It was years ago,(more than I care to admit), but I had learned to paddle
lead before I spread bondo. The instructors at my school, Ferris State
College/University now, here in Michigan, said bondo was a passing phase. It
would never take hold. Well, we learned to paddle lead with the best of
them, forsaking bondo. Graduated, and out in the real world I was asked if I
ever used bondo. Nope, just lead, I said, proudly. Needless to say, I could
only find a job sprucing up trade ins for resale.
Anyways....lead shouldn't be used to fill holes, they should be welded OR
brazed closed first. Primer/paint may not adhere if repaired area is not
ground, or sanded, or cleaned of the FLUX from brazing rod.....or the WAX or
TALLOW used on the paddle We used Dupont Prep-Sol with good results, don't
know if it is still sold under that name. A tip here....small holes such as
emblem holes, etc. should be slightly indented with a ball peen, area
ground, brazed, (minimum heat, we used wet asbestos putty to create a heat
dam. Yeah, it was safe then!), ground again to smooth the weld and remove
any flux. Then tinned with TinsTyter (trade name, was a red, thin liquid) on
a clean rag over ground area. Tinned with solder, excess wiped off
immediately. Then solder was melted off the stick and paddled to shape with
wooden paddle dipped in tallow or motor oil (to prevent molten lead from
sticking to wood). Lead should cool naturally, minimum of working with
paddle. If not, lead could crystallize if continued to be worked as it is
cooling. Result then is poor adhesion, and cracking. When cooled to touch,
body file is used sparingly to bring area down to surrounding surface. When
in doubt, use more lead the first time. Dang near impossible to reheat area
and add more lead, 'cause the existing lead turns molten and looses shape
then. Put enough on the first time. Body file, hand sanding block, just like
bondo from here on out. Lead should be blended in surrounding area, no gap,
lip, edge, etc. Can even use a skim coat of bondo too, but frowned on by
metal finishers!
Clean, clean, clean...no wax, tallow, motor oil, or flux; I/we never had a
paint adhesion problem. Lead will adhere to brass rod when brazed area is
prepped properly. Apologies for the length of this, but brought back old
memories. And lead can be paddled with a propane torch also, though a bit
unwieldly.
Ed in Mich
'57 3100 (emblem holes to be leaded)
----- Original Message -----
From: <SurfDudeSC@aol.com>
To: <oletrucks@autox.team.net>
Sent: Thursday, February 06, 2003 10:31 PM
Subject: [oletrucks] fixing sheet metal holes?
> Hi group:
>
> Time to start the bodywork on my 57 GMC. Now I'm a very good mechanic but
> relatively inexperienced when it comes to bodywork. What's the best way
to
> restore sheet metal? I've tried some leading on the holes but it kindda
just
> leaks through. I've filled some small holes with brass, this seems to
work
> pretty good. Now I'm thinking of brazing on some patches behind the sheet
> metal and leading on the front side. What's the best way guys?
>
> David
> 57 GMC 100, 270 Engine
> oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
|