Hello,

I am replacing a leaky main shut off valve to my house. I duplicating the exact set up that was there before except I am using brass valves / nipples instead of cast iron. The problem I am having is attaching the 3/4" brass shut off valve to the main water line coming from the city's shut off valve. A small amount of the cast iron (male) threads broke off when I removed the existing shut off valve. Now, I can't get the brass valve to thread onto the cast iron. It almost seems as if the 3/4" brass is too small, but I know a 1" valve would be way too big. Any suggestions for attaching the valve would be great. Also, I can email a picture if need be, but I can't seem to get them to upload to the forum. Thanks in advance.

Seth

Use "go advanced" to upload pictures. They may have to be re-sized. IrfanView - Official Homepage - one of the most popular viewers worldwide (http://www.irfanview.com) is a free program.

It's probably galvanized. You will probably have to cut and re-thread the galvanized. The dies will be NPT (National pipe thread)

You'll need to add a dialectric union before attaching the brass valve.

OK, you want to know the size and say you want to know it accurately. Take a piece of string/paper/almost anything and tape it around the pipe and cut with a razor blade. Remove and measure with a ruler. This is the circumference. Divide by 3.14 and this is the diameter.

Then look at this table for the external diameter for a schedule 40 pipe. http://www.snapfour.com/pdf/Table_38-39.pdf

Then find the nominal size.

Post a pic.

Please, post photos...

How much threads broke off? And how are the rest of the threads? And how much thread will be left once you get rid of the bad threads and carefully hacksawed off the bad. The other problem is that the brass female can't even help straighten a couple of the worn/slightly damaged threads on the male a picture would defiantly help. The brass is a softer metal there in-lies the problem. I don't know exactly what side of the meter you are on. But if you are past the meter and the bad pipe is on the house side I would cut the pipe and re-thread new threads on it. Or the other option is look to the next threaded connection a coupling 90 or T and can you spin that off and start a longer run? Obviously the nipple is now to short But in my area Lowe's and home have a rigid pipe threader to cut longer nipples/length of pipe. To help remove the next connection heat it up at the threaded spot to make it easier to spin off. Old pipe dope can get like concrete.

1 black iron pipe needs good threads for softer brass.
2. clean up black iron threads better try again ( not recommended but might do the trick)
3. clean up threads and use pipe threader to add a bit more threads and it will maybe straighten the bad out.
5. carefully hack saw of the bad part and make sure there's still enough thread left to start the pipe threader to get more threads
6. spin off this damage pipe section to the other connection and get a new piece.
One of these methods will work. But a picture would be better to see how bad it is.
Hope this helped

21boat: black iron pipe is used for gas installations, not for water. If used in water piping, black pipe will rust very rapidly...

I would suggest that he uses either Galvanized nipples or Brass nipples

Wow, thank you for all the responses.

The amount of pipe that broke off is probably around an eighth of an inch.

Since the wife is out of town this weekend, I can have the water off for an extended amount of time. Is it a bad idea for me to go all the way to the city's shut off valve with copper (I'm planning on repipe the house sometime in the future).

Thanks again,

Seth

SORRY I get to used to working on our 100 year old homes in our city My city as founded in 1734. I do see how long they last and yes they will cored in time. Although not to defend it that way I have seen pipes 40 plus years still working. That's the rehab we work with. Again your correct. I missed that just trying to help out. We also work with a lot of lead bend and oakum and lead problems.

Seth: it is always good idea to replace water main with copper - especially if you plan on repiping whole house later. Please, post photo of your present situation. Thanks...

OKay, here are the pictures.

The broken threads are on the pipe going into the ground (Closeup in second two photos). Hope this helps.

Seth

This is when it pays to have a surplus place nearby:

Harbor Freight Tools - Quality Tools at the Lowest Prices (http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=94101)

Are you using teflon tape on the threads?

I put teflon on at first, but then realized I couldn't get the valve onto the threads. So, after that I tried without teflon, and again no luck.

Yes, that tool would be quite handy.

If I were to take the pipe out all the way to the city's valve (about 10 -15 ft.), what type and size of copper should I use (It obviously is going to be buried). And climate-wise, I'm in Sacramento, California.

Nice visual... That pipe looks crystallized to me...

If you can rent from Home Depot 3/4 thread cutting die - rent one. Put cutting oil on threads, grab the pipe about 6" bellow the threaded area. Now, insert the 3/4" die head over the threads and cut couple more threads on pipe. Make sure the pipe is not twisting or it may crack lenghtwise ( that's why you are using wrench to counter-balance twisting pressure on pipe ). Install only brass valve on top of black pipe.

Type M or L. M is hard and should be used for straight lengths. L is soft.

You will notice a difference in the wall thickness.
Copper used in domestic hot water is actually tubing, not pipe.

These things: Google Image Result for http://www.drillspot.com/pimages/153/15381_300.jpg (http://images.google.com/imgres?imgurl=http://www.drillspot.com/pimages/153/15381_300.jpg&imgrefurl=http://www.drillspot.com/products/53187/Watts_3001A-2_Dielectric_Union&usg=__cjGl3W4f6RfOtZlBOyKsPEdL4Cw=&h=300&w=300&sz=107&hl=en&start=3&tbnid=Gdnoj7-HUDgf6M:&tbnh=116&tbnw=116&prev=/images%3Fq%3Ddialectric%2Bunion%26gbv%3D2%26hl%3De n%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official%26sa%3DG)

Should be used to connect dissimilar metals.

Copper:

M = above ground only
L = suitable to be buried
K = is threadable, used mostly in commercial and industrial plumbing applications

These days, nobody wants M copper in residential installations since L has twice as thick wall and tends to lasts bit longer...

It's against my city code to use M except for boilers. L for all domestic water also the buried water line in our county has to be covered in rice mix stone min 12" above buried service lines. If you end up replacing more buired line keep this in mind and check your local code.

1 The reason is on back filling it helps prevent possible damage to buried service line(s) If sharp rock(s) hits new service

2. So if it needs service repair down the road you know when you scrape with the backhoe /pick/ sharp shovel point it gives early warning your getting close to the service ( I spent 29 years step digging when my hoe just sits there).

BERGS4 check your code before backfill

Good luck!

Molo nailed it with.
If you can rent from Home Depot 3/4 thread cutting die - rent one. Put cutting oil on threads, grab the pipe about 6" bellow the threaded area. Now, insert the 3/4" die head over the threads and cut couple more threads on pipe. Make sure the pipe is not twisting or it may crack lenghtwise ( that's why you are using wrench to counter-balance twisting pressure on pipe ). Install only brass valve on top of black pipe.
And here's what they look like. (see image) If the pipe's not ate up simply clean up the nthreads. Good luck and thamk you for rating my answer. Tom

Thanks to everyone for their help. The die cutter worked perfectly. Now, the only thing I need to do is buy a house bib that points outward instead of inward.:(

Seth

Thanks to everyone for their help. The die cutter worked perfectly. Now, the only thing I need to do is buy a house bib that points outward instead of inward.:(

Seth

Will this hose bib from Nibco do the job? (see image) Regards, Tom

It looks like it would. Is that something HD / Lowe's might have or is it an online order?

When you re-do it, sleave the penetrations with a piece of PVC and caulk.

Nice job. The hose bib can wait till spring. <G>.

Okay, will do. Thanks.

Seth