Whats the best goop to put on damaged pipe threads ?

[machinistbcb]

I am working on setting up my pressurized storage tank and I have several female pipe fittings on the tank that will need to be pluged. Alot on the threads in the fittings are damage, rusted, etc. Does anybody have a favorite way to seal up damaged threads ?

Thanks,
Brian

 

[EForest]

I had some damaged threads on one of my tanks and used lots of Teflon tape and TRU BLU thread dope by Rectorseal. Be generous on the male side and use very little on the female tapping or the dope will end up floating in your tank. The tru blu will give you a permanent seal that won't dry up and crack. Give it a chance to set up before you fill the tank.

best of luck, Ed

 

[trehugr]

Weld them closed if their damaged

 

[deerefanatic]

I had a large hole in the top of my milk tank. I tried to weld it shut, but couldn't get it water tight... I gave it a generous coat of hi-temp RTV silicone (available at Napa and other such stores) and it sealed.... Gotta get the steel reaaaallllllyyyyyyy clean... But if you get it to bond, you can't hardly get the stuff off.....

 

[Eric Johnson]

dope-tape-dope

 

[jebatty]

You also could re-tap the female fittings and improve the tightness of the fit.

 

[steam man]

dope-tape-dope

Get the right size pipe taps and clean up the threads. If they seem to fit ok, try the dope-tape-dope trick. On larger threads you can try dope + cheesecloth-Be warned-they are tough to take apart. Welding can be done but it has to be right. If you weld around the plug make sure the threads are ground down with a disk grinder thoroughly in the weld area to make sure you do not get any slag inclusion in the threads. It will probably leak if this is not done and it is a pain in the ass if you have to keep trying to fix it. If your only around 12-15 psi I would think tape/dope and cleaning the threads would work unless we're talking severely damaged threads.

Mike

 

[Willman]

I have had decent results with Loctite® 55™ Pipe Sealing Cord for shaky irreplaceable threads. It gets in the root of the thread, maybe even wrap with a flat teflon on top with some sort of dope, I use teflon for lubricity.There is nothing better than properly cut threads with a sharp tap or die. In your case try the sealing method and pressure test for a longer time period. No substitute for heat and pressure though. Let us know how you make out.
Will

 

[machinistbcb]

I think I will try cleaning them the best I can then the tape-dope-tape option. Two of the threads are 3 inch dia and I am having a hard time finding a tap that big. Basicly the reason most of them are damaged is becuase they all had about a 1/2 inch lenght of broken off pipe in them. So I had to cut into them lenghtwise and chisel them out. That left me with a scar on each fitting where I cut into the minor dia. of the threads with the sawzall. I thought of welding too, but I would rather try to plug as you never know when you may need a fitting in the tank.

Brian

 

[jebatty]

My Tarm came with British female pipe threads on the boiler water fittings, which I think are just straight rather than taper threaded. Tarm supplied a twinw-like cord and some thick pipe goop, with instructions to wrap the male taper pipe threads with the cord, rub in the goop generously, and then thread into the female British fittings. Worked well.

You might try a similar approach with your damaged threads. The cord should give some grip power, and with the goop, good sealing power.