MGB - galvanise panels?

  1. Dragnet Member

    Messages:
    62
    Location:
    Cornwall, UK
    I'm going to have to do some bodywork soon. I hope my MIG skills are up to the task!

    I can't find a good answer as to why I shouldn't get any new panels I buy (or old ones I clean) galvanised or electroplated. It's going to be better than a zinc-rich primer, which I hear is also going to be a soft coating so Bondarust over that won't improve its resistance greatly.

    I know hot-dip could distort car bits because they're quite flimsy compared to RSJs, but I've not heard first-hand evidence of this. Zinc electroplating would remove this problem, and then I'd have highly resistant panels. Bondarust on top followed by numerous coats of cellulose and the car would be ready for another fifty years.

    ...wouldn't it?
     
  2. optima21 Forum Supporter

    Messages:
    3,086
    Location:
    halifax, England
    for car panels Im not sure zinc plating would be used in then, they would use zinc plated sheets of steel (zintec or electrogalvanized) to make the panels from. if you want protection on a completed panel you might be looking at electrophoretic painting where the panels are dipped into a paint and electricity is applied to bond the paint to the metal. this method gets into all the nooks and crannies so is what car manufactures use.
     
  3. Dcal

    Dcal Forum Supporter

    Messages:
    2,353
    Location:
    Antrim Northern Ireland
    Electro zinc plating is a fraction the thickness of hot dip galv.
    It won't hurt but a good paint system should hold the rust at bay.

    You can now get zinc rich epoxies but I would not put it on the shiny bits. (fine for underneath though)
    An epoxy primer followed by a 2K top coat will be far better than what it got painted in 50 years ago.
     
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  4. hermetic

    hermetic Member

    Messages:
    187
    Yorkshire UK
    C+ars rust from the inside out! you will probably find that all the replacement panels are zintec coated, and if you use stonechip on the sills andlower psnels before you paint and waxoyl or morris anchor was in all the hollow sections including inside the door it will take a long time to rust
     
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  5. CompoSimmonite Member

    Messages:
    4,610
    Location:
    Werrington, Stoke-on-Trent
    There is a galv'ing firm at, I seem to remember, Liverpool who galvanized a whole Fiat 500 bodyshell.
     
  6. johnser

    johnser Member

    Messages:
    2,131
    Location:
    North Cornwall
    I relatively recently got all of the tinwear (minus very top of bonnet+ dash) for an mf35 hot dipped.

    Results were as you might expect, flat sections were a bit wavy and stuff with compound curves less affected.

    So your sills, or complex 3d shapes might fair reasonably well but flatter stuff, probably not.

    Thing is though, tractor bits are bolt on, you're going to have a mission welding in hot dipped stuff and then the welds will be exposed (but somewhat sacrificially protected) anyway. The galvanized surface can also be a bit rough, so extra painting prep needed there. Plus you'll have to fully remove the transport paint before dipping.

    Don't think I'd bother hot dipping bits for a car that aren't bolt on or are on show.

    Edit; for example. I restored an old beetle a while ago. If I did it again, and intended it to be used hard, I'd consider getting the whole chassis and floor plans hot dipped.

    I might consider doing the wings too as repro ones are cheap and don't fit well anyway and hopefully they're curved enough to minimise distortion.
     
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  7. Burdekin

    Burdekin Chief Bodger

    Messages:
    5,274
    Location:
    Aberdeen
    Where you weld will be the problem for future rust. Best to prep really well and use a decent epoxy. I like Jotamastic as it's designed to bond to less than perfect substrates.
     
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  8. Shox Dr

    Shox Dr Chief Engineer to Carlos Fandango

    Messages:
    16,044
    Location:
    East Yorkshire
    The biggest reason for not hot dip galvanising is damage and distortion. No cold quench would help, but even landrover bulkheads warp unless put on a jig
     
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  9. RWD3M

    RWD3M Forum Supporter

    Messages:
    1,149
    Location:
    Wiltshire, UK
    Please, just don't.

    From distortion, drilling drain holes, potential weight gain (the car not you :) ) to cleaning out every captive nut, it'll just be too much trouble and you'll also struggle to get a good finish on the paint afterwards.

    If you want to protect your bodyshell then have it e-coated once you have finished the repairs.

    https://www.surfaceprocessing.co.uk/classic-vehicle-solutions/electrophoretic-coating-system/

    By the way, don't forget to post pictures! :thumbup:
     
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  10. julianf

    julianf Member

    Messages:
    5,063
    Location:
    devon, uk
    Galvanisers vary in skill (or attention) massively.

    I'm sure some will be able to dip a panel without too much bother, but your general Wedge group monkeys (in both my experience, and the experience of others that I've spoke to) will make a pig's ear of most jobs that vary from dripping farm gates in the tank.

    If you go for it, test out your local plant with a cheap panel and see how it comes back. That's how you will ultimately know.
     
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  11. steveo3002 Member

    Messages:
    5,559
    cambridge uk
    you will have to grind it off everywhere theres a weld , and thats where the rust will start anyway

    decent prep and epoxy primer plus a good cavity wax will make for a long lasting job , plus im guessing after all that work you wont leave it caked in salt all year round?
     
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  12. RWD3M

    RWD3M Forum Supporter

    Messages:
    1,149
    Location:
    Wiltshire, UK
    That's sound theory but in my experience, most of them have a minimum charge so it could work out expensive. And it ain't cheap to begin with these days.

    I had the chassis of my GT6 done about 12/13 years ago and it cost me £47.

    Chassis on trestles.JPG

    Last year I took a small frame (a stand for my small blast cabinet which was less than half the weight) and they wouldn't touch it for less than £85. Oh, plus the vat!

    Oh and you're so right about Wedge! Certainly in Newport :vsad:
     
  13. julianf

    julianf Member

    Messages:
    5,063
    Location:
    devon, uk
    I suspect you are right. But then the type of firm who won't dip a small bit as a test to then gain your business probably is exactly the type of firm who will do a sh** job anyway.
     
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  14. jpmillermatic

    jpmillermatic Member

    Messages:
    1,062
    USA-NY
    If they dont get it, they dont get it!...I agree with your sentiment, Julianf....

    JP
     
  15. Dragnet Member

    Messages:
    62
    Location:
    Cornwall, UK
    It's nice to see some first-hand experience of my suspicion, that hot-dip is not worth it! Especially for a B where there isn't a chassis as such, though I haven't a problem with running a tap through holes. I didn't know that an electroplated coating had such a different thickness as a galvanised one, Dcal. It could be that the extra protection is negligible compared to a good base of paint, though I like the idea of sacrificial zinc! I thought that, like a boat anode, the point of the plating is that any exposed steel will not rust, as the free electrons from the zinc will complete the valence shells of the atoms that would otherwise form the oxidation compounds, until the zinc is depleted.

    I notice the new panels one can buy come with a black coating (I've only seen pictures so I don't know if it's a treatment or just paint). I suppose it must be weld-through. I'll be doing the painting myself so I don't want to touch 2k with a bargepole; while I'm happy with cellulose.

    It feels as though there must be some way of approaching modern-car levels of rust-protection on the panels, even though an MGB is not clipped together with plastic clips so one can't avoid cracking the paint with bolts and screws.

    Currently I'm considering rolled-on "Bonda Rust + Zinc", followed by anti-stone-chip below, and sprayed or rolled-on cellulose in many coats above. I haven't tried spraying before and my budget is very small, and currently the car is on a gravel drive with neighbours. However, I have a lot of time so can't see that sanding back any roller/brush marks will result in a markedly different finish from spraying. It will just take more time. If I can get it in a garage then spraying becomes more feasible.

    It is my first and only car, so it's what they call a 'Daily Driver'. I don't try to leave it caked in salt, but it is Cornwall and I haven't got a garage! It does have marks in the boot from transporting rocks, so it's not a prize puppy. Lockdown was a boon because I could pull bits off without having to worry about travel. I must say I'm looking forward to the next one for the same reason. Front suspension rebuild here we come!
     
  16. steveo3002 Member

    Messages:
    5,559
    cambridge uk
    EPOXY , USE EPOXY

    IT GREAT
     
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  17. Burdekin

    Burdekin Chief Bodger

    Messages:
    5,274
    Location:
    Aberdeen
    For me you can strip it fully back removing all rust and then epoxy primer and stonechip.

    or pressure clean, remove loose rust and underseal, treat with rust converter and then underbody and cavity wax treatment.

    I did a mix of both with my recent project where I did the first bit on the wheel arches and spare wheel wells and then the second all of the underneath of the car.

    To do the first method is a lot of hard work as you need to get good surface prep for the epoxy to stick.

    There is a company near Glasgow preserve and protect that will do the second method with removing all the old underseal and a new underbody wax treatment for £600 to £700. Might be a similar company down your way. Money well spent if that’s the way you fancy going.
     
  18. RWD3M

    RWD3M Forum Supporter

    Messages:
    1,149
    Location:
    Wiltshire, UK
    Electro plating is measured in microns, galvanising in hundredths, sometimes tenths if done poorly!

    That black coating is a water based primer and will offer scant protection. And no, not 'weld through' if you are using MIG, so you'll need to remove it. Easy enough though of course it will burn off as you weld.

    There is. The electro phoretic coating (did you Google it yet?) is what is now used on all modern cars and is in part what is responsible for the lack of rust that we always used to associate with 10 year old cars. It is pricey I'll grant you, but...

    Blimey, that's bold! :)

    Goood luck and don't forget the pics :thumbup:
     
  19. bricol Member

    Messages:
    1,525
    N.Yorks, UK
    Most places will do you a "freebie" if you are going to put proper continuing business their way - but a one off job for a few hundred quid . . . probably not. Especially if its going to be on full of hassle - which car panels undoubtably will be when you complain its gone a funny shape .. .
     
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  20. ghound

    ghound Member

    Messages:
    270
    norn iron
    I make all my door skins out of zinc plated sheets, makes a proper job of them. 20200721_162724.jpg
     
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