[TheForge] Repair job

[Peter Hirst]

Paul:

Thanks for the lead info.  Photos indicate pretty clearly that lead in this 
application is strips, like lead flashing.  The apprach of drilling to 
relieve compaction,still applies however, and will be the first thing I try 
if simple extraction does not work.  Do you happen to know whether lead 
weakens significantly at a temperature significantly below 620?

Keziah


----- Original Message ----- 
From: "paul" <forge at wi.rr.com>
To: "Blacksmithing List Sponsored by ABANA" <theforge at mailman.qth.net>
Sent: Wednesday, May 07, 2008 9:28 PM
Subject: Re: [TheForge] Repair job


>> I have been asked to repair a pair of antique boot scrapers that an idiot 
>> contractor damaged in a sill replacement job.  1719 house with the 
>> matched pair nicely leaded into the granite front step.  In replacing the 
>> sill, idiot (or worse) contractor cut the boot scrapers off (not quite 
>> flush) rather than move the step.  I need to remove the nubs, reweld them 
>> to the scrapers and reinstall.  Anyone have any experience with R&R of 
>> lead-mounted iron in stone?  I have thought of three ways to do the 
>> extraction of the remaining nubs:  (1) vise grips and slide hammer 
>> (preferred), (2) stud extractor and slide hammer ( would rather avoid 
>> drilling out the original nubs); (3) heat (prefer not to destroy the 
>> original lead or risk cracking the stone: they are 3 inches from the 
>> edge.
>>
>> Also, the weld itself seems tricky.   I am inclined to use gas to 
>> reattach the nubs:  They must be butt welded and SOLID to retain shape 
>> and structural integrity.  Forge weld seems dicey considering the weld is 
>> at the point that gets nearly all the stress in use.  Is pure iron filler 
>> rod avaialble, or am I ok with ordinary mild steel rod?  One of the 
>> scrolls needs to be replaced, but I am ok with a forge weld for that, 
>> since its a faggot weld along about a 3" surface.
>>
>> Any advice  welcomed.  I can post pics if there is interest in this 
>> project.
>>
>> Kezia
>
> Kind of sounds like the original was installed with lead wool, which is 
> still available btw, sort of like steel wool but 'coarser'. The advantage 
> at the time was, of course, that it was installed cold and 'caulked' 
> around the metal with flat nosed chisels. No heat no problem.
>
> see
> http://www.acehardware.com/sm-alpha-metals-lead-wool-alpha-metals-lead-wool-price-18--pi-1290612.html
> http://www.santarosalead.com/lead_ingots_wool_waterproofing.htm
> http://www.answers.com/topic/lead-wool?cat=technology
> http://www.gravitaindia.com/leadwool.html
> more than you ever wanted to know about lead wool, but you are encouraged 
> to hit it COLD...
>
> The safe way to remove the lead would be to drill many small holes around 
> the perimeter of the stubs, say 1/4" diameter or so, until the stock could 
> be pulled out.  We still use the drilling method to dis-assemble cast iron 
> pipe where open flame would be un-friendly to the existing structure.
> You probably should use the lead wool to remain true to the original, but 
> there are many epoxy or polyester anchoring products that would be 
> excellent except for their lack of historical accuracy. You would still be 
> able to tell if lead wool was used even after you pull out most of the 
> lead by picking or drilling, as it will retain its string-like structure 
> even after it was caulked (compacted). Even if they used strips of lead 
> instead of the lead wool, the wool would be a lot easier than cutting up 
> sheet lead to make the strips...which would be easy but boring.
> Lead melts around 620* and 63-37 solder melts about 350*
> see
> http://www.efunda.com/materials/solders/tin_lead.cfm
>
> Solders are much harder (less ductile) than pure lead, and since both 
> metals shrink upon cooling, which is why we caulk them,  the solder, which 
> might look like a good lower temperature alternative to the higher melting 
> point lead, is harder to caulk, and might require enough force to risk 
> breaking the granite.
> sorry about all the commas, it's late for me today...
> -- 
> Paul Sperbeck
> WB9HCO
> jadap
>
>  "The difference between genius and stupidity is that
> genius has its limits." -Albert Einstein
> "Life is hard...it's harder if you're stupid" John Wayne - Sands of Iwo 
> Jima
>
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