Re: [MV] Shrinking Metal

CHAZ (chaz.mackenzie@virgin.net)
Thu, 04 Jun 1998 00:01:58 +0100

Gary Halcom wrote:
>
> Has anyone tried heat schrinking metal that has been stretched like you
> see in trailer floors or fenders, hoods and cabs. It is supposed to
> reduce the amount of body filler one would use and in some cases reduce
> it completely.
>
> Whispers.......

Hi, heat shrinking works great. It's not hard to do if you think about
each step as you do it. First try and dress any creases flat without heat,
working towards the centre using a small hammer with slightly curved
face and a "dolly" behind the panel. This should get you a smooth bump
in the panel with the excess, stretched metal at the centre. Use an
acetylene welding torch to heat a small spot in the centre of the dent.
Set the flame to have slight excess acetylene, the flame cone should
be slightly feathered, not sharp.
You must get the "spot" red hot very quickly, with the minimum spread
of heat to the rest of the panel, so aim the flame at the spot to be
heated and bring the torch rapidly towards the panel and hold it there
only untill the spot is red hot then remove it. This should be so quick
that you hardly have time to see it happen. If it takes longer than
that, the jet size is too small or you've set the flame incorrectly.
Do not quench with water yet. A small nipple shaped lump should appear
as the metal moves towards the centre, assist the movement by dressing
gently round the hot spot with your hammer and a dolly behind the panel,
start at the edge of blue bit and work towards the centre, finally
dressing the nipple flat. Don't hit it too hard, you only want to move
the metal , not stretch it again. Now cool the panel with a sponge and
water. You will usually have to shrink several times to remove the
stretch from a dent, as you shrink the first bit another lump will
appear a few inches away as the metal moves. Let the whole panel cool
properly before starting the next lump.
Note:- remove the paint from the area to be heated before you start
otherwise you won't be able to see what's happening.
This all sounds like a lot of hassle, but after you get the hang of it
it's very quick and effective. When you've finished shrinking you will
still need to use some filler for a perfect finish, but only a tiny
amount to fill the wrinkles where it was red hot, nowhere else.

Hope that helps,
Chaz
Scotland

===
To unsubscribe from the mil-veh mailing list, send the single word
UNSUBSCRIBE in the body of a message to <mil-veh-request@skylee.com>.