Jumpy Guy
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| posted on 23/7/04 at 10:03 AM |
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Getting the POP out of metal bodywork!
My scuttle has been had crafted from the finest steel sheet, and looks kinda OK
however, its a bit wobbly across the top, especially where the welds on the 'dashboard edge' bit are.
So i was going to use nice filler before i paint etc.
which leads my to my problem- there is a 'pop' in the middle of the top of the scuttle.
so, what to do?
do i push the pop in, and fill the dentwith filler? or pull the pop up, but then how do i make it stay on that position?
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zilspeed
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| posted on 23/7/04 at 10:57 AM |
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Start welding a bead into the middle of the depression, spiralling out. This will shrink the metal. You could then grind the bead back flush. Has to
be better than filling the low spot.
P.S. The bead is only to shrink the metal - not as a filler.
P.P.S. You would use a mig welder to do this - I've seen it done on a stubborn wheel bearing outer race to shrink it out of place.
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Mark Allanson
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| posted on 23/7/04 at 05:37 PM |
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Grinding the spiral of weld will probably stretch it back again, Two methods, 1, heat the centre of the depression with oa until you get a yellow glow
about the size of a penny (new). put a block of hard wood underneath and lightly rap it with a wooden mallet, preferably a panel beater one, repeat
sprialing outwards. 2, get a shrinking hammer and dolly and spirally tap the two together, use a body file to clean up and paint.
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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The Shootist
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 posted on 23/7/04 at 07:46 PM |
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Check an auto body supply...
and get a "Shrinking Disk". Fits on a disk grinder and has a fluted outer edge. Apply heat via friction to the dent then when the metal
begins to take-on a blueish appearance, slap a cold wet rag on the spot to shink it back.
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Mark Allanson
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| posted on 23/7/04 at 08:07 PM |
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Got any pictures, links? Sounds like a painless method
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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MikeP
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| posted on 23/7/04 at 09:41 PM |
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Couple of more techniques:
Heat a spot just like Mark describes, but quench it quickly with a cold rag and it will pull in on itself. Tends to make the metal a bit brittle but
is pretty easy. Do a different spot every time and watch for cracks. I've tried Mark's method, it works well but you need two people -
it's hard to put the torch down and get the dolly and hammer ready before it all cools off  .
Another that I've seen done but haven't tried myself: Carefully bang egg sized bumps into the sheet. Use a soft (plastic or rubber)
hammer backed up with a shot bag. Then use a plastic or hard rubber hammer to flatten the bumps onto themselves against a smooth metal dolly. The
metal thickens slightly and shrinks. You need to be careful to dent rather than stretch at all times. Takes longer but is gentler on the metal.
I've never had any luck with shrinking hammers, I just mark up the metal without make much progress. The metal shaping guys told me to throw it
away - not sure if that was a comment about my technique or the hammer  .
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Mark Allanson
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| posted on 23/7/04 at 09:49 PM |
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Shrinking hammers are totally useless without the matching dolly
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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MikeP
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| posted on 25/7/04 at 12:58 AM |
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Hi Mark - I think the shaping guys are against anything that marks the metal - they're fanatics for using polished hammers and dollies for
everything - that was the reason they told me not to use them.
I don't remember what I used to backup the shrinking hammer, but I know for a fact it wasn't a purpose made shrinking dolly 'cause I
didn't even know there was such a thing . What do they look like?
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type 907
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| posted on 25/7/04 at 07:34 AM |
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Hi Jumpy Guy,
IF there is access, could a "top hat" section be spot welded to the underside of the scuttle to hold it flat? or welded in place with
tiny spot tacks?
OR if you are fitting a windscreen, could the windscreen frame be used to keep it flat? i.e. a row of rivets or self tappers from the underside into
the frame.
I havn't done mine yet, but intend to make my scuttle with a gentle curve to the top, as large flat areas tend not to remain so.
I hope this is of some help.
Paul G
Too much is just enough
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Mark Allanson
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| posted on 25/7/04 at 09:39 AM |
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quote:
Originally posted by MikeP
Hi Mark - I think the shaping guys are against anything that marks the metal - they're fanatics for using polished hammers and dollies for
everything - that was the reason they told me not to use them.
I don't remember what I used to backup the shrinking hammer, but I know for a fact it wasn't a purpose made shrinking dolly 'cause I
didn't even know there was such a thing . What do they look like?
They look like a normal dolly exceptthat they are crosshatched with 0.5mm grooves to match the grooves in the hammer
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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Peteff
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| posted on 25/7/04 at 11:53 AM |
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Not really relevant but
I picked a lump of metal up at a local junk shop thinking it might be handy for something. I found out it's a heel dolly while looking at a
metalworking book. I'm now the proud owner of a 20p heel dolly  and no longer the owner of a weight.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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Mark Allanson
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| posted on 25/7/04 at 08:38 PM |
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Lucky sod, good quality ones are about £60
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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Jumpy Guy
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| posted on 26/7/04 at 02:08 PM |
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OK, if i have to heat the metal to a penny sized circle, how do i heat it? will a blow torch do ? how hot does it have to get?
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Mark Allanson
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| posted on 26/7/04 at 06:51 PM |
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Sexy Ahotalene is best because it focuses the heat, but a good blowtorch should do the job in thinner steel, dull red is about right for the heat
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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