to adding a less durable product to it, and as it peels off will look terrible.
If you are really concerned, simply have the railings zink coated prior to powerder coating. More money.
Beer was created so carpenters wouldn't rule the world.