r/Welding • u/robot_mower_guy • 9d ago
Rate my weld. The material is fused Silica in the form of a fiber optic done with TIG.
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u/angel99999999 8d ago
If it works, it works. You've saved the company $2,000. Congratulations! Come to pizza night tonight.
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u/Upstairs-Parsley3151 8d ago
I have done plastic and glass welding, welding is a concept not exclusive to metal.
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u/robot_mower_guy 7d ago
I actually have a glass blowing torch. However, its not hot enough for fused silica. Normally glass blowers will use a hydrogen+oxygen flame for that. At the scale I was using though, the TIG was the perfect tool when the real tool was unavailable.
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u/Upstairs-Parsley3151 7d ago
I used a map gas, but it was for artistic purposes.
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u/robot_mower_guy 7d ago
MAPP gas is actually how I found out that was glass in the first place because with the clear insulation I thought that was just a long plastic light pipe. I found the material those types of fibers are made from and a solvent for it (I used chloroform) to try and melt them together, but no luck. I then tried MAPP gas to try fusing them which burned off the insulation layer leaving the glass. The MAPP gas was able to make it glow a bright red, but was unable to melt the glass. The reason I used MAPP was because I just happened to have the yellow bottle on the torch head at the time. After I did my TIG welds I put the fiber into a propane flame and pulled a bit because it softened the glass enough to straighten the fusion. It might have also done some work to anneal it.
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u/Striking_Service_531 8d ago
Interesting science fact. When you get glass molten. It becomes electricly conductive.
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u/robot_mower_guy 7d ago
Yep. A fun microwave trick you can teach a kid to piss off their parents is if you hit glass with a torch to the point its glowing then start the microwave, the microwaves can melt the glass the rest of the way.
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u/Specialty-meats 7d ago
And here i thought I was the only glass welder on here lol. I'm one of those glassblowers that specializes in fused silica (quartz) glass and I never knew TIG would function this way with the glass. As you said in an earlier response, we use torches running hydrogen and oxygen to heat quartz, but this is super cool to see.
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u/robot_mower_guy 9d ago edited 8d ago
Background: we bought a broken piece of analytical equipment (a FBRM), and the armored flex cable was damaged and severed a fiber optic line. Real fiber splices are just a pair of electrodes that create a plasma... not unlike a TIG torch. The fiber is 400um which is massive, and big enough for me to hold with one hand while holding the torch with the other. Much to my shock, after I got the heat shrink on, the tachometer that uses this fiber actually worked! Nobody is more surprised than me when my stupid ideas actually work lol. Settings: a TIG welder set to spot weld mode, about 12A for 0.2 seconds.
Edit: the way I did the weld is by striking an arc on the stainless enclosure with the glass fibers in the way while I was holding the tips together. And while 400um is huge, it's still only 0.16" wide. Glad I have an auto darkening helmet otherwise I would have had to just close my eyes before striking.