[TowerTalk] FW: Mast material

[Matt]

Just an add to Grant's good comments - look for any stenciled markings which
can give a clue as to the material.

KM5VI

-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of Grant
Saviers
Sent: Thursday, June 27, 2013 11:00 PM
To: mike stokes
Cc: Tower and HF antenna construction topics.
Subject: Re: [TowerTalk] Mast material

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.
>

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