17 replies to this topic

[Dan]

I would think of MAPP as acetylene myself. It's cooler than oxy-acetylene (you really don't want to use oxy with a jet trorch as DK says, it'll cut straight through the body) and it's cooler than air-actylene which is what a big body shop or restorer would probably be lead loading with but it's a lot hotter than propane-butane. As Koss says it's what roofers use but bear in mind that they are only softening lead, not melting it. Lead is joined with tinmans solder in most building applications and solder isn't pure lead, it melts cooler. Myself I would use a MAPP gun. I think if you were using propane-butane you'd go through a lot of gas to get a flame that was both wide and gentle enough and hot enough at the same time. It may well be cheaper to go for a MAPP gun in the end than to buy all the propane-butane you'd need.

Obviously don't go out and get an oxy set for this job, you don't even want oxy, just air acetylene if that's what you want to use. You don't need a big set and a service contract, it comes in small size K cylinders too.

Oh yeah, also disolved acetylene (that's how neat acetylene is supplied) is nightmarishly dangerous stuff. The cylinders need proper looking after. You see them just lying about in the corners of garages all over the place which is frankly scary. If the cylinders get to a certain temperature they go into a chain reaction and no amount of cooling will then stop it exploding. And the older cylinders are wrapped in asbestos so when they explode, everyone who isn't killed by blast or shrapnel gets cancer or asbestosis. The liberated gas itself is also dangerous, it kills in the same way as carbon monoxide so you don't know if you're dying from it. If you use it to cut or solder copper or silver, you can make a proper high explosive as a by-product which is not a good idea in the presence of such a hot flame so don't do that. If it's not burning properly it produces carbon monoxide so again, you die. All in all it's not nice stuff.

Personally I'd probably use MAPP.

[midridge2]

ok guys, this is advice from some one who has been lead loading cars for 35+ years.
for starters it does not cost £500 a year for oxy/acety rental from boc.
use fryalux sp flux, other fluxes tend to be rubbish, cover the panel with the flux, using oxy/acety torch with a number 2 tip heat the flux and wipe over it with a clean cloth and it will change to a silver colour, this is now ready.
use the torch and warm the panel and play the heat onto the solder untill it starts to melt, use the tip of the torch to push lumps of the solder onto the panel.
when you have enough lumps on heat the solder and using your paddle flatten the solder into the shape but dont over heat or it will run off.
using a body file, file the lead into shape,dont us a grinder or sander as this is illegal because the fine particals can be breathed in.
when you have the shape use 80 grit producting paper to get rid of the thick groves,if you are good you can finish with smoother paper or go over the top with bodyfiller, remember before the body filler or primer to wash the flux off with the correct cleaner or you can use celly thinners.

[biggav]

I have a rothenburger Superfire torch (or 3!!) and use it for copper pipe joining and lead work. best bet is to get some lead solder from a plumbers merchants (1/4 price of B&Q!!!) and some laco flux (i find it runs much better than Everflux or powerflux which are paste like.
A decent torch head will cosr IRO £45, then about £5 a time for propane or mapp gas refills (i get mine free!!) molten lead is harmfull if fumes are breathed in, but also mapp gas is aparently carcaegenic too (once had an american bottle given to me with a big california warning though everything is dangerous in california!!!)

Or find a friendly plumber who will lend you the suff, or do it for you. i'll be using lead instead of filler on quite a few of the little repairs needed on the stealth where there are scars fom de-seaming.

Oxy would be better though as it will melt the lead quicker... also note, i've not done a car before but some huge lead valleys and feature work on stately homes and churches.

Edited by biggav, 14 June 2007 - 09:43 PM.