Reduction, Oxidation and Strike

[Cathy at the Beach]

This is probably a really dumb newbie question- but I"ve gone through hundreds of posts looking for info on various kinds of flame use and haven't been able to find much specifically on reducing- oxidizing- and striking glass.

I would like a little definition on each and what their differences are.

I know that to reduce glass you turn your oxygen down- to oxidize you turn your propane down- but what glasses do you do this on? Obviously it doesnt affect all glass- so theres one question.

What exactly is striking- how do you know if the glass is striking glass. IS this where you heat heat heat and cool cool cool then flash through a nuetral flame.
Sorry to sound so nuts- but I just switched from a HH to a minor and now have some control over this but can't for the life of me figure out where to start!

Thanks a bunch!:roll:

[theglasszone]

Hi Cathy!

Check out this wonderful list from Hayley which lists which glasses are reduction and which are striking:

http://www.lampworketc.com/forums/showthread.php?t=77479

I can't help you much with your new oxy/fuel set up, but here's my Hot Head Tutorial on working with reduction glass (specifically Black Nebula) and I show the HH flame in neutral (as neutral as a Hot Head can be) and also a "reduction" flame just to compare:

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

It might give you a little help; hopefully though someone with a oxy/fuel torch will pipe in and give you more information (pics?).

De

[Bunyip]

REAL quick rundown (I'm assuming you're working in soft glass):

Reduction glass is glass that changes color in a reduction flame. Typically the mechanism for this is that there are metals in the glass which get pulled to the surface by the lack of oxygen in the reduction flame.

Oxidizing flames burn off the metals from the surface of glass and don't allow it to reform. They may also impart a metallic sheen in some glass.

Striking glass is glass that changes color at a specific temperature. One of the mechanisms for this is crystal growth. At a certain temperature, crystals grow, and the more they grow, the more the color changes. Cooling and re-heating may assist this process.

Some glasses may benefit from all three flame characteristics, but probably not at the same time. Example - Iris orange reduces to a silvery sheen...or pops wild colors as "raku".

Edit: another downfall is playing with the pressure on your regulators - don't do it. Once you have the proper pressure set on your regulators leave them alone. Arrow Springs recommends the following: "oxygen is between 20 and 25 pounds. Use 10 to 15 pounds for the propane." Most torches recommend less, but once again according to Arrow Springs those should be taken as a minimum.

Flames -

Oxidizing: Hissy intense flame, short all blue candles- no yellow. Typically cooler than neutral flame.
Neutral: 1/4" candles with white/yellow tip.
Reducing flame: Longer, mostly yellow candles. Too reducing and your beads will soot up. Not enough and you may not get effects. Typically cooler on glass than neutral flame although it may FEEL hotter to the lampworker.

Note: Depending on your setup, you can add or remove gas either gas. Instead of defining flame types by what you add or remove, it may be useful to think of the three flames this way (although it's not 100% technically true) Oxidizing: More oxygen than propane, Neutral: "equal" amounts of oxygen and propane. Reduction: more propane than oxygen.

[Hayley]

Cathy - if you are looking into working with reducing and striking silver glass, I have some tutorials and information on my blog (in addition to the exchange thread De has provided the link for).

http://envisionsf.blogspot.com/search/label/Silver%20glass%20101

Chris - Arrow Springs' recommended oxy/propane setting (20-25 psi oxy and 10-15 psi propane) does not work for those of us who use oxycons since the most we can get is between 8-9 psi for a 5-lpm and 15 psi for an 8-lpm oxycon. The oxy/propane ratio is about 2:1 (some people like it more 3:1) . . . thus 8 psi oxy and 4 psi propane.

[Bunyip]

Too true. I'm on concentrators as well at the moment. I get about 10 psi on my dual 5LPM oxycons (souped up models!) & I use between 4 & 5 psi for my propane. I've just seen too many beginners struggling with the regulators trying to figure out how get their flame chemistry right, so I added as much information in there as I could. Once you get the regulator right, there's no need to fiddle with it while torching. If you're on a concentrator, different rules may apply for your oxygen, but you can still adjust at the torch.

[Corinne - GOC]

Does anybody have a breakdown of some of the striking/reducing/oxidizing effects of non-silver glass, like effetre or cim?

[Cathy at the Beach]

Wow!!! this is wonderful info- THANK You all!

When I got my Minor- the paper work said to set the regulator to 5psi. So I can change this to a higher psi if I want??? It isn't dangerous?
(I know I sound really dumb but I have no info other than what I received with the torch!

I run on one concentrator only (5 lm)
Thanks

[Hayley]

Cathy - I don't know of anyone using the high oxy/propane pressure (20-25 psi) unless they are using ginormous torches like the Phantom. I would keep the regulator set at what the torch recommendation is.

[Otter's Flame]

One thing I would also add....... experiment with your glass.... no matter what it is. Even though a glass might not be known to "do tricks" as far as reduction or oxidation... it may benefit you a great deal to experiment and see. Some glass when combined with other glass and reduced will make beautiful lines where the colors touch. Some glass may react unexpectedly in different flame chemistry. It is GREAT that people have taken the time to list what colors will do what and how to make them work properly.... what an invaluable resource.

Every time I get a new glass I run it through Otter's Torture Test lol. I reduce it, I oxidize it, I try and strike it, I do several combination of reducing and oxidizing and then I take those methods to the extreme. I add copper to it, I add silver to it, I add brass to it and anything else I may have laying around. I work it cool, I work it hot, I try and burn it, I try and burn the color out of it. I pull it thin and apply it over other colors, I apply it thick over other colors, I encase it and anything else I can think of.

I realize I probably do things backward but only after I torture the glass is when I may go look for information about it. I do not want to know ahead of time what the glass is "supposed to do". I want to know what I can make the glass do and then what others are making it do.

Just my .05 cents.

Otter

[Bunyip]

I didn't mean to get bogged down in regulator discussion. Read up and make your own choice. The point I was making and would like to reiterate, is that flame settings are set at the torch, not the regulator. Think of your "neutral" flame as "normal" and realize that you can change EITHER gas to achieve the flame type you want... or both at the same time...It's just knowing what the proportions are. (edit: and whether you have enough oxygen to turn it up, of course)

[Cathy at the Beach]

ok...I'm back after trying to strike some glass called carnelian. I believe its moretti.

I heated - cooled-- heated cooled..it began to turn darker orangey red....when I put it in the kiln it was a good carnelian colour but when I took it out-- it was pale and pinky!

What did I do wrong? I am trying to match it to a carnelian cab I purchased and wanted to use the cab along with the beads. Is there any hope?