Explosive air gas mix

98:2 seems like a lot of O2 for the amount of Acetelyne. I think 50:50 would be a better starting point. JMO. Cutting is what? Between 4:1 and 8:1 depending on the torch?

Don't know about your ignitor. I would like to know more about your project.

If safety is a concern I might consider a solid fuel model rocket ignitor as your ignition source. Then you can run as much wire as is needed for safety and touch it to a car battery for positive ignition. The model rocket controllers us a 9V transister battery but we learned as kids you could launch all day off a car battery, and we never had any misfires that way. If that's not enough heat/spark you can try using the whole rocket engine.

P.S. When I was a kid a welder next door used to fill rubber ballons with gas and toss them into a burning trash barrel. He got some pretty impressive fireballs. Don't know how much real world explosive force that generated, but he always made all us kids keep well back to watch. I recall he played with the mix to see what worked best.

Can we see a picture and/or diagram of this gopher getter thing?

I think you are way way light on fuel and way too high on O2

Gunner

"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.

Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner

The mix can generate real explosive pressures. I have personally seen a 2 inch branch on a tree blown apart when a friend was trying to get rid of a large hornet's nest. He hauled a large balloon full of the proper mix up with a string, with an electric ignitor attached. Never wanted to experiment with it myself after that. He got the right mix by lighting a torch with a small flame, tuned it to a neutral flame, then 'popped' the flame out by touching the tip to a metal surface. Then placed the balloon over the tip to fill it.

About ten years ago, a guy in our area was killed while filling garbage bags with the mix. He was filling a bag placed in a trash when it went off in his face.

The mix is supposed to be 95/5 using propane. At 40 and 4, you were using twice a much mix as they recommend. You were probably much too rich.

We used to make cannons this way in tank shops years ago.

We would just light a torch, adjust it to optimum burn, slap it out on a flat piece of steel plate (gently), charge the cannon barrel with the torch as much as we dared, light the correctly flowing torch quickly, and use it to touch off the cannon.

VERY effective. Be careful. We launched a dead rat over 500' with ease, from a 4'x4" sch 40 pipe.

The rat cleared two bridge cranes and exited the building through the crane door at the far end of the building. Leaving a vapor trail all the way. I laughed so hard my sides hurt. Nothing like working second shift.

Based on my experience with Ox/Acc, a garbage bag would be totally INSANE. I did a 1/2 gallon paper milk carton one time, and the results were incredible. I was in a building about 150x1000, and it shook dust off every purling in the ceiling. Do NOT use a large container until you have experimented with 8 oz. paper coffee cups. You are dealing with a lot more force than you realize.

(snorp)

Bob, he is using propane. Where did you get Aceteylene?

Oops. Sorry. My own experiences have been with acetylene.

Chist, I'm chuckling just picturing the flying rat! No film? Speaking of vapor trails, back in my second shift goof offs, we had one of those foam rubber Nerf footballs. We soaked it in LN2 to see what it would do. After taking it out, the liquid quickly drained off, and the outer surface of the fotball warmed up quite nicely, while the interior remained cold. When we tossed it, vapor trail! It lasted a long time, and made for an entertaining game of catch.

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I think it's about 8 to 1 for methanol, isn't it? But I thought that would be for AIR. I wonder how much pure O2 would change the requirement.

A guy in my college dorm captured the gas from a charging motorcycle battery into a small baggie, and set it off with a time fuse in the lavatory. It was REALLY LOUD.

I can see one thing clearly. God protects drunks and idiots. I was using a common cardboard apple box all taped up. Good thing I didn't get it to go off. I think I'll just experiment with smaller objects, or lengths of schedule 40 pipe that will give me a safety shield. Once I get it right, the local gophers should be out in force. Then I can try it on tunnels, but I still think I need a better sparker. We'll see.

Watch for me on the news.

Kinda reminds me of the two old guys in Second Hand Lions.

Steve

This seems a bit risky to me because you will get a flashback to the mixing chamber which might blow the single pipe to smithereens.

Have you tried 5 parts oxygen to 1 part propane ? Maybe with separate feed pipes and flashback arrestors at the combustion tube end.

Upon examination of the commercially available model, I see that it uses a cutting torch mixing chamber, then takes the mix down a single pipeline. It has a commonly available air squeeze valve common to tire inflators. I built the first one out of a weed burner with some brass fittings and various things. I'll take some photos tomorrow and show. It is slighly crude, but for testing was adequate. It didn't work, and I'm out about $20 for parts, but parts that will go into my parts bins.

I had the thought that the overpressure from the oxygen was keeping the propane from freely flowing into the single line after they made connection. The answer to that would be to simply run two lines separate, which may be the next step.

Upon reading of some of the violent reactions by others in the group, I will be getting a piece of sch forty pipe and doing the detonations in them. Probably weld one end shut, and direct the concussion and noise upward.

This would make an awesome Fourth of July or New Year's Eve noisemaker.

I'm going to look for a mixing chamber, and do the next one with the squeeze valve, and maybe a cheap stun gun flash activator.

When I was in town a few weeks ago at a local welding supply house, I talked to them about it. They said a local guy tried it, but his major problem was the oxygen. It seems like it used large amounts of oxygen. They started putting liquid oxygen containers on there for the additional oxygen supply. What's wrong with this picture? Anyway, they abandoned the project after some considerable R and D money.

I'll work on it some more, but will try to keep the cost down, as I think it is a workable idea with just a few quirks one has to find. I even thought of a tbsp of gasoline, sealing the tube in the tunnel, a flow of one minute of 40# of O2, and then a spark.

Good thing is that I have lots of ground to experiment on, and lots of gophers. I just need to keep my wits. And eyebrows.

Steve

I was disconnecting a battery from a high output charger when I was 16, and the battery blew in my face. Although it stung my eyes and face, I got to a source of water quick enough no real harm was done. I was probably very lucky. But it was strong enough to blow the top off my battery.

I loved that movie, and yes it does relate.

Be very cautious. When you get the mix right, it is very powerful. You will be surprised.

I saw a demo on a website that seems very lame by comparison. I wonder if their mix is close to optimum from the strength of their results.

that, or there is a lot less area in most gopher holes than I would have imagined.

This is starting to sound like something from "Caddyshack"...

"Maxwell" wrote: I was disconnecting a battery from a high output charger when I was 16, and

^^^^^^^^^^^^^^^^^^^^^^^^^ There is a lesson in that: always turn off the charger before disconnecting.

Yes indeed, with the high output chargers especially. It was probably at least a 50 or 60 amp quick charger. I have never had a problem with a trickle charger, which is about all I use anymore, but it could still happen.