The Home Machinist!

Are there any construction articles out there for building a small reflex type water glass for either a 3/4" or 1" scale locomotive?

Even the Live Steam Warehouse small scale reflex water glass is too big for my 1" scale Yankee Shop copper boiler not to mention for a 3/4" scale Hudson.

In LBSC's book "Shop, Shed and Road" he shows a general arrangement for such a water gauge with a stilling well but with no details.

Look on the IBLS web site there are many prints for the 3/4 scale engines,of all kinds of thing's you may want or need.

I've not seen a place to obtain the ribbed glass in small sizes. I'm assuming the stuff is molded, not ground, and probably not easy to do in the home shop!

The rest would be easy!

Pete

many folks that make 'reflex' glasses in that scale dummy it with a round tube up through the center and a piece of non=pressurized glass on the front.

BvB had a very nice design for that scale, but it was not 'reflex'

The reflex gauge is so easy to see!! Much more visible than the round glass. But I'm not going into the glass molding business...


Pete

I have an old Langworthy casting for a 3/4" reflex glass designed for his Hudson....had it for 40 years - have no idea what to do for glass..

Not so sure that in that size it is easier to see than a glass with a light / lines / whatever behind it..

Full size the grooves are ground in, not molded. We found that after about a month and a half we had to turn the glass upside down because grooves would erode away. That made it harder to read, when the new bottom eroded we would replace the glass.

Hi,

If you really want to make a reflex or transmissive gauge glass of this type, there are two methods you could use. Remember, the gauge glass works because of the ribs on the inside; they reflect and scatter the light where there is no water and where there is water, the light passes straight through.

The easier way would be to epoxy a piece of plexiglas onto a flat piece of glass of the desired thickness, then use ball end end mills to shape the ribs in the plastic. You would probably have to polish the plexiglas to a transparent state afterward for it to work.

Now the hard way (but better), would be to make a cast iron mould and cast the glass into the proper shape. The mould has to be the size of the finished part with no sharp edges. The glass for the full size gauges would have been made this way (much stronger than trying to work the glass in its cold state). Glass is very strong if it is handled right. If you "point load" it, it will break. It also has no definite melting point; it behaves more like taffy.

Once you have made the mould, use Aquadag which is a colloidal mixture of graphite and water to prevent the glass from sticking to the mould. Paint or spray the Aquadag on after every few parts. You should be able to melt the glass in a crucible. I would use Pyrex glass, not soda lime because its coefficient of expansion is much lower. Both glasses would have to be annealed but Pyrex glass would require an annealing temperature of about 650 degrees centigrade. Soda lime (window glass) would be about 150 degrees lower. For annealing, bring the part up to that temperature and then slowly cool it down to 300 degrees C.

Melting broken Pyrex glass would require a temperature of at least 1,500 degrees Centigrade (almost a white heat). Anyone who does their own casting should be able to do something like this if they really wanted to.

I worked at Corning Glass Works for 30 years and that's where I learned about this as well as many other things.

Richard Trounce.

I don't see how plexiglass would work. It's melting temperature is about 320F, which is below the temperature of saturated steam at 100 psi.

Here is a picture of the "reflex" glass I made using tubular glass, as can be noted, there is a small slit in the back of the body allowing light from a grain of wheat bulb. Very happy that I did that, the glass is quite easy to read in use.

david griner wrote:Here is a picture of the "reflex" glass I made using tubular glass, as can be noted, there is a small slit in the back of the body allowing light from a grain of wheat bulb. Very happy that I did that, the glass is quite easy to read in use.

Hard to see the details so I'll ask: You have a round glass tube inside a flat front reflex type housing? The housing is closed on the sides and back with the exception of the slit you mention? How have you arranged the seals for the tube?

I love the look of the reflex and the protection the housing offers the tube!

Thanks,
Pete

Link to reflex plans on IBLS: http://ibls.org/mediawiki/index.php?tit ... ater_Gauge