Try local suppliers for grade A513 DOM tube. A513 is the process -
welded and then drawn over mandrel = DOM.
Onlinemetals.com sells 8' of 0.25" wall (probably overkill for 8') A513
1020-1026 alloy for $120, and likely will supply longer if you are
willing to pay the freight. They have it in 8 wall thickness from 0.065
to 0.50", so whatever strength you need, they have. Use one of the mast
calculators to find the wall thickness needed for 72ksi steel (their
spec). A513 alloy 1020-1026 has a yield of 72ksi, so likely twice or
more whatever ungraded/unknown alloy IPS would be for the same
wall/diameter. A513 is not galvanized, so a good paint job is needed in
and out. Or take it to a hot dip galvanizer, $100 minimum here or
$0.55/lb of steel going into the vat.
DXE says "4130 A513" which is one of about 25 steels A513 can be made
from. However, other suppliers say the 4130 yield is 80ksi, the ASTM
spec is 80ksi and the "100ksi yield, 110ksi tensile" is the DXE spec.
Other specs I found for 4130 normalized range from 64ksi to 90ksi yield.
I never figured out what hot dip galvanizing does to normalized steel
(1500deg), but I doubt it raises the yield point.
http://www.industrialmetalsales.com/addtocart.sc?productId=1199&quantity=1
shows 6' x 0.25" wall A513 for $46, an even better deal if they will
ship 8'. Not clear what steel alloy. Ask.
here is a chart with some A513 choices
http://www.amcastle.com/Download/tubingqg240b.pdf Armed with alloy
data, you will likely have a more productive discussion with suppliers.
and for bedtime reading the ASTM A513 spec
http://www.industrialtube.com/client/images/A513.pdf I note that the
OLM claimed yield numbers are higher than those in this spec for A513
1020-1026 as well.
Increasing the diameter of a mast pays back much better than increasing
the wall thickness. So thicker than 0.25" wall is pretty much a waste
of dollars vs going to a larger diameter.
Grant KZ1W
On 5/12/2015 14:07 PM, Patrick Greenlee wrote:
I am searching for a less expensive source of tubing than DXE and
UST. I found that US Tower sells CM tubing in 2 inch OD with walls
that are .25 inches thick and .375 thick. The 1/4 wall is $379.95
plus freight and the 3/8 wall is (brace yourself) $1699.95 plus
shipping. You order through and pay HRO, UST ships it to you.
I found an on-line retailer who sells by the foot from 1 to 8 ft with
8 ft priced more than 22 ft from HRO or DXE. Still looking. If I end
up buying 22 ft I will probably use less than half and would likely be
looking to sell my surplus.
I agree with Bry, there has to be a source of intermediate lengths at
more reasonable prices. But where?
Patrick NJ5G
On 5/12/2015 3:12 PM, Bry Carling AF4K wrote:
I have found a local surplus source for tubing that is well below the
high retail prices at
ALRO. These probably exist all over the country too...
Bry AF4K
On 11 May 2015 at 11:58, Scott Johns wrote:
One thing I have run in to with Arlo, which may be reflected in their
lower pricing, is Foreign alloy. Some of the foreign alloy has been
different enough in sizing that the 0.58 sections will not telescope. I
have not run into that problem with US alloy.
73, Scott W3TX
On 5/11/15 11:51 AM, "Jon Pearl - W4ABC" <jonpearl@tampabay.rr.com>
wrote:
Hi Roger,
I've found them very easy to work with when purchasing DOM tubing as
well as aluminum plate. They'll even cut plate to dimensions for a
few
bucks per cut.
73,
Jon Pearl - W4ABC
www.w4abc.com
On 5/10/2015 8:10 PM, Roger (K8RI) on TT wrote:
On 5/10/2015 2:54 PM, Jon Pearl - W4ABC wrote:
Orlando is right around the corner from you...
http://www.alro.com/locations/locationsmain.aspx?Loc=FL
Standard disclaimer: I have no interest in Alro other than being a
satisfied customer
I didn't realize they were so wide spread, but Alro has an outlet
about 20 miles from me up here in Michigan.Their prices, up here are
better than the local supply. Although I may purchase 10 stock
lengths of 1.5" and 2" diameter 6061T6 and DOM steel tube, at times I
have called over with a relatively small order that I had planned on
picking up. They delivered it right to my door. A small order is
not
just one piece of mast. I assume they must have had another, larger
delivery in the area.
As with large companies with multiple outlets, I assume policies may
vary between outlets.
73
Roger (K8RI)
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