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periwinkle
2009-08-07, 10:12am
I've read plenty of messages about how you must find the sweet spot depending on the gas used when working with a hothead, but I can't seem to find it with the new MAP gas.

I was using MAPP gas up until recently, but then the formula changed and now it's still called MAP gas, but I understand that it's propylene.

I've read a lot on this forum about how it's necessary to find the sweet spot, but no one seems to say about how far out that is...

When I used the old MAPP gas, I found that about 4 inches from the tip of the torch was perfect.

Now, I find that the propylene burns so much hotter that I keep getting nasty soot marks in all my beads. What I keep hearing people say is to work further out, well that's what I'm doing! And, it seems like I just can't find that sweet spot. I'm working 6-8 inches out and I get terrible soot.

For instance, I was making a bead with a transparent base, and I could see the soot marks on the bead even while it was molten. I continued working on it anyway. I placed my white dots and noticed that they got sooty and that was further out in the flame (about 6-8 inches). Then I covered these dots with a colored transparent and put smaller white dots on top of the previous dots. This time, I worked in much closer - around 4 inches from the tip of the torch and this second round of white dots did not get sooty. Now, it would seem that I've found the sweet spot, but I was also melting the base of the bead in this are, and it got sooty here, as well. This sweet spot seems to be very hard to locate!

I've read that I need to turn my torch down, well, I do. But what I find is that if I go too much, it just goes out. So, it seems that I have it turned down about as low as it will go without blowing out, but I still have sooty beads and it seems like I keep hearing that I need to work out further in the flame, but that just dirties up my beads.

Could someone who uses propylene successfully tell me approximately how far out their sweet spot is?

Also, I've been thinking about switching to propane so that I can use the bulk tanks as these 14.1 oz containers just go way too fast, so I'm wondering where the sweet spot is with propane?

I just hate wasting so much glass trying to find the sweet spot. Normally, I use a minor burner at the glass studio where I make beads (Mesa Art Center in Mesa, Arizona), but it's between sessions right now and I'm having serious withdrawals.

lunamoonshadow
2009-08-07, 11:06am
http://www.nlcbeads.com/articles.php
"where it is" with a drawing. Nikki's got a great little tutorial on her site, & she TEACHES on hotheads...& worked on bulk propane for years & years. She also walked me through how to get my hothead to work it's best on bulk--she's a sweetheart!
~luna

Dale M.
2009-08-07, 1:27pm
Also try and turn torch down as much as you can... IF you are wide open, its a fuel rich( reducing flame)...

Dale

tammydownunder
2009-08-07, 4:17pm
Also try and turn torch down as much as you can... IF you are wide open, its a fuel rich( reducing flame)...

Dale

word. I found the sweet spot when I turned my torch down to the point it would just work. You don't want to have it on inferno as you will burn your glass, reduce your glass, smut your clear and waste your gas.

periwinkle
2009-08-08, 11:48am
Thank you all. I finally found it! At least it only took one more bead. It was the same place as before...Just beyond the blue cone. Dale, it really helped to turn down the flame. It actually was so low that it went out near the end, but I was able to light the torch again and finish the bead. In a way it was good, because I needed a dark blue, and when the torch went out, I grabbed it from inside the house and finished the bead!

chimehk
2009-08-19, 1:34am
How about rubino oro, where's the sweet spot for it? I'm still getting alot of black scums in using the map pro. Also with effetre grass green, there's the black webbing effect coming out.

tammydownunder
2009-08-19, 2:46am
Work much higher in the flame. Rubino will get the black nasties if it gets too much heat.