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Old 12-09-2019, 10:47 AM
Gabriel Greenlaw Gabriel Greenlaw is offline
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Reduction disappearing in annealer

Does anyone one know why a piece may look brilliantly reduced (gold, silver, opalescent) when being boxed, but then when it comes out of the annealer barely looks reduced at all?

I've noticed this more on pieces that have interior reduction as apposed to reduction on the exterior of the pieces.
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Old 12-09-2019, 11:40 AM
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Pete VanderLaan Pete VanderLaan is offline
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Reduction needs to be defined. "Reducing" one element by the transfer of oxygen from a host ( Say silver oxide) to another element, ( potentially a carbon rich gas flame) transfers the oxygen from one element to another to support ( or, reduce) combustion in a balanced equation. You get shiny!

Now in the lehr, the atmosphere is no longer fuel rich, rather the opposite unless you heat it with gas, so the atmosphere gives the oxygen back to the reduced surface and the effect vanishes. The kiln is really oxidizing. Glass in the interior is not affected as much by surface chemical interaction. Glass tends to be affected in the top one half inch by the conditions of the kiln or furnace and the remainder of the material responds to local conditions. The effects of this can be seen in all sorts of ways.

People try a variety of things to maintain redcuing effects in a lehr. I've seen people throw M&M's in, I've seen wood chips. They do work but are predictably messy. Almost all clear glasses are oxidizing in nature although they can be formulated as reducing glasses which I do all the time. Most of your color rods high in silver, gold or copper will tend to be reducing in nature. As temperatures fall in a lehr, the molecular activity is diminished making it harder to affect a change.
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Old 12-09-2019, 11:55 AM
Shawn Everette Shawn Everette is offline
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I've had it happen when I place things in plaster. I've known people to put a bowl of activated charcoal in the kiln to "soak up" the extra oxygen, don't know how legit that is.
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Old 12-09-2019, 01:12 PM
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Pete VanderLaan Pete VanderLaan is offline
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Plaster- Calcium Sulphate with a big O3 hanging off of it and it will readily give up oxygen( reducing that O 3 level) to the reduced glass you had in the mold reverting a silver to a silver oxide. POOF. It's gone.

I can see where the charcoal would be of assistaance in the kiln but again you have to catch it when it's active on a molecular level I:E: hotter.
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Old 12-09-2019, 01:27 PM
Gabriel Greenlaw Gabriel Greenlaw is offline
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Ah! That's really interesting. I had never thought of the annealer as being oxygen rich rather than balanced, but I suppose if it's not fuel rich, it's going to be oxygen rich instead because it's not an air tight environment.

I like the idea of wood chips. I might fill up a metal bowl with some next time I make these pieces again and see if that makes any noticeable changes. Although it will make a mess with the soot and all. Maybe I can find something with a higher flash point.

Does a clear glass that is reducing help promote reduction (if you're using bar color) or is that more for use as a base to make a color that you want to be able to reduce?
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Old 12-09-2019, 01:29 PM
Shawn Everette Shawn Everette is offline
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It was interesting because it was only the areas with direct contact with the plaster that changed, everything above the line was still reduced. Tended to use it for thicker work that was getting put away fairly hot.
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Old 12-09-2019, 01:46 PM
Shawn Everette Shawn Everette is offline
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I will say that sealing your annealer tighter may indeed help. Using a frax rope as a gasket can help significantly. That guy that would regularly "lose" his luster(in more ways than one) didn't bother to try the newer kilns that had a tighter seal. I'd regularly use all the kilns with reducers without issue and no one else was experiencing it, so there may have been some user error involved too.
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Old 12-09-2019, 03:32 PM
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I wouldn't call it "Oxygen rich" but it is indeed an oxidizing atmosphere It's just best to consider the term "reducing" as one thing taking something alway from something else. A neutral atmosphere, neither oxidizing or reducing. Happy atoms.

Start small on the chips.
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Old 12-09-2019, 03:46 PM
Rosanna Gusler Rosanna Gusler is offline
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a reducing atmosphere is hard on electric kiln elements
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Old 12-09-2019, 03:55 PM
Shawn Everette Shawn Everette is offline
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Yeah, I wouldn't exactly go for a "reduction" environment, just one neutral enough to maintain the reduction you've created.

No matter what you're going to get a fair amount of air transfer by just loading, especially on a top loader. Try to keep your in's & out's quick, and do your best to seal the door.

On an aside, what color are you trying to use, or is it having the same effect on multiple colors.
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Old 12-09-2019, 06:47 PM
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I got my best colors out of a gas annealer.
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Old 12-09-2019, 08:21 PM
Michael Ahlefeldt-Laurvig Michael Ahlefeldt-Laurvig is offline
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I have one annealer with a blower inside making the temp very even in it. Then I have another one with no blower. For whatever reason the one without blower wont lose reduction/fuming effects.
specially on the bottom floor. I always figured it was becouse it was colder, - but still in annealing range.
But I dont know for sure. Maybe what Pete says makes sence in this too.
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Old 12-10-2019, 02:10 PM
Bob Meyer Bob Meyer is offline
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[quote=I've noticed this more on pieces that have interior reduction as apposed to reduction on the exterior of the pieces.[/QUOTE]

Gabriel,

By "interior reduction", do you mean the reducing color is encased?
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Old 12-10-2019, 03:47 PM
Gabriel Greenlaw Gabriel Greenlaw is offline
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The annealer I'm using currently is not very tight now that I'm looking at it. Looks like the frax gasket has been compacted over the years. I'll refresh that as well.

The colors are K-105 and K-103. Silver blue and silver green.

No, the reducing color is not encased. It's placed directly on the head of the pipe or on a collar. I meant interior reduction like the inside of a cup, compared to the outside of a vessel. The reduction on the outside of the pieces don't seem to fade quite like the inside does.

Thanks for all the input.
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Old 12-10-2019, 06:06 PM
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In that case, the only part of the color being affected by kiln atmosphere is the inner face. I simply can't comment on color numbers. I don't use that stuff.
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Old 12-11-2019, 10:22 AM
Shawn Everette Shawn Everette is offline
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I find it odd that it would effect one face more than the other, but especially in that order. I would think that the outer face would have a more turbulent interaction with changes in the kiln for something with a cup shape.

Color wise I can't help either, my go to reducers are the 200's reichenbach's, and the gaffer lusters. R713 and 719 may be good substitutes, pricey, but most of the others have a lot more chroma.
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Old 12-11-2019, 10:36 AM
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The way I read that Shawn is that the color is stuck to the pipe and I imagine it's cased in clear and blown out as a bowl or whatever, so the interior color is directly exposed in the annealer and the outer color is under a clear layer. Perhaps Gabe can elaborate more.
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Old 12-11-2019, 12:16 PM
Shawn Everette Shawn Everette is offline
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I've done collar pickup reductions, but this is what I'm referencing, "The reduction on the outside of the pieces don't seem to fade quite like the inside does." It looks like he's applying on both sides, but the reduction loss on the interior is worse. Generically I'm thinking that there is going to be more air exchange around the exterior of a piece rather than on the interior, the wall of the cup should insulate it from air movement. Maybe try boxing one upside down?
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Old 12-11-2019, 12:57 PM
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We need more clarity prior to the wild assed guess. Gabe?
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Old 12-11-2019, 04:20 PM
Gabriel Greenlaw Gabriel Greenlaw is offline
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Yes, you are correct that the color is only exposed on the inside of the vessel. After the color is placed on the collar, it's gathered over two or three times.

What I meant by the color on the outside not fading as much is that when I use this color on the outside of an ornament (wrap or frit), I have no problem getting a beautiful metallic reduction. It stays even after going through the annealer compared to the interior vessel reduction which typically disappears/fades.

I thought I might be using to little of the color so I tried adding more color to the collar and this did not seem to create any noticeable difference other than the overall piece being darker.
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Old 12-11-2019, 06:52 PM
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Pete VanderLaan Pete VanderLaan is offline
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That's what I thought. Your clear is essentially "oxidizing" unless it was engineered to be reducing. No commercial cullets are other than oxidizing becuae those oxidizers make the glass fine out way faster. You can indeed engineer a reducing glass- and I do it regularly but they take a long time to fine out which I could go into but it's been covered elsewhere in my past.

So, looking at your experience, the inner glass is open, and is exposed to the kiln. It was reduced as a color, taking away any oxygen from it and leaving metal as the thing you see. At the same time , the same color rod is cased in a clear, which is oxidizing and wants to interact with the color it is exposed to. The color needs to be either a straight silver with no O2 to shine, or some other metal, copper and gold are the regulars here. Look at that column in the periodic table.

There's no surprises. Everyone want their glass, clear or color to be reliably homogenous and sadly , it isn't unless it's stirred constantly. If you made your own color you would seen mottling in the color when reduced even if gathered from a pot only containing that glass. Calcedony rod is the classic demonstrating the lack of mixing in the pot despite our best efforts. If it was mixed, you'd hate it. Try to remember : this is a supercooled liquid without a regular molecular structure. The Si04 can just bop along and suddenly combine with silver instead of sodium and that's what it does. It's what we presume it will do. Irregular molecular structure.

But the commercial artist glass worker wants consistency and it ain't gonna happen. You are gonna see "Blotchy" because the material is engineered without sufficient controls that make it "Non Blotchy" .

It makes it fun. It breaks your heart. It drives you crazy if you try to make money off it.

It's only glass after all.
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Last edited by Pete VanderLaan; 12-11-2019 at 06:56 PM. Reason: I can't type at all.
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Old 12-12-2019, 09:28 AM
Shawn Everette Shawn Everette is offline
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I'm not exactly following.

I get that gathering over a reduction removes it, both glasses are in a high temperature state, and the oxidizing clear can easily give the O2. But when you've just reduced a color before boxing, interior or exterior, how is the clear glass active enough, with just kiln temperature, to oxidize the reduction? If that were the case, wouldn't placing anything clear, or on the oxidizing side, remove the reduction from everything in the kiln?
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Old 12-12-2019, 11:42 AM
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Pete VanderLaan Pete VanderLaan is offline
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I just think the intimate contact between the two glasses in question is sufficient. It doesn't happen instantly. It takes some time for the glasses to get back to balanced. It's an opinion.

I think of glass a lot like I think about the wind in the air. We like to think it's constant but then again, there's the wind. If pressure could be equalized, there'd be no wind.
Cords in glass are like the wind in glass. They show that it's not evenly mixed at all or there would be no cords. Your results may vary. If you were to make up your own cullet glass and dope it with a lot of copper, it would reduce to plate copper on the surface in an atmosphere that drew oxygen off the surface BUT it is inevitably mottled and sometimes rather difficult to maintain as a plating in that same environment. Think of the wind. It can also be lost in the lehr. It really is why I loved my gas annealers but Jeez, they're really dangerous.
There's always a temptation to add a small burner to create a reducing environment but it's hard on the electrical elements.
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Old 12-12-2019, 10:08 PM
Shawn Everette Shawn Everette is offline
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It's just not following a pattern that makes any sense. If atmospheric proximity was enough for a base clear to remove reduction, then you couldn't have a silver wrap over clear. You couldn't put a clear piece near a reduced one. A collar pick up and color drop should have the same reaction. I get the surface contact of the plaster and it being chemically active at kiln temperature to cause change, but at 1000* clear glass shouldn't readily be releasing enough oxygen in the environment to affect the reduction near, but not in direct contact, with it.

You're absolutely right that glass isn't homogeneous, that's the exact reason why the exterior clear layer shouldn't be able to interact with the interior surface reduction in a piece like this. The reduction should essentially be insulated by the rest of the color layer.

Back to Gabriel; you're not flashing these things at the end, right? Cause that's a sure fire way to remove reduction. Got any pics?
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Old 12-12-2019, 11:17 PM
Nick Delmatto Nick Delmatto is offline
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[quote=Pete VanderLaan;146261]

It really is why I loved my gas annealers but Jeez, they're really dangerous.

Pete, I've annealed with gas for 35 plus years without a computer & I bring them down manually using thermal mass as my friend. Also, my shop is on my property, close to home. Why is gas annealing dangerous?
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