to look into the use of lead solder on my body repairs for a
number of reasons:
It was the
traditional method used in the fifties when my truck was
has much better ductility and strength characteristics than
I was told
that it couldn’t practically or realistically be done these
days, which I took as a personal challenge. I hate these
sort of excuses or reasons for not doing something I think
should be done.
wanted to have a go at it, to be able to say I had tried it.
embarked on the truck rebuild I decided that even though I would
be making quite a few modifications over the stock setup I would
try, wherever possible, to do things the traditional way and not
that many modern plastic fillers are very capable and in some
respects are as good if not better than the old methods
(especially in the preparation and finishing side).
to look into the use of lead solder. My research was helped
greatly when I joined an evening class on Classic Body Repair
techniques. I would strongly advise an evening class of this
type if it is available to you. You can easily read books (and
articles written by recently turned amateurs) but there really
is nothing like having a go and being shown how and what to do.
Materials – Tools and Supplies
leading you don’t need a lot of tools or supplies. I bought a
Solder Kit from a restoration equipment supplier, Frost
Restorers Equipment. This company is located in the United
Kingdom with a web address of www.frost.co.uk.
The kit contained all of the items that you need to get
started. It was not cheap at about $90 but contained the
- Solder Paint
(Flux/Tinning paste) This is a combination of lead solder
and flux mixed to a thick paint of paste.
- 2 Paddles, 1 Flat and
- Flexible File holder
and blade (Vixen File)
- 3 sticks of Lead
- Body Solder book (
About 50 pages containing tips and advice with quite a few
addition to the kit contents you will need a heat source for
melting the lead, some water (for cooling) and some rags.
solder supplied in the kit did not have any identifying marks on
it but I believe that it is a 30/70 mix, 30% Tin to 70% Lead.
This is the usual body solder composition. Pure lead melts at a
very specific temperature, whereas a lead/tin alloy melts over a
given temperature range with a solidus stage. This is when it
is not yet a liquid (Liquidus) but is at a stage where it is
plastic, and can be manipulated and spread.
by using an oxy acetylene torch to heat the areas being leaded,
but soon changed to a MAPP gas torch. The MAPP gas torch has a
much gentler and wider heat spread, which is what you want when
leading. If you use an oxy acetylene torch, you should use a
slightly carburising flame, i.e. one that does not have as much
oxygen as a welding flame. This flame will be blue with no
yellow. This will give a softer more controllable heat. It is
also possible to use a heat gun, such as used for paint
The rags and water are
needed to cool the area being worked just after applying the
lead, this helps prevent over heating and warping.
Applying – Laying on the Lead
not a definitive guide, but is the way that I have found that
works for me. It is based on the tips and advice from the book
included in the kit and also what I picked up at my evening
Cleanliness is key - Before you begin, make sure everything is
you attempt to start spreading any lead you must make sure that
the work piece is very clean and free from anything that could
contaminate the lead solder, especially oil or grease. The flux
will do a good job of cleaning the area, but it will struggle if
the area has not first been degreased and cleaned back to a
can see the front fender cleaned off just prior to working on
contains a combined flux, solder, and tinning paste that you
paint on to the area being repaired with a brush. There are
various other methods of applying flux and tinning such as
powder and liquids but this is what my kit used. The paste
cleans the area to be worked and also "tins" the area with a
thin coat of solder, which helps the bar solder adhere to the
brush, paint the paste over the area being repaired plus a
couple of extra inches to allow for feathering the edges.
painting the area with the paste, apply heat with the torch in a
careful manner, gently moving the torch around the work area so
as not to overheat any one portion. When the flux starts to run
clear you are near the correct temperature.
With a bit more heat you will see the solder start to bead and
stage the idea is to ensure a good coverage or "Tin". This is
done by wiping the area with a cloth to spread
the solder and remove any excess. Essentially you wipe the area
to get a nice shiny covered surface or "wet the surface". Any
pitting or blackened areas indicates
the area has not been cleaned sufficiently and you will have
trouble applying the lead. When this happens, the best thing to
do is to clean the area again. Remove all excess solder by
wiping it off with the cloth.
Applying the Lead
easiest way to apply the lead is directly from the bar. You
apply heat to the end of the bar and also to the area that you
have already tinned in order to get them both to a similar
temperature, which is just about the plastic stage. When the
lead bar is about to the correct temperature it starts to shine.
At this point you want to push the end of the bar onto the
panel and effectively crumble the required amount of lead onto
the work piece. It is important that the tinned area is also
heated to a similar temperature so that the bar sticks to the
repair. Otherwise it would simply fall off of the work piece.
Once you have the required amount of lead stuck to the work area
it is time to start to spread it.
This picture is
me applying the lead to the fender.
clean the fender is, and the less shinny area around the lead
bar. This is the work area that I have tinned.