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D2 - Axles, Brakes, Suspension and Steering Brakes, Springs, shocks, steering racks, steering columns, suspension arms, wheel hubs etc.

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  #11  
Old 9th January 2020, 04:18 PM
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I'm a fan of POR15 too. I'm planning on painting the '65 Chev frame with it eventually. Very tough and it can be sprayed or brushed depending on preference.
You can also get zinc rich primers such as Galmet, for addition corrosion resistance.

Also not a fan of powder coating. It has one significant flaw, once it chips, it may as well not be there as far as corrosion is concerned!

If you're concerned about the heat, instead of hot dipped galvanising, you could use a sacrificial annode? Works for bridges and ships (and one fancy looking opera house in Sydney).
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Old 9th January 2020, 08:03 PM
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As it happens I once used to work as an apprentice in an aerospace electroplating company and once in a while we would get company's boses mates ask for their jag suspension parts to be cadmium plated.
We would first degrease them, then sand blast, then rinse and then leave in highly concentrated hydrochloric acid for 10 minutes (the stuff was so strong it would go through you if it dripped onto your body) and then it would get plated.
Hot dip galvanising is a totally different process but preparation should be the same.


I rang about for a few quotes and the cheapest I got was 900 for the single front subframe which is nuts!

I will ask my contacts in Poland maybe they can find a place that does it really cheap, but already this idea is starting to look very expensive and long winded.
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Old 9th January 2020, 09:00 PM
spannerrash spannerrash is offline
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900, wow! I didn't expect that. Well that is a real shame. I had almost convinced myself to get one done this summer and was actually looking forward to seeing how it turns out.

It's still cheaper than getting hold of a new one (rear) but that's a big chunk of cash. I was kind of thinking 400 or so. Guess it just shows I know nothing about galvanising.
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Old 9th January 2020, 10:17 PM
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Does Cadmium plating still exist? Extremely toxic isn't it?

We used to get blokes asking for "Cad plated" bolts when I worked in that industry.
What that usually meant was bright Zinc plate. But sometimes they specifically wanted yellow Zinc.
There was a belief it was a better coating. I was never sure if it was due to being fractionally thicker, or less reactive with the additional chemical treatment to turn it yellow, or whether it was just the placebo effect?
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2002 Audi S8 - Project
Replacement head coming arrived thanks to MJ
Silver with Black interior. All features as the '01, with the 'S' mode auto shifter. Dodgey rear tint (need to find a way to get rid of that).
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2009 Volvo XC90 V8 R Design
- has a louder more obnoxious exhaust than the S8, sounds great! Love this thing - Q7 was double the price, and certainly not double the car!

Sold:
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Old 10th January 2020, 08:29 AM
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Galvo process is a caustic bath, rinse, pickle, rinse, flux, galvo dip.
From memory the zink bath is around 500c

We know the areas they tend to go, and as they seam to rot from the inside out we can repair these before going to dipping to help prevent and distortion where it might be a bit thin.

And 1000 yeah right oh. We get charged on weight, A farm gate is heavier than a subframe and you can buy one of those for about 200 quid brand new, galvanised.
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Old 10th January 2020, 01:39 PM
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Quote:
Originally Posted by 27litres View Post
Does Cadmium plating still exist? Extremely toxic isn't it?

We used to get blokes asking for "Cad plated" bolts when I worked in that industry.
What that usually meant was bright Zinc plate. But sometimes they specifically wanted yellow Zinc.
There was a belief it was a better coating. I was never sure if it was due to being fractionally thicker, or less reactive with the additional chemical treatment to turn it yellow, or whether it was just the placebo effect?
Yes Cadmium plating still exists and yes it causes bone cancer, hair loss to name a few.

On its own cadmium plated components are light gray and you passivate them in chrome which causes them to go yellow. A 10um coating can whitstand 10 000 hours in a 60C salt bath which translates to many many years of normal use in a car without any corrosion as long as there's no mechanical damage to the coating.

Here are some pics of the jag parts before and during plating. Once again this was a one off favour for the company i used to work bosses mate:



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Old 15th January 2020, 03:09 PM
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I've spoken to another hot dip galvanising company who said they would not do the subframes as the holes in them are too small to allow for air to escape as soon as they are dipped in the 450-500C vat which would cause an explosion or deformation.

They also said the best course of action is to sand blast it then get it powder coated to a rough finish and then paint it with some proper boat paint for best result.

They also said that its the temperature shock which can warp and cause the subframes to crack and that ovens that poweder coats use heat up gradually to completley avoid this risk...

so it looks like a no go unless someone else has a better idea?
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Old 15th January 2020, 07:00 PM
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Quote:
Originally Posted by Ronin View Post
I've spoken to another hot dip galvanising company who said they would not do the subframes as the holes in them are too small to allow for air to escape as soon as they are dipped in the 450-500C vat which would cause an explosion or deformation.

They also said the best course of action is to sand blast it then get it powder coated to a rough finish and then paint it with some proper boat paint for best result.

They also said that its the temperature shock which can warp and cause the subframes to crack and that ovens that poweder coats use heat up gradually to completley avoid this risk...

so it looks like a no go unless someone else has a better idea?
I'm sure I mentioned that.

The holes issue is not a problem as long as there is a hole. I use a 6mm dia hole in 42.2 o/d heavy tube ships hand rails, drilled on the underside of tube right where its welded to the last stanchion. That hole is big enough to let the air escape as it expands. So the big holes in the subframe will be fine. Distortion however is another thing all together and I don't know how you'd control it. Still think a basic steel jig to check after, it would be interesting to try one. You can buy brnd new glavo chassis for a land rover be interesting to know how they manage it.

Marine paints need a full application to work, I have Jotun primer I use at home. It's thick and needs thinning to use, also goes off quick throw the brush away job. It's a zink rich primer and I rate it. Pop round with a jam jar or 2 and I'll fill them for you.
Top coats are all different, under the waterline ships use an antifouling paint, that would useless to you. Above waterline it rots fast, anyone that has been to sea on a ship will all say the same, its a constant battle. International, hempel, jotun all do good emamel topcoats but I really don't think it'll help the rotting from inside out.
Do what they do with Land rover chassis, waste oil and diesel mixed.
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