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So has anyone done it. I am thinking of polishing the chassis in the engine bay area. I started cleaning it up today and polished an area. Looks good albeit hard work. Will it make the chassis more open to the elements etc.

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No metal specialist mate but sure that will remove the galvanise! Not a good idea as the exhausts are near the chassis and will promote rust mucho fast me thinks! Would look the nuts though but very hard to keep clean and will be extremely time consuming! just my two pence

Regards danny

Edited by silverfrost

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I did the chassis hoop, lower links and drive shafts a couple of years ago on a whim and it looks pretty cool I think. I occasionally wipe it down and put some wax on it and haven't had any rust issues. Not sure I'd want to do the whole chassis though as it probably would start rusting eventually.

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1995 S4s

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Galvanizing is a thin plating of zinc. The zinc serves as both a barrier to protect the steel as well as a sacrificial anode (sacrificial anode is a more active metal that is intentionally placed there to corrode first).

The best thing you can do to protect your unpainted galvanized chassis from corrosion is paint it, or coat it with something (wax/oil/etc.). Or you can leave it alone in its ugly gray color, because the oxidized zinc on the outer surface (zinc carbonate, I think) is a super-durable protective coating itself. If you polish (or worse, sand) it, you are almost certainly removing the layers of zinc protection. What you then have is exposed bare steel, ready to rust.

Porsche have been galvanizing their unibodies since 1976 or so, and every now and then on a Porsche web forum there is some doofus who posts up a thread where they sand their Porsche to the bare metal and brag about their "bare metal respray" . . . . I cringe. :)

Edited by Tony K

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Esprit S1s #355H & 454H

Esprit S2.2  #324J

1991 Esprit SE

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Galvanizing is a thin plating of zinc.

Hot dip Galvanizing can be very crude, compared to electro plating its quite thick. Often used on railing and gates. You can see all the lumps and bumps on the chassis. I think the best think to protect from rust is to leave it as it is. This is an ugly colour but how many times do you see ESprits that need welding? Not very often on the Galvanized chassis and when it does need it its often from where a heatsheild had broken.

I painted my chassis with POR15 Chassis paint and top coated it with POR15 Aluminium chassis top coat. I think this looks quite nice and clean. its not the easiest job get in to clean and paint but I think it looks better than it did.

IMG_9222.jpg

Buddsy

 

"Belief is the enemy of knowing" - Crrow777

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I totally agree with Buddsy - the galvaising on the chassis is about 1/2mm think from what I have seen with is HUGE in electroplating terms.

In the UK stripping or polishing the galvanised chassis is not a very clever thing to do, I wouldn't touch an Esprit with 2 barge poles if it had been polished in the UK.

State side you might get away with it becuase of the environment - over here, nah.

My SE is 20 years old now and looks like new underneath on the chassis - the hot dip may be crude but Lotus did an excellent job of securing the chassis and some other parts, wish they'd done it all over !

The only place i have ever seen Esprits repaired is just infront of the left side rear wheel arch on the horizontal beam running forward to back, it's right next to the turbo and gets upto 140 degrees C (measued it the other day) I have put a small heat cover on mine but over the years it's burned the zinc off and started to rust a tiny bit - some Esprits I know have a patch welded on there.

If you wanna be good to the car take the engine out and the suspension off and rub the chassis down with a pan scourer - this will get it smooth and all the poo off without attacking the zinc, then POR-15 it.

This is my GT3 that has been POR-15'd

430760562_c9dba51109_b.jpg

Granted it doesn't look anything like that now but when the time comes to work on it again you just take an oily cloth and wipe clean the dirt and re-paint if necessary.

There is another way which is nickel plating over the top:

http://www.frost.co.uk/item_Detail.asp?pro...=&subCatID=

Dunno how good it is, frost stuff is usually a bit crap tbh, never been totally impressed with the wizzard gimmik things they bring out but nickel should give you a nice finish.

Only prob with electro plating is that there is no way this can give you much more than a thousand/inch of plating which can come off in the breeze.

POR15 is probably the better choice, drys hard as nails and easily wipe clean.

Edited by Jonathan

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HI,

I'm starting to paint my bare chassis.

Personally I wouldn't use a 1K paint like POR 15.

I have try some POR 15 and other urethane paint on some suspension parts and really it does't like me.

At the end I have ended with 2K Epoxy base and silver color, specially developed for Zinc coated steel.

It's nearly impossible to grind off also with a srewdriver and any solvent is like water once hardened.

Yes, it's more expensive but IMHB the best choice for a definitive job.

Ciao

Giorgio

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As noted by Giorgio, painting on top of zinc is a nightmare, you have to prepare it especially to accept a specific paint which bonds itslef to the zinc. You may think of plate steel being flat but it's far from that, it's full of microscopic places for the paint to secure to, unfortunately zinc is far more flat and thus normal paint doesn't adhere to it well. Think of trying to use wood glue to glue acrylic together, it just cannot key to it.

I looked into this a lot for the Landy, and came to the conclusion that if the zinc coat is good, it's already about as protected as it can get, painting can actually reduce effectiveness of the zinc. The zinc acts as Tonk said, a sacrificial metal (like a ship's sacrificial plates of zinc that are attached to the hull, they do not coat the hull with zinc), if yhe galvanisation becomes damaged in an area and the corrosive material (water with air etc) gets to it, but not ot any zinc you get rust, if zinc is also in contact with that same corrosibe material the steel will be left alone and the zinc will be oxidised.

Paint it if you will. It's nicer to look at, but may not actually hep protect the chassis. At best it will seal the whole chassis and prevent any oxidation of the zinc and steel, at worst it will prevent oxidation of the zinc if both paint and zinc coats are not perfect.

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As noted by Giorgio, painting on top of zinc is a nightmare

Honestly never had a problem with POR-15, the only times it did come up I went over it agan and it stuck like sheet to a blanket - I assume it was where I didn't prep it properly.

As I say I did scrub the thing back with a scouring pad and totally de-greased it to prep.

The best adhesion I got with POR15 was on the galvanised chasssis without a shadow of a doubt - it's so well on there.

A chissel will get it off, and a grinding wheel but thats about it...even on the edges as you can see on the radius arm below I didnt do the whole lot.

If I had the choice again i'd get the removables dipped and then paint over, I'd definatly paint the chassis just becuause you can wipe it clean for working on the car (Its a chassis I dont really care what it looks like as long as its OK) - is nice to just wipe the area around the workplace and work in a totally dirt free environment. My GT2 lower links are goldz zinc coated, POR-15 over that as well stuck down like a mofo.

I also used a spray in wax on a huge pipe to coat the inside of the chassis - again who knows whether this really helps but I was bored and fancied messing around.

Not sure I buy into that sarcraficial anode thing, it has to be in an electrolite such as salt water for the reaction to take place, I very much doubt simply coating in zinc wont make it a sacraficial.

If the zinc coat is broken the steel under will rust, the GT2 has a small break in the zinc and it's rusted there on the steel. I know loads of applications where paint is applied over zinc coating without an issue that I know of.

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I have to say that POR-15 chassis coat sure is one hell of a paint. Its goes on like water really thin but you just cant clean it off anything once dried. Its like a kind of plastic coat. I didnt bother trying to clean up brushes just bought cheap ones from B&Q and threw them away each time. Once dried on your skin it doesnt come off for ages.

Buddsy

 

"Belief is the enemy of knowing" - Crrow777

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okay so i made and a decision and have chosen to go with the POR 15 silver chassis paint. I have ordered a pint. Will this be enough. Shame as the chassis would have looked great polished. They do a clear POR 15 but i guess this would still be weaker than the galvanised finish?

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Well to be honest you probably done need it but POR-15 Chassis coat isnt UV stabilised and can breakdown in sun. There is a top coat which protects the chassis coat from sun!!

Buddsy

 

"Belief is the enemy of knowing" - Crrow777

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Thanks Buddsy

I think i will also look at that as well. So being that i have bought a litre will this be enough for the chassis in the engine area?

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On the chassis you dont need it - UV they mean direct sunlight, UV has bad bouncing characteristics so wont hit the ground bounce up and zap your paint like visable light does.

Mines been on for years without a problem - I did test POR-15 and it goes yellow/golden within about 1 month in direct sunlight so for mine to still be the same colour silver it's fine.

If you really need to you can get over coats for POR-15, like a laquer, or just use a silver spray can.

I did this on my GT2's rear cross member, hammerite silver over POR-15, just key it with a scotch pad 1st.

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  • 2 weeks later...

Can you take a pic of what youve done so far? Might be enough.

BTW, best place to get POR15 paints in UK?

"Intellectuals solve problems; geniuses prevent them." Albert Einstein

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Also judging by how much i have used so far i reckon just a small 1 litre tin will do but then im only doing the engine area bothe sides at the moment. Will do the rest as i work my way along

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POR-15 should be 1-2 coats, you need to stir it for a good few minutes or it'll come right off.

It's all in the preperation, short cut that and it wont work.

Think Frost are the ONLY distributors of the stuff in the UK.

Always get the small tins, reason being is that the pain loves to weld the lids onto the cans :rolleyes:

Seriously it's so tough you'll never open the tin again - I used to decant mine into a jam jar and work from there but it does go off very quickly.

Woring from the dinky cans you reduce waste.

Also it kills brushes if you dont clean them with the correct solvent (nothing but the correct solvent works) - just buy a load of cheap brushes and chuck em out.

Good luck with it - remember prep prep prep.

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And where Frost says that smooth surfaces should be prepared with metal-ready, would that include a clean galvanised surface? Would metal-ready damage the zinc coating?

Does'nt sound like its needed from what you say, Jonathan. And your prep is clean, degrease, scotch pad, right?

"Intellectuals solve problems; geniuses prevent them." Albert Einstein

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