Identifying the tin side of float glass when painting?

I have been working on non-float heretofore, painting on opals. But, I was told to get a UV light to identify the tinned side of float glass. I went out and bought a UV bulb (like a lamp bulb.) Could not see any "clouds". So I went and found a tubular UV black-light. Still no "clouds." The past two days i had off and could have done a lot of painting and firing on a bunch of float glass i acquired, but don't want to waste my time on the wrong side of the glass. Went to fusionheadquarters site and they are OUT of UV "tin lights". Rainbow doesn't have any since no one around Sacramento paints on glass. VERY frustrated. What KIND of bulb do I need and where can I find it SOON, so i can get to work. Any manufacturer (sony, sylvania, phillips, GE...) or model number of the correct bulb would be great. Just so i can get one and get to work. I have 26 colors or FuseMaster and Reusche but don't want to run all the tests until I know i am doing it right on the correct side of the glass. It took weeks to find these two bulbs, but neither is doing the trick. Thanks!!!

* This could be controversial, but here goes:
Taste the glass. Really! If there is a metallic taste, that is the tin side.
No really! I do it all the time. I bought the testing light for around $10 at a pet supply shop. They use them to test for urine spots. It confirmed my taste buds every time. Now I just lick n go (tm).
Seriously, these are not old wives tales, even if I am one...er...have one!
(caveat: it may well be the amalgam fillings in my teeth that allow that to happen for me, some have never tasted the tin).

* You might want to make sure the glass cleaner is well rinsed off first.
Mike

* With the right kind of UV light you can barely see the light source itself because of the deep filter. However, the tin flouresces quite dramatically. There is no doubt which side is tin. Possibly the reason your other UV lights didn't work is that too much of the spectrum is emitting and making it too bright to see the effect. The one I have used for years is just for that purpose. I usually take the sheet to a darkened corner - out of the direct room light.
Raf

* I think it was Andrew who recently posted a link to a less expensive short wave UV flashlight.

* You need a SHORT wave UV bulb, not a regular black light. Stamp collector stores, and rock (mineral) store sometimes sell them.


* That is right, you need amalgam fillings.
One substitute us to put a piece of aluminium foil into your mouth for testing. Not so sensitive as amalgam
The two metals amalgam/aluminium and tin
form a slight electric current you can taste.
Lick both side and compare the taste
-lauri

* I work with float all the time and found a tin light at Mamas Minerals for $45.00 plus shipping. Works great. Item EQU-SWLMP

* This is it. It is a piece of crap that falls apart without tender handling. I'm on my third and duct tape is my friend. Good though...

* That's basically the same light as the ones I posted for as much as $150.00. Someone has some nice margins

* It's exactly the same. A company I once consulted with had ordered a Bohle light from CRL. CRL had it shipped from Germany and marked it up accordingly. Of course Bohle had already had it shipped from California to Germany. I seem to recall the CRL model costing a bit less, but today it is $149.95 Made by UVP
The one referred to by either Andrew or Gary (can't remember which one) cost less than the UVP from mama.

* I bought a UV "tin scope" in 2005 from Tracy's Stained glass for $53.95.
The manufacturer is UVP Ultra Violet products in Upland CA. They sent me a booklet explaining their various UV lights. For $18 I bought their UV Spectacles #UVC-303, Contrast Control. Not strictly necessary when using the UV light but I chose to be safer. Without the specs you should not look into the light.
Bea
P.S. On some float glass it is very difficult to see the glowing tin side, eg. some 40 year old window glass. Other purchased glasses leave no doubt with their bright glow.
Please explain.

* First, I tried a bulb style, and it didn't work. Then I tried a tube blacklight, it didn't work. Then I called everyone I found on line who sold UV lights. Finally two things happened. I found the perfect light for $45. at UVP Ultra-Violet Products in Upland CA. (UVP.com) I spoke with Erica at (800) 452.6788 and she explained to me that UVA light is longwave, 365 nanometers like sunlight. UVB is 302 nanometers, and UVC is the shortwavelength 254 nanometers and that is what us glass hounds want to use. $45. bucks and was here in two days. Shortwave, 254 Nanometers, Model R-52 and UVG-11. Works like a champ. You have to be in a dark room, and the glass should be clean, but BINGO the tin shows up immediately. And, you don't have to lick the light to sense the tin That's ONE thing.
The second thing hails to my ignorance about glass. When testing the first pieces, I went into my shop and grabbed 4 pieces of float glass from the bin and took them to my garage to test. AFTER I finalloy got this new light and tested those pieces, they STILL did not flourese (sp?). That is because the glass I pulled out was from a 100 year old frame I bought a poster in and cut up. It had no tin to begin with. So I tried two cabinet doors in the kitchen and there it was. Moral of the story..... look for tin on float glass, not 100 year old clear rolled glass. Despite my stupidity, I found a great light, got it cheap, fast and it is pocket size, runs for years on 4 AA batteries and make my white shirt look greatr in a darkened garage

* I can feel the tin side if I run my nail down both sides of the glass. So far it has worked ever time for me.
Andrea

* I don't mean to pull this off topic - but what is significant about the Tin side of the glass?

* Brookman, When painting float (window) glass some enamel colors react with the tin ions in the glass on the "tin" side of the glass and produce undesirable colors. Therefore, it is necessary to determine the tin side to avoid this problem. Also, many fusers prefer to assemble float glass with the tin side down against the shelf in the kiln.
Beamax, float glass has only been produced since 1960. Any glass older than that was produced by some other process so it has no "tin" side. The lack of the tin fluoresence is a pretty good indicator that the glass was made before 1960.
Best wishes,
Tom in Texas

* thank you for the reply. Does the tin side affect the fusing at all?

* The tin side protects the bottom from sticking to stuff. It effects colors when applied in contact with it. It causes bloom when compressed (the top side of a bowl).

* Had to smile at this thread
I might have a mouthful of fillings but they seem to be the wrong type!
I licked both sides of several different pieces of what I thought was float glass and nothing happened
I'll continue notwithstanding the weird looks I get when someone catches me doing this .................
Just the other day I had a customer ask me if the glass tasted good and when I explained the theory we both grabbed our own pieces of glass - now that was an interesting scene for the next customer who walked in gave us both weird looks as she grabbed her item and practically fled ........

* Art or stained glass is not produced by the float process so 99% of the colored glass you find will not have a tin side. Float glass is used mostly for windows and mirrors of all sizes. Be careful which windows you go around licking.
Best wishes,
Tom in Texas

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