Hammerite - different age formulars reacting?

  1. julianf

    julianf Member

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    I inherited a load of old tins of hammerite.

    I just tried to spray modern hammered finish over old smooth hammerite (which was fresh)

    I did this as I only had a single can of hammered (new) and loads of old smooth, so I figured I'd do the "work" of the job with the tinned stuff and get the finish from the spray at the end.

    ...I've almost finished taking it back to bare metal!

    The new spray instantly wrinkled up the finish. I'm guessing there has been an incomparable formular change or somthing?


    But now I'm not sure what to do. I have a tin of hammerite thinner acquired with the box of tins. But how do I know what paints this is compatible with?

    My 'in a hurry' back up plan was to thin down some paint from a tin and spray that, but I fear this all going wrong too.


    I don't have anywhere proper to do this work at present else I'd just get the 2k out. So I'm trying to "bodge" it - I'm aware of that, so please, no sermons!
     
  2. julianf

    julianf Member

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    Ps when I say "fresh" when speaking about the bottom layer, I mean 24 hrs, rather than 5 mins or 5 years.
     
  3. mr haynes Member

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    472
    Location:
    Scotland
    Vague memories of this happening from the same tin....overlapping a day later. Instructions used to be something like 6 weeks before overcoating again once dry

    I used to spray smooth hammerite thinned with standard boggo celly thinner with no problems
     
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  4. julianf

    julianf Member

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    It looked like, I guess cling film, over somthing wet, but with creases pulled into it.

    Almost the inverse of the palm of your hand when slighly cupped.

    I did a couple of coats with the brush, and that was absolutely fine, but, when the spray went on, it rucked up as I watched.
     
  5. mr haynes Member

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    472
    Location:
    Scotland
    Can you put a dab of old down, leave to go tacky, then a wee squirt of the new on top? Would confirm compatibility

    You wil have to remove the 'wrinkled' stuff anyway
     
  6. decca

    decca Forum Supporter

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    Crawcrook, Gateshead.
    They change Hammerite a few years ago and you don’t need the thinners for the new stuff just white spirit so the new stuff is just like normal gloss. Think you will have to remove the old stuff or find some kind of paint that is compatible with both to use as an undercoat and seal the old from new.
     
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  7. It always was a six week curing time before overcoating, if you missed the window.
     
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  8. julianf

    julianf Member

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    I have removed the old now. Its taken 3 days in a caustic bath with scraping periodically. Which is kind of sad as it had evidently stuck well!

    I did etch the surface with phosphoric which gave a real nice key (felt to the touch like fine wet and dry paper - ie the paper itself, rather than the metal)



    I guess it may be simpler to present it like this -

    I have a mild steel box, now clean again, that i need to turn black. Box is an indoor item but needs to resist chipping, and look smart.
    I have a gun.
    I have various pots of old hammerite, and one can of spray hammerite (new)
    I also have (but have never used it, lecher epoxy primer)
    I have 2k paints, but nowhere to spray them. The weather is no good for outdoor stuff, and, whilst i have air fed, im not going to use them in the places currently available to me, due to other living things!

    I dont really have an option to go acquire more stuff right now. As i say, its an indoor thing, so 1k is probably going to be fine. I just need a passable visual finish (ie no brush strokes)


    How would you do it? I mean, not how would "you" do it, but how can "i" do it now? : )
     
  9. julianf

    julianf Member

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    4,428
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    I even ordered Lechsys Industrial two-pack matt polyurethane paint for the job, but find myself messing about with ropey old tins of hammerite.... : (
     
  10. I never had a problem spraying Hammerite smooth or hammered with normal thinners. Cheaper than Hammerite thinners too. It's the same price as Chanel No5.
     
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  11. mr haynes Member

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    472
    Location:
    Scotland
    Thin your old smooth hammerite and do a spray test, see if you're happy with appearance. It touch dries pretty quick and no 2k worries.
    I used to use one of the blower fence sprayer gun thingys for it and was happpy with the finish, mainly on suspension/chassis components. Saved getting the air lines out
     
  12. julianf

    julianf Member

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    Thin it with the hammerite thinners?

    And put it on to the steel direct? Its new steel, not rusted - but, as i say, i etched it with acid before (and washed well)
     
  13. You have the solution in the Lechler tins. Use it! Then put an aerosol satin black over the top.
     
  14. mr haynes Member

    Messages:
    472
    Location:
    Scotland
    If that is what you have then yes. Basically think of it as gloss paint straight on metal.
    I am guessing you don't want to 2k in your current situation, so spraying the thinned hammerite not really any different to an aerosol.
     
  15. It might have been because the time between coats was wrong. I recoat within 6 hours. If I can't do it in that time, I leave it for six weeks in the greenhouse. Never had a reaction. The formula changed because of the EU Nazis moaning about VOC's. With the new stuff you can recoat after 4 hours and it doesn't matter when you apply the second coat. I stick to the old instructions though.
     
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  16. pedrobedro

    pedrobedro Man at Matalan

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    Location:
    CX Derbyshire
    Old Hammerite wrinkle finish had silicone in it. Anything would react with it unless it was ages old.
     
  17. jordan1 Member

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    2,028
    Location:
    Yorkshire England
    Yes, within 3hrs or after 6 weeks for next coat IIRC.
     
  18. julianf

    julianf Member

    Messages:
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    Location:
    devon, uk
    Right, so it's no sports car finish, but, as I said above, I had to use what I had availible to me. No time left for ordering extras.

    I found a tin of hammerite thinners in the stash of inherited tins, and matched it up by label design (so hopefully date) to a tin of black, mixed 1:2 and sprayed using a cheap gun.

    Came out ok, but didn't harden up very quickly at all. But that's not unusual for hammerite at best of times.

    With regard to recipe change - looking back over these tins, there are at least three different solvent warnings through the ages, so it's not like they just changed from old to new. It seems like they've always been meddling with the brew!


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