Trailer Hinges: How To Refinish

The hinges and other hardware for my trailer doors are rusting - again.

A few years ago I removed all of the hardware from my trailer doors (hinges, lock hasp, cam keepers, bar retainers, etc) and removed all the old finish and rust with a wire wheel on my bench grinder.

I then dipped all of the parts in a clear finish that was supposedly made to prevent rust. I'm pretty sure that the product was recommended in this group, but I don't have any left so I can't tell you the name. What I do know is that it didn't really last very long. When the parts were first coated, they looked great, but less than a year later the finish began to peel off and the parts started to rust again. Now, 3 years later the finish is cracked, crumbling and peeling.

The finish was like a thick coat of polyurethane, but I know it wasn't just polyurethane, it was something specifically made for coating metal that was exposed to the elements. When it was first applied, the bright, shiny metal showed through but today the parts are black where the finish hasn't peeled off and rusty where it has.

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So, short of replacing ~$100 worth of door hardware, what are my options for refinishing what I have? If I clean all of the parts again is there something that will prevent rust for a significant number of years? I considered spray paint, but I'm not sure how that would look. It's certainly not going to look like real metal.

Suggestions welcome. Thanks!

Reply to
DerbyDad03
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Hi, IMO, replacing whole parts with SS or bronze ones would be better. I don't have my fiver any more so those works are passed. GL,

Reply to
Tony Hwang

Cold galvanizing paint after thorough cleaning?

Reply to
Pete C.

Never heard of that, but just read up on it. Sounds like it might be what I am looking for.

D*mn, just got back from Home Depot...wish I had read your post first.

Reply to
DerbyDad03

Looking at your photo, I'd say that your cleaning job was less than stellar. Scale like that takes a while to develop; and as it does, it pops the paint.

I'd suggest you...

  1. remove hardware
  2. chemically/physically remove paint
  3. physically remove the rust & scale that is easily removeable
  4. remove the rest of the rust galvanically
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  5. paint immediately
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  6. top coat if desired

Neither that nor anything else will keep the hinges from rusting where one knuckle rides over another...whatever you put on them will eventually wear away. The only permanent solution is SS, bronze or brass (or monel, do they make monel hinges?). Including the pins.

Reply to
dadiOH

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I'm not sure how you came to that conclusion. When I was done cleaning the hinges and other parts there was absolutely no rust on any part. What I couldn't get with the wire wheel on my bench grinder, I got with my Dremel. I then wiped all parts down with mineral spirits before dipping them in the coating and hanging to dry. As I said in my OP, the parts were bright and shiny and looked great after they were recoated.

What's your definition of "a while"? I don't recall when I did them, but it's probably been at least 4 - 5 years, maybe more. Keep in mind that the finish started peeling off in roughly a year, exposing the metal underneath, so we're looking at at least 3 - 4 years of exposure in salt laden winters.

Just to make sure we are on the same page, they were not "painted" They were dipped in a clear coating made for metal that was supposed to prevent rust. I wish I could find/remember the name of the product, but I can't.

Someone else suggested the cold galvanizing compound. I've look into that and it will probably be the way I"ll go.

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Reply to
DerbyDad03

If your plannmng on keeping the trailer forever replace all the hardware with NON MAGNETIC STAINLESS,,,,,

Reply to
bob haller

Yeah that is probably the right answer

Electrolytic derusting will prep the metal the best you can if you want to try painting the old ones again

I like the idea of cold galvanizing paint. POR-15 is another option. However pretty much any good paint should work well if you electrolytically derust as the surface will not have any rust to spread and will have decent tooth for adhesion.

nate

Reply to
N8N

I don't know if I'd go to all the above steps, but agree in general with the approach. I was thinking wire brush off all the loose, rusted stuff and then use one of the Rustoleum primers designed for rusty areas, followed by two Rustoleum top coats.

Reply to
trader4

Thanks, but...and then what?

What would you suggest I use as a finish coat? Reading the instructions for the Cold Galvenizing Compound seems to indicate that any type of primer wouldn't make sense because you want the compound to interact with the metal itself.

It's not 100% clear to me yet, but it appears the CG compound can be applied over rust to transform it as well as hide it. Obviously loose, flaking rust needs to be removed, but apparently not all of it.

Thoughts?

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Reply to
DerbyDad03

You can make scale nice and shiny but it is still there. IME, wire brushing won't remove it, just shines the surface. The only way I know to get it off is to chip it off; a chipping hammer works well but any hammer and a cold chisel works too.

Reply to
dadiOH

Phosphoric acid is normally applied to shiny metal to etch it. It also converts light rust, turns it black. Additional converter can be added to heavy rust. Then primer. I normally use a self etching primer.

Greg

Reply to
gregz

Not arguing, just wondering...

Once the hinges and other parts were wire wheeled and smooth and shiny, there was nothing to "chip off", at least nothing visible.

Imagine 16" of smooth metal. What would I take a chipping hammer or cold chisel to?

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Reply to
DerbyDad03

The long and short of it is nothing you do will ever be permanent. You will have to clean and recoat every few years to keep the rust at bay.

In order for the paint/coating/whatever to "revent rust" it has to have 100% perfect preparation, 100% perfect adhesion, and can never ever get chipped dinged worn scratched in any way.

In other words, it's impossible. You will notice that when you read the guarantees on these "no rust" products: "We say it won't rust, but if it does it's your fault because you didn't apply the paint properly to a properly prepared surface."

All it takes is missing one little speck of rust in your prep, one little ding or scratch, and rust will soon take over.

Reply to
dennisgauge

Nothing at all if there were no scale.

Reply to
dadiOH

Ok, so now you've confused me. First you said my cleaning was less than stellar, to which I replied that it was nice and shiny. Then you said shiny doesn't mean no scale, the scale could be shiny and it needs to be chipped off. When I asked what I would chip off if the metal was shiny, you say "nothing if there was no scale."

So does that mean my initial cleaning was indeed "stellar"?

Reply to
DerbyDad03

I have no idea. There appears to be scale in your photograph; usually, it takes a fair amount of time to develop. If there were scale there before it could easily have appeared shiny after wire brushing. Was it there? I don't know, didn't see it. You did.

When I say scale can be shiny and metallic, here's what I mean...this engine has tons of scale but note particularly the area in the center near the bottom.

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Reply to
dadiOH

Ok, got it.

Take a look at this photo. One is a before, and one is an after. I may do a little more wire wheeling on the after, but what is your opinion at this point? Do you see anything that you would consider scale, as opposed to simply pitting?

This is basically what all of the parts looked like when I went through this exercise a few years (4 - 5?) ago.

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Thanks!

Reply to
DerbyDad03

I haven't read every post in this thread, so if someone has already made this suggestion, my apologies.

If I wanted to coat something steel so that it would last forever, I wouldn't even consider a paint or a clear coat. I would have it nickel plated at any shop that does chrome plating.

Nickel is a fairly hard metal, so even if these hinges have wearing surfaces on them where they rub against other metal surfaces, the nickel plating will outlast any other coating on that same surface. Electroplated coatings are probably the most durable coatings you can put on metal.

Nickel is an important metal in making stainless steels because, just like chrome and many metals, it forms an oxide film over itself that's extremely impermeable to air and water. So, the formation of that oxide film protects the underlying nickel from further oxidation. It's so thin, in fact, as to be invisible. That's why nickel and chrome don't appear to "rust". The oxide film they form is only a few dozen atoms thick, and light passes through it almost unaffected.

(Gold and platinum don't form an oxide film AT ALL. Most metals form some oxide film over themselves.)

In metallurgy, there's a general rule that when you mix metals, the properties of the alloy will be largely determined by the properties of the parent metals. So, if you mix a lot of nickel and chromium into iron, you get a steel that forms an protective oxide film over itself, just like nickel and chromium do. That's exactly what the various kinds of stainless steels are; iron with enough other stuff in it to make it behave like that other stuff.

So, if you can't buy stainless steel parts, the best alternative would be to have the ordinary steel parts nickel plated to give them the same self healing oxide film that stainless steel has.

Reply to
nestork

I've found with dipped coatings (I use a rubberized dip on pliers and other tools) you have to use more coats/dips than the manufacturer typically recommends. It's like paint, fertilizer or anything like that - they very often overstate the coverage to make the product seem more economical.

Once a pit or surface imperfection of any kind occurs, the corrosion process can work from the inside out. The thicker the coating, the more resistant it becomes to mechanical damage that can lead to corrosion. The obvious problems you face are that some items won't function correctly with too heavy a coating and as DadiOH pointed, mechanical wear may strip even the heaviest coating eventually.

You may have to save some of the coating material in a touch-up bottle and inspect the unit from time to time for signs of coating wear and treat accordingly.

Reply to
Robert Green

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