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Ever straighten pot metal? school me

Discussion in 'The Hokey Ass Message Board' started by ZZ-IRON, Mar 18, 2011.

  1. ZZ-IRON
    Joined:
    Feb 28, 2007
    Posts:
    1,952
    Location:
    Northern Coast Minnesota

    ZZ-IRON Member

    Just got a pair of 53 Studebaker grilles good driver quality one has a high spot the other has a low spot

    the problem areas are in the center at the rear of the grille, the front edge is fine that the part that shows the most

    re chroming is in my plans down the road
    has anyone ever straightened a large area maybe a foot long and a 1/4" thick

    or is this something a chrome shop can do?

    [​IMG]
    the high and low areas
    [​IMG]

    [​IMG]
    front view you can see the high and low areas
    [​IMG]

    since the 53 Stude coupe did not have grilles just the grille surround bezels i was happy to get these
    and with luck correct the defects

    Thanks for any input
    Last edited: Mar 18, 2011
  2. Three of the four headlight rings on my 63 Mercury grille were damaged when I got them. Two of which were D shaped.

    I used a propane torch to heat them and beat them gently back into shape by laying them in my sand bag and lightly hammering them with a urethane mallet. I did end up with cracks at the highest stress areas.

    My intent is to have the chrome stripped and then use something like Muggy Weld to repair them before rechroming. Most people don't even notice the cracks though.
  3. oldrelics
    Joined:
    Apr 7, 2008
    Posts:
    1,198
    Location:
    Calgary

    oldrelics Member

    I have used a heat gun successfully, go SLOW and use blunt wooden tools to avoid marks....
  4. 1971BB427
    Joined:
    Mar 6, 2010
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    5,404
    Location:
    Oregon

    1971BB427 Member

    I had to straighten some of the horizontal grille pieces on my Austin. I took the grille sections out and put them in the same position on a bench, then used a clamp and a block to hold one end of a metal flat bar and after slipping the bar through the grille I gently pushed down on it until they were straight.
    I worked slowly moving to each bent bar in the various grille pieces and they came out perfect. Just keep gently pushing down and checking until they look good. Never thought of heat, as I didn't want to rechrome the grilles.
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  5. Bruce Lancaster
    Joined:
    Oct 9, 2001
    Posts:
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    Location:
    Madison NJ USA

    Bruce Lancaster
    ALLIANCE MEMBER

    Agree...push, pound, force rouded objects into collapsed hollows.
    If you are not a knowledgable flame wizard lkke El Polacko, I would say get a good heat gun that allows peak temp to be set. There is not a whole lot of wiggle between slightly more malleable and molten metal running into your socks.
    Think of it as somewhat brittle sheetmetal.
  6. ZZ-IRON
    Joined:
    Feb 28, 2007
    Posts:
    1,952
    Location:
    Northern Coast Minnesota

    ZZ-IRON Member

    Thanks for all the tips

    Just posted the photos so you can see the problem areas now

    I'll look into the the options posted

    The cool thing i bought them from a member of Ron Hall's Studebaker Avanti crew
    Ron broke 200 mph at Bonneville with a built Studebaker motor

    Ron's video of his Avanti #1963 running at Bonneville and that sound
    that was the reason i went to Bonneville in 2000

    Going to Bonneville is with me forever and i'll never forget it, hope to make Speed week 2011
    Ron Hall passed many years ago
  7. porknbeaner
    Joined:
    Sep 12, 2003
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    25,567
    Location:
    Raytown, MO

    porknbeaner Member

    Just looked at your pics.

    Just take a crescent wrench a tweak them a little then take a hammer and larrop the hell out of them.

    On second thought don't I can't afford to replace them. :D:D

    You already got plenty of good advice, the main thing or only thing that I could add is do it slow real slow and a little at a time.
  8. ChromePlaterJosh
    Joined:
    Feb 15, 2009
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    Location:
    Farmington Hills, MI

    ChromePlaterJosh
    ALLIANCE MEMBER

    Good advice so far. Considering how broad of a dent/tweak your relatively wide pieces have, I would be surprised if they would straighten back to perfect, but they can certainly be improved. I would probably try to tweak them back with my hands over my leg or a wooden tabletop. Take not that pot metal work hardens very quickly and will crack easily, especially if any hammerwork is done. It will be very easy to make them worse, I know this from personal experience.

    Many times, parts like that will be forced into position by installing them on the car, but that only works if there are enough attachment points to use.

    Another concern, those grills look somewhat flimsy in how they are built, so they might try to go back to a tweaked position in the rechroming process. I fI were restoring them, and you specified you wanted them straight, I would strongly consider welding some reinforcement underneath to keep them from bouncing back later.
  9. pimpin paint
    Joined:
    May 31, 2005
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    4,964
    Location:
    so cal

    pimpin paint Member

    Hey,

    Back when vehicles featured pot metal trim, most metalmen had a trick or three to straighten it.

    These can be straightened with the use of torch, some wooden formers, and the careful use of a hammer. Cold working potmetal/Zamac isn't a great idea, as many times the piece had cracks you can't see until it goes snap! Sometimes, on sightly tweeked pieces, boiling water can be used to warm up the bent area @ 212 degrees yer well below what zinc melts at, and this can be just enough to get the zinc to move. Try and avoid hitting plated pieces with a steel hammer-use wood or plastic only to shape them. On larger, thicker pieces a torch with a carborizing flame will be needed to gently warm up the part BEFORE you try to hammer or push it back into proper shape. Carefuly heat the damaged area always keeping the flame moving, and stop well before you leave any firescale on the chrome. Again, work over some plywood or a sheet of Masonite with ''soft'' tools. If at first it doesn't move, reheat and rework until it does.

    Potmetal can be soft soldered to repair cracks or missing pieces, but will require replating afterwards.

    " The real pity in America is that the people who really know how to run the country are all tending bar and cutting hair " - George Burns -

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