================================== I tried it (lead loading) because I saw it being done on expensive Jaguar renovations near Bridgnorth. They used ordinary grinding disks on an angle grinder which looked pretty clogged up to me. Maybe I only saw the start of the process but there was no obvious use of other tools in evidence.
If I ever feel the urge to try lead loading again I'll remember to try a rasp which I've used on roofing lead to shape around pipes etc.
Cic.
================================== Point taken - health warnings are never out of place, I think. There will always be somebody seeing them for the first time.
Cic.
Means Rolls Royce must have used rusty steel on their new cars, then. I owned one where the lead loading was lifting through corrosion - and not where you'd expect 'normal' rust. Decent body filler used over clean steel doesn't seem to do this.
I'm willing to bet lead loading isn't used these days - apart from on restorations where they are picky about accuracy.
Seems lead loading has gone lead free...
Old Astons have an entire chassis fabricated with it. The "superleggera" construction (not just Astons) uses a lot of brazing for tube joints.
Yes I've tried a small one and they zing along. As I said apparently you can get these that do tig and mig also and can be picked up in one hand!
I used a large MIG at work that would weld 5/8 plate in a single pass, this had an independent wire feed like these inverter units but the whole thing weighed a few hundred kg.
AJH
Wasn't it called wiping metal? I still have the 1930s panel beaters manual that my wife's grandfather gave me in 1969 and wiping metal featured in that.
AJH
I suppose that's what you get for running around in common tat. My vehicles exhibits no such tendency...
I'm willing to bet that I'll have Shredded Wheat for breakfast - your point being.....
Julian
Yes, I've seen them - about £1000 just now. I wonder about spares in a few years time? If one component goes duff you could loose the lot maybe
What always worries me (prolly without good cause) is the strength of weld you get. You'll not be getting the penetration of stick. I prefer to see MIG used on mass production work like galv water troughs or gates perhaps - leave the serious stuff to stick...
Julian.
That there are more suitable modern ways. Thought that would be obvious.
I don't know but it was welding a lorry propshaft (450 hp) and the fitter welded as I rotated the shaft, using coogar shielding gas. The weld looked very clean and it held for the period I was driving the machine. I don't think I would have done as well with stick. The advantage with mig seems to be that you can actually build up a thick fillet with good fusion where the stick risks inclusions and the slag forming limits how long you can dwell and thicken the bead.
I assume I only achieve dip transfer with my hobby mig, in this mode I wonder about the effects of chilling at the joint as effectively you're dropping a blob of hot metal onto a colder bit of metal and the blob has to carry all the heat to fuse the two, no problem with thin sheet but I wonder on thicker stuff. I too tend to use the stick welder on pieces over 3mm thick.
AJH
Depends on your grade of "hobby". I use a couple of larger "hobby" machines, a 300 quid Cebora and a 500 quid Murex and they'll both do spray transfer easily. The idea that spray transfer is unachievable outside of a factory is a myth spread by people who either bought a SIP, or who persist in using CO2.
That's not dip transfer, that's globular transfer (the bad one). Dip transfer sticks a cold wire into a warm pool on cold metal, then heats all of it in situ. penetration isn't as good as spray, but fusion is perfectly good.
Of course they did! In the mid-70s at least. Jaguar too. This was one of their major quality problems at the time -- panels were coming from Pressed Steel Fisher and all sorts of things were happening en route, often involving pallets sitting around in rain for days whilst shop stewards finihsed their sandwiches in Downing Street
The one I was referring to was a Cloud I registered in '57. Made out of extremely thick steel - although some panels were aluminium. It used lead loading in a few places to blend panels together.
FWIW I'd expect problems (in time) where two very dissimilar metals are electrically bonded like this - you get a chemical reaction.
Depends somewhat on their relative electronegativity. Aluminium's a hassle, lead and steel aren't so bad. It's also much more of a problem where there's a _poor_ connection between the pieces and you get corrosion cells formed. If they're well soldered over a broad area then they're simply polarised.
This is of course why Astons are such dreadful rot boxes and Bristols aren't. They have similar potential problems with Al body panels, but Bristol's background with aircraft taught them how to avoid it.
Richard
It is obvious, that's why you left me perplexed! Of course nobody has the time (or skill) required to use lead loading when repairing modern vehicles. The vintage and restoration world is another story however, and judging from the 'Frost' catalogue it's still very much alive.
Putting polyester filler on your old Rolls would be like sticking Marley tiles on an old tythe barn IMO.
Julian.
I'm sure you're correct, I just have a mental blockage when I see hefty lumps of structural steel welded with a thin wire. But of course it works fine - tried and tested.
Julian.
I'm not talking necessarily about repair, but original build. I've done some lead loading and it's not *that* difficult a skill to acquire. But the reasons it's not used now is that there are better, lighter, cheaper and safer methods to get a perfect contour.
Frost would only have to sell one item a year at their prices to make it worthwhile stocking.
Very old vehicles probably don't have much in the way of lead loading. It became popular with '50s curvy shapes that were impossible - then - to press properly. I'd not be worried about a better filler or primer etc being used on such a vehicle.
No, so you have to shape the V notch more first. Then you use multiple passes. Fusion is still good (lots of power density).
The problem with stick is that _any_ welder, of any competence still has to stop and change rods. That's time to cool down, and time to start getting inclusions. For that reason, and that reason alone. continuous wire-feed has an advantage,
A lot of heavy structural steel isn't MIG'ed anyway. It's done instead with a submerged arc process, where there's a groove-following robot, a wire feed and power supply like MIG, but shield gas is replaced by a powdered flux (like manual stick) instead. There's a slag layer to clear off after each pass, but a pass on a long weld can be done in just one go.
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