Rust/Corrosion cause, repair, future prevention?

Submitted: Saturday, Oct 31, 2015 at 13:46

ThreadID: 130748 Views:3461 Replies:5 FollowUps:11

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Member - Sam39

Hi, we have recently returned from a 5 month trip through mainly North Western WA and Northern NT. We did approximately 20000km with an estimate of 5 thousand on dirt, rock and sand roads of all descriptions before our return to Melbourne. Overall a great way to spend winter.

Towards the end of the trip I started to notice some corrosion on various parts of the galvanised pieces of the tray which to me look like surface rust. The corrosion appears pretty much the same on both sides and appears to me mainly in the line of the wheel spray. We took precaution around salt water to rinse the splashed areas but I am unfamiliar with what has happened to our tray. We have a slide-on camper that goes on the back so we are not towing anything.

The vehicle and tray is only 14 months old and I would like to do many more trips. Could this be a warranty issue? I took it to the place that makes the trays and they said they hadn't seen anything like it (the tray is alloy with steel sides). They said that they thought the best way was to replace the damaged pieces as they would provide them pretty much at cost.

As I haven't seen anything like this before, what is the likely main cause of this damage or it is normal wear and tear? See photos below

What would be a good way to get it repaired? I am planning to get the ute detailed at some point soon to bring it back to life as best we can. Are their detailers that could repair this type of damage or should I maybe talk to accident panel beaters who are used to bringing cars back to life. Which order should I do the work in, fix the tray first or get it detailed first.

How would we prevent this type damage in the future on another similar trip as we defiantly hope to do a few more?

I assume it will continue to get worse if we do nothing. As you can probably tell I am very unsure of how to address the problem so any assistance will be most appreciated or any suggestions of places to go in the inner north or west of Melbourne would be great.

Inside front wheel arch

Rear wheel back of mud flap and tray support

Rear wheel front arch

Rear tail light mount on tray

Post at front of tray

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Reply By: Member - peterdre - Saturday, Oct 31, 2015 at 15:01

Saturday, Oct 31, 2015 at 15:01

Had a similar appearance on the leading edges of aluminium framework on a camper trailer when we travelled Savannah Way a few years back. Looked just like rust, but couldn't be rust on aluminium!. Got it off with a No 2 cutting polish, but took a bit work.
Your steel work on the tray looks like "gal tube"?
Suggest you try a small area and see if it comes off.
Pedro

AnswerID: 592184

Follow Up By: M&N's - Saturday, Oct 31, 2015 at 15:29

Saturday, Oct 31, 2015 at 15:29

Hi all Could it be Kimberly/Pilbara red dirt/dust stain ,try truck wash and elbow grease might need to apply a few times good luck mickb

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Follow Up By: Member - Sam39 - Saturday, Oct 31, 2015 at 15:54

Saturday, Oct 31, 2015 at 15:54

When we washed the camper, we tried some car wash and rinsed off with the gerni and it didn't seem to make much difference other than removing the dirt. The ute hasn't been thouroughly cleaned yet so there is still a bit of dirt in places, we did have a decent crack at a couple of the corroded places as I want to see if the car wash and gerni would move it.

It definitively looks corrosive, a mate has offered to lend me his gear to buff a bit off and see what happens but I haven't got around to this yet. Its only on the gal surfaces and not all of them,

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Follow Up By: AlbyNSW - Sunday, Nov 01, 2015 at 09:43

Sunday, Nov 01, 2015 at 09:43

The red staining is rust staining from the high iron content of the dust
You can often clean it off or greatly improve the appearance with an oxalic acid based cleaner like Rustbuster or similar. Chemtech chemicals makes one and is or was available at Bunnings in the cleaning products aisle.
The rust is not structural and is not your tray components base metal rusting only the dust on the surface tarnishing the appearance.

Oxalic acid is what is used to remove rust and tannin stains from brickwork, timber and other masonry surfaces in the construction industry, it is also used on fibreglass boats to remove rust stains as well
It is not an aggressive acid like hydrochloric acid but it is a corrosive chemical and needs to be treated with respect

A quite like seeing the red staining on my vehicle, it is a great reminder of the good times had in the outback ??

As a side note, my car detailer uses a water based degreaser to remove the red dust stains from the black rubber around your car windows and doors with great success too.

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Reply By: Whirlwinder - Saturday, Oct 31, 2015 at 15:29

Saturday, Oct 31, 2015 at 15:29

Sam,
I have the same on our Kimberely Kamper. It seems to be a reaction between the iron in the road dust, especially where you have been, and the galvanised steel or aluminium and is difficult to correct. I say correct as it is a chemical reaction not just a deposit on the surface. I have tried on ours with no luck but if you are successful please post the details,
Good Luck.
Ian

AnswerID: 592186

Follow Up By: Member - Sam39 - Saturday, Oct 31, 2015 at 15:59

Saturday, Oct 31, 2015 at 15:59

What did you try on yours without sucess? I will definitely post if I manage to solve it.

The guy I spoke to at the place that makes the trays seemed to think it was a chemical reaction to something on the road but he didn't know what, his guess was something acidic.

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Reply By: The Bantam - Saturday, Oct 31, 2015 at 16:25

Saturday, Oct 31, 2015 at 16:25

First thing you must understand is most of what you are seeing is dirt ....... it may be chemically adhered dirt but it is dirt all the same.

second thing you must understand is most types of plating are sacrificial coatings, in that they are sacrificed to protect the undelying metal.

Third the material I am seeing is all sheet metal, it will be relativly lightly plated on the flat surfaces, the edges will be raw unprotected steel where they are cut.

All of the above is normal.

If you have been in an area with high iron content in the soil, you have basicly been driving on rust ........ you may well find if you have been driving on iron bearing dirt and combined with moisture and or salt, this may A/ accelerate the deterioration on the plated surfaces considerably, B/ may cause the irin bearing dirt to adhere chemically to the plated parts such that it wont just wash off, not even with some pressure cleaners.

what do ya do about it ...... well, it depends on if you are more worried about apperance or mechanical integrity .......... there are vehicle that have been in this environment for a very long time without developing actual problematic corrosion ..... most simply would not worry.

If it concerns you, the vehicle needs to be scrubbed to get rid of the adhered dirt, and then see if a problem actually exists .......... If the light plating on these parts has actuelly been erroded, the best bet is to get it back to clean sound metal, be that bare steel or remaining plating, and paint it with an anticorrisive paint such as Galmet Duragal, which I have had excelent results with.

remember pretty much all plating is a sacrificial coating ....... appropriete paint will provide better protection in all casses.

cheers

AnswerID: 592187

Follow Up By: Member - Sam39 - Saturday, Oct 31, 2015 at 16:49

Saturday, Oct 31, 2015 at 16:49

Thanks, I am not overly concerned about the appearance, the only time I might be concerned is if I ever want to sell it which hopefully will not be for many years. At that point it maybe probably worth replacing the worst bits.

From your post I think you might be saying to get it cleaned up properly which may include some buffing and see what problem I am left with. Any idea of the types of places that would do a good job at this?

I guess the main concerns are structural integrity and it getting worse now that I am out of the environment of salt, iron dust etc. Will it continue to corrode away?

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Follow Up By: wholehog - Sunday, Nov 01, 2015 at 06:57

Sunday, Nov 01, 2015 at 06:57

Excellent post Bantam..I had a similar occurance with gal plated sheet metal protection covers on water tanks etc on a Tvan that we spent a few months in..on the Pilbara red dirt areas.

Its no big deal, just more cosmetic to the very particular eye and lack of understanding by many of us. I was the same.

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Follow Up By: Member - DingoBlue(WA) - Sunday, Nov 01, 2015 at 17:43

Sunday, Nov 01, 2015 at 17:43

Galvanising is used because it is far more durable than anti corrosive coatings. Galvanising electro plates almost pure zinc onto the steel subsrate which gives excellent adhesion and sacrificial protection. Anti corrosive coatings such as dura gal are also sacrificial, using zinc particles encapsulated in a resin binder. Anti corrosive coatings rely on mechanical adhesion to the substrate and do not have the same sacrificial efficiency as pure zinc galvanising as each zinc particle is coated in resin which inhibits the electron flow.
If your galvanising has worn through to the steel underneath, the steel won't rust immediatedly due to the surrounding zinc sacrificing itself to protect the steel.
The area where the steel is exposed should be cleaned down and then a zinc rich coating such as duragal applied. As the coating is not as durable as the original galvanising, touch up may be required after each trip.

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Follow Up By: The Bantam - Sunday, Nov 01, 2015 at 23:17

Sunday, Nov 01, 2015 at 23:17

let me tell you, the right paint, beats plating every time, ( that is whay they paint boats) and I can tell you from first hand experience that a good film of Duragal out lasts the galvanising you will find on sheet metal hands down, it will even give hot dip a run for its money in some circumstances.

The Galmet Duragal product is not a sacrificial coating...... it is a full system metal fortified paint.
It is not to be confused with cold gal products .... Galmet also make a cold gal and a very good one.

This is because the binder as you call it is more than that, in duragal it is a whole paint package and a pretty durable one ..... the resin which BTW is a single pack epoxy like, killrust or many marine paints..... keeps the moisture and the chemical action off the parent metal and also off the metalic content of the paint ..... the paint therefore has to break down before the metalic content becomes sacrificial. .... the metalic content in turn has to break down before further resin breaks down. .......there is also more than zinc in duragal .... it is more like a modern version of Silverfrost than cold gal.

The theory if sacrificial coatings is all fine a beaut ....... but they remain sacrificial and they do get erroded very quickly in certain circumstances.

Put a piece of gal plated sheet metal on an acidic soil and add some moisture and the plating will be attacked and gone within weeks.

Throw a piece painted with duragal right next to it and it will be fine many months or even years later. ...... in fact thow a piece with any good sound paint on it and it will be fine months or years later.

I have done a lot of work with the Galmet Duragal product ..... and it stands up very well even with regular salt water immersion as in a boat trailer.

And it works very well over galvanised or zinc plated surfaces, especially those that are heavily weathered.

cheers

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Follow Up By: Member - DingoBlue(WA) - Monday, Nov 02, 2015 at 09:01

Monday, Nov 02, 2015 at 09:01

I've only spent 50 years in the manufacture and application of anti corrosion coatings, electroplating
Metallising and cathodic protection so will have to bow to your superior knowledge Bantam.

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Follow Up By: The Bantam - Tuesday, Nov 03, 2015 at 11:26

Tuesday, Nov 03, 2015 at 11:26

Face it..... the components on this vehicle have been lightly plated because it is cheaper than doing a propper or any paint job, not from any thaught of superiour corrosion protection.

And if you are from the electroplating and cathodic protection industry ( of the zinc mind) I have no doubt you believe that is superiour to painting.

But paints have moved on in the last 50 years. ... There are some very good products out there that outperform plating in particular galvanising hands down. ...... most importantly they are not sacrificial coatings.

I have over 10 years of personal experience using "Galmet Duragal", and on work that I see regularly and have been able to observe closely over the period.
I have seen it in comparison to several cold gal and zinc rich sprays that I have used before and since, there simply is no comparison, ....... because it is not a sacrificial coating.

Yeh I have head several people complain that Duragal does not perform well or last ....... my conclusions are .....

# that they have not seen it applied correctly ...... it is very often slashed on to cover welding with little or no preparation and in only 1 thin coat ........ enough to get the job out the door.
# that they are not using the Galmet product ..... I was sold a tin of competing product that I was asured was the same ...... not even close
# that they have never used the product at all....
# that they conclude that it is like some other product that they may or may not have used without actually using or knowing about the Galmet product.

Where I have found duragal to excell is in overcoating deteriorated or worn plated surfaces ....... this is exactly the OPs problem.

Particularly when used over aged galvanising it provides way superiour performance to hot dip galvanising alone....... because it does not allow chemical action direct on the galvanised surface.

cheers

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Reply By: Member - Odog - Sunday, Nov 01, 2015 at 09:10

Sunday, Nov 01, 2015 at 09:10

We have the same thing on our camp trailer, seems mainly on the galvanised bits, the gal stone guard frame, and the gal latches... Have tried using like a steel wool type thing, doesn't want to come off. Seems to be in areas that have copped a bit of spray from rear wheels.. Definitely not rust, but looks like it.. Have heard once you have the red dust stain, never get rid of it.. Cheers Odog

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Reply By: Member - Sam39 - Sunday, Nov 01, 2015 at 19:12

Sunday, Nov 01, 2015 at 19:12

Thanks all for your replies, as it doesn't sound like I am likely to have a structural issue I will get it detailed and see what sort of a problem I am left with.

At worst it sounds like I might have a shade of colour that isn't often seen around these parts which is certainly isn't a bad thing. Will it continue to get worse if I do nothing now that I am out of that environment?

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Follow Up By: Member - DingoBlue(WA) - Monday, Nov 02, 2015 at 18:58

Monday, Nov 02, 2015 at 18:58

You can use 'Galmet Duraga'l which is an aluminium based coating which is designed to look like Duragal steel. This will tend to hide the red discolouration. Check the underside of your guards etc to see if the galavnising has worn through. If so, then application of virtually any coating will inhibit the development of rust by encapsulating the steel and stopping moisture and oxygen from causing corrosion.
As I mentioned previously, no coating is as durable as galvanising so will need to be touched up after each trip.
trust this helps.

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