We used to make oxygen/acetylene bombs by putting them in balloons and placing them in a paper bag and lighting the bag.
As I remember the cutting torch mix had the best definition with the loudest bang
As creative teenagers we decided to step it up and got a 55 gallon drum and were ready to
Fill it but getting the drum down to the river bed was another challenge in itself.
When our brains returned to our heads, it was static electricity that told us to not go there
As I remember the cutting torch mix had the best definition with the loudest bang
As creative teenagers we decided to step it up and got a 55 gallon drum and were ready to
Fill it but getting the drum down to the river bed was another challenge in itself.
When our brains returned to our heads, it was static electricity that told us to not go there
And you waited until almost a WEEK after The Fourth to post this tip?? You know we won't remember it in 355 days.
With the collapse of Plastic Recycling... has anybody experimented with a decent (horsepower) air compressor into a plumbing-plug in a 2-liter poly bottle? (I have 200 feet of airhose and 800 feet of land.)
I was on the Texas Instruments TISTAR hardware development group, and eventually the last remaining engineer.
Early on we used Motorola VME bus 68000 systems as the basis for the system. We ran UNIX as our operating system and all the firmware developers claimed it was immune to windows viruses.
That proved NOT to be the case with the Monkey Virus. This was a boot sector/partition table modifying virus. It took me almost a month to convince the FW guys that we had a really serious problem.
Somehow, someone got a floppy with the virus mixed up with the normal boot diskette in manufacturing.
It played hell with manufacturing for almost a month until I did a demo and proved it was an issue.
Early on we used Motorola VME bus 68000 systems as the basis for the system. We ran UNIX as our operating system and all the firmware developers claimed it was immune to windows viruses.
That proved NOT to be the case with the Monkey Virus. This was a boot sector/partition table modifying virus. It took me almost a month to convince the FW guys that we had a really serious problem.
Somehow, someone got a floppy with the virus mixed up with the normal boot diskette in manufacturing.
It played hell with manufacturing for almost a month until I did a demo and proved it was an issue.
Prior to the invention of the light bulb limiter all repaired or home brew amplifiers were initially plugged in at the end of a 100 foot extension cord. After the first exploding rectifier threw pieces of hot shrapnel in my face. I invented the light bulb Limiter in 1982 trying to figure out how to safely power up a CS800 right after repair. When I first posted that suggestion on rec.audio years later I was nearly run off for good for daring to suggest anything so unsafe and unprofessional.
I wouldn’t even do electronic fireworks without one - although it may be 10 100 watt bulbs in parallel.
I did something similar with a power supply in the NAVY. I was working Organizational Maintenance on 1KW amp with a 400Hz power supply. Apparently there was a short in the transformer winding. Fortunately I was wearing a pair of Bausch & Lomb sunglasses at the time or I would have lost site in at least one eye.
Speaking of the NAVY. I heard a nice story about some NAVY exersize bringing online a second generator on the ship. They may have not been properly trained about the phase meter and threw the online breaker when the generator was liekly out of phase. The result was fairly violent causing a large rotor to flip up to the ceiling and forcing the ship back to port.
I figure they needed to put a picture of two semi trucks crashing head on at the bottom of the phase meter to indicate what is going to happen.
I figure they needed to put a picture of two semi trucks crashing head on at the bottom of the phase meter to indicate what is going to happen.
Yeesh - that sounds like a fairly nerve-wracking procedure even if you do understand the meter. Presumably this operation is more automated with modern equipment.
Back in the day some reprobate friends of mine shared a multi-bedroom apartment which became known as the Hangover Hotel with people passing through (and out) at all hours. One of the regulars (I can't remember whether he lived there) got a job with the school board, going to schools and going through the cupboards in the Science department and removing old and dangerous items. He found a 2 lb block of sodium or potassium (I can't remember now and I swear I wasn't there) in a jar of mineral oil and took it away from the school, but brought it to that apartment. Very late at night the boys took it down to the street and put it through a grating into a storm sewer (I still don't know how they lifted the manhole cover or whatever). A short time later there was a pretty big boom and toilets broke up and down the street.
For many years myself and some of the neighbors in Florida kept the block up late at night on New Year's Eve and the 4th of July. Most of the neighbors had store bought fireworks, but someone might have made some DIY stuff. Technically this kind of activity is highly illegal, but the cops tended to look the other way on those two days unless there were complaints. One of our neighbors was a cop, but two of his kids were part of the fun. Usually a cop car would do a slow drive through during the 4 hour long event.
Shortly after a particular crazy New Year's Eve (2002) the cop across the street told me of a meeting that occurred at the county level where the state's "destructive device" law (big "firecrackers" and the like are a felony) and it's enforcement were discussed. He warned me against doing that again.
I got a copy of the law, which was very broad, but basically anything that could destroy property due to a "chemical reaction" could subject the possessor to felony arrest and imprisonment....you didn't even have to use it. This included the old "lye and pool acid in a 2 liter bottle" devices we made as kids. In fact they were explicitly called out due to their use by some gangs.
It is not clear if a "phase change" is or is not a "chemical reaction" according to the law. Physics class and the law are two very different things! Dry ice (frozen CO2) will not generate enough pressure to blow a bottle, it will simply melt and remain a liquid even in the Florida sun. Liquid Nitrogen is a different story, but you can't get it at the grocery store.
So if chemical reactions are out, what about compressed air? Experiment time.....
My "Coleman Powermate" 27 gallon "5 Horsepower" (it plugs into a regular outlet, do the math) compressor tops out at 125 PSI. It will not explode a standard 2 liter Coke bottle, even if the bottle sits in the Florida sun at this pressure for a whole day.
I did not try a NOS bottle from a race car. They run about 900 PSI depending on fill level and ambient temp. Far more than my 10 year old air hose could hold, and would require a DIY fitting adapter.
The air compressor will however explode a 1 gallon Gatorade or Ocean Spray cranberry juice bottle, and the ensuing bang will get the attention of a very angry cop who threatened me with arrest despite the combination NOT being illegal. I had to agree not to do it again to get him to go away.....he also took a couple of the exploded bottles with him promising to return if he was right.
I used the cap that came off the bottle. I drilled a hole and mounted a standard air hose quick disconnect fitting in the cap and slathered on lots of epoxy. Screw on bottle, connect to 100 foot hose, crank compressor to max and wait for a full tank. Plug in hose and after 1 or 2 seconds a cherry bomb sized bang will occur. The cap with fitting could be reused several times before it failed, so I made a few.
Note, Ty-Rap the air hose to something like a fence post or a tree near the bottle to avoid having it whip around like crazy resulting in the loss of the cap / air fitting.
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That science experiment used to be called “sodium pop”. Works with sodium, too. Into a fish pond from a 2nd story window.
You guys are sick. Sick. 🙂
Oh alright. As a young teen, I'd buy Estes model rockets. A couple of times, I'd take an inexpensive one, like the Corporal, omit the parachute, run a fuse wire from the engine up to an M-80 where the parachute would normally be, and launch that puppy.
But the most fun was to cut the heads off a couple books of matches, stuff them into an empty 30-30 shell casing, stick a fuse wire into it, crimp the end shut, and fire it out of a piece of conduit.
I'm lucky I still have ten complete fingers.
Oh alright. As a young teen, I'd buy Estes model rockets. A couple of times, I'd take an inexpensive one, like the Corporal, omit the parachute, run a fuse wire from the engine up to an M-80 where the parachute would normally be, and launch that puppy.
But the most fun was to cut the heads off a couple books of matches, stuff them into an empty 30-30 shell casing, stick a fuse wire into it, crimp the end shut, and fire it out of a piece of conduit.
I'm lucky I still have ten complete fingers.
In high school, we used to strip apart firecrackers to make bigger firecrackers.
Then I discovered the wide variety of chemicals available at the local pharmacy.
There is one particular compound that can be made from Iodine crystals plus household cleaning agents.
I do not recommend making it if you figure out what it is.
The resulting compound is so sensitive that if you put it in a dark closet and let it dry, then open the door and let light shine on it, it can detonate.
It was lots of fun to paint on lock mechanisms for lockers. Wait at break time for someone to open their locker!
Then I discovered the wide variety of chemicals available at the local pharmacy.
There is one particular compound that can be made from Iodine crystals plus household cleaning agents.
I do not recommend making it if you figure out what it is.
The resulting compound is so sensitive that if you put it in a dark closet and let it dry, then open the door and let light shine on it, it can detonate.
It was lots of fun to paint on lock mechanisms for lockers. Wait at break time for someone to open their locker!
When I went from a a drain follower to a source follower, I forgot the bias voltage wasn't 5V anymore and blew up 2 16V caps LOL Oops! They are 450V now since that's what I had handy.
And in that endeavour, I also blew up a few MOSFETs... That gate-source voltage doesn't like even the slightest peaks... It was protected by back to back 12V zeners, but I guess they took longer to clamp or let a short spike through that the MOSFET blew.
Oh, and I made a 50W 1R TO-220 resistor sublime LOL switched to a cement resistor and all is well again.
Who else is blowing stuff up these days?
And in that endeavour, I also blew up a few MOSFETs... That gate-source voltage doesn't like even the slightest peaks... It was protected by back to back 12V zeners, but I guess they took longer to clamp or let a short spike through that the MOSFET blew.
Oh, and I made a 50W 1R TO-220 resistor sublime LOL switched to a cement resistor and all is well again.
Who else is blowing stuff up these days?
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Won’t be for a few months yet. The tube amp stuff has been set aside for the time being - the weather is finally hot and dry, so I can do the finishing, sanding, and painting of 20 big PA cabs I’ve built over the last couple summers. The past two or three have been too wet to take speakers outside to sand/bondo, and too much humidity for the Duartex to cure (or even spray on) correctly. Have to take the opportunity now or risk losing it.
The dead parts pile has been pretty stable for the past month. I did manage to blow one of those white 5 watt cement resistors in an attempt to squeeze 300 watts from a single pair of 36LW6's. All was happy at 250 watts where the tubes were just into the dull red glow in a dark room zone.
I turned the knobs up to 300 watts, which put the tubes into clipping, sending the screen current way up and blasting my "safety" resistor into openness. It's far cheaper than a tube or two, or worse an irreplaceable OPT.
I will replace it with the same resistor for further testing. It's cheap insurance. Yes, the drive is somewhat unbalanced so that one tube is working harder than the other. I'm using the primary of a small Edcor matching transformer as the PI. Next step is a proper PI, and more testing.
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250W from a PAIR of tubes is basically insane to me, but what about triode? I've had good results in triode without having runaways like you documented. I use the Soviet tubes though... Maybe that's part of it? 360V triode mode in 6P36S @ 80mA per tube. Sounded pretty damned good but the tubes didn't last the year...
How much power you can get in AB1 triode with 6LW6? 😛 I got 110WRMS @ 30Hz into 1k or so at 300V B+ peaking over 1A but the 6P 45S made more power 🙂 I think that's about the limit for 300V unless I go to like 600R output and deal with the added Dtot. What do you think?
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Didn't read to see if this was just about electronics?, but today I destroyed a hornets nest. I like to let things live always where I can, but these buggers set up home a few feet from my entrance door and they got me good yesterday with a few stings (for no reason I might add).. I never even noticed that they were there until I got the stings, and it was quite an impressive sized nest with many buzzing about.. Anyhow the last thing a guy needs after a long hard day at work, where it was 40c with the humidex outside is a welcome home like that lol. So now they are all done, yay! My sting was more than theirs, although it freakin hurt big time when they got me ,and now my stings are really itchy, ugh! But I'm alive and they're not... I win 🙂
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The traditional connect the screen grid to the plate method of making triode curves with a pentode doesn't work well with modern sweep tubes. Some older designs like the 6AV5 will work fine, but my experience with the 6LW6 has not been good. 4 out of 4 tubes dying over a period of less than 2 years, all in the same manner, runaway, led me to abandon those efforts 10 years ago.
I was convinced there was a better way of doing this, and it took me about 10 years of experiments, but I found it. There is a way to get pretty triode curves from a pentode, and it was first mentioned in Schade's paper back in 1939, but feeding feedback and drive signal into the control grid has it's share of issues.
So I connect a resistor from the control grid directly to the plate, and apply only feedback to G1, put the drive in somewhere else. The previously mentioned 250 watts from a pair of 6LW6's was using this method, and the composite curves look just like triode curves, except now we can adjust the Mu. The tubes act like a triode, with it's low Rp and THD.
Here are the curves that I plotted from a small sweep tube, the 6GF5 which have no problems cranking out 75 watts per pair.
My plan is to build a 500 WPC amp using 6 X 36LW6 or 26HU5's per channel.
This should lead to lots of destroyed stuff, but the carnage has been low recently. That wasn't the case in the early experiments. I had a vacuum tube explode a little over a year ago, and shattered another......dumm blonde arithmetic error, and a seriously nasty power supply with 1000uF inside wired directly across the output. It goes to 650 volts at 1.7 amps, so when something goes wrong, it becomes quite obvious.....it no longer exists!
See these threads for more information:
UNSET is coming?
https://www.diyaudio.com/forums/tub...sing-mosfet-ultralinear-feed.html#post6267790
The last few posts here:
Those Magnificent Television Tubes
