Flame Characteristics and Glass

sjglass · #1 2007-12-13, 10:12pm

Well, I've been struggling at making my flame do what I want. I've been using a GTT Mirage for a few years now - although I can make it work, I want to make the torch work for me.

Example 1: I want to do switchbacks on hollow tubing - After drawing the lines, I want a reducing flame that allows me to create tight switchbacks (wig wags, whatever).

I like to make like 3/4 inch candles with light normal oxy and light inner oxy. It gives a kinda steady flame with wide candles that have a bit of orange at the end of them. Maybe I'll take pictures?

But most of the time I end up making switchbacks but my glass thins out instead of gathers. Is this my technique, flame, or what?

Also, I've been trying to use some snow white and light greens that boil quite easy. for me to be able to get these to melt without boiling I have to turn my oxy way down to get a busy soft flame. This makes my torch get hot which GTT's aren't supposed to do. It's quite annoying. Am I using to much propane or oxygen or what's the story?

So in addition to those specific questions, how many main flame characteristics are there, how do you achieve them (80%propane 20% oxy), and what effects do they have on colors and tubing?

Cosmo · #2 2007-12-14, 6:41am

A reducing flame will have no effect on how tight your wig wags are. If you want tight wig wags, pull your tube down thinner before twisting, then gather it back up.

To gather it back up, work in sections. Start at the end furthest away from your blow tube. Blow it into a small bubble. Then work on the end closest to your blow pipe and blow that into a small bubble. Then work on the middle, and eventually work the whole piece into one large bubble.

If you are having problems boiling the colors, I would try doing a stick stack with those colors so that they are encased and the flame never hits them directly. A stick stack is also more efficient as far as color goes. http://www.glassartists.org/Gal12061...tick_Stack.asp

boroburner · #3 2007-12-14, 8:06am

there are 3 types of flame enviroment that you really should know(note: all 3 enviroments are within the same flame)....reducing...tends to be right in front of the torch just ahead of the candles. This area will have unburnt propane in it that is searching for oxygen to complete its combustion. This atmosphere will steal oxygen from you glass causing lustering of metal colors(i believe this is how it works anyways....). Neutral is going to be the part of the flame that is a solid & even. In this area there is a fairly even ratio of oxy and prop and with any luck will not be robbing it from your work. Oxidizing is in the end of the flame, where it starts to flick and break apart... there is surplus oxy here. If you run you mirage at 7 and 30 you shouldnt have any problems setting a workable flame.

sjglass · #4 2007-12-14, 10:11am

I run I think at about 8 and 30... Maybe we could incorporate some pictures to help me out? Do you have time to do that?

kiko · #5 2007-12-14, 11:50am

When I do switchbacks with my phantom. I apply the color with a nice oxyflame on the lynx then add the outer flame to melt in the color and condense and elongate the tube. I use the extra oxy so that I can work shorter candles on the outer and have a bit cooler flame to melt in touchy colors and keep in control of the tube. Then switch to lynx to wig-wag the sections and condense a bit. Then the outer again to condense and blow.

You shouldn't use a reducing flame on your mirage unless it is to pull up the metals briefly.

sjglass · #6 2007-12-17, 6:10pm

anyone else have input on this?

Cosmo · #7 2007-12-17, 6:22pm

More input as in what? Did the advice posted in this thread not work for you?

sjglass · #8 2007-12-17, 9:55pm

no it helped great. I was hoping to hear what others had to say and i'm hoping to post some flame types and categorize them.

Thanks for making me clarify

boroburner · #9 2007-12-19, 7:58am

thats the thing......Most flames have all 3 zones within them....ie reducing neutral etc..
Its a matter of figuring out where within any given flame is the enviroment you want.

mikeshelbo · #10 2007-12-19, 1:45pm

Quote:

Originally Posted by boroburner

thats the thing......Most flames have all 3 zones within them....ie reducing neutral etc..
Its a matter of figuring out where within any given flame is the enviroment you want.

exactly .... break up the flame into three regions and you will find that from the burner tip 1/3 the way out is reducing, 2/3 out is neutral and the last third is neutral to oxidizing.... this is the exact reason why most have problems with color and control and so much more.... example - you can work soft glass on premix torches no problem as long as you work in the correct region of the flame... check the diagram in Bandhu Dunhams Contemporary Lampworking....

shelbo

sjglass · #11 2007-12-20, 7:43pm

what does an oxidizing flame do to colored glass besides keep it warm?

Cosmo · #12 2007-12-21, 10:59am

It will keep colors from reducing. A neutral flame is the hottest, while a reducing or oxidizing flame is cooler, so colors that are sensitive are usually worked in a cooler flame. Oxygen will promote boiling however, so if you are having problems boiling colors, you may have too much oxygen. A lot of people work crayon colors in an oxidizing flame, but I have found that they work better in a reducing flame.

sjglass · #13 2007-12-21, 6:46pm

Wow I never would have thought a neutral flame to be the hottest, when I want to heat something quick I put it just in front of the candles. Wow, that's really interesting. So as heat is concerned it goes on a scale from 1 to 3 with 1 being the hottest

nearest the candles - 2
in the middle of the flame - 1
at the flickering tail of the flame - 3

Cosmo · #14 2007-12-21, 7:10pm

Well, it's kind of weird. A neutral flame is the hottest, but a slightly reducing flame will penetrate quicker. Not sure why.

mikeshelbo · #15 2007-12-27, 4:55pm

the piece gets hotter faster closer to the candles because the flame is more intense.... it is also reducing at that spot in the flame because of the way the gas is combusting throughout the length of the flame... so in most cases when you set your flame to reduction you are having a slightly cooler and bushier flame but when you break down the regions of the flame you always will have a more reducing area closer to the torch head.....even when you have your flame set to neutral....

if you are intentionally reducing your piece you will find more success trying to get luster or metallic sheen by kickin up the propane on your torch and passing your piece through the reducing flame a second at a time.... dont just set the flame to heavy reduction and hold your piece in unless that is what you are trying to achieve (overreduction, super heavy saturation)

sjglass · #16 2007-12-28, 8:01pm

What i've been trying to do is find the right flame to reduce hollow tubing while wig wag'n but its either too hot and my tubing crumples or I have bad technique and stretch it out instead of condensing it. Also if I turn my torch down so low that the candles are tiny and the amount of heat doesn't wrinkly the tubing my mirage starts to get hot which isn't supposed to happen with GTT's. I'm pretty sure that's a bad thing.

There lies the problem. Flame to small torch gets hot, flame bigger tubing folds under the heat. Maybe my tubing is to thin, i work to directly in the flame or do I just need more practice?

murf · #17 2007-12-28, 10:48pm

what is being discussed is out of my league at the present; I understand the three flame types and there uses. My problem lies in using the flame and controlling it or my work in it. the one true draw back to videos is the flame just doesn't film well. I took a class with John Kobuki and what really surprised me was the lack of a raging torch. I just assumed that these big torches just ran wide open. if there is one discipline presently I need to work on, its flame control. I am able to make some pretty nice things that I'm happy with, but am very disgusted by what means it took to make them. Shameful
Murf

Cosmo · #18 2007-12-29, 8:24am

Quote:

Originally Posted by sjglass

What i've been trying to do is find the right flame to reduce hollow tubing while wig wag'n but its either too hot and my tubing crumples or I have bad technique and stretch it out instead of condensing it. Also if I turn my torch down so low that the candles are tiny and the amount of heat doesn't wrinkly the tubing my mirage starts to get hot which isn't supposed to happen with GTT's. I'm pretty sure that's a bad thing.

There lies the problem. Flame to small torch gets hot, flame bigger tubing folds under the heat. Maybe my tubing is to thin, i work to directly in the flame or do I just need more practice?

I think your technique is probably more to blame than the flame you are using. If you are stretching it out, then that's definitely your technique. Try working a little further out from the torch where the flame is a little cooler. When I'm doing wig wags and such, I dial my flame down to a needle point and work slowly. Let it get hot and soft before you try to twist it. If you twist it before it gets hot enough, you will get wrinkles.

Here's a little trick I have used with students in just your situation. It may help you:

Take two pieces of clear borosilicate maybe 6-7mm in diameter (both should be same size). Heat one end of them and bend them into a hook shape, then let them cool. Once cool, hook a rubber band between the two hooks and practice rotating the rods keeping even tension on the rubber band. It will also help you keep your rotation even between both hands if you concentrate on not twisting the rubber band as you rotate.

sjglass · #19 2007-12-29, 6:45pm

wow that's a great idea... thanks!