Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.


Brunton Member Posts: 9

I'm having a problem getting the hot water valve spud in my cast iron radiator to seal completely. When I install the spud (3/4") into the female thread (both parts are new, by the way), the spud bottoms out before it's quite tight enough, and I still have a slow drip from the joint.

Based on someone's suggestion in my bleed valve thread (which I got to seal finally), I tried putting lampwick on the threads of the spud, then dope on top of that. Problem is, when I go to screw the spud in, the thread won't go into the connection - it piles up at the top of the female thread.

So obviously I'm missing SOMETHING! I'm using only one strand of the lampwick, and it nearly fills the groove on the spud thread.

How exactly do you use this stuff? Do I wrap the entire length of the thread, or just a couple of times around, or do I unwind part of one strand and use it, or what? I don't know what to try next.....

Thanks for your time,

Mark B.


  • Ron Schroeder_3
    Ron Schroeder_3 Member Posts: 254
    seal parallel thread

    You might try some hemp thread sealing fibre. Comb this carefully down into the thread with a small brass cleaning brush. Remember to wrap in the opposite direction as you are turning the fitting so that the hemp does not push out during installation.
    Where do you find such thread you ask? As someone who regularly installs Viessmann DHW tanks. More is provided than one needs so they should have some left over.
    If you cannot find any, call me a 604-533-9445 ext 224.
  • gerry gill
    gerry gill Member Posts: 3,058
    iv'e had great success

    with using cotton first aid gauze as one would use teflon..dope, two wraps of gauze, three for a sloppy joint, dope again, then install...hope this helps.

    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
    Serving Cleveland's eastern suburbs from Cleveland Heights down to Cuyahoga Falls.

  • bob young
    bob young Member Posts: 2,177
    lampwick school.

    start at lead thread & wrap clockwise. use spool not ball. not enough --might leak. too much -- might not run far enough into tapping. after wick, give it a schmear of compound [any kind will do ] after about three minutes you should get the drift of the whole scenario. pretty much idiot proof. pretty much gauranteed not to leak.
  • Glen
    Glen Member Posts: 855
    and -

    my former master (long a dead man) insisted on permatex sealant. Messy but effective - permatex, lampwick, then permatex again.
  • bob young
    bob young Member Posts: 2,177

    with pematex you cannot go wrong.iit usually works as a last resort when the others fail.bailed me out countless times.
  • Big Ed
    Big Ed Member Posts: 1,117
    Quick wick

    We call Quick wick , lamp wick, multi strand lamp wick is used for packings . Quick wick is a spool of cotton string or thick thread.... Come in different thicknesses for larger pipe threads........ Thick cotton sewing thread works on smaller threads....

    My way of using it, hold with your thumb the end of the thread , near where the uncut pipe and with the pipe threads finish. Run the thread up to the second from the starter pipe thread. Run in the groove around and over the thread your holding with your thumb, over and over to the second to the last pipe thread. This would keep the quick wick in place.....
  • bob_50
    bob_50 Member Posts: 306

    Get the threads nice and clean and put some 5min epoxy on them.
  • Mt. Falls Mikey
    Mt. Falls Mikey Member Posts: 30
    The way my Dad tought me

    Was to wrap the candle wicking around,or pack it in the leaking spot with a small screwdriver,driving it in with a small wood chisel or screwdriver. Also, Permatex red / black RTV is a good choice on threads that are a little funky. Must let it set up before putting pressure on it tho.
  • ScottMP
    ScottMP Member Posts: 5,884

    Now that everyone has told you how to do it let me add my two cents.

    Its sounds as if you have too large a size lampwick, ( by the way I was told "cotton wicking" ). Got to a plumbing supply house and get a another ball. Take a short trand and then pull it apart to get one small thread, not much is needed. Now apply like these guys have told you, opposite to the thread so it dos'nt run off when you tighten it.

    Godd Luck


    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
  • Big Ed
    Big Ed Member Posts: 1,117

    My Dad loved Permatex, it was my job to wick ,cut & thread. Before the days of using latex . It was great for sealing but bad for a hot date :)
  • Glen
    Glen Member Posts: 855
    absolutely -

    and I was in error assuming that our friend was using one or two threads and not the whole strand.
  • David Sutton_6
    David Sutton_6 Member Posts: 1,079
    Loctite 55

    This works real well in a seal like you have.
  • ScottMP
    ScottMP Member Posts: 5,884

    Do I type WAY to fast ... looks like I don't know how to spell :)


    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
  • sinkdoc 43381
    sinkdoc 43381 Member Posts: 6

    use a compound called xpando with lampwick then forgetaboutit
  • jeff_51
    jeff_51 Member Posts: 545
    love xpando!!!!!!!!!!!!!!!!!!!!!

This discussion has been closed.