Help removing brass closet flange from copper pipe

[mappley811]

I'm trying to remove a damaged brass closet flange from a 3" copper drain pipe. It's my understanding that the flange is soldered to the pipe in the same way that copper water lines are soldered, so I'm trying to un-sweat it. But something's happening with the sewer gasses when the pipe starts to warm up, and the flame seems to be drawn down the pipe instead of concentrating at the top. I've spent a lot of time trying to get the pipe/flange hot enough to release with no results. Any tips for dealing with the draft issue? I might also go out and get a MAP torch.

 

[Breplum]

Two good MAP turbo torches working together work even better. If you were using small type propane tank/torch, it is not much heat.

 

[Sponsor]

 

[Sylvan]

Better have a fire extinguisher ready if your using two mapp gas tanks

 

[mappley811]

Two good MAP turbo torches working together work even better. If you were using small type propane tank/torch, it is not much heat.

I'm seeing online that modern MAP (which is actually MAP/pro) only burns like 10% hotter than propane. They don't make true MAPP anymore. Does the extra 10% make a noticeable difference in heating time?

 

[Breplum]

Yes, MAP/Pro is noticeably hotter when it comes to soldering

 

[Fitter30]

Torch that is under size doesn't matter how long its heating a big fitting will never get it hot enough. The heat is also heating the pipe and traveling down its length. Mapp torch get one with a big tip.