Clearing rusted shower p-trap

[Brucet99]

80 year old shower trap in a mountain cabin, either galvanized or CI, I guess. What was common in 1940?

Anyway, for 30 years the method of freeze prevention was to pour a cup of salt in. Past 50 years we used antifreeze. Drained more and more slowly for the past 15 years, but pouring bleach in helped where Drano did not. Now it has become so clogged with corrosion that it hardly drains at all. Friend dug out corrosion in the visible half, but could not get around the bend. No way to know how far the corrosion extends. Likely just in the trap where there would be water all of the time.

Access from below could be accomplished by taking down some ceiling 3/8" T&G bead boards, but I'm not sure I could replace the trap anyway without destroying the pan.

Any ideas for "boring out" the second half of the trap?

 

[John Gayewski]

You need a bladder type drain cleaner. Stick it in the pipe and turn it on the bladder expands and forces water at full pressure down the pipe. There's really no reliable way to clean past a small trap.

 

[Sponsor]

 

[Brucet99]

You need a bladder type drain cleaner. Stick it in the pipe and turn it on the bladder expands and forces water at full pressure down the pipe. There's really no reliable way to clean past a small trap.

Does that clean out rust?

 

[John Gayewski]

Does that clean out rust?

Well water carved the grand canyon so I do think it can handle a ptrap. Just a matter of how long you let it run and if you think the time it worth it. Sounds old enough to just remove and repipe.

 

[Reach4]

The drain bladder is cheap and easy to try. I am thinking that the higher the water pressure, the more likely it could work.

If chemically treating, I might use Iron Out powder, but I am not sure that is going to do it. The smell is not that good, but not the worst.