[ATM] Fifteen inch tube

[Bob May]

One thing to consider is to get your own rolled at a local
fabrication shop.  That may mean that they will also have to put
together two pieces  by welding but it shouldn't be too
expensive.
Then there is always air conditioning ducts that may work.  The
steel of those is pretty light and putting in baffles will tend
very strongly to improve the rigidity of those tubes.
Bob May
Due to the large volume of SPAM thaat I'm getting, add an open
square bracket to the subject line or my spam filter will reject
your post~
rmay at nethere.com
http: slash /nav.to slash bobmay
http: slash /bobmay dot astronomy.net
Replace the obvious words with the proper character.