I'm still struggling with this silver glass shenanigans ???
Think I have got striking down now - letting the bead cool then heating back to a glow at the tiip of a normal flame?
But it's the reducing part I'm having problems with, I know that I need to turn down the oxygen but I'm not sure if it's supposed to go off all the way so I'm just left with a propane flame, or somewhere in the middle. I'm also not sure what part of the flame I need to use...
Any advice would be much appreciated! I'm feeling a little deflated
I usually leave the oxygen alone and turn up the propane :-) Then work right at the end of the yellow part of the flame.
me too
I never touch the oxygen. I just crank up the propane until it's an orange flame, then reduce at the tip/end of it :)
And me (are you detecting a theme here yet ;))
It's always a good idea to do a search of the forum. This question does come up a lot, and I found this in a post from a few months back, on this board :)
http://www.doublehelixglassworks.com/DH_guides_striking.pdf
I do both.....
Thanks very much everybody - I have been turning the oxygen down so will have a go at just increasing the propane tonight and see if that makes any difference
If it works I may even put a pic on!! :o
i increase propane cus i dont think the oxycon likes to be messed about with too much ....
Hmmmm....I turn the oxo down - but that might be 'cos I work with two oxycons lashed together. I actually leave the propane as it is. I usually only have a "bushy" flame - so not as much propane as you might think. i.e. I turn the oxo down until the cones are about 2cm big and bushy and yellow.
You need to remember that reduction is a CHEMICAL process and NOT a heat process.
You might experience more joy if you let your bead cool for a few seconds before putting it back in the reducing flame. Then, waft the bead through the flame, or keep it moving by spinning it quite quickly through the flame. If your bead starts to glow you're too hot - and it won't reduce. The idea is to keep the bead exposed to the reducing flame without too much heating, if you see what I mean.
'Reduction' is used in some forms of ceramics glaze firings as well.
The reaction is caused when then 'flame' which needs 'oxygen' to burn does not get enough. When this happens it will take the 'chemically combined' oxygen from the metalic oxides in the glass - which changed the chemical composition of them. For instance - copper oxide (Cu2O - two copper molecules and one oxygen) in an oxygen rich flame should be green, but in an oxygen poor flame will turn red.
So, effectivley either method should work, or even a combination of both - but what you will need it time to allow the process to work. ;D
Terri
I'm confused whats the diff between striking and reducing , do we do both or just one depending on the glass.
Am I just being thick and just not getting it ??
People tend to use the terms together but they're two totally different processes.
Striking is a thermal process - so the glass has to be at a certain temperature to do it's stuff. Striking glasses aren't just about the silver glasses - like Double Helix Terra or Luna (which strike), they also include most of the transparent reds and oranges and glasses like rubino oro, which has a tendency to strike in the kiln. Striking temperatures occur at a lower temp than the melting temperature so to get a glass to strike you usually melt it into the require shape at the normal temperature, let it cool for a few seconds and then gently bathe it at the top of the flame where the temperature is lower
Some glasses will reduce - like Double Helix Triton, Aurae and even rubino oro. This process has little to do with the temperature the glass is at and is more concerned with what type of flame you are using. It's called reduction because a reducing flame is oxygen starved and will "steal" oxygen from the glass. Oxygen is a bit of a slutty molecule - it'll go with anything(!), so some glass will readily give up it's oxides to the oxygen starved flame. When this happens there will be a colour change - usually the glass becomes metallic or lustred. But this only happens if the flame is oxygen starved (and therefore propane rich). The hothead will reduce glass readily as it is a problem getting enough oxygen into the flame mix of the hothead anyway.
Sometimes reduction and striking can be reversed - to reverse reduction you just add more oxygen. To reverse striking you heat the glass up to above the striking temperature and the glass will lose its colour.
Some glasses will display both properties - such as Double Helix Ekho, and funnily enough rubino oro so that may be where the confusion arises.
I think that striking is done in a neutral flame, where as reduction involves more propane.
Please feel free to correct me if I'm wrong!
Okay - I need to correct you then Fruddy, as although you're correct broadly speaking, you can also strike in a reducing flame, as a propane rich flame tends to be at a lower temperature than a neutral flame, and as I have said striking is purely a thermal process. But I'm being pendantic now. ;)
Good explanation there Sal, thanks! :)
cheers ;D ;D