NYPlumber Your correct. Black and White IS fantastic and Yes it is ideal for Cast Iron (and brass and bronze)
I used it on many cracked steam radiators and cracked hub Cast Iron Joints and even a cracked engine block (long story).
We used B&W especially as an apprentice when the hub cracked in the winter when pouring a lead joint and packing the lead too hard working in NYC high rises and alterations.
My local 2 training was amazing in the jobbing aspects
I do not know of any jobbing shop including my own that we don’t have B&W on board the van.
The reason I didn’t suggest B&W is the high concentration of Sulfur and having an unskilled person using it with even a propane torch
could cause a major fire or burns especially in the home.
Most novice folks either over heat the base metal Or worse put a direct flame on the B&W and hello melt down city.
Ever see B&W dripping on fire?
Remember NYPlumber we work in one of the oldest cities in America with some of the worlds tallest buildings with the most stringent plumbing code / building codes in the nation.
How many boon dock ditch diggers can boast about using NY Steam 125# PSI or installing 8″ leader lines 47 stories high connected to an 18″ trap?
Ask 99.9% of the folks reading these lists what is a suds pressure zone.
Very few of the folks would ever think of using Quality Holby mixing valves instead of the cheap crap as they just dont know better.
When I wrote about TP copper or yellow brass I received over 57 E mails asking “What dat”
For example Eutectic in Long Island City makes custom welding rods for almost any application the same with Nassau Research corporation as I used them a few times for getting special aluminum rods that can weld using a Turbo torch.
The rod is not the key, it is the preheating and cooling down of the cast iron that makes it difficult for the average non mechanic to comprehend.
The preparation like drilling the crack so it cant spread or grinding a slightly “V” so it gives a better joint bed for several passes for better root penetration.
Hey some moron on this list went to a home center to ask the stock boy about “PLUMMMMIN” in his run down abode.
Could you imagine someone saying “Sure my man go out get propoxy and dont worry about a thing as you cant see it from my house”
Giving advice on here I try to be slightly on the technical side as to let folks know plumbing/gas fitting and ever drain cleaning can be very unforgiving if not performed by a professional.
This one low life went to a home center picked the stock boys mind THEN came on here seeking “professional” advice.
Sight unseen to go back to the store clerk so he can play big shot.
I told Lorenzo many times that we should be very careful on the advice we do give on here as telling someone to solder a joint sounds easy BUT what do we tell them about the dangers of using flux?
Have a great one and again GREAT minds do think alike LOL.. Sylvan