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View Full Version : Glass torch, could use some advice.



gary hart
08-18-2011, 01:43 AM
Wanting to make a small glass chimney for an alcohol burner for a hot air engine so a breeze won't blow flame out. Also playing with glass sounds like fun. So, need a torch for glass.

Made a ring burner with 1-5/8" ID. This works good using Oxy-acetylene but only for about 5 minutes as flame impingement generates more heat than the ring dissipates.


http://img.photobucket.com/albums/0903/ghart3/Tools/ring.jpg

Made a pair of flat burners with each burner having 60 holes of .016" diameter. This don't work on oxy-acetylene as it will back fire as pressure is too low to keep flame from moving back inside tube and if pressure is turned up the flame wants to jump away from burner and go out.

http://img.photobucket.com/albums/0903/ghart3/Tools/flat.jpg

Is there a simple formula for deterring size and number of orifices for oxy/acetylene or oxy/propane burner/torch??

Evan
08-18-2011, 02:01 AM
The way you keep the flame from crawling back inside the burner is to use a very small orifice for the fuel which is directly followed by the air mixer and burner. Study a regular propane bottle torch to see what I mean.

For example, the flat burner you show, which looks very cool, would have very much smaller orifices (orfi?) and would have directly above them a plate with aligned larger holes. Each orifice would pull air from the side in the gap between plates to mix with the fuel as it exits the plate to burn. The very high velocity of the fuel gas stream prevents back firing.

BTW, for your chimney you need borosilicate glass. Regular bottle glass will shatter very easily with rapid changes in temperature.

gary hart
08-18-2011, 02:20 AM
My understanding is that for borosilicate glass that the fuel and oxygen needs to be premixed for enough temperature for working the glass. For soft glass (whatever that is) surface mixed or fuel and air gives enough temperature for working the soft glass.

I'm using a gas welding torch to mix the oxygen and fuel and then piping to burner.

macona
08-18-2011, 04:29 AM
Don't use Acetelyene. Its too dirty for glass work. Propane or natural glass with air is used for soft glass and with oxygen for boro.

I have a couple bench glass torches if you want to borrow one.

-Jerry

HWooldridge
08-18-2011, 09:40 AM
I used to work at a place that did a lot of glass work and they used oxy-hydrogen torches. You can probably pick up a small fuel bottle then use your existing O2 bottle and standard torch.

gary hart
08-18-2011, 11:49 AM
Thanks for offer Jerry, might take you up on borrowing one if my frustration level gets too high trying to make something. Was planning on using propane and oxygen, out of propane so was using the acetylene.