Recommended torch for spot of lead burning?

[tsoutherwood]

Hi,

In the near future, I need to joint some pipe flashing onto a flat lead roof for both a boiler flue and a soil stack vent.

The joint does not have to be perfect as I'll be lipping the hole in the roof in such a way that the joint is intrinsically rain proof even if unwelded. It's more a case of tacking the flashing on so it doesn't fall off, though it would be nice to do a continuous burn along the upper edge at least. Roof is most likely Code 4 lead or thereabouts. I'm comfortable dry-working lead, but never had reason to weld it before, though I've participated in lead pipe soldering yonks ago.

Would one of these with MAPP gas be a good starting point?

http://www.transtools.co.uk/store/p...thenberger-micro-fire-lead-gas-torch-set.html

Soldering is also an option - but as the lead is set on wood, I don't realy want to get a large area of lead hot for long - a small very hot flame for localised fast work seems like a better bet. I can get some heat shielding under the lead around the joint - but not much further.

Of course, I will practice on some scrap first. It's a ground floor roof with easy access so no issues there.

TIA

Tim

 

[weldingscotty803]

take you ages with a pencil torch mate. practice with a normal butain torch , what filler size you using and the thickness of the flashing?

 

[tsoutherwood]

I don't have the flashing yet, but I guess about 3-4mm thick, and about 300x300mm.

That's if I use a "lead slate" with a bit of tube formed in.

The other option is just to roll up a bit of flashing into a tube, pre weld the seam, then weld (tack or seam) the base to the roof (over lapping the upwards lip I'll have previously formed around the hole). In which case, it's a 100mm flue pipe, so the tube will be a touch bigger in diameter.

Did you mean "butane" as in a regular torch? That's what I'd use if I was doing a tallow and solder job - but I wondered if using a very hot pencil flame in short goes would avoid having to dump a ton of heat into the roof for a prolonged time.

I've done MIG welding before, so the nearest I could describe it is: what torch would be good to make a very small area insanely hot very quickly so I could at the least tack weld it on without having to heat up half the roof and risk damage to the wood underneath?

As to filler - fairly small I would have thought - something like a strip 5mm wide?

Ta

Tim

 

[runnach]

Take a look at "lead burning" thread within this section, you should find the info you require.................

 

[tsoutherwood]

Ta.

I do see MAPP mentioned, along with hyrdrogen/oxy and oxy/acetylene.

Tim

 

[weldingscotty803]

try it on some scrap with the pencil burner then. the only downfall i can see with the little flame is the wind blowing the heat away. think the 5mm filler will be a bit overkill tbh. with such a small flame, the puddle wont be very big, maybe 6-8mm, try it on some scrap first. maybe try some soldering lead the 3-4mm stuff. you may get away with 5mm
you wont know until you try.
keep us posted how you get on

scott

 

[tsoutherwood]

try it on some scrap with the pencil burner then. the only downfall i can see with the little flame is the wind blowing the heat away. think the 5mm filler will be a bit overkill tbh. with such a small flame, the puddle wont be very big, maybe 6-8mm, try it on some scrap first. maybe try some soldering lead the 3-4mm stuff. you may get away with 5mm
you wont know until you try.
keep us posted how you get on

scott

Ok - will do

I need to fabricate a tube out of flat lead first and seam weld that - so there's a bit I can try on the kitchen table, so to speak, except the kitchen table will be outside! *choke*

Cheers

Tim