I am no sure what the 4v stands for and don't take my word for it, but
if the titanium has a 3 rather than a 6 the strenth is 90,000 (6 is
160,000 4130 is 120,000.). I priced a 1 inch tube 60 inches long the
price was $550.00. There is a web site that sells cut ends much cheaper
(Titanium Joe   www. titaniumjoe.com) about 1/5 the price.

  Welding Stanless requires an argon gas purge both side. The difference
with titanium is the gas coverage for titanium on the out side needs to
be larger so a standard tig cup will not work. You need a traliing purge
as well or in a box. The oxgen has to be below .1 % and should be 0.

Harry

V= Vanadiaum
the 2 types I've worked with in bike building are 2.5/3 and 4/6  the
lower numbered alloy we used for riders who wanted a softer ride.. the
flex properties of the metal are tremendous yet withstand extreme
impacts such as rocks on a bottom bracket at 60kph..  the higher
numbered alloy is much stiffer we used this on road racing frames where
weight and the ability to transferr pedal power to the frame without
loosing any input effort to flex..

Ian
BAS