Re: Rubber brake air hoses: a disappointment.


Andy Carlson
 

I looked up EPDM, a likely injection molding compatable rubber like substance, which may be the material used for the HiTech air hoses, on the internet. It is listed as having great resistance to UV radiation (Sun light) and a tolerable range of temperature up to 120ÂșC. I assume this material should be a thermoplastic and I hope to perform experiments by heating up the hoses to a temp that may relax hoses enough to lose their memory, and reshaping them to the curve suitable for our expectation. I will also try to see if a shortened hose could be reattached, perhaps with Barges cement. I will get back with my results.

-Andy Carlson
Ojai CA




________________________________
From: rustonman1 <rfederle@...>
To: STMFC@...
Sent: Thursday, December 18, 2008 6:17:43 PM
Subject: [STMFC] Re: Rubber brake air hoses: a disappointment.


Prototype appearances. I have sen prototype air hose knuckles drag
over grade crossing timbers and railheads. This of course while
switching and air hoses NOT connected. For prototype appearances, and
eliminate the dragging of the air hoses, they will have
to "connected". To do this in HO scale may be a feat, no matter what
the hose length.

Robert Federle

--- In STMFC@yahoogroups. com, Denny Anspach <danspach@.. .> wrote:

Paul Lyons comments-

I absolutely love these new HiTech rubber air hoses. I think
they
are far superior to anything we have had to date. Yes there are
a
few short comings. I did not realize that they are a bit
long ...
if .050" really makes a visual difference. I?seriously question
that
it?will make the difference you describe in your email. On the
other
hand, I agree,?a real short fall is that they cannot be curved
to
the prototype shape. A bit unforunate, but certainly off set by
the
pluses.

I am mounting these hoses to the PSC bracket on most models.
They
look dynamite! The two big pluses of rubber air hoses?are they
do
not break if "hit" and they do not foul the coupler if the
bracket
is not set the "perfect" distance from the end and coupler box.
The
rubber these things are made out of is so flexable, that if the
air
hose is in a?SLIGHT conflict with the coupler, the coupler will
just
"push" it out of the way. You have to see it to believe it.
I do not disagree with a good deal of what Paul says, and to a
large
extent it depends upon what else we are doing on the ends of our
cars,
and to what degree any one of us tolerates the appearance of any
particular out-of-scale detail. That the flexibility of these
rubber
hoses offers considerable cover to routine handling and coupling/
uncoupling operations is certainly true, but this feature cannot
cover
up the fact that if the hoses are mounted at the proper height off
the
railhead, they will indeed bounce over close rails, grade
crossings,
etc.- not an operational problem, certainly, but a visual
distraction.
22" vs. 27" is a relatively large difference, hard to ignore,
especially if one has taken considerable efforts to detail other
significant nearby elements (coupler, coupler shank length,
coupler
box, etc.) also to prototype measurement.

However, as in all we do when are attempting to edge closer to
precise
scale, when we do so, we are also likely to bump up against other
unforeseen issues. When I am describing the problems that I have
with
these new rubber hoses, I am not only complaining about the (to
me)
serious out-of-era, out-of-scale lengths and lack of angle, but
also
as they relate to couplers that have a semblance of scale size,
coupler boxes that have scale widths, and in particular- and most
important- couplers whose shank length approximates that of the
prototype. The latter group includes the Accumate Proto, the
Sergent,
and the Kadee #152s. Some of the short shank larger-head couplers
come closer, but the large head defeats them. The Kadee #5s and
clones, and #78s have long shanks so that perhaps these over-long
rubber hoses might reach, but will still drag on the ground unless
mounted much higher than prototype.

However the long unprototypical shanks also push the coupler head
out
far enough that with wide swings any angle cock stays well inside
out
of the way. With the short prototypical shanks, swinging coupler
heads can butt up against the angle cocks, unless some care is
taken
to specifically mount the brackets out of the way.

A brief review and measurement of coupler hoses in a variety of
steam
era cars and locomotives on museum display nearby demonstrated the
following in real time: 1) All air hoses (the hose proper, not
the
angle cock nor the glad hand) were 22" long. No exceptions.
2) The railhead clearance from the lowest tip of the glad hands
was
almost uniformly between 5" and 6", with outliers of 19" and 3".
3) All anglecocks were angled toward the car centerline.
4) The normal angle of repose of the hoses were slightly curved
almost
to the vertical in the longitudinal plane with the tip of the glad
hand resting under the coupler. In the lateral plane the angled
angle
cock already points the hose toward the centerline, so little
shaping
is required.
5) At the very tip of the brake hose, the glad hand is then angled
slightly outward toward the next car, a reflexion of the attitude
is
has taken from being attached to many other similar airhoses.
6) Not a single air hose was straight, or even close to it.

BTW, the Kadee angle cock bracket that they designed many many
years
ago for their logging cars is indexed so that their air hoses can
only
be put in at an angle- perhaps one of the very few -or only-
manufacturer that recognized this signature feature.

Denny

Denny S. Anspach MD
Sacramento






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