Copper Tubing size

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Dom61

Senior Member
Joined
Aug 26, 2010
Messages
100
Location
USA
Vessel Name
Brandi Jo
Vessel Make
1975 Marine Trader 34
Hi , I Have a 1975 MTDC it came with a electric stove.The builder installed a copper tubing from the flybridge throught the wall into the galley, in case you want to switch to propane anyone have any idea what size the tubing is it is to small foor 3/8 and to large for 1/4 Thanks Dom
 
Outside diameter or inside diameter? Plumbing refers to ID, refrigeration refers to OD. There is a 5/16" OD refrigeration tubing. You could just pull a new pre made propane rated hose in using old copper to fish it thru.
 
5/16 is rare but does exist. I would re-plumb to 3/8 or better yet use appropriate hose and fittings. Make sure you have the right shut offs also.
 
its called 3/8 copper tubing...I have sold thousands of feet of this stuff while in the RV business years ago..its standard in the propane industry. don't try to measure it ...it will just make you crazy. ask for 3/8 FLARED copper fittings from your dealer.
 
The nominal size of copper tubing is neither the OD nor the ID (that would be too easy). There are tables online.
 
Most likely 5/16 They used it for most things in the 70-late 80's My trawlers fuel etc is all 5/16" difficult to get correct fittings nowadays. Most of the trawlers from that era also have lots of 1/2" however it's thick wall imperial that now has been replaced by modern 1/2" thin wall copper. the older stuff can be connected to the new by a (old copper) metric 14mm to 1/2" connecter new pipe.
 
Copper tube size usually goes by its outside diameter then by its wall thickness. CTS (copper tube size) is its designation. Could be measured in outside dia. in mm if the boat was made overseas. K and L are designation of wall thickness. The easiest way to do it is to take your flaring tool and lock it around the tube then read the size off of the handle of the flare tool. Yours is probably 3/8".www.copper.org/publications/pub_list/pdf/copper_tube_handbook.pdf
 
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