I have read before about problems with the hoses used for the Smith
little torch and thought that I may have a solution, but I have
hesitated to respond.
I am going to this time, but I want to preface this response with a
clear understanding that I am presenting a possible idea of what is
happening and a possible solution. This may be a start to a
discussion, it is not presented as an absolute identification and
solution to what is happening.
I want also to say that I am very happy with my torch and use it 98%
of the time for the work that I do on the bench. (I am excluding
casting) I use my torch with propane and oxygen on a daily basis.
Quite a few years ago, I suspected that my hoses on my torch had
been damaged and I checked for leaks by submerging them in water to
watch for leaks. It was not successful because of the woven material
covering the hoses, but I did on various occasions use water and soap
on spots for leak detection. I checked the ends of the hoses most
Eventually the hoses simply looked rotten. They lost their
elasticity and split and crumbled.
I was not happy to replace them (again) thinking that the
replacements were unjustifiably costly. So I did some research and
decided that the hoses were a polyurethane tube.
There appears to be essentially two kinds of polyurethane tubing.
They are ether and ester. Both appear to be resistant to chemicals.
However the ester type is attacked by… water!!!
That would explain my experience and it may explain many other
experiences. Those who write about hose problems often are using
them outdoors, in a shed or a damp basement. Humidity may be the
source of the problem.
I was sure that I could find a better source of tubing and one the
one that was not going to rot. One day I was in an aquarium store.
There I saw tubing. It was about the right diameter and reasonably
flexible and very inexpensive. It is used to deliver air to the
bottom of an aquarium… underwater!!
I bought 10 feet and took it home. I do not know for sure if this is
silicone or polyurethane, but somehow I was lead to believe that it
was polyurethane. I was also led to believe that it was also used for
fuel line supply in other applications.
This tubing was a little oversized for the nipples on my torch and
regulators. I used binding wire to secure it tightly. The tubing may
be somewhat less flexible than the original hoses, but not so much
that they are restrictive.
Over three years have passed since I changed the rotten tubing for
this semi transparent blue tubing and they have not leaked, caught
fire, or degraded in any visible way. I just looked at them and aside
as they did when I first put them on. I do not recommend using
binding wire to secure the tubing. I used it as a temporary solution
that became permanent and I should replace it with a better clamp, it
is easily done.
I cannot say for sure that the problem is ester polyurethane being
used for the Smith hoses and I cannot tell you that the tubing that I
found is the right solution. I caution you that there appears to be
different kinds of blue tubing available, one is polyurethane and the
other is silicone. Beware that I /may/ have used a polyurethane
tube, and I cannot be sure that silicon can be used.
I can say that I found a solution that has worked for me.
I can also say that my experience is worth further discussion. The
collective knowledge here will be useful, please add it.
Regards to all.