Re: Removing or Melting Lead From Cast Iron Pipe (Tub Drain)
Posted by LonnythePlumber on July 06, 2004 at 13:03:46:
In response to Re: Removing or Melting Lead From Cast Iron Pipe (Tub Drain)
: If you decide to melt the lead anyway, a propane torch _will_ eventually get the fitting hot enough for the lead to flow, but it takes patience because all that cast iron makes for a pretty good heat sink. With a regular propane torch it can take 30 minutes or more to get a 4" hub in a cold basement hot enough for the lead to flow. A real torch rig or mapp gas is faster. Once the fitting gets heated up it goes pretty quickly. If the line is horizontal the lead will drip out and you can collect it. Vertical is a bit tougher but you can usually wiggle the pipe in a circular motion to force the lead to slosh out. The oakum packed behind the lead will probably catch on fire so have some water on hand. Once the lead is gone you can wiggle the fitting out (use heavy gloves unless you like third-degree burns). It's messy and it's easy to burn yourself, so be careful. Make sure you're not going to light the building on fire and stay away from water lines, gas lines, etc. for obvious reasons.

: When you install the new tub check with your local inspector to see what methods are approved for joining the new tub drain with the old cast iron--there seems to be considerable variation in preferred methods even in areas that use a standard plumbing codes. Good luck.

I presume this is a 2" horizontal. I've never had oakum in a lead to solder joint in my area. It takes me about four minutes for the solder to start dropping out of the joint and maybe 15 minutes all together to get the lead wiggled out. That's with my Mapp and good tip. 30 minutes seems pretty long even with propane and needle tip. Sometimes the lead is flared out on the inside which requires bending the lead in from the brass with a long screwdrive or wood chisel.
However I think you should replace all the cast iron piping you can. Build up cases it to drain slow. LonnythePlumber

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