It's so that the fittings will fit any thickness. Mike Eorgoff
----- Original Message ----- From: "Royce Woodbury" <[EMAIL PROTECTED]> To: "Multiple recipients of sslivesteam" <[EMAIL PROTECTED]> Sent: Monday, April 15, 2002 4:02 PM Subject: Re: of boilers and things > > So Harry, I can understand why a so-called 1 1/2" tubing would be 1 5/8" OD if > the tubing has a wall thickness of .0625. But are the other wall thicknesses > still 1 5/8" OD, letting the ID vary ? Seems an odd way of doing it. It would > seem that the ID is the most important "characteristic" of tubing as all the > action takes place inside the tube. 1 1/2" tubing should have an ID of 1 1/2", > regardless of wall thickness. It is the outside that should vary. What have I > missed here ? > > royce in SB > > PS, my tubing holding brackets are coming along nicely. > > Harry Wade wrote: > > > At 07:12 AM 4/15/02 -0700, you wrote: > > >So here's a question to "pick things up a little". > > >I have a piece of boiler tubing from a kit 1 1/2" in outside diameter with a > > >wall thickness of about .035". > > > > Royce, > > Even if you did go to a thinner wall thickness (which would be > > difficult because what you have is below Type DVW at .042") if you plugged > > the parameters into the standard formula for bursting strength of a tube > > you would find that it's still well in excess of your intended maximum > > operating temperature. So it wouldn't be a No-No from purely a pressure > > standpoint necessarily. What would be the first and primary problem with > > thin tube would be it's ability to be machined or worked without deforming > > (such as while drilling bushing holes) and then after it was annealed > > during silver soldering, it's ability to retain its shape, especially > > around bushings, when being installed. > > > > >>If one were to go thicker, the heat transfer properties of the boiler > > would >>change. > > > > Yes, and for the better. Thicker material will absorb and distribute > > the heat more evenly. Thin material will tend to spot heat. > > > > >And the same for the flue tubes. My question is, is it a bad idea to > > increase wall thickness for whatever reason ? > > > > IMHO, no. If a flue fails the boiler is usually toast, or at least > > toast without a very tedious repair job, so for flues I use the thickest > > walled tubes (Type K) because I want them to be as resistant to damage from > > the various forces acting upon them as reasonably possible. This would be > > especially true of coal fired boilers where the flues would be subject to > > abrasion from brushing. The only drawback to this is that Type K and L > > tube aren't usually available at local D.I.Y. stores so unless you have a > > shop which will cut tube to length must mail ordered, or be bought in 20 ft > > lengths. > > To give our friends on the list who buy tube by "gauge" an idea of what > > tube "types" refer to, in the U.S. a 1-1/2" (nominal) copper tube will > > actually be 1.625" O.D. and will be made in four common wall thicknesses > > (types): Type K = .072"; Type L = .060"; Type M = .049"; Type DWV = .042". > > > > Regards, > > Harry > > >
