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Old 12-10-2016, 10:10 AM
Shawn Watt Shawn Watt is offline
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ring tests

When making ring tests and looking at all the variables. thickness of the wall ,how much color to clear ratio ,diameter of the ring and the gap itself. Looking at all this, how do you come to the final conclusion if the glass fits or not. I started using a micrometer and feeler gauge to make the measurements and am wondering where to draw the line for compatibility.
Example I am testing a black against clear
OD on the ring is 3.25 in
Thickness is .043 in
black to clear ration is about half with black on the outside
gap is .026 in

i am reading that gap as out of range. what are your thoughts?
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Old 12-10-2016, 10:24 AM
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Pete VanderLaan Pete VanderLaan is offline
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It reads the glass on the inside has a gap and is slightly lower expansion than the outside glass. The proportions are very good. The very fact that the ring survived the saw is a solid indicator that the two glasses are reasonably matched. Ideally, you want the scored vertical part to simply sit at rest, neither opening or closing on itself. I would either add a small amount of soda ash to the black, or a small amount of silica to the outer glass. Small for me is about 25 grams in 30 lbs or so. Then melt and measure. One of the two glasses would of necessity have to be a batch glass to add the sodium or silica although it's possible to add soda or silica to SP87. Otherwise, it simply is what it is. At .026 I would try to close the gap.

Good Job.
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Old 12-10-2016, 03:47 PM
Shawn Watt Shawn Watt is offline
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Thanks Pete. So when you see a gap either way do you have a measurement that you say "once the gap goes behold this point it is not compatible to use with the clear?" I think i remember reading if a piece of paper fits the gap it tolerable. Is that right? According to the internet a standard piece of paper is .1 mm thick. Should i assume if the gap exceeds the .1 mm that it is out of range. Obviously all the other variables are going to effect that gap.Maybe im looking for a rule that doesn't exist.
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Old 12-10-2016, 04:13 PM
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Pete VanderLaan Pete VanderLaan is offline
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my experience tells me that if the thing survives the sawing, It's likely to be compatible. My rings tend to be kind of thick and the ratio of each type of glass not so perfect. BUT if they survive the saw and then I can score it vertically and tap it open, I can see something I can judge. It really will break on the saw right away if it's out by much. A piece pf paper thickness would be a nice fit in my book. I do like to get it to just sit there.
My great advantage is that both types of glass are always batch glasses and that gives a real advantage when you're making the adjustments. I find that particularly true if you are putting a bunch of stuff in your batch that is not factored by E&T. The Third edition of Glassnotes had a huge error in it that listed factors for metallic oxides. That came from Paul Manners back around 1976 where he included a set of factors that were commissioned in the enamelling industry in I think 1925. They were based in a completely different temperature range than the ASTM standard dictates. In the fourth edition, I had pointed out that they should not be in there and Henry removed them.

Appen has some numbers for the colorant metals but you have to use the whole system and then you really want to do mole calculations, not percentages.Running a set of factors for the colorants is something that is still missing. The big glassmakers simply don't care since they never laminate production stuff.

Scott Benefield, who is a far more skilled glassworker than I am was able to do live tests on the blowing floor making thin blown rings. I never had the skills or the assistant it needed.Nice to get fast results though. When you pop them clean, the expansion is really exaggerated and takes some sober breaths to work with.

I do think that the ring coupled with the Hagy seal is a good combo. Learn to make seals. Pull tests can be very deceptive. I remember Ed Skeels doing cane pulls that looked terrible and then he annealed them and they came out absolutely straight.

The real trick is to not kid yourself on fit. When a piece blows up, we all have a weird way of rationalizing it. That's not good. Eventually the physics will have it's way. In this tortured round I've done recently with mating my unoxidized color batch replete with the tin and silver to the clear Tom mixes per my specs, I knew I had issues yet I had pieces that went through grinding and were set aside. Most broke after about six weeks. Some have yet to break. If you sell it, it will break soon. When I'm doing this junk, I still need to write on every piece the date and the batch info.

Trying to make everything perfect through the whole color system will make you crazy.Just remember the A to B to C logic I occasionally refer to. Whenever you try to put fifteen colors in one piece, Buddha's nose is getting quite out of Joint and he calls in Heidi Broderbund and her 15% rule. At that point you need really good muck boots for the deep shit you will find yourself in.
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Old 12-10-2016, 04:33 PM
Shawn Watt Shawn Watt is offline
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what do you mean by "live tests" ? Like self annealed cups ?
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Old 12-10-2016, 04:40 PM
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Pete VanderLaan Pete VanderLaan is offline
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you're fast. I was simply editing my last post and here you are again. Do read my editing.

What Blenko could pull off which I'm sorry to say I don't have the skills for was taking a color in question- every morning and casing it in the clear or whatever of the day. They would blow that out ( a live test) really thin. Scott could take the thin things and shear out a ring of it hot. As soon as it cooled, it could be scored. We did it that way down at Josh Simpsons when I was working out the formulas for the Corona series. Make an ultra thin goblet cup, cool it a bit, scoreit and pop it open.

I like having the ring so I stick to what I normally do. It's reasonably constant. That ring goes in a bag, stapled to the other results and tied to the formula. I have something to refer to. In my first class they nailed the bags to the sheetrock wall in the hall. We had about fifty of them. It wrecked the wall but everyone could see what was happening. Teaching is quite an experience. I'd be into substance abuse in no time. when you get someone who's serious, it's important.
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