copper plumbing in 1965 Trade wind

[Dr Dan]

I recently had to replace the kitchen sink in my 65 Tradewind and decided to cut the copper line where it bends to go vertical up to the faucet and put a 90 degree cut off there and finish out with a flexible supply line instead of the more ridgid copper. Big mistake so far. It seems that back in 1965 airstream used some bastard sized copper line, which I'm sure had some advantage, but at this point I can't find fittings for. It looks like a 1/2 inch line, but is actually larger and 1/2 inch fittings will not slip over it. The only other possibility is that the line got larger over the last 45 years, but I'm not buying that. Does anybody know where I can get a fitting that I can sweat on or use a compression fitting on that will fit this line? The flared end looks to have been slightly reduced to accept a 1/2 inch fitting, but you can't slide it back more than 3/4". I'm stumped and so is the guy at a good sized plumbing store that I went to after trying lowes. Neither store has anything that can help me. The factory sweated a 1/2 inch male fitting and replaced the majority of the plumbing in the rear with pex last year and I have an email and photo in to them, but I was hoping to get it up and running this weekend.
Thanks,
Dan

[TG Twinkie]

I think your problem is that the line is 3/8" or 1/2' tubing. Not 3/8"or 1/2" pipe. I replaced all of the copper in my Argosy; except for the two lines going to the shower faucet. I was able to adapt the old copper to the PEX with a "compression" fitting. The type with ferrells. You should be able to find these fittings that are threaded on one end to attach you new flex lines and have a compression fitting that will attach to the copper. I found the fitting I needed at a place called Menards, it's like Home Depot and Lowes.

[Dr Dan]

Well, the answer is that back in 1965 they did use a copper tubing that is an oddball size used in the mobile home industry that's a little bit larger than 1/2". No one uses it anymore except perhaps HVAC folks, but I was able to dig around in the basement of a RV place and find some antique adapters that reduced it to 3/8 OD and got it fixed.
Thanks for the suggestions,
Dan

[hartley1212]

I had the same issue in my 68 overlander. There are 3 different sizes of copper tubing, all of which are not used anymore accept for hvac or refrigerant. After about 5 trips to home depot here was my solution.

Found a copper tube that fit snugly inside of the existing pipe. Used copper bond to fix that joint then used a compression fitting to connect to pex. Wish I would have found an adapter in the basement of an RV store though cause that sounds a lot easier!

[RickDavis]

In addition, if a copper line has ever frozen and not broken it expands. 3/8 od becomes 7/16

[putback]

Odds are the lines froze in the past. As Rickdavis said soft copper will expand severly w/o spliting. Mine had the same problem. Soft copper is measured on the outside, ridged copper [home plumbing] is measured on the inside. You can buy sweat fittings to connect the two for a buck, usually at smaller hardware stores. BUT, if frozen/expanded its near hopeless. They often look fine, but a set of calipers will tell you the answer. You can also usually see it at a flare fitting, copper expanded so much you can't slide the fitting back. You can follow the pipe upstream to an unexpanded spot to splice a new line in. Bad news is if it froze up high behind the sink down at floor level especially in the back the condition is probably worse. I got so P Oed dealing w/mine I replaced it all. Pex on the long runs, copper for the distribution center.