Is there anything (just for example, some heat treatment/blowtorch type of thing) which might temper old (already removed) flashing lead, (30 year old stuff), and make it acceptable for re-use? I have ~100Kg of it after extension works, and I now need to make up about 10M of new flashing.

I could take all the old for recycling and buy new, or try to flatten and temper the old to make it workable.

Any experience/views/metalurgy on this?

Lead is malleable, so perfect for forming using (mostly wooden) hand tools that is why it has been used for building for so long.You would 'temper' and heat treat a high carbon steel chisel for example to keep an edge - heat treatment of lead is not usual in fact it can make it brittle as the temperature nears it's melting point. Lead is also easily weldable which means that if you want to create something complex or fit a difficult shape or make bigger sheets then it works - it just takes time, some skill and care (you don't want pin holes in the weld, preparation is time consuming etc). You must be careful not to burn the lead as you weld it - as the fumes won't do you any good and make sure that you wash your hands after working with it. I have recently been welding/making 'bat slates' out of 100 year old soakers and it works fine. Just don't bash it too hard and it will work (ie shape) again. I just leave it for a while so as not to overwork it and once it and me have had a rest off we go again.Don't forget to apply patination oil or you will get awful white run off. I agree with TomW, unless it's been subjected to really adverse conditions 30 year old should be still usable - many years ago I was working with a group of architects in an old church crypt, the undertakers were moving old lead coffins from 1700 and they were immaculate (lead still workable) - ones which were next to damp walls had broken down rather badly.

If your not too bothered about reusing it I would prefer to go for new - that way you know that whatever your putting in will be sound, better in the long run.

question for blacksmith - what's a bat slate? I can guess but I don't really know.
thanks
RobinB

Sounds good. Thanks!

I remember doing some lead welding on telecomms cable some 40+ years ago whilst jointing lead sheathed 2000 pair cables. I recall we used tallow as flux and something called a moleskin (not real moles!) to push the molten solder around. Photo 2 above looks as if insufficient flux was used or/and overall temperature of the lead base was to low and perhaps too narrow a heat point. In a different life phase when restoring stained glass windows I found that old lead is difficult to work with especially thin sections and anything other than horizontal creates big problems. With the above work I would have fitted the lead to the chimney to a good fit, removed it to the workshop and there welded a patch, probably bigger than was used above, using a solder that had a high tin content (up to 50% or 60%) as this flows much better and has a lower melting point than plumbers solder with about 6 -10% tin. Whilst welding I would move the work continually to maintain the horizontal plane of the molten metal. After repairing the piece I would return it to the chimney and dress it (bash it) to its final good fit. Of course the experts would do the whole thing on the chimney horribly quickly and without the rafters catching on fire, but then experience usually counts with practical skills.
Peter

Yes, but it wouldn't be so much FUN! I didn't use a solder (though I fed in new lead from prepared strips) I just made everything perfectly clean and I did achieve some very good welds whilst practising this way (there was no mention of solder on the course) - I'm sure it is true that this stuff is probably too thin to weld in situ (ie vertically) after cleaning (thinning) and as it was mostly roughly the right shape (welded) I judged it too difficult to move off the roof without further damage - still, I am confident my eventual 'solution' will not leak!

One thing to note Justin, betterroof is right for his situation but I am temporarily retired doing everything DIY and as cheaply as possible, my time costs nothing; hence, I would not have replaced this lead with new lead if I had sold it - probably I would have used bitumen coated with a thin layer of copper (the copper is indented with a patten to allow it to be folded (within reason) like un-coated bitumen (E10 ish per m2).

Here is a pic of the stuff showing how flexible it is - OK maybe you won't get 300+ years from it and you wouldn't use it somewhere you 'aught' to have lead but it'll last out my 13 year old if he stays here.

A further thought to my post above, there is a difference between welding lead together and soldering lead together, welding implies creating a homogeneous joint by melting the parts to be joined sufficiently to create a unified mass, sometimes filler material is used as with arc welding sometimes not as with forge welding. Welding reused lead with strips of lead, I would think very difficult, (see pictures above!). Soldering on the other hand is easier as you are not trying to melt the lead to be joined in a controlled (or otherwise) manner but rather to heat it sufficiently to get to the melting point of the solder so that the lead tin mix can properly adhere to the lead. (A bit like brazing) Much easier with old lead and for repairs. Like car radiator builders / repairers you should chose the solder mix for the job, the thinner or more fragile the lead the lower melting point is needed, also on complicated work different temperature solders can be used to have even more fun working from high melt point first down to the low melting point.

Justin,

I am quite sure P-in-H has done some wonderful lead soldering and quite possibly welding too but the pics are actually mine, as is the wife (well obviously I don't own her!).

Peter, yes I was aware of the difference and I was welding. I feel a little better now hearing how difficult what I tried was, better still that I actually managed it 'on the bench' with just cleaned up old lead. Seems like the next time I should try soldering, albeit getting that tiny gap required for the solder to 'run' up hill and throughout the joint due to capillary action would at first hand appear rather difficult for old lead!

Anyway - Justin perhaps a pic when you have finished....can't be more embarrassing than my attempt!

Regards all, Duncan

Gotanewlife. - Quite, sorry to mis represent your pics!

And funcrusher, Yes, good point about the dust. Thanks. I had quite a lot of white dusty stuff from the underside of the old lead yesterday when banging my old sheets flat. After the first 15 minutes I twigged on the dust issue, and began taking more care and wearing a mask. Perhaps dealing with them while wet would help. - I'm not planning any welding this time!

BTW, what is patination oil? I never used it in the past, but I do have have plenty of ageing linseed oil. - Probably do the trick

Justin:

Lead salts inc lead oxides dissolve easily in hot water, but not cold. Pour a kettle of boiling water onto the lead and it will clean up like magic (but beware where the waste water goes - probably best into the sewers where it will dilute a million times. Likewise, wash yourself in hot water after working with lead; wear rubber gloves where pos.

Do not use linseed oil: done that, bad news. Patination oil is very thin so a little goes a long way. However, neither oil offers anything other than a few month's protection. If it's appearance that worries you, paint with black paint. Otherwise, leave it alone.

Well without really waiting for an answer I went ahead and treated all my lead with linseed oil last night. Quite apart from now making a nice smell, it eliminated all the dusting from the oxide on the back and meant I could bang it about with less concern. It's ready to go in from tonight. Seems OK to me.

But thanks Funcrusher for the hot water tip. I'll try that next time - provided I can bring myself to deliberately wash old lead salts into .. er where exactly?

Rgds