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MG Midget and Sprite Technical - Lead loading a frog bonnet

Late Saturday afternoon, not the best of times to decide having a go at a new skill! But I have had a go at lead loading a seam on the frog bonnet - not having paid any attention at all to the poor thing for months!

But I was pleased with the result for a first time attempt. It has pretty nicely filled the area of the seam between the lead edge of the bonnet and the lower front valance on one side. Cut back and reshaped with a rasp and it looks OK. The lead is a little low in a couple of places, but unlike modern fillers which can be topped up, I presume lead cannot be as all of the first layer would melt and run out if I tried to add to it. I will have to make good later with a little body filler instead.

BUT -- having done it I am now not sure if that seam should be filled on a frog bonnet! Perhaps it is supposed to be visible. Does anyone know?

Guy W

Guy.
It's a very long time since I did any lead loading, but I was taught by a man called George Westgarth. Long dead and much missed - he was a truly nice bloke.
He learned the craft as a coachbuilder at "The Jag" as he called it. The Jaguar factory in Coventry. What a superb craftsman - it was a joy to watch him.
It is indeed possible to build up the fill, although it's not easy. We used BIG clunky sticks of lead bar, sometimes called plumber's bar, and the trick is judge when the bar is just about to melt before applying it and the torch to the fill, which is relatively very slightly cooler. It's a very fine balance, but you could use some scrap to practice and develop the art for yourself.

By the way George was made redundant from "The Jag" after a blood test showed dangerous levels of lead in his body. He was 48 when he died. Please take care to protect yourself.

I haven't the remotest idea of that seam should be filled. I expect somebody cleverer than me can tell you.

Well done for your enterprise. Any chance of a photo?
Greybeard

Guy,

You can add more lead filler to a local area if needed but it does depend on your skill and equipment. The thing about the filler alloy used is it has a large difference between the liquidus and solidus temperature so you have a large band where the filler is pasty and can be worked to varying degrees depending on the temperature. Liquidus temperature is where it is fully liquid, solidus temperature is where it is fully solid. a eutectic alloy would be no use in this application as it changes from liquid to solid and visa versa at one distinct temperature.
David Billington

There y' go. I thought there'd be somebody cleverer along!
Greybeard

The seam is visible and not meant to be filled in!
Bob Beaumont

Oh dear! And I was quite pleased with the result!

I suppose I can melt it out again, or use a Dremel to re-shape a new crease. The original seam wasn't perfect as it was - which is why I thought it needed filling. Somewhat dubious accuracy for replacement panels when I rebuilt the bonnet last year - new wings, valance, air box etc. but nothing lines up without a good deal of "dressing"
Guy W

Seconded - any pictures Guy?
Tragic story Greybeard; made redundant presumably so the company didn't have to pay out for 'death in service'?
Jeremy Tickle

Could photograph, but its really not worth it. Its roughly brush painted over and there's really nothing to see.
Guy W

Lead poisoning is no joke when leading body work, I did a little in my 1st year in auto body shop,and we were tje last class to be (shown) that skill

I wouldnt do that agian without good ventilation or even outside up wind of the fumes

But it is an interesting skill set

Wow.. almost 40 years ago

Prop
Prop and the Blackhole Midget

IIRC at the temperatures needed to work a lead solder filler there should be no issues with any lead vapour, if that is an issue then the filler and likely the steel underneath would be on the floor. The fumes from the flux may be a minor issue so read the warnings for the flux you chose. Basically try to minimise direct handling of the solder bar and wash your hands thoroughly if you do before eating etc to avoid ingesting any lead.
David Billington

Guy. Be very careful using any kind of power or air tool on lead. If you must do it, be sure to wear a mask and keep the mask on for a while when finished, or leave the workshop till it's settled. You really don't want to be getting any airborne particles of that stuff in your lungs.
Bernie Higginson

Thanks for the H & S advice. I will take it seriously.
The solder stick melted at quite a low temperature. Certainly a lot lower than for soldering plumbing fittings. I was heating the steel with a propane torch and then applying the lead stick to the warm steel, not attempting to heat the stick directly. There were no visible fumes.

For shaping I was using a coarse hand rasp. No power tools, so this should have been Ok.
Guy W

This thread was discussed between 05/09/2015 and 07/09/2015

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