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Posted: 8/30/2013 10:47:45 AM EDT
My crack pipe is way too long, and I wanted a shorter setup....er.....

I can buy steam boiler sight glass in bulk packs of 12 that are 5/8" diameter and either 10" or 12" long for like $10.00.

I can buy individual sight glasses pre-cut to 7.25" (size I typically use) for $28.00 each.

Do the math.....

How do I cut round glass? They are typically 1/8" thick wall, but I'll need to see what they send. Does not need to be thick wall, just hold 1.5lb of pressure. Should I buy 10" or 12" to make cutting easier? about same price.
Link Posted: 8/30/2013 10:48:35 AM EDT
[#1]
Carefully
Link Posted: 8/30/2013 10:51:07 AM EDT
[#2]
Link Posted: 8/30/2013 10:52:09 AM EDT
[#3]
I always just take the little fake rose out of the tube and then smash the rounded end off... no need to be fancy.
Link Posted: 8/30/2013 10:52:19 AM EDT
[#4]
my 7th grade science teacher cut a 1/4" pipette tube with her diamond engagement ring.  she scribed a line around it a couple of times, and then snapped it off cleanly.  funny, i haven't thought of that in years, but it was one of the cooler things i'd seen at the time.

I am sure there is something like a pipe/tubing cutter with a diamond wheel that could be used.



edit:



$35 here
Link Posted: 8/30/2013 10:53:42 AM EDT
[#5]
Google "cutting glass tube" - plenty of instruction there
Link Posted: 8/30/2013 10:53:57 AM EDT
[#6]
Score, heat the up the score line with a lighter, then run an ice cube around it. No joke, actually works. Use a fine file to smooth the edges.
Link Posted: 8/30/2013 10:53:59 AM EDT
[#7]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Are you sure the sight glass is actually glass and not Pyrex?

To cut, you score it, then snap it off, heat up to smooth the edges.  Just like plate glass but in a circle,   A small file corner will cut, unsure how square you need the edge.   This was all taught in high school chemistry.

View Quote

This.  Surprisingly easy, at least with thin glass tubes.
Link Posted: 8/30/2013 10:54:33 AM EDT
[#8]
typically you would make a jig to old the tube at a certain lenght, and put a triangular file at that point to score the circumferance of the tube lightly.



then, wrap the tube with a piece of paper towel (to keep glass fragments from going all over the place, bend glass from both sides, and it should snap at that point. I seem to recall putting a drop of water in the scored point, for some reason (think it helped cause it to break easier, or something like that - use to play with glass blowing).


Link Posted: 8/30/2013 10:54:55 AM EDT
[#9]
Hammer and chisel, just like anything else!
Link Posted: 8/30/2013 10:55:24 AM EDT
[#10]
5/8 is pretty big, I would be scared of scoring and snapping. If you try it wear gloves and safety glasses.

You can probably just do it with a dremel and a cut wheel if you go super slow and maybe fill the tube with sand first.

When you cut chimney flues by hand packing them with sand absorbs the vibration so they don't stress crack, I'm sure the same principle will hold for glass.
Link Posted: 8/30/2013 10:56:05 AM EDT
[#11]
This might work the same for you.
Link Posted: 8/30/2013 10:56:21 AM EDT
[#12]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Are you sure the sight glass is actually glass and not Pyrex?

To cut, you score it, then snap it off, heat up to smooth the edges.  Just like plate glass but in a circle,   A small file corner will cut, unsure how square you need the edge.   This was all taught in high school chemistry.

View Quote

The inside does etch with time from the acidic water cascading down it. I have some in my hall of shame collection that are etched right through.

Could be Pyrex, though. If so, cut like glass?

ETA, edges will be up inside the upper & lower sight glass holders, and gaskets hold it just inside the retaining nut.
Link Posted: 8/30/2013 10:56:44 AM EDT
[#13]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Hammer and chisel, just like anything else!
View Quote


Beat me by mere moments dammit........
Link Posted: 8/30/2013 11:03:07 AM EDT
[#14]

Link Posted: 8/30/2013 11:09:57 AM EDT
[#15]
So I'll but the longer bulk ones. Then try every suggestion. we will determine a winner.
Link Posted: 8/30/2013 11:10:00 AM EDT
[#16]
In the real boiler shops I've worked in in the past we bought our sight glass tubes in 3 or 4' lengths
and cut them to fit.

I don't remember for sure, but I think Ridgid made the cutter.

Kind of like a tubing cutter but with a carbide wheel. It would score the tube deeply and then you would
tap the scored tube on the edge of a workbench at the score mark and it would snap right off.

We use pre-cut tubes these days, but they are expensive.
Link Posted: 8/30/2013 11:13:32 AM EDT
[#17]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
In the real boiler shops I've worked in in the past we bought our sight glass tubes in 3 or 4' lengths
and cut them to fit.

I don't remember for sure, but I think Ridgid made the cutter.

Kind of like a tubing cutter but with a carbide wheel. It would score the tube deeply and then you would
tap the scored tube on the edge of a workbench at the score mark and it would snap right off.

We use pre-cut tubes these days, but they are expensive.
View Quote

That's where I'm at. I would replace more and do the real fix if I had stock and at that bulk price, I will include a new sight glass at no charge.

Nevuh' bin dun bafo!!!!!
Link Posted: 8/30/2013 11:14:58 AM EDT
[#18]
i was going to recomend the method in the making drinking glass vid posted above
Link Posted: 8/30/2013 11:15:52 AM EDT
[#19]

Scribe carefully around the tubing with a diamond or similar scribing tool, then break it. Wrap it carefully in a clean rag and wear gloves for this.

Use a gas flame to polish the ends.
Link Posted: 8/30/2013 11:21:08 AM EDT
[#20]
I use a die grinder with a cut off wheel or tubing cutters with a need blade
Link Posted: 8/30/2013 11:21:37 AM EDT
[#21]
I had to do this once...

I used a standard glass cutter clamped down in a vice. Then I used a piece of 2x4, cut a groove in it with a table saw, and that groove is where the glass tube set.

I used some wood blocks to place the 2x4 at the same level as the clamped glass cutter and then twisted the glass against the cutter to get an even score.

I did it this way because no way was my hand steady enough to get a straight line around a round object
Link Posted: 8/30/2013 11:29:26 AM EDT
[#22]
for bigger pieces of glass (larger diameter) you score the glass, then on the cheap, you can use a the flaming string trick, or, better, set up a hot wire system - if you aren't doing many, a bunch of d batteries, wired to some ac extension cord wire, to some nichrome wire, or even simple bread twisty wire with the insulation removed. lay wire in scored line (wire doesn't have to go completely around tube, but on big pieces, it was better if it did) let it get hot for a few seconds, drop cold water on it, and it would crack along the scored line.



as mentioned above, you can smooth out the end by gently heatiing in a propane torch flame, or, fine grit wet or dry sandpaper will smooth it out also (takes more effort, not as smooth as the flame).


Link Posted: 8/30/2013 11:38:07 AM EDT
[#23]
Do you have an SOG multitool?  I managed to cut a boiler sight tube using that grit-saw thing.

Posted Via AR15.Com Mobile
Link Posted: 8/30/2013 11:39:47 AM EDT
[#24]
Throw it down the driveway.
Link Posted: 8/30/2013 11:42:30 AM EDT
[#25]
Honest answer I have never had a problem using a wet tile saw with a glass blade from Pearl.  YMMV
Link Posted: 8/30/2013 11:48:28 AM EDT
[#26]
Just as an FYI the reason you put a bit of water on the fresh scored glass is to corrode the glass further. Plain water is corrosive to non-oxidized glass. (Told to me by a PHD glass expert)
Link Posted: 8/30/2013 11:54:07 AM EDT
[#27]
Quoted:
My crack pipe is way too long, and I wanted a shorter setup....er.....

I can buy steam boiler sight glass in bulk packs of 12 that are 5/8" diameter and either 10" or 12" long for like $10.00.

I can buy individual sight glasses pre-cut to 7.25" (size I typically use) for $28.00 each.

Do the math.....

How do I cut round glass? They are typically 1/8" thick wall, but I'll need to see what they send. Does not need to be thick wall, just hold 1.5lb of pressure. Should I buy 10" or 12" to make cutting easier? about same price.
View Quote


Your still will require more turns or colder coolant with glass than it would with metal.  
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