National 3a blowpipe torch

[mlt298]

Hello all, I am new to flameworking and so far I have a hothead torch setup on a 20 pound propane tank. I use only 104 glass so far and I don't look to get into boro anytime soon.
with that said I have a really old school NATIONAL 3A BLOWPIPE TORCH with a few of the compressed air tips (not the oxy tips) now I have read that this premix torch won't work for this "soft" glass, but my question is this. If I ran propane and compressed air it would not be as hot. Do you think I could get away with this, without destroying the color in the 104 glass.

the hot head works fine but it sounds like a jet taking off, not sure the NATIONAL 3A BLOWPIPE TORCH running would be much quieter? I am not ready to step up to the oxy/acc or oxy/propane just yet.

[hyperT]

You say you have gas/air tips for the 3A, well that's what they are for.
There are a few different sizes for gas and compressed air.
This set up will give you a wide range of oxidizing or reducing fires.
You will get a gentle hissing sound from the torch.

317026

Since I build my own workbenches, I would cut a small rectangular hole in the bench top so the torch would fit up through it. Then clamp it between two opposing L brackets with a couple hose clamps to secure it. This stands the torch up and makes it stable and adjustable. I also would use two of these torches facing directly at each other for a crossfire set up. You work in the center of the two "crossfires" to heat the glass from both sides at once. This will speed things up a lot.
I don't know where you read it won't work for soft glasses? It's what it's made for LOL. I have used them for half a century now LOL.

Have fun, Wayne

[hyperT]

They also sell all the tips you would ever need and replacement parts for the National 3A 3B blowpipes.

Search on their site for them.

[mlt298]

Thanks for the info, well I had not found much about the use of compressed air with the torch. From what I read it was more to do with the type of torch surface mix vs pre mix for hard/soft glass. I was confused :)
One last question, I only have the torch and tips. Not sure what type of regulator I will need for the compressed air. Is it just a air regulator?

[hyperT]

Yes any that will work with your compressor. Some compressors already have one built in. About 10 psi should work well. And a normal bbq regulator for the propane. That yealds about 5 psi on the gas.
Just get nipple fittings for both to add your fuel lines to. I always used clear Tygon tubing for the lines with small hose clamps. Warm the end of the tube up and slide it onto the nipple then clamp it
The torch itself has a built in Venturi Mixer so the two gasses are mixed through it. Turn on the gas slightly first then light it, then add the compressed air slowly.
The 3A torch has nipple fittings on the fuel lines. The 3B torch has screw on fittings for the fuel lines.

[hyperT]

I want to mention a little quirk the 3A has along with many other torches. Occasionally it may backfire so you probably want to use a fuel gas flashback arrestor inline with it for safety reasons. Even then it may backfire and start to burn inside of the torch. When it is doing this it will make a strange whistling sound. Turn the fuel off to put the internal fire out. Then start over. If left burning it could actually melt the torch.
In the link below we have Gianni Toso, an italian master working with a 3A so watch it in action.
He is using a Multi Hole tip with oxy propane.

https://www.youtube.com/watch?v=FYEQncNl4W0&index=16&list=PLx9b2TiEudYcZ0c8onXdulY8T_Rto37sg

[mlt298]

Thanks for all the info. I may end up trying this out as I have most of the parts already, your advice has helped me a lot!
Thanks again.