Maybe one of the most overlooked or just plain ignored areas during a restoration project is the lead work. Perhaps this is because itís thought that the factory lead work will last forever and unless you absolutely have to, itís best to just leave it alone or maybe itís just that fewer and fewer people really know how to do it correctly.
Practically all unibody cars have lead in the top of the windshield posts and in the seam between the sail panel and the roof. Some also have some leaded seams in the rocker panels.
The real concern is that there is no way to know for sure that the lead on your car is secure. It might be OK, it might not, but considering the amount of work that goes into a typical resto project and the extreme hassle that you will encounter trying to fix this type of damage after the car is done, we believe that it is very cheap insurance to spend a few hours redoing all of your leaded seams.
There is no secret mystery to working with lead. Once you know the basic principles, and with a little practice, youíll find that working with it is not that much different than working with other body fillers. We get most of our lead supplies from The Eastwood Company. They even have complete kits available to get you started.
Here are the basic tools and supplies youíll need. One tub of the tinning butter will be enough for your entire car but make sure you have plenty of lead. You donít want to be running out part way through a seam. Have at least ten sticks available for a quarter panel seam this size.
The lead is removed by simply heating it up until it melts and falls away. Be very careful you donít splatter any on you. Then, thoroughly clean the metal with a 50-grit wheel and a 3M Bristle Brush. Clean off a very generous area around your seam and plan to start the work right away as surface rust can literally form overnight.
The first step is to coat the entire area with tinning butter. Tinning butter is flux paste that also contains lead. Lead (actually 70% lead and 30% tin) will only stick to areas that are prepped with this so be generous with it and cover the entire area youíve cleaned.
While this can be done with propane, we much prefer to use a welding torch as we have much greater control over the amount of heat. This is what your flame should look like.
Now using only the tail of the flame, gently heat the butter. The solder will melt out of it and coat the metal. A clean rag soaked in baking soda water will remove and neutralize the flux. Use a second clean rag after the first pass and finally wipe the surface dry.
OK, here we go. Start by heating the sheet metal. Youíll know itís ready when it gets shiny. Keeping the end of the tail of the flame on the metal so it stays warm, heat the stick in the flame until it works like warm butter. If it runs, itís too hot. Now just push the stick onto the metal until you have a decent sized gob of it and then take a wooded paddle and start shaping it into the seam. Be generous with the lead. Leave a mound of it on the surface. Itís easy to remove but much harder to add more if you come up short. Again, keep enough heat on the area so the lead feels like warm butter.
If your paddle starts to stick to the lead at all, melt the surface of the tallow and dip the paddle in it. You can repeat this as often as necessary. You also might find that different shaped paddles will be handy. Feel free to make you own if you like.
As you move to a more vertical surface, the correct heat becomes more important but donít worry if the lead runs a little. Just back off the heat until it stays put. Remember, lead will not stick to anyplace that is not tinned. Again, be generous with the lead. You want to be sure that you have plenty covering the entire area.
There are various file types available for working with lead but if you have a straight round file, a straight flat file and a flexible file, you should be in good shape most of the time. Use the straight round file to knock down the high spots and then the flexible file to shape the area to match the contour of the metal. Do not push the file straight in line with its length but rather work it at about a 30-degree angle with its length. This is really the same basic technique as stick sanding body filler.
Use a 50-grit grinder to clean up the drip rail. Be gentle though.
The last step is to use an 80 grit D/A to final feather the edges, remove any file marks, and smooth the surface to get it ready for primer.
- Questions, comments, article ideas? Let us know!
- Check out the other restoration articles available here at the tech section of musclecarrestorations.com!