# How to repair a hole in cast Iron pipe?



## Mike Swearingen

The "best way" is to cut off the cast iron with the hole and replace it with PVC white plastic connected with a no-hub coupling from the cut-off to a new toilet flange bolted to the floor (with ony the thickness of the flange itself above the finished floor level). You can cut cast iron with a reciprocating saw and metal cutting blades or with a snap cutter made for the purpose.
Another way is to sand the area around the hole, run a bead of clear silicone caulk around it, wrap it with a piece of rubber (gasket material or inner tube) and clamp over it with a stainless steel gear clamp(s).
Good Luck!
Mike


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## bofusmosby

Thank you Mike for your response. The hole is about the size of a pencil eraser. I feel that someone from a foundation company that had done work on my house several years ago put this hole there. The pipe appears to be in great shape, except this perfectly round hole put in the pipe. This foundation company tried to back out of the work they had said they would do, and I let them know that I would not be paying them the second half amount of money until they did all the work they said they were going to do. The owner of the foundation company called one of his workers off to the side, and whispered something to this worker, just before they started to do the final work I told them they must do. Just a gut feeling though....No proof.

Since this pipe is under the house, and there is little clearance under the house, I am going to try to repair the hole. Looking into the hole, I can see the complete thickness of the metal, and believe that there is no other way that hole could have gotten there. 

Thanks for your advice!


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## jogr

You might try a good expoxy if you can get the hole clean and dry. Otherwise go for Mike's clamp and rubber gasket.


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## bofusmosby

Unfortunately, because this hole is in the middle of a "t" connection, there is no way of installing a clamp, and rubber patch. I got some of this Epoxy putty. I plan on using a wire bruch on the pipe to clean it, then wipe it down with rags with acitone. This evaporates fast, and will remove all the rust dust. I hope I am able to clean inside of the hole as much as possible, and use this putty.


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## Frank Steele

If the hole is small as you say get your hands on a chunk of hard roofing tar (not Henery's roof mastic, the hard stuff they melt down for flat roofs). You heat the end of it to get it soft then smear it over the hole untill it is sealed. When it cools it will bond and be as hard as a rock.


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## nacko

find a machine screw that is just bigger than the hole and is about 3/8" long. go to this chart and get the drill size and also buy the right tap
http://www.engineersedge.com/tap_drill_chart.htm

drill out the hole, tap it, get some epoxy putty, or some super blue thread sealant, put the thread compound in the hole, screw it in, voila, good for life.:thumbup:


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## Tommy Plumb

I've never tried to drill cast iron but I'm positive it would be very difficult. The same goes for attempting to tap it. You are also now running the risk of cracking it. Putting a screw in the pipe even if it's just in a little bit will create a magnet for clogs as things get stuck on it and build up.
The only correct way to fix it is to cut it out and replace the piece.


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## Mike Swearingen

I agree with Marlin.
Cut this out and replace it with PVC fittings, etc. Then, you never have to worry about it again.
Sounds like the foundation company jerks deliberately sabotaged your line with a drill.
Unfortunately, such a small thing is not worth the legal hassle and expense to take any action, and proving it would be another story also.
Mike


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## jpplumber

Ideally it would be best to cut it all out. The next best would be to use either the epoxy or the tar. By all means *do not* try to tap it and insert a screw into the pipe.


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## bofusmosby

Thanks guys for the advice. Where the pipe is located, makes it out of the question for replacement. Its just a small hole, perfectly round. I see no other way this hole could have gotten there. Now I am wondering what else those idiots might have done. I would never try to put in a screw. The risk is too great. If it were located elsewhere, I would just replace it. I am going to try some of the epoxy putty. I'll be doing this this weekend. I will post my results.

Thanks again for the advice guys. I appreciate it!


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## bridjon

*How did you fix it*

Hi 
I have a similar problem in a verticle cast iron pipe. What did you plug the hole with?


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## bofusmosby

Gezzz, I can't believe that I forgot to post the results.

I used the epoxy putty, and it worked fine. I used to sandpaper (rolled into a small tube) and cleaned the inside of the hole, as well as sanding the outside of the pipe to remove any loos dirt, rust, etc.. Then I applied the epoxy putty, making sure that the epoxy also went into the hole a little.

Bofus


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## majakdragon

JB Weld will solve the problem. Just don't overfill the hole to make a "hanger" for paper when flushed. I have patched cracks in water pumps with it when the company could not remove the pump or would not buy a new one at the time. No patch is ever as good as replacing the pipe, but sometimes it is not an option at the time.


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## 4just1don

Somebody took ALOT of time and wrecked numeerous drill bits drilling cast(without cracking it) Dont overlook a previous homeowner etc, that wanted a dehumidifier drain,,,or other similiar small drain tube installed


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## bofusmosby

Hmmm, that thought never entered my mind.


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## skatestoked2000

*My Situation*

I too have a hole in a pipe that needs to be fixed asap. It's about the size of a nickel. The pipe is under the kitchen sink and the hole is on the inside of the bend on an elbow piece. I would just replace the pipe but the other end goes straight through the back of the cabinet and disappears into the wall. No $$$ for a plumber right now, finances are thin due to holidays so it's not an option. If anybody has any ideas i'd appreciate it. Thanks.

- Jeremy


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## tribe_fan

Skates - you may want to start a new thread and post a picture -

To the original poster - the hole may have been drilled to see where a clog existed , or to try and insert a a thin snake ?


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## bridjon

*Cast Iron Pipe*

Thanks guys if I do need to plug it I will make sure that there no bits to cause snags When I sanded down to the bare metal (no power tools used) I took a closer look at the hole which is situated on the weld join. I tried to poke a tooth pick through, it would not go through. After some time I decided that this “fault” has been there since 1955 when then house was first built. So I was left with the Problem of identifying where the long rust streaks are coming from. After filling and emptying the bath and flushing the lavatory at the same time I guess I have given the pipe a good test… but no leak! The pipe is exposed in a cold (unfinished) part of the basement and the other side of the basement is finished with a gas fire installed. There are doors Etc dividing the 2 rooms. We are keeping our fingers crossed that what we are seeing is condensation caused by the gas fire emissions from the family room drifting through and coming in contact with the cold metal. The pipe is now lagged with insulation and anywhere I could see any pitting or tiny holes (3 places) I have taped some tissue over the hole with clear tape. I will leave that lot for about a month and report back my findings. As Majakdragon says “If you have never made a mistake, you haven't done much”


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## HelpingHands

*What about spot welding/soldering it with*

Using This stuff? Anyone try this on cast iron drain lines?

http://www.cisoldit4u.com/castaloy.htm

The last thread above, mentioned a hole in the "weld joint" So cast iron is welded together right.. mmm Seems plausible..If its joined in MFG by WELDING, why then couldnt it be REPAIRED BY WELDING/Soldering as long as the section was cleaned and the "weld" could be done safely?

I have a very similar problem mentioned in this thread, its just a small hole which is rusting out and leaving streaks on drain pipe.. no bigger than a pencil lead its also easy very easy access for me.. Before I found the link above, I figured I could ARC/ROD weld a spot to fill in the hole (isnt most cast iron weldable?) I am asking because My friend welds cast iron ornamental iron onto his railings when doing curls and stuff... and it holds very well. I am wondering if regular arc welding rods would work? Just clean the area spot weld grind smooth?

Or the stuff above should work too and it doesnt seemt to even require a Arc Welding Kit, just a regular propane torch and some flux? 

Seems to me either method would work for small holes/cracks, as long as the pipe is easily accessable and a torch/arc welder can be used safely? I dont think the welded plug in any case would protrude too far into the hole to become a problem.. larger holes might be an issue, but I bet you could even build up the material slowly?

Just my 2cts 

Any opinions or experience trying welding or this rod system above..welcome.. I will also post how mine turned out.. My pipe is a drain line which is open in a garage and completely painted.. so the hole/rust line is pretty visible.. and any further leaks would be quickly apparent. I was thinking about cutting the section out and replacing using G WormCouplings, but the rest of the pipe seems fine.. Besides if this works and I can confirm it, it should be MUCH easier than cutting out pipes, and should be MUCH stronger and more permanent than other methods like epoxy/silicone.. etc.?

Only other danger I could foresee would be igniting the "Methane GAS" in the drain line! ahhaa ALA Tim Taylor.. Probably not likely.. worse case would make an underwater flame bubble in the camode.. or flash out the vent pipe? hehee.


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## bofusmosby

As far as the methane gas goes, you might want to catch it on video. I can see it now, a 6 foot flame shooting out of the toilet. You would win the Americas Funniest Videos award of $100K.:laughing::laughing::laughing:


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## scrubby

*different goop*

believe it or not bondo works great on stuff like that, its used on wooden boats in places where you would wouldnt think, tiger hair is even better, its just a drain pipe


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## jogr

The problem with using tiger hair is that tigers are very hard to find, much less catch. And then when you pull out some hair they get very very cranky.


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## Daniel Holzman

There are several different types of iron pipe. Cast iron is typically more than 30 years old, it has been replaced with ductile iron pipe (closer to steel than cast iron). There is also wrought iron, very hard to find, used almost entirely for decorative railings and sculpture.

Cast iron is hard to weld due to the distribution of carbon grains in it, ductile iron is easier to weld, and wrought iron is the easiest to weld, or so I am told by people who work with wrought iron.

i have seen ductile iron tapped using a steel drill bit and a tap on commercial projects. Cast iron is hard to tap, tends to crack. Not sure if you can tap wrought iron, pretty irrelevant since you will never see wrought iron in residential use for piping. I had a broken fitting on my furnace, couldn't weld it or solder it, so I used epoxy putty. Worked great, has lasted more than 10 years now, no leaks.


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## scrubby

*stripes are good*

mayby true, a tiger is hard to catch, im not to sure but i think some one else catchs it a puts the hair in the can


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## Michael Thomas

Just adding this comment because this thread was referenced in another post today: when cast iron drain pipes are developing holes (as opposed to cracks along the length of the pipe, which usually result from freezing) - and especially if they're horizontal rather than vertical runs -it's not uncommon for there to be other nearby sections of pipe which are also nearly rusted through, in which case it makes sense to just bite the bullet and replace all of the material that is reasonably accessible.


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## DangerMouse

Good point! But in some cases, there is just a tiny hole dripping in an easily accessible spot that the solutions offered here are ideal for.
THEN you just hope the rest of the pipe lasts a few more months/years until it all needs replacing. 

DM


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