Galvanizing a chassis or part of (ie replacement outriggers)

[bsdnazz]

Having started to hijack pauldavies85 Upgrade list/ideas I thought I'd do the decent thing and start a new thread!

My Chim will need new outrigers in the not too distant future and I want to get them as well protected as possible and galvanization seems the way to go.

In the Paul's thread Mikly400 wrote:

Milky400 said:

there hasbeen a recent posting on zinc coating with pictures and plenty of opinions, looked awesome.

do a search to find the topic

I found malc_grn's Cerbera thread which is very interesting to say the least!

Reading through the comments on malc_grn's thread it's interesting to see the various comments:

• chassis cost about £75 to hot dip galvanize at McArthur Group Ltd, in Bristol
• McArthur's did not think distortion would be a problem due to the type of construction
• I doubt that McArthur's would take responsibility of there were distortion
• the extra weight of the zinc is low - an 80 micron coat is that not heavy
• extra holes need to be drilled into the chassis to vent hot air from enclosed spaces and let zinc in
• the chassis will heat up to approx 460C in the bath of molten zinc
• steel is annealed at 650 to 690C
• partial annealing of a work hardened chassis might even be a good thing!
• welding galvanized steel is a bit of a pain
• a fireman can strip a Cerb chassis in 3 days!
• it's worth coating the galvanized chassis - power, two part epoxy paint etc

Questions still to answer

• how bad could any distortion be? Could it be 'taken out' with a big lever?

I think I'm going to give hot dip galvanization a go.

I've had a couple of email exchanges with Ian at Sportmotive and he's happy to supply me some bare outriggers to take away, galvanize, and return to be fitted.

I see that the Galvanizers Association WWW site lists a couple of galvanizers in Stoke-on-Trent. One is a 10 min drive away, the other is 20 -25 mins away.

I see a plan forming...

[pwd95]

This has been done a couple of times now without any distortion. It seems to be the best solution if it can be reliably done. I wonder if some sort of bracing can be bolted to the chassis for the dipping process as a fail safe.

[constablergt]

HI had my chassis hot dipped about six months ago and then filled all the holes with quick steel to prevent the ingress of moisture. Then it has been powder coated on top for extra protection. I am now in the process of rebuilding slowly though. If you have any Questions fire away. Thanks

[CHGRIFF]

Remember, if you galvanise you will have difficulty welding at any future date if that becomes necessary.

[bsdnazz]

CHGRIFF said:

Remember, if you galvanise you will have difficulty welding at any future date if that becomes necessary.

As I'm probably going to be doing just the outriggers this problem will have to be addressed!

Looking around the internet it's perfectly possible to weld galvanized steel but a few precautions need to be taken. Mostly to do with vaporising the zinc, ventilation and preventing the weld from rusting.

A search on Google for 'welding galvanized steel' comes up with some interesting links:

• Sperko Engineering (pdf)
• Galvanizers Association

[constablergt]

bsdnazz said:

CHGRIFF said:

Remember, if you galvanise you will have difficulty welding at any future date if that becomes necessary.

As I'm probably going to be doing just the outriggers this problem will have to be addressed!

Looking around the internet it's perfectly possible to weld galvanized steel but a few precautions need to be taken. Mostly to do with vaporising the zinc, ventilation and preventing the weld from rusting.

A search on Google for 'welding galvanized steel' comes up with some interesting links:

• Sperko Engineering (pdf)
• Galvanizers Association

I had to do two small welds once it had been dipped it is not a problem at all. I had remove the galv from the area that i was welding then it welds like normal. As long as do all the repairs to the steel before you galv there is no reason why would ever want to weld the chassis as it is never going rust or corrode to the same extent. Once i had welded it used some cold galv (from a spray can) then it went into the powder coating oven to de-gas with some compond on it. After which it could be re-powder coated.
this is the current state but still off the road after 9 months sadly.

Edited by constablergt on Friday 25th September 22:16

[constablergt]

bsdnazz said:

CHGRIFF said:

Remember, if you galvanise you will have difficulty welding at any future date if that becomes necessary.

As I'm probably going to be doing just the outriggers this problem will have to be addressed!

Looking around the internet it's perfectly possible to weld galvanized steel but a few precautions need to be taken. Mostly to do with vaporising the zinc, ventilation and preventing the weld from rusting.

A search on Google for 'welding galvanized steel' comes up with some interesting links:

• Sperko Engineering (pdf)
• Galvanizers Association

I had to do two small welds once it had been dipped it is not a problem at all. I had remove the galv from the area that i was welding then it welds like normal. As long as do all the repairs to the steel before you galv there is no reason why would ever want to weld the chassis as it is never going rust or corrode to the same extent. Once i had welded it used some cold galv (from a spray can) then it went into the powder coating oven to de-gas with some compound on it. After which it could be re-powder coated.
This is the current state it is still off the road after 9 months sadly.

Edited by constablergt on Friday 25th September 22:17

[pwd95]

Do you mean off road?

P.S. where did you get the job done? did they 'blast' & dip in one process?

Edited by pwd95 on Friday 25th September 21:59

[constablergt]

pwd95 said:

Do you mean off road?

P.S. where did you get the job done? did they 'blast' & dip in one process?

Edited by pwd95 on Friday 25th September 21:59

Oops, yes thanks

[pwd95]

Be interesting to see the calcs on Galvanising for a TVR chassis compared to a Lotus chassis. The TVR Chassis seems to have all the neccesary bracing in place........Maybe a few bracing posts can be installed to stop any chance of warping......

[GreenV8S]

It's good to hear that people have been able to get their chassis hot-dip galvanised without problems, but the risk of distortion is still there - it's done at the owner's risk surely?

There is an alternative process using aluminium (I forget how it's applied, but it's done cold) which seems a lot safer. Aluminium doesn't offer as much galvanic protection as zinc but it's better than a simple passive coating and pretty tough too. There's also a zinc based paint (Zinga) although I don't know how effective that is.

[bsdnazz]

GreenV8S said:

There is an alternative process using aluminium (I forget how it's applied, but it's done cold) which seems a lot safer.

Googling around I've found references to aluminium electro plating, IVD (Ion Vapour Deposition) and hot dipping.

I do like the idea of zinc electro plating as it can be done cold but my Googling has yet to turn up a UK facility doing this.

The two things about zinc hot dip that worry be a bit are results of the heat. The potential for distortion and the need to drill vent holes to let out the air trapped inside sealed tubes.

It's a trade off between distortion and vents holes vs rust.

[bsdnazz]

Of course, havging posted this

bsdnazz said:

I do like the idea of zinc electro plating as it can be done cold but my Googling has yet to turn up a UK facility doing this.

I've now done this Google search for zinc electroplating and come up with lots of interesting looking results.

[GreenV8S]

bsdnazz said:

IVD (Ion Vapour Deposition)

That's the lad.

[saml666]

I will soon be visiting MacArthurs for a chassis dip, having had new outriggers made (bought some CDS tube for £140, replaced what needed replacing.

Before the dip it will go to surface processing ltd in the midlands where it will be thoroughly cleaned of rust, paint, grease etc. This will find any potential thin areas, leaving them clean to repair.

Will post some befores/after if anyone is interested. It won't distort, I'm feeling lucky

Cheers,
Sam

[bsdnazz]

saml666 said:

Will post some befores/after if anyone is interested.

Shock news - I'm interested!

[nawarne]

bsdnazz said:

GreenV8S said:

There is an alternative process using aluminium (I forget how it's applied, but it's done cold) which seems a lot safer.

Googling around I've found references to aluminium electro plating, IVD (Ion Vapour Deposition) and hot dipping.

I do like the idea of zinc electro plating as it can be done cold but my Googling has yet to turn up a UK facility doing this.

The two things about zinc hot dip that worry be a bit are results of the heat. The potential for distortion and the need to drill vent holes to let out the air trapped inside sealed tubes.

It's a trade off between distortion and vents holes vs rust.

I work in a refinery, and our preferred method of steel protection is now "Thermally Sprayed Aluminum". Local applicators are quoting a 25 year life for the coating, and this where duty can be salt water and/or reasonably hight temperatures.

Our inspection people are advocates of this system. However, having helped Richard on the Cerby forum (boosted cerb?) lift his tub onto the repaired and epoxy 2 pack painted chassis, I'd say this paint was pretty durable too!

Nick

[hiltonig]

saml666 said:

I will soon be visiting MacArthurs for a chassis dip, having had new outriggers made (bought some CDS tube for £140, replaced what needed replacing.

Before the dip it will go to surface processing ltd in the midlands where it will be thoroughly cleaned of rust, paint, grease etc. This will find any potential thin areas, leaving them clean to repair.

Will post some befores/after if anyone is interested. It won't distort, I'm feeling lucky

Cheers,
Sam

Keep us posted on this, would like to typical costs from surface processing, dont they zinc it for you ?

[saml666]

hiltonig said:

Keep us posted on this, would like to typical costs from surface processing, dont they zinc it for you ?

Just delivered chassis to SPL today, I also gave them all 8 suspension arms, engine mount brackets, various other stuff. Quoted £450 to de-grease, de-paint and chemically de-rust. Will see it again in 2-3 weeks hopefully.

They offer a process called E-cote, but at £700 + on top of the above I decided to give glav (under £100!) a go. As has been pointed out already, if it does warp I can still get it corrected on a jig and be quids in. MacArthur in Bristol say they've done plenty of TVR chassis though without problems. When we repaired the outriggers we compared measurements of various sections side to side ... ahem, quite different! So maybe a bit of warping in the right places will do it good?

joke!

OK, here's the bit that will make the feint hearted keel over right now though ... last night, ready for SPLs process and MacArthurs Galv I drilled something like 50 or more 5mm holes in my chassis! Apparently, at SPL, the chemicals WILL get past the welds so you need to allow the chassis to drain. I quite like the idea of de-rusting the insides of things though (TVR drilled a few holes for self tappers etc remember so it's by no means spent its life sealed) and likewise letting the galv process get everywhere too doesn't seem like a bad thing. Was careful to drill in a way that would minimise airlocks too and of course by having no sealed tubes expanding gasses within the tubes won't be a problem either.

Yeah, I have to upset some galv to weld the holes up again but at least I will be able to treat those welds with zinc paint from fresh and know that there really isn't a spec of rust anywhere on the chassis whatsover. Moreso than if I just blasted it.

So there it is, will post a new thread in a week or three (I hope) for the next steps.

Tarra,
Sam

[GreenV8S]

Rather than weld over the holes, there are standard bungs available that are often used for the job.