[TowerTalk] Mast material

[Grant Saviers]

Tubing usually means the OD is measured in fractional inch increments, 
usually 1/16", eg 2", 2.25" etc.
Pipe usually means conforming to the Inch Pipe Standards - the inch 
"size" e.g 2" is not 2" od or id.  One reason is the wall thickness 
varies with the "schedule" designation - most commonly schedule 40, but 
schedule 10, 20, 40, 80, 160 and others are available.  The od's for all 
schedule sizes of a given IPS pipe size are the same so they can be 
threaded with the same dies.  Look it up on wikipedia for the id and od 
numbers.

So if you measure, you will know tubing vs pipe, but not the alloy or 
temper, which is what really matters for tubing.  Sch 40 pipe is 
generally a bad choice for masts (unless lightly loaded) because of the 
way it is made and the uncontrolled steel alloy used.  A file test can 
be done on steel tubing - if it's hard then you have something that is 
better than sch 40.  Drill pipe surplus is common in some locales.  It 
is hardened and a better grade steel.  If you can see a weld bead inside 
a tube then it is not the grade usually used for masts, which is smooth 
inside as it is DOM - Drawn Over Mandrel after welding the seam, and 
then heat treated.

Without some instruments, it's almost impossible to determine what the 
aluminum alloy and temper is of an unmarked piece of Al.

Definitely caveat emptor!

Grant KZ1W


On 6/27/2013 8:35 PM, mike stokes wrote:
> I have a line one some used masts.  Both aluminum and steel.  Is there
> an easy way to determine if they are actually tubing or pipe ?  or
> what type f material they are made of ?  The are from the estate of an
> SK so not much help there.
>
> Thanks in advance.
>