Had a sight glass for my Bing 1637 [130/112?vulcan?] and didnt want to use or break the original. I had 3.5mm od and 2.5mm id sight tube left from a weeden repair.
I decided I wanted to keep the original and run with a replacement.
Its very tricky to bend glass. it is not mechanical in the least or engineer based. it seems more artistic and casual for sure.
I tried making a jig the first round but thats too structured and serious for glass. Instead I found it was easier to heat the measured bend spots and let gravity and coaxing with a metal tool worked best. Then a full cool down.
This was either pyrex or borsilicate tubing. You need to slowly casually heat it.
it stays pliable for quite a while. It doesnt spread heat as far as I thought. I didnt use gloves but then again I do not feel pain [only emotion]. I think it turned out well.
As for the Bing engine I used wilesco rubber gaskets that fit around the glass and some wilesco washers and its the most water tight sight glass I have.
any questions ask. any advice appreciated. let me know if u want to see a bigger image.
sorry for spellings and punctuation im on my phone.
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Jason, I take a similar approach to making water level tubes/viewing glasses as you do. However, I take conventional glass tubes with the diameter and thickness required in each case. I cut the tube to the required length with my Dremel and a thin cut-off wheel. It is also possible to run a simple glass cutter around the tube once under light pressure and then break it off.
I have built myself a simple tool from dry beech wood, similar to yours. I drilled a hole in the diameter of the tube 2 cm from one end of the beech wood. This hole is flattened by me towards the bending side (the end of the wood 2 cm away) at the top of the edge. The required dimensions of the tube, where the bend is to be made, I mark with a black pen. I put the tube into the hole up to the first mark and lightly glow the glass at the marked spot with my small gas burner. Then the glass tube is simply bent at right angles by hand. I repeat the process for the second bend.
Please do not think that I have fireproof hands and fingers.
I always use very thick leather work gloves when bending the tube.
By the way, you can deburr the sharp ends of the tubes by annealing them briefly with a gas burner. I make the seals of the tubes from matching silicone tubing. It is cheaper than the Wilesco seals and can be cut to the required thickness with a very sharp knife or a scalpel.
Good description both. Using Wilesco gaskets is good to know.
Update. After second run we are leaking again I think im going to use a little silicone gasket seal. In the meantime since there was the leak I took the time to paint the glass in what i think and believe they were painted. looking at metal hardware i can see paint remanants (and gasket) anyone aware? seemed my "original" sight glass had similar paint. I love how much more visable it shows. I tried to match the flywheel with the color visable thru the water. [ Guests cannot view attachments ]
Pretty Sharp looking if ya ask me! [ Guests cannot view attachments ]
When I get one of these old machines, one of the first tasks I do is I take down the water level and see what the condition is. Usually the pressure plate for the seals is affected by rust. The plate is then meticulously cleaned of dirt, paint residue and rust. Then I paint it 2 - 3 times with rust converter. Works great as a primer and prevents rust from forming again. Then I paint the plate with a commercially available enamel paint from the model building sector. I have not yet tried the Wilesco cardboard seals. These gaskets are very good for sealing connections from steam whistles, filler plugs and safety valves to the boiler. However, they must be replaced depending on the frequency of operation. I therefore prefer the homemade silicone gaskets, which are much more flexible. Important when installing the water level tube and the pressure plate is the absolute cleanliness of the parts. Also the holes in the boiler for holding the tube, and their surroundings must be metallically bright, so that the seals in the surface can lie cleanly.
On a machine that was visually in good condition, I have experienced a nasty surprise. I have not paid the necessary attention to the water level and heated the boiler. The machine started very well. After about 1 minute steam came out at the seals of the tube. The discharge was then explosive and caused a huge mess. One of the previous owners had sealed the water level with window putty. Water, heat, window putty and pressure, not a good clash.
Fortunately, no one was hurt. That was a lesson to me though. You can see why I'm a little picky about this now.
I'm in the process of making a U bent glass now. The first bend is easy.... then I came to this thread to see how to make the second. I need to make a jig I guess. Getting both bends at the same angle and the correct distance apart is a little challenge
It's a little late and time to go to bed. If you have time until tomorrow, I'll post a sketch.
I just cleaned up the old fittings and it looked like window putty was used to seal the glass. The sight glass got broken in shipment so I never tried to run the engine. I have had one blow on me and it was kinda scary to say the least.
I broke the first glass 1/2 way through the second bend. I'm leaving the glass long but may try Jurgen's approach of cutting to length first, if I can't get a clean cut after bending. I'm glad I have a lot of glass
Talk to you tomorrow Jurgen...
Hi Bob,
I'm afraid, I didn't do a very good job with the sketch, but I hope you can still see how the tool works. To get the exact length of the tube, measure the distance of the holes in the boiler from center hole to center hole. Transfer these measurements to a piece of hardwood. I usually use beech. Then drill the holes in the diameter of the glass tube into the wood. Cut the wood exactly in the middle of the second hole. Bevel the edge there. Don't forget to bevel the edge of the other hole towards the second hole as well.
I hope you understand my description. If not, just ask.
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Hi Bob,
I'm afraid, I didn't do a very good job with the sketch, but I hope you can still see how the tool works. To get the exact length of the tube, measure the distance of the holes in the boiler from center hole to center hole. Transfer these measurements to a piece of hardwood. I usually use beech. Then drill the holes in the diameter of the glass tube into the wood. Cut the wood exactly in the middle of the second hole. Bevel the edge there. Don't forget to bevel the edge of the other hole towards the second hole as well.
I hope you understand my description. If not, just ask.
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Thanks very much Jurgen,
Yes, I can follow your instructions.
I'm in the middle of the process. The sight glass is for a Schoenner I posted it on the Mamod forum. I have trouble posting pics here.
I'll go over your other instructions to see how this all works. I was thinking of picking up a Dremel to cute glass.
If I goof on any of the cuts or bends it's start over.
Thanks again, Bob.