Reduction?!?

[MardiGrasGlass]

What is "Reduction"?

I read somewhere that you can "reduce" the oxygen flow in a HH by covering the air holes with heat resistant gloves. Is this what "reduction" means? Reducing the flame to nothing but pure fuel?

I was going to order some frit just now and started reading user comments, and "reduction" and "reduces" were mentioned, so it scared me off.... I need to know what this means and what it does before I spend money on frit.

Any help is appreciated.

[Kevan]

I don't know how it's done on a HH ,but the idea is to make a flame that is more fuel than oxygen. A yellow flame.

[MardiGrasGlass]

And what does this cause? Whats the purpose?

[Kevan]

It creates a mettalic finish on most reduction glasses. Some will get blues and greens, some will get gold.

The dots on this bead are Iris Gold.


This is Triton by Double Helix

[MardiGrasGlass]

AH... So "reducing" the flame to pure fuel, causes it to get hotter, which then causes a color change in the glass? I'm assuming because you get a metallic effect, the glass has metals in it, and are brought to the surface by the superheating of the fuel only flame? Have I put all the facts together correctly?

[Carolyn M]

I'm linking you to the Double Helix page which explains how to reduce specific glass colours. DH make the most wonderful silver glass colours
http://www.doublehelixglassworks.com...ingguides.aspx

[HelleAlice]

Originally Posted by MardiGrasGlass

AH... So "reducing" the flame to pure fuel, causes it to get hotter, which then causes a color change in the glass? I'm assuming because you get a metallic effect, the glass has metals in it, and are brought to the surface by the superheating of the fuel only flame? Have I put all the facts together correctly?

Actually, its not heat that is doing it.The metals in the glass are in oxidized form, wich means they have lost one or more electrones, and are turned into ions. This is the form that minerals are in when you take them as supplements i.e., your not chewing iron filings when your blood count is low. When you change your flame chemistry to reductive, you are putting the electrones back in the metal oxides in the glass - reducing them - wich make them appear metallic again.

[Sue in Maine]

Good explanation, Hels, and I think the flame is actually a little cooler when you're reducing the oxy. Can someone correct me if I'm wrong on this. Adding oxy fuels the flames and makes them hotter. Take away the oxy and it runs a little cooler.

Sue

[JavaGirlBT]

Sue, you are right. A neutral flame is hotter than a reducing flame.

[Sue in Maine]

Originally Posted by JavaGirlBT

Sue, you are right. A neutral flame is hotter than a reducing flame.

Thanks! I thought I was but I'm still claiming my right to a senior moment! lol

Sue

[glassmaker]

Originally Posted by MardiGrasGlass

AH... So "reducing" the flame to pure fuel, causes it to get hotter, which then causes a color change in the glass? I'm assuming because you get a metallic effect, the glass has metals in it, and are brought to the surface by the superheating of the fuel only flame? Have I put all the facts together correctly?

Well, not exactly...

The word "reduction" has little or nothing to with physically "reducing" the air flow of your torch. It refers to the oxidation/reduction of chemicals in the glass - in this case primarily silver or other metals (although other things in there oxidize and/or reduce too). As Helle mentioned above, the low oxygen content of a reducing flame causes the glass to capture electrons from the flame, thereby "reducing" some of the metal ions to their metallic form, which can create a metallic surface lustre.

An example of reduction would be the equation representing the reduction of cuprous oxide to metallic copper: CuO > Cu + O

Reduction can be thermal too. Changes in heat can cause different components of the glass to trade electrons back and forth, reducing one and oxidizing another. This is what causes most (though not all) striking glasses to change color.

As far as flames go, neutral to very slightly reducing flames are the hottest. A widespread myth is that adding oxygen to a flame always makes it hotter. That is true if the flame is not getting enough oxygen to burn optimally already. But too much oxygen can actually cool the flame - as can too much gas. If you question this, just stick a glass cane in the flame and play with the adjustments. It shouldn't take long to see what heats things fastest. This is easiest if you use clear boro for the test since it takes more heat to soften. Soft glass gets runny so fast that it is harder to see the change in temp.

The flame of a Hothead is naturally on the reducing side.

If this hasn't confused you enough already, for more info than you ever want to know on reduction and oxidation just google "redox".

Brad

[MardiGrasGlass]

Originally Posted by glassmaker

The flame of a Hothead is naturally on the reducing side.

If this hasn't confused you enough already, for more info than you ever want to know on reduction and oxidation just google "redox".

Brad

Brad & Everyone,

Thanks SO much! I can't claim that I understand everything completely, because I dont have a chemistry degree, however it is MUCH clearer than it was.

So "reducing" and "striking" of a glass rod, doesn't require any changing of the flame. They will both occur through normal heating correct?

[Sue in Maine]

Originally Posted by MardiGrasGlass

Brad & Everyone,

Thanks SO much! I can't claim that I understand everything completely, because I dont have a chemistry degree, however it is MUCH clearer than it was.

So "reducing" and "striking" of a glass rod, doesn't require any changing of the flame. They will both occur through normal heating correct?

No, reducing DOES require you change the flame. You usually work in a "Neutral" flame and when you reduce, you turn DOWN your oxy OR turn up your fuel. Reducing flame is one that runs with more fuel, less oxy.

Striking glass has to do with temperature. For example, rubino oro (ruby gold) if it is worked too hot will lose its color and go clear. Sometimes when you get it tooooo hot, you can't bring the color back so work further out in the flame on this one where it is cooler BUT for those times you have it go clear, take the bead out of the flame and let it cool for a few moments... then bring the bead carefully back into the flame FURTHER OUT in the flame and you should see the color start to come back. You have "struck" the color. Some glasses you NEED to strike to get color. Some (if you get too hot or unlucky) you can bring color back by striking. (And, yes, you can strike in your normal neutral flame.)

Jump in and correct me or clear me up, ladies and gents.

Sue

[MardiGrasGlass]

Awe crap! In my first order of glass, due to be delievered soon I hope, I bought striking red, orange, and yellow I believe.

So in order to use striking colors, or frit, I'm going to have to do that trick where I cover the holes with heat resistant golves to reduce the oxygen flow into the flame?

Am I putting too much thought into this and making it harder than it really is?

[MelanieG]

Someone correct me if I'm wrong, but I think you won't need to do anything special with your flame to strike those colours. They are pretty easy to strike and should just strike through normal heating and cooling.

Those particular ones are called striking because they are clear in the rod but develop colour after you've 'struck' them in the flame and gotten them hot.

[theglasszone]

All right you'z guyz!!! Hope you don't mind me piping up...

I lack all the chem knowledge and ins-and-outs of the actual specifics on "what happens" (scientifically, that is!) when one "reduces" or "strikes", but I'd like to post a couple of personal observations:

As a Hot Head user, the word "reduction" (as in working with "reduction silver glass"), for me at least, means "reducing the oxygen" and working a "fuel rich" flame to evoke the "metallic" effect that reduction glass can achieve - even on a Hot Head!!! Don't get me wrong, I'm no "expert" on the meaning behind the word and all the technical stuff - I just find that this is my "dorky" way of remembering to "reduce the oxygen when working with reducing silver glass", that's all. I believe the "striking silver glasses" require quite a bit more (temperature) heat than can be yielded from a Hot Head torch (no matter what fuel you are burning) and hence, they can be very difficult to work properly on a Hot Head, no matter what you try.

At this point, Christopher, I'd like to segue (shamelessly, I might add) to my "Black Nebula on a Hot Head" Tutorial, linked below. It not only applies to Black Neb., but as you can see from the more recent posts (and check Naos/Amber's post from today or yesterday - awesome!!!) this technique applies to just about every "reduction" silver glass I've tried. Check it out:

http://www.lampworketc.com/forums/sh...ad.php?t=86417

Now here's my take on the "striking" glasses:

There seems to be a difference, at least at my bench, between the behavior of "striking colors" and "striking silver glasses", in that I can in deed "strike" the conventional "striking color" glasses (i.e., Rubino, Striking Red, Striking Yellow, Striking Orange, etc.) without a great deal of difficulty. I find that getting these pretty hot - but not so hot as to go "clear", then waving them up close to the torch head several times, makes the color pop! Sometimes, depending on the ambient conditions of my studio, it seems to work better to wave the bead at the back of the flame (farther out from the head) - but I'm not sure exactly why. I usually just try one area (front of flame near the torch) and if that doesn't work, I move to the back of the flame. The "striking silver glasses", though, I've not had so much luck with.

OK - hope this helps!!! If you think I can help you further, please post here or feel free to PM me...I'm all about sharing and helping where I can!!!

Carry on....

DeAnne in CA

[Sue in Maine]

Originally Posted by MardiGrasGlass

Awe crap! In my first order of glass, due to be delievered soon I hope, I bought striking red, orange, and yellow I believe.

So in order to use striking colors, or frit, I'm going to have to do that trick where I cover the holes with heat resistant golves to reduce the oxygen flow into the flame?

Am I putting too much thought into this and making it harder than it really is?

Relax! I have both the striking red and orange. Just make your bead and when your bead is picture perfect in the shape you want it to be, take the bead out of the flame and let it cool. Then slowly bring it back into the OUTER flame, wafting it back and forth thru the flame. It's really neat to see the color come back. Sometimes beads will strike back in the kiln- in fact, some boros want to be kiln struck. I think there is also a new 104 that likes to kiln strike- but can't remember what it is. (I know I don't have it.)

Worse comes to worst, you'll wind up with a clear bead rather than red, orange or yellow.

Sue

[theglasszone]

Originally Posted by Sue in Maine

...I think there is also a new 104 that likes to kiln strike- but can't remember what it is. (I know I don't have it.)...Sue

Would that be the gorgeous, alluring, works-for-some (but not me yet, damn it!) beautiful-when-it-does "Pandora" you speak of?

I sure love what some have been able to do with it!!! Me, NOT SO MUCH

I agree with everything you said about the Striking Colors such as Rubino, etc. It IS neat to watch the color come back, too! I'm so easily entertained...ha!!!

De

[Listenup]

Red is the only striking color of the 3 you mentioned that may give you a bit of a problem. If you overstrike it, it will go clear. I assume by about now your head is swirling with all this info. All you do is need to remember that if your red goes clear on you, let it cool off just a bit and then put it back in the flame.

-Kay

[Carolyn M]

And don't forget, reduction and striking are two different processes