Comparing Water Glasses

[Chris Hollands]

Today Daves sight glasses turned up so I thought I would compare Bobs and Daves.

PLEASE note this is not about saying one is better than the other ,because I don"t know ,this is purely about what I wanted to know before I bought Daves ,as I had Bobs for a few years.

Im sure there are a few people like my self who wanted to know and see what my understanding is very similar products, except for how the glass is viewed ,one is a proper reflex the other is a clear glass with a red light for viewing ,Bobs has something similar in his lense.

Construction is quite different ,Daves is cast ,Bobs is machined ,so the finish is quite different.

I have modified Daves a bit as the face was semi finished ,but still basically a cast face,so I cleaned it up to get a lot of the casting marks out of the face and use 400 emery followed by the deburring wheel to get the finish to what I wanted.I also changed the nut and stud for 3mm button head screws ,this was my choice .
Im not that keen on the nut and stud on both styles of gauges and I would probably change Bobs as well ,they just dont look quite right ,but economics takes over with commerical nuts and studs.
Daves gauges are very good value for what you get at about 1/2 the price of Bobs.

I did have a issue with Daves threads on both gauges Barrys fittings would not thread in to either gauge ,but screwed into Bobs quite easy ,no big deal I will just have to take the threads a bit deeper.

Remember this is my view and I changed things to my liking ,I am not saying anything bad about the products or who made them.

It is so people can view the items and see if they are right for them

[Chris Hollands]

The next photos try to compare the glasses on the Challenger backhead to try and give some view of fit,both gauges have Barrys new blow down valving arrangments so we are comparing apples with apples ,the photos may or may not help to compare ,but we will give it a go.

The start of the actual glass is at aprox same postion in all photos, 1/2 - 12mm above the crown sheet as per code.

[Chris Hollands]

And a couple more

[Trainman4602]

The use of studs on the Mercer gauge glass is for the purpose of simulating an actual full size gauge. I used stainless steel set screws putting the hex in rather than on the outside so it looked more like the end of the “U” bolt. Economically it was more costly and much more work then it looks. Try threading 500 bolts on some small set screws.

Mine are just for looks but Bob’s actually hold the face on. Remember the great gauge glass set screw controversy of 2009?

Chris I don’t see how you can say “they just don’t look right” when they are simulating “U” bolts in fact I continue the look on the back side where is can’t even be seen.

As far as the 5/16-27 thread. I find some differences between manufactures so I made them on the tight side and figured that customers could tap them deeper if need be. It is better than being loose and sloppy.

I made this gauge with a round tubular “red line” glass for two reasons. The red line is painted on the outside of the glass. If is was painted inside it will burn of after a couple of firings.

One it is much easier to read then the reflex glass. If you don’t thinks so wait until the LSB etches the back of the prism. I had trouble reading the reflex glass and ran the K4 low on water thinking I had water when in fact it was very low.

Two it is readily available just about anywhere. It uses simple square “O” ring seals also easily obtainable anywhere. Mc Master Carr carries the seals and the glass.

The Mercer gauge is longer giving more range for the water level.

I personally set the gauge below the crown sheet. I know I’ll get some flack on this one. SO WHAT. That is what I do.

Setting the gauge below the crown, marking it with some red paint will tell you exactly where the water level is. Setting it above well it is anybody guess where it is.

Is it there? Is it below the crown? I know where my level is. and when it gets low which happens on a good steaming locomotive I can open the injector and bring it to the proper level.

[gwrdriver]

Setting the gauge below the crown, . . . will tell you exactly where the water level is. Setting it above well it is anybody guess where it is.

That's not necessarily the case. Years ago in my club there was a lot of loco swapping (you run mine and I'll run yours) and teaching of inexperienced or learning drivers. I was one of those who benefited from that practice. To make this safer the loco builders in the club agreed upon a gauge glass convention which was to set the bottom of the gauge glass, meaning the lowest point where water was visible, at the point of minimum safe crown cover. Then, so as far as running water level was concerned, there was no need to know where the crown sheet was . . . if you could see water in the glass you were OK, if you could not see water or saw only some "surf", you add water. Simple as that. Whether or not this practice survives with the few builders there are nowadays I don't know, but that's how I will set the gauge on my current project.

[nkprr175]

I came to live steam hobby from running the full 1:1 gauge steam locomotives. I can tell you that all of the site glasses were always placed a few inches or more above the crown sheet on the full size to add a safety factor that you would never run the boiler out of water or expose the crown to high heat.

I would highly suggest in the live steam area that you place your glass a inch or so above the crown sheet to not over work your boiler and stress your metal of the side sheets and crown. The boilers in live steam can become scared and burn your metal to the point of failure or will cause a shorten life space of your firebox area.

I have recently seen a boiler that was run on low water so many times its crown developed a crack because the theory was our live steam boiler are so over built that we can get away with more abuse then the large scale ones. So a boiler that was built 3 years ago is now dead because of running the water to low all of the time. So just my 2 cents set your lowest point to be above the crown sheet that way you always have water in the boiler and never have to expose your boiler to cold water shock and over heating your metal with a hot fire.

Best Regards,

Steven H.

[Fender]

Chris,
Thanks for posting this comparison. Could you provide photos of the two gauge glasses half full of water?

[nkprr175]

Chris,

Thank you for posting on the site glasses. Can you give your opinion on how the look a night when they lit with the proper lighting? Also the glasses you are comparing are from Bob Dean and Mercer in this case?

Thanks!!

Steven H.

[Andypullen]

I came to live steam hobby from running the full 1:1 gauge steam locomotives. I can tell you that all of the site glasses were always placed a few inches or more above the crown sheet on the full size to add a safety factor that you would never run the boiler out of water or expose the crown to high heat.

I would highly suggest in the live steam area that you place your glass a inch or so above the crown sheet to not over work your boiler and stress your metal of the side sheets and crown. The boilers in live steam can become scared and burn your metal to the point of failure or will cause a shorten life space of your firebox area.

Best Regards,

Steven H.

I am going to agree with this statement.

Plus....for the most part we are riding on the tenders and have to look down on the gauge glass. You are getting a parallax view of the water.

My gauge glass is set so the bottom of it is 1/2" above the top of my crown sheet. As long as I can see water in the glass; I know that the crown is covered.

Chris was just pointing out the differences between the 2 glasses. Both are nice.

Andy Pullen

[Chris Hollands]

Dave you are way to sensitive and should read what I said a bit closer ,I will answer a couple of his comments.

Remember this is what I have done to suit my taste ,I am not bad mouthing any thing or one ,I am only comparing the 2 gauges to help people in the future.

Regards I dont know how you can say that -Remember when you live in a democratic dictatorship like Canada and the US you can say most things.

Regards the studs and nuts I have stated economics takes over ,hand making these items would kill you.
- That being said I also stated what I have done is my view ,I know the stud and nut are to simulate the real thing ,but commerical nuts just dont do it for me ,they dont scale very well .
- I may still change what I have done and make one piece nut and stud ?

Regards the 5/16 thread i agree pipe threads do vary in size and to small is better than to big -I said I would tap to suit my fittings.

Regards the gauge glass level,my boiler was built to the Australian boiler code which from memory requires the start of the readable glass to be 1/2 - 12mm above the crown so I dont have a choice ,but to me it makes sense to do this.

Regards which one is easier to read , I will fill with water and take a picture and post later ,I would say Daves, one reason the viewable glass area is quite a bit larger than the reflex so they are not quite the same there ,Im not sure why you are commenting on the red line arragement I had no comment other than they have a red line or back ground on both gauges.

You should be pretty happy Dave free advertising ,that polished face on your gauge makes the gauge look petty good ,Id buy it.

[Trainman4602]

Just what I expected to hear but 1 inch above? Then you better ware your rain gear while running. You will defiantly get a face full of water.

Gauge glass with water half full.

[nkprr175]

Yes in this hobby 1" would be excessive. Let me clarify. I should say you do not want your gauge to be level with the crown sheet as it leaves no safety factor with your water level. As Chris has stated 1/2" would leave plenty of space to keep your locomotive covered with water.

As a final ask...I have figure out the one glass manufacture is Bob Dean...I'm in the process of building my Hudson and will need glasses shortly and I like the look of the other person better then Bobs as I can see the water level better. Can you please identify the other manufacture or are they listed on the boards sellers section where I can look them up?

Thanks!!

Steven H.