LEAD LOADING

For some time, it looked as though lead loading was a dying art. Concerns over health and safety combined with a great leap forwards in plastic filler technology, not to mention more accurate body pressings and manufacturing processes in the factories, seemed to have confined lead to a few classic workshops who were keen to recreate the original production methods on their projects. And there is no denying that body filler is far easier to use – just mix it with hardener, spread it on and then, when it is dry, sand it back to shape.

There is no shame at all in using body filler thinly in this way, and modern fillers can be excellent products. Yet lead has some excellent properties of its own that mean it is still relevant. Those properties include its suitability for deep fills; unlike body filler that becomes more liable to crack the thicker it is applied, lead is untroubled by such problems. It also remains flexible, and so is ideal for finishing joints on thin bodywork or large panels.

It has to be said, however, that lead loading is a skill that takes practice to master. For one thing, with lead you are applying lots of heat and this can cause more damage through distortion if you get it wrong. And that brings us on to the subject of the tools you will need. You can use an oxyacetylene torch, but this is very fierce and the heat is very localised. Keep the torch moving and it can be a quick way of lead loading, but it takes a lot of practice to get right. A plumber's blow-torch is better, not least because it gives a wider flame.

The picture sequence shows the main steps to take when lead loading, but there is no substitute for simply trying it out on a test piece and learning by your mistakes. That way you will get a feel for how far to heat the solder flux

– if you don't get it hot enough, then you'll wipe everything back off with the rag. And you will know you've done this when you try to apply the lead, as this will simply roll up and get blown about by the heat gun as it will have no grip at all on the bare metal, even if the panel has been scuffed up with 80 grit paper first.

If you want to give lead loading a try, then Frost (www.frost.co.uk) sell a starter kit for £65.99, and a more comprehensive one for £189.99. That's a great way of testing the waters before you move onto the real thing.

As ever, the first step is to clean the paint off a large area on either side of the repair to be filled. The lead will only stick if the area is totally clean. As well as being pushed firmly into crevices like this, capillary action from the heat will also help to pull lead into a seam in much the same way as brass will creep into a join if you are brazing. You need some equipment to get started with lead loading. As well as this basic gear, you will also need a blowtorch. The tape is optional – it was used in step 5 to catch falling lead! The first step is to brush on a layer of solder paste (flux) over the whole area. This both chemically cleans the metal and lays down a thin layer of lead, in much the same way as you need to tin electrical connections before soldering them. 2 3 1 4