Sight glass for fuel tanks etc

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pat_pending

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Hi, after playing around and wasting a load of time cutting my own glass disks to make sight glass on the Webster and other builds, I went searching for somewhere I could buy them pre-cut. Took me a while and thought I'd share with anyone thats interested. In the end the right search term was "flash light glass lens" and I ended up finding some on Ali Express at a reasonable price. Since postage was over a month, i bought a lifetime supply :).



Cheers,
Patrick

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pat_pending

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Very nice. How did you fasten them and seal them? Bob
Hi Bob. I used Cyanoacrylate glue. No problems with petrol/gasoline, Coleman fuel, Nitro glow fuel or Ether/Paraffin model CI engine fuel. The only annoyance is the white residue that can form on the inside of the glass as it dries.... not a biggie.
 

Ken I

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Hi Pat, Just for future reference - here's how I managed to cut glass disks for a Mendocino motor.

I needed to make a couple of 30mm diameter glass disks for the end stops. All attempts with a diamond coated hole saw resulted in disks that could be done better by a Neolithic flint knapper (Photo - bottom right).
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I eventually succeeded (Photo - Top right) by first glueing scrap pieces of glass with cyanoacrylate to either side of the target piece.

The rubber ring was also glued down as a cofferdam to hold water / coolant (you can use modeling clay).

First attempt failed along with the adhesive - you need to let it cure for about an hour.

Second attempt – very much better - but my drill press chuck does not run very true - transferred to the minimill where I finally succeeded.

You do not have to apply a lot of force - being particularly prudent at the breakthroughs. Make sure the glass is spotless in order that the superglue layer is very thin (dust specs will increase the thickness).

The diamond bit went through about 10mm of glass (3+4+3) in under a minute at about 500 rpm.

After removing the three layered glass sandwich from the bit, I heated it (slowly) with a propane torch until the glue decomposed - cleaned the disk up and voila.

I suggest the sacrificial glass be thinner than the target glass – I noticed a tendency for the sacrificial pieces to crack during heating – probably due to differential stresses and the splintered edges – so if the sacrificial pieces are thicker then the target disk might crack.

When glueing – make sure the pieces of glass are cleaned spotless – any dust will hold the glass apart making the superglue layer thicker which detracts from performance – also allow the glue to cure for about an hour before drilling – if the glue fails during drilling so does the method – guess how I found that out. By the same token don’t glue large pieces of glass together – unevenness translates into areas of thicker glue, which will lead to failure of the method.

Regards, Ken
 

minh-thanh

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Hi !
More :
1 / with hand drill : draw a circle according to the diameter of the drill bit, then incline drill about 30 - 45 degrees and drill along that circle with water. when there is a groove about 1mm deep put the drill 90 degrees and drill.
2 / Use Glass cutter Roller pen cutter : seems more complicated
 

Engine maker

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If you need Glass for fuel tanks I always use this site. Been using it since 2009. They have Flat Mineral Glass watch crystals in many sizes. This is just one page. You may want to bookmark this page as it's quite a large site and easy to get lost. They have thicknesses from 1mm to 3mm and diameters go up by .003"


Jim G
 

pat_pending

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If you need Glass for fuel tanks I always use this site. Been using it since 2009. They have Flat Mineral Glass watch crystals in many sizes. This is just one page. You may want to bookmark this page as it's quite a large site and easy to get lost. They have thicknesses from 1mm to 3mm and diameters go up by .003"


Jim G
cool! have bookmarked though not sure what the postage from US to UK might be... will have a look.
 

pat_pending

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great thread. Excellent to see other people's approaches. While we're on the subject of not 'cheating' and making your own. The one shown on the tank above was cut as below with a circular glass cutter. Took about an hour and great result. Without a lot of practice i got a near perfect glass lens just needed to diamond file/emery off the edges a bit. I opted to buy some pre-cut now as the glass disk cutting 'badge' was already achieved.

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Thanks,
Patrick
 

ds engines

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Hi I found a cheap solution by using the lens from an old led bulb which is 45mm diam and slightly curved. I have made two fuel tanks with these and stick the glass in with a thin bead of JB weld .
 

L98fiero

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I have read about (but never tried) cutting glass with a bit of copper pipe, running in a diamond grit slurry. Has anybody here tried that?
It works but is a lot slower and you do need to use a sacrificial piece of glass under the part you are cutting, typically it's adhered with rosin, at least in the amateur astronomy crowd. The abrasive is generally just loose 60 grit SiC.
 
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Slightly off topic, but has anyone posted use of common household sink downers for tank main bodies? Nice thinwall brass 1.5" dia., various lengths, cheap and available. Nowadays unfortunately many of these are chrome plated.
 

pat_pending

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Slightly off topic, but has anyone posted use of common household sink downers for tank main bodies? Nice thinwall brass 1.5" dia., various lengths, cheap and available. Nowadays unfortunately many of these are chrome plated.
Worth a try! Wondering how to strip off the chrome plating though. Perhaps Lye?
 

pat_pending

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Even more off-topic....I had good success using replacement glass meant for a Vape device thingy to make a fuel tank for an aero. Worked a treat but was a tiny bit too small for the 1.8cc Boll Aero as it was only enough for a 2 minute run.

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Bentwings

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great thread. Excellent to see other people's approaches. While we're on the subject of not 'cheating' and making your own. The one shown on the tank above was cut as below with a circular glass cutter. Took about an hour and great result. Without a lot of practice i got a near perfect glass lens just needed to diamond file/emery off the edges a bit. I opted to buy some pre-cut now as the glass disk cutting 'badge' was already achieved.

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Thanks,
Patrick
That’s really cool I sa veo n how to cut the sight glsss tubs . Ow butvwarwaterjet ?
this spell check is really dumb .
Byron
 

bluejets

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What's a "sink downer" ??? Guessing some American plumbing fitting as opposed to some truckie drug.
 
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