I.m thinking about building a bike frame, without the use of welding
equipment. Will "JB Weld" work for my bike frame? Is it really as
strong and shock resistant, as a weld done by the tig welder.? l like
how about re-attaching a busted off blade to a boat props, and fixing
sheared bike cranks?
Generally speaking, NO, it won't work.
Sometimes, joints in bike frame are brazed when the joint is correctly
designed for brazing, which requires substantial overlap of the pieces
Here's why a non-fusion process won't work for a bike frame. Several
of the joints in a frame are butt joints in tension (forces work to
pull them apart). If you glue them together (which is what a
metal-filled epoxy does) the glue does not have sufficient attachment
to the metal parts of the joint.
When the joint fails, one of the metal parts parts participating in
the joint will just slide out of the JB Weld, leaving both intact but
On Fri, 4 Jul 2008 22:53:09 -0700 (PDT), Mullin9
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JB lists its strength at 3960 PSI, which is a little stronger than the
best values for wood but less than bamboo. So it should be OK for a
spruce, yellow pine or oak bicycle frame but inadequate a frame made
of high-performance bamboo tubing.
There are all types of epoxy type substances in addition to JB Weld. They
are designed for specific purposes. This is possible with the substance
designed for this application. Built up a shaft two years ago where the
bearing had chewed into the shaft. Machined like metal, has worked like a
new shaft since. Not cheap, $100.00 for a pound. Cheaper than a $1000.00
For reference, chromoly 4130 steel sometimes used for bikes has a tensile
strength around 60,000 psi. The weakest mild steels I think run in the
30,000 psi range.
J-B Weld is not meant for high stress applications like holding together
That completely ignores the numerous bike makers that produce high
quality lugless frames using fillet brazing such as
http://www.sheldonbrown.com/schwinn-braze.html and see bottom of page
here http://www.argoscycles.com/custom-frames.htm . Regarding this post
while I think the OP is a troll various frames have been bonded such as
Graptec? with carbon fibre frame tubes bonded into cast aluminium lugs,
I have also read that some modern frames using Reynolds tubing maybe
bonded rather than brazed or silver soldered to preserve the material
properties although Reynolds now produce air hardening alloy tube sets
which can be welded.
I ride, daily, a bike that was made back in the 1970's using an epoxy
bonding process, instead, of TIG welding, brazing, or silver soldering.
Tubing lugs, similar to the lugs used for brazing, or silver soldering,
were used for all the tubing joints. The epoxy was used in place of the
I do not know about the use of JB Weld, but other expoxies have been
used in the past, as, evidenced by what I ride.
I do agree that fabricating the frame without the use of lugs would
cause the joints to fail when bonded together with epoxy.
I used TIG, though, to make accessories for the bike, but not while
connected to the epoxy bonded frame.
i think the aerospace program has shown that anaerobic adhesives can
work well when properly applied. as has several brands of bike frames,
particularly in the original aluminum days. of course, in those days,
we also saw what can happen when anaerobic adhesives weren't properly
applied. what was the name of that brand again?
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