Clogged 3/4" Gray PVC conduit

[Degolyerent]

Muratic acid would be the ticket use full strength , we use it diluted to clean brick and concrete , full strength would dissolve cement

 

[brandoro]

I'm also an electrician and have used vinegar and a piece of fish tape on a drill to break out small blockages in conduit. The other acids suggested should be much more agressive so should do the job more quickly.

 

[DiskDoctr]

To DiskDoctr
As I understand the problem the cement plug is inside the conduit and we want to make the cement brittle in the conduit. Then flush with lots of water.

Craig Clayton

Yep. Wear gloves and eye protection.

 

[dstig1]

Too late to the party. It seems you all beat me to it. Most anything mechanical you would do will destroy the PVC. Acid is the way to go. It won't touch the PVC unless you get something seriously industrial, and you likely don't have access to that. Watch your eyes (goggles, not glasses), skin and especially clothes. You'll find out where you splashed it on your clothes after the next washing Last thing to watch is that the reaction will liberate some hydrogen gas, so no open flames/sparks.

*** You should dig out the other end before starting the acid pour. You need to get there anyway, and you need to know when it breaks through. You may need to plug the bottom to let the acid sit and work on the concrete without just running out after it breaks through. Rubber stopper should do the trick.

Cover the whole pillar in plastic, and do it shingle-style so any acid that runs down won't touch the stonework.

Baking soda to neutralize as needed, and lots of water.

Oh and - the warmer the temp, the faster the reaction. I would go with Hydrochloric Acid = HCl (aka Muriatic), avoid sulfuric as it is very nasty.

 

[not2old]

I'd go with the acid method as you'd be less likely to damage the conduit and because I'm lazy, it will take less effort.

 

[tcartwri]

If there's any water standing in the pipe, you will get a pretty violent reaction. Make sure you blow it out first.

 

[socallly]

I will blow out the standing water before starting. I located some 50% Muriatic acid at a lab supply store 500ml bottle, the strongest I could find.

How much of the 500ml should I pore in the conduit?

 

[beppington]

Wow what a pain in the boo-tay

 

[DiskDoctr]

I will blow out the standing water before starting. I located some 50% Muriatic acid at a lab supply store 500ml bottle, the strongest I could find.

How much of the 500ml should I pore in the conduit?

My guess would be about a cup or two. It's only 3/4" pipe. How tall is the pipe?

FYI. Lowes has Muriatic acid, a bit less than $8/gal.

BTW, water in the pipe isn't a problem for the reaction, but will dilute the acid. It's better to get it out first.