Old copper pipe smaller than todays 1/2"

kalisitiane · July 7

I have a 1930s lake cottage with rolled copper tubing for the plumbing. A small 2" section of this tubing burst during a freeze. I removed the damage section but a new 1/2" coupler was too big by 1/16"-1/8" and 3/8" fittings were much too small. Were there variations in sizing back then? Do I need to crimp down both ends of a 1/2 piece of tubing to allow a good repair?

hot_rod · July 7

Possibly 3/8 OD that expanded when it froze. That is common with hard drawn 1/2" in homes when they freeze.

I've used a flaring bar to size it back down to put a fitting on.

mattmia2 · July 7

what is the OD? there is tube size copper tube that is sized by the od and pipe size copper that is sized by the id. was you half inch coupler tube size or pipe size?

ChrisJ · July 7

https://forum.heatinghelp.com/discussion/201695/old-copper-pipe-smaller-than-todays-1-2

What part of the world are you located if I may ask?

pecmsg · July 7

metric or refrigeration tubing (ACR) that goes by the outside dimension

1/4 , 3/8, 1/2, 5/8, 3/4, 7/8 etc

kalisitiane · July 7

Northern Wisconsin, so definitely a frozen pipe expansion and then a burst was possible. I'll put a caliper on the portion that's more interior and compare the two. Thanks for the input.

Larry Weingarten · July 7

Hi, Sometimes silver solder is the simplest approach to burst tubing. I've repaired many frozen solar collectors this way.

Yours, Larry

STEAM DOCTOR · July 7

Might be 3/8" TP pipe. Which is essentially brass, if I am not mistaken. Needs special adaptors.

Pumpguy · July 7

Nominal rigid 1/2" copper tubing has an OD of 5/8". Many people don't understand the difference between nominal and actual.

If you're dealing with rolled 1/2" copper tubing, it might in fact actually have a 1/2" OD.

In any case, you'll need to know the actual OD before you can specify what fittings you need.

mattmia2 · July 7

you can also use a swagging tool to expand one or the other to make them match up if it really is copper and really is between sizes.

If it is some local standard brass size you can not expand it although you could expand copper to fit it.

retiredguy · July 8

Regular domestic water plumbing is measured by it's ID and refrigeration tubing is by OD. So, someone may have used 1/2" OD in lieu of 1/2"ID especially if that person was in the refrigeration or A/C business. Try going to a refrigeration supplier and buying couplers for 1/2"OD and see if that works. 1/2" copper for domestic water has an OD of 5/8" while 1/2" refrigeration tubing has an OD of 1/2". So, for example, 5/8" refrigeration tubing is the same as 1/2" nominal domestic water tubing. I said nominal since the actual ID of domestic water tubing changes with the grade of the tubing being M, L, or K, while the OD remains the same.

Mad Dog_2 · July 8

Silver braze the split closed. Simplest fix. Mad Dog

ChrisJ · July 8

If he has 1/2" OD refrigeration tubing the 3/8" fitting he bought should have fit. The OD of refrigeration tubing and plumbing pipe is the same, the descriptions are different.

At least that's been my experience.

mattmia2 · July 8

https://forum.heatinghelp.com/discussion/comment/1859693#Comment_1859693

except fittings sold as '3/8"' are typically tube size unless it is someplace that really knows plumbing.

Larry Weingarten · July 8

Hi, I'll just throw it out there that some freezing in copper tube can expand the tube a little, so it is no longer the size of either plumbing or refrigeration tubing. So the choices are to either cut a bit more tubing out, back to where it didn't freeze, or silver braze/solder the leak. Finding a way to keep it from freezing in the first place would be nice, as soft copper can only be expanded so much… or maybe this is a good place for PEX. 🤔

Yours, Larry

Old copper pipe smaller than todays 1/2"

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