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Mounting Water Glass

Posted: Fri Nov 17, 2017 8:29 am
by jlakes85
Hi all,

I think I know what needs to be done, but I'm assuming that the glass will need to be cut to length, unless it can be mounted on an angle, for which I don't think I will have the required real estate. The gauge I'm looking at has both a valve and shutoff cock on the bottom to allow for blowing down properly. I would just need to add a valve on top to complete the setup. Any input is greatly appreciated as always

-jlakes85

Re: Mounting Water Glass

Posted: Fri Nov 17, 2017 9:17 am
by Marty_Knox
The water glass should be mounted so that the lowest reading is a minimum of 1/2" over the top of the crown sheet. On my own locomotives I make the lowest reading 1/2" over the front of the crown sheet on a 5" grade. The top fitting should enter the shell within 1" or so from the top. The bottom fitting should project into the water space about halfway into the water space.

Re: Mounting Water Glass

Posted: Fri Nov 17, 2017 9:38 am
by Marty_Knox
Marty_Knox wrote:The water glass should be mounted so that the lowest reading is a minimum of 1/2" over the top of the crown sheet. On my own locomotives I make the lowest reading 1/2" over the front of the crown sheet on a 5" grade. The top fitting should enter the shell within 1" or so from the top. The bottom fitting should project into the water space about halfway into the water space.
Here is a copy of a page from the Baldwin Steam Locomotive Standards.[attachment=0]Water Glass and Column.

Re: Mounting Water Glass

Posted: Fri Nov 17, 2017 9:40 am
by Marty_Knox
Marty_Knox wrote:The water glass should be mounted so that the lowest reading is a minimum of 1/2" over the top of the crown sheet. On my own locomotives I make the lowest reading 1/2" over the front of the crown sheet on a 5" grade. The top fitting should enter the shell within 1" or so from the top. The bottom fitting should project into the water space about halfway into the water space.
And here is the ALCO page on locating the water glass

Re: Mounting Water Glass

Posted: Fri Nov 17, 2017 11:35 am
by trivettj
Marty is 3/4" above the top of the crown sheet safe for the bottom of the glass ? Would that be about the same as 1/2" above on a 5 percent grade?

Re: Mounting Water Glass

Posted: Fri Nov 17, 2017 11:55 am
by Marty_Knox
How long is your firebox? Finding the height is an exercise in simple geometry.
On my Green Goddess, a modified RGS 20, it is 1 5/16" above the rear of the crown sheet.

Re: Mounting Water Glass

Posted: Fri Nov 17, 2017 12:39 pm
by trivettj
I probably should try to raise my glass then it's on a Tom artzberger rgs 20 also. I put the bottom of the brass glass holder 3/4 inches above the crown sheet so I will need to remeasure and see how far up the actual glass is from the crown sheet cause I really don't want any problems I thought I was being safe putting it that far up but that's what I get for thinking.

Re: Mounting Water Glass

Posted: Fri Nov 17, 2017 1:09 pm
by Marty_Knox
That should be fine as long as you remember to keep a little more water in on a grade; I don't think I would move it.

Re: Mounting Water Glass

Posted: Fri Nov 17, 2017 2:27 pm
by Fender
From my experience, there are more problems with the water level when starting downgrade. Usually the engine has been working hard with a hot fire going upgrade, then you stop working steam, switch to a downgrade, the safeties lift, and the water rushes to the front of the boiler and out of the water gauge.
But in terms of an upgrade situation, the water level over the crownsheet could be deceptive. I measured the firebox for an RGS 20 to make new grates, and it was 4”W x 16”L, I believe. So using 18” for the distance from the front of the firebox to the water gauge, and a five percent upgrade, the water level at the front of the firebox would be 18 x 5 / 100 = 0.9” lower than the level in the water gauge, quite a difference.

Re: Mounting Water Glass

Posted: Fri Nov 17, 2017 3:24 pm
by Kimball McGinley
I think maybe trivettj could just slip a short piece of brass tube around the glass to "raise" the lowest visible point? Maybe a touch of superglue to hold it down?

Re: Mounting Water Glass

Posted: Fri Nov 17, 2017 3:58 pm
by Marty_Knox
Fender wrote:But in terms of an upgrade situation, the water level over the crownsheet could be deceptive. I measured the firebox for an RGS 20 to make new grates, and it was 4”W x 16”L, I believe. So using 18” for the distance from the front of the firebox to the water gauge, and a five percent upgrade, the water level at the front of the firebox would be 18 x 5 / 100 = 0.9” lower than the level in the water gauge, quite a difference.
Which is why I mounted my water glass so the lowest reading is 1 5/16" higher than the crown sheet at the back, so I still have 1/2" of water at the front on a 5% grade.

Re: Mounting Water Glass

Posted: Fri Nov 17, 2017 4:59 pm
by Pontiacguy1
I have done what you suggested to a locomotive before... Added a ring of brass around the bottom of the glass so that it would raise the lowest visible point. It worked fine and provided the margin of safety that I was looking for.