Leading 101



A RatStang Exclusive





Leading has become a lost art in the automotive world.

In this page I will make an attempt to show you how it is done.

This is by no means a substitute for experience using lead as a filler.

You will make many mistakes before you catch on to the technique.

Don't get discouraged as in some cases there is no substitute for lead.






First thing you have to do is prep the whole surface you cannot tin any Paint, Primer, Oils, waxes, etc. I Cleaned the whole surface with 80 grit on my Sander/Polisher.

Then I wiped the surface down with Wax and Grease Remover (Wipe on Wipe Off)



Next step is to test the metal for Heat Flex.

This is critical.
You heat it up with your torch if the metal starts to dive inward you have to take the torch off so that you don't cause it to oil can. You want the metal to go belly out come towards the heat from the torch.


Let it cool.





Figure out were you have to Tin.

Tinning is like applying a prime coat of lead. This allows the further leading to have a surface it can grab on to.

Tinning Butter is a mixture of lead and flux.

What you are going to do is mark the low areas that will need filling.

 (The best leading tool I have found is a strait edge and a permanent marker)


Next step is to heat the whole surface.

Not a piece at a time but All of what you are going to lead.


Then you apply your tinned butter to the area. The Tinning Butter should melt to the surface and thoroughly cover the area to be leaded.

If you don't the lead well not stick to the metal.






 Next is to heat the area enough to melt the Tin in the butter.

You have to heat it up enough to get the tin in the butter to solder to the surface.










Next step

Heat the entire surface as good as you can then heat and wipe the “Tinned” Butter around to insure the area is covered.

I have found that a shop rag works a lot better then Steel Wool or Bronze Wool



Let it cool once again



Then wipe it down with Lacquer Thinner or Wax and Grease Remover.

And again with baking soda water to disable all the acids in the Tinning Butter.

Wipe all of the surrounding exposed surface within 12 inches just to help prevent the acids form causing surface rust over night.


Now I like to grab my strait edge and my permanent marker and mark were the low spots are now.


At this time you will want to tallow your paddles.

Your paddles are made from wood and the tallow protects the wood and prevents the lead from sticking to the paddle.

Heat the tallow and wipe your paddles in it making sure you get all of the bottom, sides, and the tip of the paddles.

This will protect the tip from heat.











Heat the whole surface again.



Grab your lead bar (keeping the whole surface hot)


Heat the lead bar tip 1/4 to 1/2 inch at a time.

Heat the tip just enough to soften the tip.

Just to where it begins to flex.

Heat the surface to be leaded again.


Try not to get the surface too hot where once you put the lead on the lead melts off.

You want the surface just hot enough to let the tip of the lead bar stick but not melt and run.


Press the melted tip of the bar into the surface and twist the bar to break the tip off.



 Then keeping the tinned area hot enough grab your paddle and press the lead into the area being filled. Work in small areas at a time.

It will be like pressing cake frosting into a hole in a cake.

 Then paddle it around and repeat till desired results are achieved.

Avoid overheating and causing voids under the lead.

If you heat too much the lead will melt and flow right off the surface.

Keep the lead at a


Make sure you keep your paddles tallowed

You got to remember that lead is a incredible heat sink so it well melt from the center out so it well melt and drip inside itself if you get it to hot, And if you get it to cold it will not adhere correctly and it will flake, Once you lead you well know what I am talking about.



Try to get the Lead shaped as good as possible. Shaping with a File is not fun, And you will regret trying to do all of the shaping with the File










Then were ever you can I like to make a Masking Paper Basket to catch all the lead


Then start to file




Shape it as good as you can.

If you have a part that has a dip in it that you need to raise, heat
the surface tell it starts to get shiny if you get it to hot it well melt under itself and well become mis-shaped
Then you do the same thing heat this tip of the bar and jab it into it lightly then twist






Then grab the Permanent Marker and Strait Edge and mark all of the low spots






















Then the only sanding I like to do at this point is just roughing it up for the plastic filler.

All of them were less then 1/10th of an inch so I filled the rest with Rage Gold.


And sand the surface to desired finish




You want to clean all of the surrounding surface with Metal Wash, Zero Rust Prep Step, or Metal Prep, or all of the metal surface surrounding the lead well be covered in surface rust caused by the acids in the lead


But remember safety, guys Lead well not harm your hands or skin but it well give you lead poisoning if you breath the dusts or take lead internally in any way And the acids in the lead and in the tinned butter well harm you to so wear a dust mask for sanding and use a Organic Vapor filter Respirator for applying the acids
I wear a full face supplied air respirator or a full face mask with filters approved for dust and some fumes at all times whether I am sanding lead based paints or any paints for that matter and when I spraying paints working with acids etc.