From: jws@billy.mlb.semi.harris.com (James W. Swonger)
Subject: Lead Bodywork
Date: Mon, 4 Jan 1993 19:30:20 GMT
Distribution: na
Organization: Harris Semiconductor, Melbourne FL

... got a few requests for the whole thing so here it is....



                       Lead Bodywork Stories

                           J. W. Swonger


 I brought in the latest issue of Cars and Parts since I had been asked for
the address. It occurred to me that the article on lead bodywork ought to 
appeal to the folks here, so I'll summarize (sorry, no pictures).

 The magazine folks are doing/contracting the restoration of a '57 Chevy
convertible and documenting the steps and progress. They had MIG-welded on
a new rear quarter and the seam was too visible to leave, requiring fill.

 They chose to use lead rather than plastic filler. The lead bonds better to 
the steel and is soft enough to absorb panel flex and stress without popping 
loose. The body man who was doing the work claims to be doing restorations
that last 20-30 years and won't put Bondo anywhere there is stress or 
movement.

 Meticulous cleaning of the area (die grinder, wire wheel) comes first. Then
a liquid flux (tinning flux) is brushed on. No brand given; a decent ZnCl
liquid plumbing flux might do. I have bottle which is pretty aggressive. Need
one that will work on steel as well as copper. May be some advantages to using
a special-purpose type. Probably want to avoid paste types as they'll leave
more of a residue.

 He uses bars of specialty 70/30 (70% lead) body solder in bar form. Uses 
the torch to heat the metal just enough to soften the lead and mushes down a
small dab of it. Then keeps the area heated with a soft flame fanning the 
surrounding metal and wipes in the lead with a folded-up shop rag to 
tin the surface. Keeps at it until the work area is smoothly and completely
tinned (no pockets or holes). Looks like proper flame and distance control
is important to prevent panel distortion.

 Now heat is applied to the bar and the work zone at once, and as the lead
bar softens it is pressed into the sheet metal to build up a work layer.
A wood paddle (they show a special one) coated with oil is used to rough-
shape the lead while still mushy.

 After cooling the lead is ground down and any low spots brought up with 
more lead as before. The grinder scratch marks make low spots obvious by
their absence. Final shaping is done with body files (coarse flat files
with scalloped, single cut teeth) and there are also specialty files for
touching up creases and grooves.

 The "popping" of low spots in the lead by hitting the backside of the 
panel with a pick hammer to raise the frontside above plane seems to be
an acceptable practice with lead fill but will cause separation of a
plastic filler even if still soft. They did a demo of side-by-side lead
and plastic fill in a dent, did this and then sawed through the center.
The plastic delaminated but the lead stayed down.

 
 I can attest to the importance of technique and proper materials. I tried 
lead work once and failed miserably due to lack of both. It seems to be more
difficult by far than puttying it up with Bondo, with some investment in tools
(like a torch, files, paddles, etc.) and the solder is doubtless more costly
too. However, the integrity of the repair is far superior both mechanically
and in terms of rust resistance - the lead-steel interface is much less
likely to harbor trapped water (no voids or delamination) and lead will not
absorb water either. 


 The address of Cars & Parts Magazine:

Cars & Parts
911 Vandemark Rd.    } 
PO Box 482           }  use either one I guess
Sidney, OH 45365
 
Cover price $2.50; 1 year (12 issues) $22. 

They also publish another magazine called "Musclecars of the '60s/'70s".

I bought one copy of that once. Not easy to find on the stand, though C&P is,
at least around here - even in some grocery stores. Anyhow, neither of these
mags are what you'd call slick. They're obviously done by enthusiasts who
can write, not journalism majors allergic to grease. The "Musclecars" mag
seems to be half amateur hour. Fine by me. I'll take an amateur with something
to say over a press hack regurgitating promo literature any day. 

I suppose I ought to commence to disclaiming now since I'm being so nice to
these folks. I just buy and read it, OK?



 I went out over lunch yesterday and bought 10 pounds of body solder ("lead")
to try it out for myself. I looked around for specialty fluxes but found
none. The lead set me back $3.85 per pound. I estimate that this is about
10-15 cubic inches of lead. Much more expensive per volume than plastic
filler; I'd do as much bump work as possible before filling the area. 

 I also couldn't find any body files or wood paddles. I am concluding that
lead is something of a lost (or dead) art. The expense of materials and the 
additional time it takes (see below) make it uneconomical for a slap-and-
spray body shop, when the customers don't appreciate the difference. The
need for tools and technique make it more difficult for the novice. Finally
there is the fact that it's flame work, which may make it unsuitable for
minor spot repairs - some paints may not take the heat well and require a
larger area to be stripped and refinished.

 Philosophy aside, I had surprisingly good luck with my first try at lead
work. (First try with proper tools and any knowledge, that is). I took the
advice of the C&P article as a starting point. However, I found that some
things do not translate well into print (especially if you're watching
rather than doing), and there are lots of little tricks that can help you
improve your results.

 I used my wife's last wooden kitchen spoon for a paddle (lucky for me she
doesn't read Usenet, eh?). I rubbed it down with ATF to lessen charring and
sticking. It worked well for a while but really needed a longer oiling; after
the ATF diffused farther into the wood the surface became dry, charred and the
lead began to stick. I had to re-oil several times and when I cleaned up I
put a heavy layer on to load it up overnight. Nothing wrong with using a
spoon in my opinion. I was satisfied with it.

 I sandblasted the work area, which I probably ought to describe. The spot
I was working on had several interesting "features". It's at the hip of the
left rear quarter. There was a dime-sized rust-through hole and several pin-
holes, and the seam along the top (this is a convertible) had separated and
in fact rotted away in some spots. The entire panel had lost its connection
to the inner support structure because the sheet metal had rusted away, and
could be pulled several inches in and out. I attempted to arc-weld it down
previously and blew another hole in the skin. I then resorted to brazing, and
this worked slightly better - I did obtain machanical integrity but at a high
cost. The panel warped badly, and the metal actually cracked in two spots. My
brazing technique is a bit heavy on the heat I think. I also brazed in roughly
formed replacement sheet metal along the top seam to match the original line.

 So the area in question contained a smorgasbord of flaws - dents, holes,
cracks, grooves, on both steel and brass. After blasting off the brazing flux
and other crud I applied ZnCl/HCl liquid flux for the lead and fired up the
torch. I'm using propane and oxygen, but I think a plain Bernz-o-matic torch
would suffice. I heated small areas slightly and dabbed the stick of lead at
them to lay down material for the tinning. Some areas I overheated and the lead
turned liquid and ran off. Vertical panels are more difficult than horizontal.
After finding the range and getting some lead to adhere I began reheating and
rubbing the lead in with a rag (denim material in this case). It worked fairly
well at first but began to char, leaving organic residue. I tinned some of the
area this way but had to re-blast and re-flux the adjacent areas where the
crud had contaminated the surface. Fluxing is more effective on a hot panel
but the heat also works on the brush bristles unless the brush is kept quite
wet and moved lightly and quickly.

 To continue the tinning I searched for things that could withstand higher
temperature. I settled on steel wool which I had laying about. This worked
quite well, better than the cloth because it would help scrub away light
residue and the lead didn't stick to it any worse than the cloth. #0000 was
better than #000; it left less iron crumbs. I would have tried bronze wool
if I had any. I'll try getting some tonight. The steel wool was not good for
areas having rough features or at getting down in grooves. For this I used
a paintbrush (natural bristle) with the bristles cut down to 1/2". This was
stiff yet pliable enough to get the lead worked into the difficult areas.
Using the steel wool for large flat areas and the brush for rough spots I
was able to tin the entire work area with no problems. 

 The tinning is complete when re-application of moderate heat leaves a shiny
surface. The initial rub-in sometimes was incompletely bonded to the steel.
In this case the lead would bead up under the flame. Re-rubbing the hot panel
worked it down better. This is one area where it will pay off to keep at it
until it's done just right; the tinning is the bond between the repair and the 
original piece.

 Building up the lead to fill the panel flaws was interesting. It's a process
which requires an acquired "touch", but unlike plastic filler you can work
and rework the lead continually. You have infinite work time. The material is
applied more slowly however.

 I deposited the lead as before but in greater quantity. The tinned surface
accepted the lead more readily than the bare steel did. There is a trick to
getting the lead onto the panel (at least vertical ones). The stick and the
panel are heated at the same time, gently. The panel should be just hot enough
to get the lead to shine. Cold lead returns to a dull luster. The transition
is the guide to tell you when working temperature is reached. Shortly beyond
the transition the lead will slump, then run so control is important. The 
panel should not be so hot that the applied lead will run off. The lead stick
should be heated in the flame at the same time. It should be taken to where
the end is shiny and begins to slump, then mashed against the surface. The 
soft part will stick and leave a good-sized blob. You may end up sticking
the lead rod to the panel but if you twist it away quickly it will still leave
the blob. I built up the lead until I had a tablespoon-sized amount sticking 
out from the surface.

 To work it into shape, the lead blob and the surrounding panel are heated
again. It's best to slowly apply the heat, backing off as it shines up and
moving in as it dulls. The entire lead bump, not just the surface, must be
heated to the slump point. Once you get the feel for the thermal time
constants of the lead bump and the panel you can get into the flow and move
along pretty well. The bump is heated up and then plastered around with the
paddle (greasy spoon). With the right heat application you can trowel it down
smooth pretty quickly. Too little and you'll find the process jerky; too much
and the lead won't hold its form but sag or run. To fill odd areas however you 
may want to overheat and keep paddling the lead back up to ensure the hole
is filled without voids.

 I did overheat a few times and some of the lead ended up on the floor. I 
saved it in a can for later. I figure at $4 a pound it's worth remelting into
another stick; I can foresee using a lot of it.

 One of these bumps was enough to bring up a 1"x1" are by about 1/4". This can
get tiresome if a large area is to be filled. It's not like mixing up Bondo
and laying it on with a spreader. I suspect that better technique could get
my application speed up considerably. I'm still learning to balance flame
intensity, distance and speed. It took me about a minute per square inch to
deposit and paddle down the lead into the work area, which was about 6"x6".

 After the rough fill was done I went back over it, softening areas and then
smoothing them in with the paddle. There's really just one basic technique
I used. I got a sort of stucco-like covering of the area. In retrospect, I
should have gone for as smooth and as close to final shape as possible using
the flame and paddle.

 After the fill is done you will have to sand it smooth. The article in the
magazine showed the body man using a face grinder to take down the lead, so
that's what I tried first. I recommend not doing this. The lead clogged and
stuck to the wheel, which began to vibrate badly. I had to pick off the lead,
which had smeared in from the pressure and frictional heat. Didn't like the 
idea of trashing a brand new face wheel; they're not cheap and I am.

 I found that 80-grit closed-coat sanding discs on the air sander worked
much better (wimpiness of my compressor aside). Less damage to the adjacent
steel and less smearing. It was slow going; lead does not sand as easily as
plastic. That, I guess, is why body files are used. Too bad they're hard to
come by locally. 

 I did get the lead down to a smooth surface, working it down until the first
bits of steel poked through. Unfortunately, these spots were above plane. I
whomped them down with a hammer. The lead held, didn't separate or anything.
Hot tip #12: Make sure the area to be filled is -entirely- below the finish
plane before staring in. Not too far below, though, or you'll be laying 
excess lead. I think using a straightedge or block is a good idea, one which
didn't occur to me at the time. 

 Lead which I paddled over the edge of the tinned area did not stick to the
steel. There was a visible separation between the two at the sanding line,
which disappeared when I got back to the tinned region.

 One problem was over the crack in the panel. Once the lead got sanded thin
enough, the crack propagated through it as well. The lead will take abuse up
to a point but will not cover -every- sin. However, it did stand up to flexing
and hammering from both sides of the panel. It's pliable but not strong.

 All in all I was very satisfied with the leadworking process and the level of
quality I was able to obtain in my first session. I ended up removing the lead
from the area in order to stabilize the cracks; the heat of brazing in 
new backup metal and redoing the support made it run from a 2" radius. Lead
should be done last. That is one nice thing about it though - it's so
forgiving. Don't like it, heat it up and hit it again.

 The heat of the lead work itself is not bad. I had primer down about 4"
outside the work area and didn't smell anything until I started brazing. I
don't know that I'd recommend lead on a painted car, but the heat and the
heat zone seem to be pretty moderate. 

 I'm not sure what sort of primer to use over lead. I've been told an etching
primer is good for the brazed areas but that conflicts with my desire for
cathodic protection, so I'll probably just blast it rough and go with the 
cold galv primer. If I run into problems getting adhesion to the lead I'll
have to find some way to deal with it. I don't know of too many things that
will etch lead either.
-- 
From: dingbat@cix.compulink.co.uk (Codesmiths)
Newsgroups: rec.autos.tech
Subject: Re: Lead Bodywork II
Date: 25 Jun 92 21:53:00 GMT
Reply-To: dingbat@cix.compulink.co.uk


I use 70/30 lead for leading, but tin the steelwork first with 60/40
plumber's solder. It's much easier to tin with, as it sticks &
spreads more readily. Costs too much to use for loading though.
Flux is the old favourite "killed spirits" (ZnCl), made as a
saturated solution of zinc metal disolved in hydrochloric acid, or
available as "Baker's Fluid".

For applying the stuff, I use a propane torch (no forced air), a few
different sizes of wooden paddle (mostly old kitchen spatulas) and a
moleskin (Thick cotton cloth pad - make your own by stitching a few
layers of old cotton corduroy trousers together).

I'm surprised the article talked about *grinding* the lead, as I've
never had any success using power tools to work it, the lead clogs
them too fast. I use steel body files, on a couple of home-made
wooden handles.

In the UK over the last few years, bodywork tools have become much
more widely available. Sykes Pickavant do the Speedline range, top
quality at reasonable prices, and there are innumerable far Eastern
cheap & nasties appearing. The Eastern smooth dollies are OK, but the
shrinking dollies (gridded face) are a bit nasty. Rounded grids just
don't work for shrinking !

Surely Eastwood tools must do some body files & dollies in the US ?

          Andy Dingley    dingbat@cix.compulink.co.uk


From: brooks@mcnc.org (Ted Brooks)
Newsgroups: alt.autos.antique,rec.autos.tech
Subject: Re: Lead Bodywork II
Summary: A couple of hints on supplies

Thanks for a great post on a "first timer's" experience! I will have to try
this myself - it doesn't sound so bad. Have you ever soldered elcectrical
components or copper pipe? If so, is the "feel" similar to either of them?

One place you ought to try for lead supplies is Eastwood - 800-345-1178.
They've got more body leading supplies than you could possibly use, including
the body files and a book on the topic. (One restoration book I read
suggested never grinding lead due to dust - to use a body file.)
 
Ted Brooks
 ______________________________________________________________________
| Disclaimer: The opinions expressed are my own, and do not reflect    |
| those of my employer. Advice is free, but you get what you pay for.  |
|                               ________                               |
|                         _____|  1955  |_______                       |
|                        /      Chevrolet      /                       |
|                       /______  BelAir  _____/                        |
|                              |________|                              |
|______________________________________________________________________|


From dionj@netcom.com Fri Jun 26 22:48:12 1992
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From: dionj@netcom.com (Dion Johnson)
Message-Id: <9206270247.AA19497@netcom.netcom.com>
To: jws@billy.mlb.semi.harris.com
Subject: Re: Lead Bodywork II
Status: R

VERY nice article.  That's the kind of altruistic, truly love-yer-fellow-man
kind of work that will get you into heaven.  

I havent seen lead bodywork described so well ever.  Used to watch my
mentor who showed me a little about it in high school (1957 for me).

Your word brought back fond memories.  You could publish that little
article - maybe you should!
-Dion

-- 
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Newsgroups: rec.autos.antique