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Author Topic: Moke Coatings  (Read 178 times)

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Mission

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Moke Coatings
« on: May 07, 2020, 09:18:15 PM »
Split from this topic, https://www.mokeforum.com.au/index.php?topic=14008.0

Hi Sharks
I have had a question in my mind for some time re galvanized moke bodies and what is the truth, which your father's research might answer. The question is what really is meant by a galvanized moke. I take it your father was presented with the problem that REAL galvanizing badly warps and buckles thin metal even my 3mm plate trailer. So what did he actually have done as I believe that the so called gal moke bodies where actually painted with the then state of the art zinc paint ( like we can now buy from the hardware called cold gal) as a weak current was passed through it ( not actually dipped). As the metal in a moke is relatively thin I assume that any electrolysis method would not be very good for it. Do you know how he had it done by the electro platers and how has it lasted ?

 
Jim

PS    Does anyone know for a fact what was the process at the factory.
« Last Edit: May 08, 2020, 12:41:00 PM by Terry »

Sharks

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Re: Re: Moke Coatings
« Reply #1 on: May 07, 2020, 09:55:29 PM »
Hi Mission.

Dad actually had the Moke dipped in molten metal. Many years ago, after convincing Furphy's that he wasn't insane, the moke was lowered face first into the pot to the halfway point, taken out, turned around and put in again. It came out very wonky but slowly straightened out as it cooled.

Dad had to strengthen many parts of the moke and drill extra holes to allow the gal to drip out, otherwise it could have cooled improperly or exploded as the molten metal tried to escape. You can see from this old photo where there is extra square tube down the sides & a new support behind where the seats should be. If he did it again, he says he would support the area around the front grill and the back of the rear wheel arches too.


The regular post 1980 moke had bodies built from galvanised metal panels, as opposed to being completely dipped after the fact. I'm not sure how they were galvanised, but the coating is far thinner than the industrial coating that ours was covered in. Quite possibly was the zinc paint you speak of.

As for how it's held up - remarkably well. No rust to speak of - the rust that can be seen on the above picture was from other items sitting on the moke as it sat in the yard for years. It comes off easily with some scotch brite or steel wool. There are some minor warps in panels and blobs of leftover gal. By no means a perfectly straight & smooth body like it started out as. The bonnet has some little gal tabs on the inside and hits on the driver's side first when you put it down, so it's not perfectly straight. You can just make out on the photo above the fuel tank compartment how the forward hole is pushed slightly up.

The subframes were galvanised too, and have not warped but do have extra 'filling' in the corners. By no means a perfect finish but very durable, and that was the goal.

So yes - warped a little bit on the long straight panels like the bonnet or inside the side boxes, but still sits straight on the road & you wouldn't notice it unless you were up close & looking for it.
« Last Edit: May 08, 2020, 12:30:03 PM by Sharks »

Mission

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Re: Re: Moke Coatings
« Reply #2 on: May 07, 2020, 10:50:56 PM »
Thanks Sharks,
The photos of your moke shell do look like proper electro plating with that sort of silver flakey look. I bet your dad got some looks from the platers knowing it was going to buckle. As yours has buckled from the plating, this further adds to the myth of gal mokes, as you say they may be just zinc anneal sheet.
I am 11 months into a total rebuild of a 79 model that is now close to paint. Along the way with lots of the panels removed I realized that the seam that runs along the outer upper edge of the outrigger boxes is the main culprit of the rust in the moke. I have sealed them up and like yours have replaced the inside with box section.

Jim

Peter_n_Margaret

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Re: Re: Moke Coatings
« Reply #3 on: May 08, 2020, 10:56:33 AM »
Just a comment or 2...
Sharks Moke is "hot dipped" galvanised (into a bath of molten zinc).
"Electroplated" as the name suggests is an electrical plating process like chrome plating except using zinc instead of chrome. This would not cause so much warpage, but would also be a much thinner coating.
In the original "gal" process, the sheet metal would have been treated like this before the parts were made. Better than raw steel by a long shot, but still not as good as hot dipped because of the coating thickness and the manufacturing welding and other operations that 'spoil' the protection somewhat.

About the only thing better than the hot dip would be the stainless steel bodies made in Caloundra some years back.
Cheers,
Peter
New Moke owner. Lots to learn.
Exploring Australia in a DIY OKA motorhome.

Terry

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Re: Re: Moke Coatings
« Reply #4 on: May 08, 2020, 12:37:27 PM »
About the only thing better than the hot dip would be the stainless steel bodies made in Caloundra some years back.
You obviously haven't seen a SS Moke up close then. :)

In the 1979 Press Release for the 'Gal' Moke they used the term Zincalume when describing the new rust free bodies. And I asked someone into the history of all this and his came back with this from someone called Ron who used to work there.
Quote
I spoke to Ron who says that the coated steel was purchased as
sheet and then pressed and welded (at Enfield), with the exposed metal
being painted over with zinc paint. The bodies were then dipped in primer,
sealer and then colour coat applied. He can't remember the product, but it
was either galvabond or zincalume. Galvabond has that speckled appearance
while zincalume has a smooth finished like you see on mufflers and exhaust
pipes.

So while I remember the announcement said Zincalume the 1980 body I have here as a garden ornament is speckled so not sure who to believe. :)

There was also a fully powder coated Moke, in Blue, around 20 odd years ago that looked nice until you saw the warping in the lighter panels like the bonnet and top of the side boxes. They don't like heat.

Terry
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666: "No, I am the scariest number."
2020: "Hold my beer and watch this."

Cujo. 1999 - 2016

moemoke

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Re: Moke Coatings
« Reply #5 on: May 08, 2020, 07:59:06 PM »
Zincalume has a finer speckle than galvanising, gal mokes don’t look like zincalume.

I presume plumbing products use the same coating process but you cannot have gal down stream of zinc but you can have zinc downstream of gal, this means you can’t have galv gutters with a zinc roof but you can have zinc gutters with gal roof.
So if anyone has a gal body lying around get a bit of zincalume and prop it so rainwater runs off the zinc onto the gal, it will rust out in about 4 years that’ll prove its gal.
1976 Moke 1275cc (Dynky),
1976 Moke(Scarlet) current project,
1974 Moke with Suzuki GTI motor (project), 
1975 Moke rust bucket,
1967 Moke rust bucket