I run mine on propane and compressed air. All I did was change the tip to a propane tip. It's much better with bottled oxygen but the compressor worked reasonably well. I made a forced air forge with propane and a hair dryer for years until I upgraded to a better blower system.
The the gas velocity out of the original nozzle is higher than propane's flame front speed until it slows in air away from the tip and you get to the actual flame front (hence the name). As you open up the air, you increase the nozzle velocity pushing the flame front further out. The flame front is where the gas velocity equals the propane flame front velocity. Generally nozzles are designed for the flame front to start just past the end of the nozzle. But you are using the nozzle end somewhat as a flame holder. You can also slow the nozzle velocity closer to the end of the nozzle by belling the end out. (VTsteam here, Ironman). Have you tried brazing with your torch?
It should work for brazing as it puts out a lot of heat. I have used the first tip with propane and 96% oxygen from a oxygen concentrater and it works well for small jobs but it will not produce a large flow for large jobs.
@@luckygen1001 if you do succeed at brazing with it, would you mind filming? Lots of heat yes, but the problem I've had is actually focusing the heat. Possible in a hearth but not easy to achieve in open air. I think the main advantage of a compressed air torch over an atmospheric isn't the amount of heat but the possibility of brazing without oxygen. But I haven't seen that accomplished...yet.
In school in the UK during the 70's we had a similar setup using mains natural gas (mostly methane) and compressed air. From memory the torch was a bit different in that the burner had concentric gas and air jets, I think due to the low pressure of mains gas (20-25mb). but they were very effective for aneling soldering and brazing. I even managed to melt the brass boiler I was supposed to be silver soldering.😀
I got the idea for this burner from the U.K. Model Engineer magazine which is about 50 years old. There were ads for their burner and I decided to build a similar to the one advertised.
Thanks for continuing to make videos. I'm finally melting aluminum and brass and copper. I can't wait to get to the point of cast iron. Not sure about propane physics but let us know in future videos what you learn
@@luckygen1001 I wonder if the ol' devil forge can Get it done?!. I was thinking about a waste oil burner next and a much more heavy duty forge I thought was required for cast iron. Do you do any cast steel?
@@RaspyOB174 Melting steel creates two problems, 1. steel has a very high melting point and my furnace will only just get over that melting point. 2. Steel is very inflammable and burns to an iron oxide at those temperatures.
@@luckygen1001 Super Interesting. I wonder how industry gets it done. Just bigger quicker hotter everything I imagine. I was doing some research on puddle furnaces lately. Turns cast iron into Steel I believe for those reading.
If you perforated about 80% of that rear "shoulder" of your burner head, you wouldn't need the compressed air. Here in the states such "weed burner" torch heads are common. The velocity of the propane creates a natural draft, sucking in enough ambient air for an efficient burn if you regulate the propane flow and pressure
That is true, but you end up burning a lot more propane that way. A lot of ‘Venturi’ type forge burners work on the same principle, and must be run at about 15psi of propane to pull enough air in to burn cleanly. Using a supplied air burner like this, you can use a much lower pressure, about 2-4psi. Much more fuel efficient.
Compressed air makes the flame blow out but what it really means is that the ratio of incombustible gas (nitrogen+ other gases around 80%)is too great ... The flair you made merely allows the incombustible gas to dilute enough to let the oxygen react with less hindrance.. Acetylene will ignite at mixtures from 2.5 percent to 82 percent, while the range for propane is 2.1 percent to 9.5 percent so you can use the standard tip if you reduce the oxygen flow greatly... however it will never be as hot as using oxygen...
Thanks for that comment, I have always known that propane burns differently than acetylene but never knew why. Because there is so much nitrogen in air a lot of energy is wasted heating it up so it will never get as hot as using pure oxygen.
@@luckygen1001 It's not that energy is wasted heating it up. It's more like there is not enough oxygen to allow it to reach higher temperatures... you can reduce hydrogen burn rate (which is the fastest burning gas of around 360 feet per second) to the burn rate of low combustion gasses of around 45 feet per second by diluting it with incombustible gasses. That is what mixing air does to a lesser degree.
I have an Oxy/Propane torch set that I bought at a hardware store. I use it strictly as a cutting torch. 1/2" frame steel is no problem. It's very effective and the only down side, imo, is getting the Oxy bottle refilled ($$$). Nicely done video, Sir. thank you. Cheers from Alaska.
@@luckygen1001 I worked most of my career as a mechanic in 'Muffler & Brake' shops. Many of which just used natural gas and a XORBOX for oxygen. Just pay the electric and gas bill and never run out of heat knife juice.
Nice video. I imagine the propane is being blown out as the air is only 20 odd percent oxygen. Another way to keep the flame inside the burner nozzle is to turn an internal taper from the outside lip the full length of the tube. Don't need much, around 3 degrees.
Looks like your Mum didn't teach you how to get a candle to stand up, but I see you improvised pretty well later on. 🤣 I tried to do a similar thing with a cheap ebay oxy-acetylene type handpiece, but I had problems maintaining a flame with the supposed propane tip supplied. I tried making a dish in the end of the tip similar to the commercial oxy-lpg tips that are available, but that made very little improvement. I ended up making a side draft burner out of some pipe etc and that works well, but the flame is a bit big for fine soldering jobs - way too big really. I think that I will try to make a miniature version of what you have done to see if I can get a really small flame. Interesting video as always. Thanks.
silly question what relatively heavy metal aloys can you resonably safely melt and cast in your kitchen on a propane stove or something similar? i been wondering about that because i am building a train model that require some strategic placement of weights and cuting them out of lead is kind of not safe for kids process many older train models had hard lead weights in them and some even used them as a construction part so i started playing with that but i started to wonder how much of a health hazard is that. if i release that locomotive project as an open source design it might be banned for containing lead quite a lot of it actually, around 35 grams of heavy metals aloy that need to be filed , drilled and taped after which it is sealed in epoxy shell but people now are scared to even touch lead let alone breating in fumes from melting it is there a way to cast some safer aloy in high temp silicone molds ? like zamak or something without the use of a furnece what metals other than brass could be relatively heavy lead replacement, it does not need to be as heavy i jcan make pieces of a frame thicker so if you have any ideas about kitchen diecasting alternatives i would be really happy to hear them
It was steel and I am not sure where it came from. I am one who keeps things as they may be useful in the future. Stainless steel would be the best choice but i did not have any so I used mild steel.
@@luckygen1001 Do you think the diameter of the pipe matters or does the 1mm hole at the end trump pipe diameter? Your pipe looked about 12mm OD. Thanks
@@gregwmanning The pipe is 8mm outside dia. but what is important is the 1mm hole. If that is increased or reduced then the length and burner inner dia will need to be altered otherwise an unstable flame will result.
Should be possible to scale this down to a size/format where it will allow you to do some oxy/acetylene type work for propane money.... Maybe not welding but everything else one would use a oxy/acetylene torch for(which for most people is their main use for it rather than steel-filler steel welding...)...
This why I made this burner, propane and compressed air are a lot cheaper than oxy/acetylene. I have made a larger burner than this one but not a smaller one so it might a bit of trial and error to get it to work.
@@luckygen1001 Thicker air-hole plate with angled holes to introduce a spin/vortex might improve air/propane mixing and make a more contained flame(quite a few commercial burners that do this)
Some years ago I was building a small-ish jet engine from repurposed jet engine parts (It was still about 1 meter long and about 254mm in diameter, so in the grand scheme of things, relatively small) and had to re-engineer a suitable multi-fuel injection and ignition system to handle as high as a pressure as I could manage to flow, ~2000psi/130bar. While it'd be a little overkill for this application, stainless steel conical nipples can be had for fairly standard thread pitch (like NPT here in the US for example, or thread it yourself of course). I'm notoriously bad when it comes to drilling out tiny bit sizes and have a tendency to snap them even when lubed and used correctly, so for me, a commercial part worked better and had proven longevity. I also tried pressure washer ones that could work if you find the right spray pattern, however they aren't normally threaded like the ones I'm talking about; nothing a quick braze/solder job wouldn't fix, but for my project, swapping the nozzles out for maintenance and orifice size for different fuels was an objective. A little anti-seize and quick rub with nano-size graphite powder made it pretty easy even after extreme temperature cycling. It might be an option if one were to adapt it to plumbing parts to burn propane with adequate air pressure behind it and you didn't want to or have the tools to machine one from scratch. I'm sure I could dig up a link if anyone were to be interested.
Be careful not to force compressed air (higher pressure) up into your propane bottle (lower pressure). It could happen if the compressor regulator set to a high pressure.
The only time that could be a problem is when the jet is completely blocked and then it could flow back to the propane bottle. Also propane has a high pressure before the regulator so most compressors would not have a high enough pressure to push air into the propane bottle.
@@luckygen1001 The regulator would also likely shut down it's diaphragm due to the increased pressure at the outlet. A cold propane cylinder could easily be at a much lower pressure than a compressor can supply so you can't simply rely on cylinder pressure.
