Classic cars forum & vehicle restoration.

[UKdave2002]

I have been told of a company called SPL Surface Processing who will take a panel or shell chemically strip it , de-rust and prime with zinc phosphate coat by a electroplate immersion process.

I'm thinking having the Morris E shell done, what your views and has anyone had experience of this firm ?

Cheers Dave

[Uncle Joe]

UK, obviously, I've no experience of this firm, but Zinc Phosphate coating is something that you should be able to do yourself - the products are easily available.

I've been trying like anything to find out if anyone has long term experience with the DIY coating, but without success so far! I do know though that this method has been around for quite a while, late '50's - early '60's, and therefore should be quite well known.

UJ

[chimpchoker]

[admin]

Whether its the same or not I don't know, but I was told many years back not to weld galvanised steel without cleaning it back first, as the fumes given off are a bit on the dodgy side...

Rick

[Uncle Joe]

Guys, though it is possible to weld through zinc, even pros try to avoid it. My own opinion is that it is not advisable for health reasons alone.

As regards the treatment, I did consider it a while ago using a local (to me) company, but discounted it when I realised the amount of disadvantages.

I'll be doing both a bodyshell and chassis myself shortly, but using one of two methods that are both cheaper and as effective.

UJ

[chimpchoker]

[UKdave2002]

[chimpchoker]

Alan[/quote]
I see your dilemma, if you weld anywhere near the zinc phosphate coating it will burn off and you have lost the benefit, no so bad if you can retreat the area, but as they apply the zinc phosphate as an electroplated coat, it will get in to all the box sections, nooks and crannies, which will be difficult to re-protect if you have to weld nearby.
The de-rust dip may expose some unknown corrosion, but shouldn’t make the structure any weaker, (if its corroded there will be little strength anyway).
I guess the most effective solution would be to do the welding first? is this is an option? Rust will start as soon as the paint is removed, if you do it in 2 stages you would want to do it quickly.

Have you asked SPL what they would advise (probably to do the whole thing twice!!)

I am in the lucky position that my shell needs no welding, I think I will do it, it has to be more effective than anything you can do at home (stand to be corrected here UJ!).

I’ll keep the forum posted with the results.

Dave[/quote]

I haven't asked spl the question but in the conversation the very helpful bloke said that the only parts that wouldn't be treated would be the parts that I had replaced or welded parts but that is quite a bit on mine I suspect. I've either seen somewhere on their site or heard when I spoke to them that the etch primer after the first dip / strip would be good for at least 4 weeks provided it was kept dry. My current thinking is to get a sander ( and very good mask) and taking off the paint at least as much as possible to see what bodge is on the body then getting rough quotes for panels / welding work etc then saving up the money for this and then taking it to be stripped getting the welding done then taking it back and getting it dipped and striped again followed by the zinc phosphate dip within the shortest possible time.

As the second dip of the rust removal will be light i'd hope for a substantial discount.

[Uncle Joe]

The way I see things are like this. Any method that can guarantee that all rust is removed is a good one. If there is still some rust left, then there is no way on earth it wont carry on spreading.

In chimpchokers case, the shell is going to be transported between Dudley and Hartlepool, a journey of what? Six hours? During that time, its could be subjected to anything that could start the rust again...and by rust I mean 'flash rust.' Then theres going to be the restoration time that will add to this.

On my bodyshell, what I intend doing is chemically stripping, neutralising, then sandblasting to Ra 12,5. Easy enough to do at home, plus it can be done in small sections, treating each one as they are done. I can expand on this in detail if anyone wishes.

UJ

[Uncle Joe]

Guys, I found this article when I was trawling, and thought that it might be of interest to you all. I'm not quite sure that it is exactly the same process, but anyway, it does give more food for thought. So lets hear some comments!

"I am interested to know if there is any disadvantage to galvanizing.

As for hot dipping vs gun spraying (called Schooperen in Holland,
after the inventor Schoop) vs electro galvanising:

- hot dipping applies the thickest layer, reaches every spot,
even on the inside, but gives the roughest surface, often with crud
nests of metal and 'drip tears'. Those can be sharp as a needle, so
watch out when you get it back from the dipper, and grind off that
crap.
- gun spraying is less rough, but has an relatively open surface, so it
*must* see an additional layer of coating. Most paint shops don't
like painting galvanized/zinced steel, so powdercoating is the best
option. Inside zinc application doesn't work.
- electro plating is the smoothest, but also thinnest. Best solution
for window frames, as mounting must be a pain with the rough
surfaces. This method also gives you access to gold plating....more
efficient than gold dipping....)

General disadvantage:
- welding galvanized steel seems to be quite bad for you health
- if you want to use method 1 or 2 for tubes or otherwise closed
steel, you MUST drill holes. Not just to give the zinc access to
the inner surfaces, but mainly to prevent it blowing apart in the
heat....)
There must be a number of holes, as they might get clogged with this
melt crud. When submerging into the hot tub, zinc has to have access
from below, and air has to be allowed to escape on top, and this is
reversed on the way out.
And if YOU don't drill those holes, then the guys at the hot tub
WILL, without mercy and with a torch. For them, everything is better
than a tube explode inside the hot tub....)"

UJ

[buzzy bee]

Hi

We have had stuff hot dipped, mot auto related items but other stuff and there are allways faults in the coating, where rust comes through very quickly, normally by the time the galvernisers delver it! I have had to weld a number of scaffolding poles in the past and it sure is nasty! I found that even after grinding the galv off it still is uncomfortable!

Cheers

Dave

[UKdave2002]

Hot dip galvanising is different to the zinc phospate process SPL use, which I believe is simular to what main stream car makers do these days. I did have a 1982 Prosche 911 SC some years ago, these have a galvanised body shell , but even so it suffered from corrosion when it was less than 8 years old! so not a significant advance !.

Dave

[buzzy bee]

Sorry I didn't realise it was different! All I know galved things still go rusty sometimes!

Cheers

Dave

[chimpchoker]

the spl version is electrostatic plated or something says he who is a technophobe.

Alan

[Uncle Joe]

I had another look at SPL's website, and found a PDF file describing the process. From the file, I see that they use a coating called Granoline.

This is a product made nowadays by Henkel, that was used on US Fords as far back as 1966. It was even promoted in advertisments of the day.

How good was rustproofing then? Could we state that the US car manufacturers were way in advance of the rest of the world, or could we say something else?

UJ