Straight Vinegar dumps to remove calcium/hard buildup in old drain pipes?

Hi,
100 year old house with slow draining from one bathroom. It is not slowing in the immediate drain below the sink, it is I believe behind the wall in the section the drain travels on its way to the stack. I am certain it is because of the calcium/hard buildup in the drain pipe there.

So, I have been dumping vinegar down the drain a gallon at a time and leaving it there for a few hours and then flushing hard with hot water. Then repeating. Definitely an improvement!

Question, as I really do not want to damage these old pipes using chemicals that could erode, will straight vinegar used like this damage the metal of the pipes? I am hoping not and I think not, but would like an experienced plumbers opinion. Note I am using straight white vinegar, not adding baking soda as when I read about this it does not seem to make sense as the baking soda would neutralize the acidity of the vinegar and you need that acidity to erode the calcium/hard build up in the pipes.

Thank you!
Dvarga

 

What are your drain pipes made of?

Vinegar is an acid. It will have similar affect as stronger acids only it takes longer to both dissolve minerals and attack metal pipes. Most commercial pipe cleaners are strong bases, sort of a chemical lye. The catch is that for either to do much good they have to be strong enough or in the pipes long enough to attack cast iron. So, to have a cleaning action it also can damage pipes. The best method to clear drain lines is mechanical with a plumbers drain snake.

 

Thanks Pilot Dane! Appreciate it.

Best,
Dave

 

Pipes are old I think galvanized

 

White vinegar typically is 5% acidic. I think I'd try an enzyme drain cleaner.