Getting the Lead On

Customizing with lead body filler was so popular in the 1950s that it gave us a new term, Lead Sled, to describe a radically customized sedan slathered and smoothed with the soft, pliable metal. Today the advent of high-quality, easily applied plastic (polyester) fillers has reduced the number of experienced lead workers to a minimum, but lead still has benefits other fillers do not. In fact, "lead" doesn't even have to be lead any more!

What It Is
Lead was the first popular body filler, used by auto factories and repair shops alike. It was melted into gaps and along seams, but if improperly applied it would crack and fall out just like the cheap plastic fillers of the 1960s. However, a good lead man was much in demand by premium body shops and customizers.


The technical term for "lead" is "body solder." For auto bodywork, it is actually a mix of lead and tin, usually a 30-percent tin/70-percent lead alloy. This is different from solder used for electronic repairs, and the two are not interchangeable. Although handling lead-based body solder is not harmful, breathing lead dust is dangerous, so hand filing (instead of power grinding) and the use of a respirator is recommended. Even better, a number of companies are now selling body solders that substitute copper and zinc for lead (still combined with tin) to form safer filler materials.


But why use lead at all? There are some instances where metal body fillers are better than plastic. Joints that are subject to stress and warping are more likely to crack plastic than metal (although lead is not a cure-all for improper engineering or assembly). And plastic easily cracks away from the thin edges of fenders or doors. Lead is also considered more appropriate for high-end repairs and restoration on collector cars.

How It's Done
Working with lead is simple, but like all crafts it requires continual practice to do it well. The basic materials can be bought in kit form or purchased separately. First, the metal area where the lead will be applied must be cleaned of all paint, corrosion, dirt and grease. A sanding disc or wire brush is used to work the metal until it is clean and bright.