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Rusting on Main - what to do?

Hi - now that heating season is over, a good time to tackle this.

This is a main line that slowly leaks. Not enough to collect much condensation in the drip cup I have below (during heating season).

I had two plumbers look at it. One said use plumbers epoxy. Another said some sort of tape that hardens and is permanent (didn't specify type and details).

obviously replacing the pipe is in option. However I'd like to explore another option.

My thought was spray rust remover then clean rust away and wrap with that tape the plumber alluded to (but I'd need to know what's appropriate).

Thanks!

Comments

  • PC7060
    PC7060 Member Posts: 783
    edited June 12
    Hi, I’m not sure not sure what you mean by “main line” but what ever it is I’d replace it.  Depending on the configuration, I’d sawsall the bad pipe in the middle, carefully back out the pipes and replace with two shorter pipe joined by a union.  

    Looking at it without any context I though it was a cast iron drain line but I do see some pipe insulation so thinking boiler but not  sure if steam or hat water system. 

    Ca you provide additional photos that show the most of the pipes and if you can show how it connects to boiler (if that’s right) that’s would be great. 
  • Jamie Hall
    Jamie Hall Member Posts: 19,432
    Looking at it I would venture that the leaking is real, and it is through the threads between that pipe and the T

    Can you fix it with tape? There are some tapes which do a pretty amazing job at that. I confess to using one particular type once in a while. However, they can't be regarded as permanent. Nor can an epoxy, such as JB Weld -- and it might be frustratingly difficult to get a good seal with.

    Problem is, if the leak is the threads, you may not be able to get a good seal because of damage to the threads on the fitting. It would probably be worth a try, however, as replacing the fitting as well as the pipe looks as though it might get interesting. I'd proceed as @PC7060 suggested -- but clean the threads in the fitting very carefully (good stiff wire brush, and be thorough) to see if they are intact. And i'd probably b3 pretty generous with the tape putting it back together.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    PC7060
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 3,657
    I remember, back in the day, cutting that pipe with a 4 wheel cutter to make an eight inch pipe section close to the leaking joint. Next was to remove the 8" section of pipe from the fitting. Following that, you need to get a pipe die and thread the long piece of pipe that remains. Then install a 5-1/2" pipe nipple (give or take depending on the pipe diameter) with a union. To make sure the leak was repaired to need to use both teflon tape and a good quality pipe dope. Back up the fitting with a 36" or 48" wrench and then use a 36" or 48" wrench to tighten the pipe nipple in that old tee fitting. Place the wrenches on the fittings only, you don't want to crush the steel pipe nipple. Just when you think it is tight enough, go about 1/2 turn more. Be careful not to go too tight, because that cast fitting will crack. If that happens then you will need another union and a new reducing Tee fitting.

    The other choice is to use a wire brush and clean that rust off the pipe. Coat the joint with JB Weld and let it set. Then add a few coats of Rust-Oleum. This way you can see if the leak gets any worse or if the JB Weld worked.

    Bottom line is, there will be no savings on your fuel usage since you can even collect any condensation in a cup. There is no sign of other water or steam damage nearby. This is just one of those things that bothers people like me because i like things perfect. I know that you can just leave it be and there will be little consequence. I also know that it is not going to get any better.

    Edward Young
    Retired HVAC Contractor from So. Jersey.
    Services first oil burner at age 16
    P/T trainer for EH-CC.org

  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 3,360
    edited June 12
    All of the previous comments are excellent; however, not easy. If you're not up for it, I recommend Denso Tape It's a cotton tape impregnated with grease; very messy to apply, but once you get a few wraps around the pipe and fittings and smooth the edges, it works wonders. Two to 5 years max. on low pressure steam.
    Often wrong, never in doubt.
  • PC7060
    PC7060 Member Posts: 783
    edited June 12
    I remember, back in the day, cutting that pipe with a 4 wheel cutter to make an eight inch pipe section close to the leaking joint. Next was to remove the 8" section of pipe from the fitting. Following that, you need to get a pipe die and thread the long piece of pipe that remains. Then install a 5-1/2" pipe nipple (give or take depending on the pipe diameter) with a union. To make sure the leak was repaired to need to use both teflon tape and a good quality pipe dope. Back up the fitting with a 36" or 48" wrench and then use a 36" or 48" wrench to tighten the pipe nipple in that old tee fitting. Place the wrenches on the fittings only, you don't want to crush the steel pipe nipple. Just when you think it is tight enough, go about 1/2 turn more. Be careful not to go too tight, because that cast fitting will crack. If that happens then you will need another union and a new reducing Tee fitting. The other choice is to use a wire brush and clean that rust off the pipe. Coat the joint with JB Weld and let it set. Then add a few coats of Rust-Oleum. This way you can see if the leak gets any worse or if the JB Weld worked. Bottom line is, there will be no savings on your fuel usage since you can even collect any condensation in a cup. There is no sign of other water or steam damage nearby. This is just one of those things that bothers people like me because i like things perfect. I know that you can just leave it be and there will be little consequence. I also know that it is not going to get any better.
    @EdTheHeaterMan
    Ed - Wow, 48” that’s a big wrench!  I’m curious how large that pipe is, I was thinking 2” based on the BX cable show in photo. 

    What’s your best guess?


  • ChrisJ
    ChrisJ Member Posts: 13,258
    PC7060 said:
    I remember, back in the day, cutting that pipe with a 4 wheel cutter to make an eight inch pipe section close to the leaking joint. Next was to remove the 8" section of pipe from the fitting. Following that, you need to get a pipe die and thread the long piece of pipe that remains. Then install a 5-1/2" pipe nipple (give or take depending on the pipe diameter) with a union. To make sure the leak was repaired to need to use both teflon tape and a good quality pipe dope. Back up the fitting with a 36" or 48" wrench and then use a 36" or 48" wrench to tighten the pipe nipple in that old tee fitting. Place the wrenches on the fittings only, you don't want to crush the steel pipe nipple. Just when you think it is tight enough, go about 1/2 turn more. Be careful not to go too tight, because that cast fitting will crack. If that happens then you will need another union and a new reducing Tee fitting. The other choice is to use a wire brush and clean that rust off the pipe. Coat the joint with JB Weld and let it set. Then add a few coats of Rust-Oleum. This way you can see if the leak gets any worse or if the JB Weld worked. Bottom line is, there will be no savings on your fuel usage since you can even collect any condensation in a cup. There is no sign of other water or steam damage nearby. This is just one of those things that bothers people like me because i like things perfect. I know that you can just leave it be and there will be little consequence. I also know that it is not going to get any better.
    @EdTheHeaterMan
    Ed - Wow, 48” that’s a big wrench!  I’m curious how large that pipe is, I was thinking 2” based on the BX cable show in photo. 

    What’s your best guess?


    2" with 1 1/4" coming out.

    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
    PC7060EdTheHeaterMan
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 3,657
    Probably 2" pipe with 1" or 1-1/4" branch. That is a job for the 36" wrench. I only had one 48" Pipe wrench and one 36". I didn't have a very large company. Six service vans/trucks on the road at my biggest. There was one 24" wrench with a broken handle. That pipe wrench has a permanent 1-1/4 x 36" long pipe wedged on it. I think I used that more than any other wrench on those big 60+ year old pipes. It was easy to attach a come-a-long to the open end of the pipe to get extra leverage.
    Edward Young
    Retired HVAC Contractor from So. Jersey.
    Services first oil burner at age 16
    P/T trainer for EH-CC.org

    ethicalpaul
  • SteamingatMohawk
    SteamingatMohawk Member Posts: 752
    Mostly good suggestions. I have a few additions.

    To maximize the likelihood of anything sticking to the tee and pipe, use a grinder and hand file to clean the surfaces only enough to get to bare metal. If this is a steam system, the pressure is low enough, it is probably not a pressure problem. If the tee or pipe is corroded significantly more, you have a bigger challenge.

    @Alan (California Radiant) Forbes suggestion is OK, but if the life of the fix is as short as he mentions, I would use a more permanent solution. It's possible, over time, the temperature of the fittings may cause the grease to soften/melt and seep out of the joint.

    If you know someone who knows how to braze, that technique may be possible. I have no experience with it. If it is possible, the biggest drawback is the size of the fittings and how much heat is needed to make a good joint.

    Soldering can be used, but searching it shows it is a questionable option.
    https://en.wikipedia.org/wiki/Solderability

  • mattmia2
    mattmia2 Member Posts: 6,007


    Soldering can be used, but searching it shows it is a questionable option.
    https://en.wikipedia.org/wiki/Solderability

    It is iron. If you clean it and use the right flux you can solder to iron. In fact the name soldering iron comes from them once being just a chunk of cast iron you heated in a fire. If the hole is large you may have to put a plug in it or regulate the heat so you can wipe the solder across the hole instead of flowing it on as a liquid.

    If you get the flux in the system you may have to skim of flush it from the boiler.
  • ChrisJ
    ChrisJ Member Posts: 13,258
    In order to solder something you first need to have good solid material.

    Rott and rust do not count.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
    mattmia2
  • mattmia2
    mattmia2 Member Posts: 6,007
    This all being said, your best bet is replacement. The first step is to see where it is leaking. My bet is in the valley of a thread where the material is thinner. If it is the threads and not the fitting, some surgery with a sawzall and/or hacksaw can cut a wedge out of the pipe screwed in to the fitting by sawing nearly to the threads then a hammer and chisel can pop that wedge loose and the pipe will be easy to unscrew at that point. Cut the pipe about an or 2 from the fitting then pop out the wedge.
    STEAM DOCTORPC7060
  • Larry Weingarten
    Larry Weingarten Member Posts: 2,637
    Hi, It's just a band-aid, but might last a while... How about using this self-fusing silicon rubber tape: https://www.mcmaster.com/rubber-tape/material~silicone-rubber/ and then adding some hose clamps over it?

    Yours, Larry
  • Jamie Hall
    Jamie Hall Member Posts: 19,432

    Hi, It's just a band-aid, but might last a while... How about using this self-fusing silicon rubber tape: https://www.mcmaster.com/rubber-tape/material~silicone-rubber/ and then adding some hose clamps over it?

    Yours, Larry

    That's the tape I've used on occasion. You don't even need hose clamps.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • ratherbfishing
    ratherbfishing Member Posts: 11
    Thanks for all the replies! In Fact it's cast iron 2 1/4 with 1 1/4 coming out of it. Low pressure steam. I believe the issue (or at least compounding the issue) is the previous owners were running steam with a faulty pressuretrol. It used to really leak but after I replaced the pressuretrol and set the cut off to 1.5 psi it doesn't drip. Replacing it would be great, but it'll get tricky. Will also likely require busting open the wall to get full access. Nice if a tape fix can buy me years. Agree, probably won't get me any fuel savings but nice to seal it up.
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,781
    edited June 27
    From the amount of scale I see, that pipe is perforated. If the holes are small enough you might be able to braze it, but I don't recommend using brazing rod in a confined space without a respirator and adequate ventilation. I'd need to see what it looks like after you clean it up. Don't bother with rust remover. Use a coarse wire brush on an angle grinder and wear gloves, goggles and a respirator. If you have kids, don't let them near the dust. There's probably some lead in that paint.

    Btw, I think the tape your plumber was referring to is a fiberglass tape with epoxy resin product they sell for replacing broken tool handles. It's very strong, but I don't recommend it for this. When you use unlike materials on something that regularly goes from 60–200°F on a daily—if not hourly—basis, they aren't going to stay stuck for very long, and you'll end up with a big mess. I'd be curious to know if he ever used it and how long it lasted. The silicone rubber products won't have this problem because they're resilient, but it's not as permanent a fix as brazing.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • Jamie Hall
    Jamie Hall Member Posts: 19,432
    The stuff @Larry Weingarten was mentioning is a silicone tape, self sealing. I've also used this: https://www.amazon.com/Rescue-Tape-RT01019-BRK-RT1000201201USCO/dp/B00AEBKYPG/ref=sr_1_4?crid=UZQGG2EGFEZM&keywords=self+sealing+silicone+tape&qid=1656375075&sprefix=self+sealing+si,aps,264&sr=8-4&th=1 with great success. Both of them stretch to flex with temperature differences, both seal well (even under a fair amount of pressure, work well wet...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • ratherbfishing
    ratherbfishing Member Posts: 11
    Thanks!
  • ratherbfishing
    ratherbfishing Member Posts: 11
    update here. finally got around to tackling this. rust came off better than expected, probably got almost all of it. I was considering spraying the bare cast iron with high heat rust oleum (https://www.rustoleum.com/product-catalog/consumer-brands/auto/specialty-paints/high-heat) before wrapping the pipe with the silicone rescue tape. advice?
    also, since the pipe looks intact, my guess is the leak is somewhere around the threads (as others assumed).

  • mattmia2
    mattmia2 Member Posts: 6,007
    You want whatever you are trying to seal it with to bond directly to the surface of the metal, don't paint/prime it (unless the primer is part of the adhesive system) until after you have made the repair. If you paint it first then the repair material has to bond to the paint and the paint has to bond to the pipe instead of the repair material bonding to the pipe.
    PC7060
  • clammy
    clammy Member Posts: 2,766
    Aside from the leak how about the why did it rot no insulation wet steam ? Instead of wasting time fiddling around just get it repaired correctly a union some nipples done and a real fitter to do it pay the piper . Insulated your piping and the bottoms of your pipes won’t rot through from all the condensate unless the boiler is piped incorrectly and tossing wet steam into your mains but heard many times steam is very forgiving and usually most w it don’t realize how bad there systems is because it’s so forgiving until it ain’t . I highly doubt pressure had or has any thing to do w rotting the bottom of your pipe that there is condensate grooving ,bad near boiler piping, wet steam ,time and no insulation are the usually ingredients for that recipe . Peace and good luck clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • ratherbfishing
    ratherbfishing Member Posts: 11
    I have a guess on the "why". bought this house a year ago. zero insulation on the pipes. pressure-trol was broken so it was running way too high of pressure. a few radiator valves were shot. Probably other things I've yet to find. basically house was a mess. money is very tight right now so i'm looking to patch this up to give me a few years. since replacing this will cost me a decent amount with not much upside, i'd like to kick the can down the road because i've got so many other repairs that are necessary and needed.
  • Larry Weingarten
    Larry Weingarten Member Posts: 2,637
    Hi @ratherbfishing , The whole idea was to patch what you have now, knowing it's a band-aid. You could add zinc primer to the pipe, but as has been said, it could be more prone to leaking, and as you do plan on replacing the pipe in future, I'm not seeing much benefit to giving it a protective anti-rust coating.
    What you have looks pretty clean, though I might remove the rest of the paint from the face of the fitting. ;)
    Yours, Larry
  • ratherbfishing
    ratherbfishing Member Posts: 11
    Thanks, appreciate the input from everyone