Noted.
I will try to upgrade my technique.



"Jeff Liebermann" wrote in message
...
On Thu, 2 Sep 2010 16:43:03 -1000, "John Keiser"
wrote:

I use it to splice "O" rings into custom sizes. If done properly [clean
single edge razor blade, square cut] holds up well as a VCR drive belt,
even in a swimming pool vacuum line leaf trap. Using a telfon "v" block
would help alignment but I've managed without.

The square cut (butt splice) doesn't work well. The problem is that
the hardened super glue goes across the diameter of the rubber o-ring.
If this diameter is compressed in any way, the superglue cracks, and
the o-ring falls apart. This is especially important for internal
o-ring seals, which use o-ring compression to maintain pressure. I've
done bench tests on various methods and found butt splices lacking. It
will work with a flexible adhesive, such as RTV, but not rock hard CA
glues.

Instead, try a 45 degree bevel cut. If you have an old 1/4" magnetic
tape splicer, there's usually a form and guillotine blade suitable for
the purpose. I do it without any alignment aids, which is good
enough. My favorite cutting device is a safety razor or surgeons
scalpel.

When glued at a 45 degree angle, you get a larger surface contact area
for the glue. The joint is also less in tension and more in shear,
which does make it slightly weaker. I haven't noticed any measureable
difference when I did some stretch tests. The 45 degree splice also
allows the o-ring to be compressed in almost all orientations, without
cracking the CA glue joint.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558