I respect what you have to say pjv, and my parents do know what's going on. Earlier today I had to stop grinding aluminum in the house due to the powder in the air, so it is currently running outside filtering the fine particles I need through water and blowing the air out with a fan. Perhaps I'll show a picture tomorrow, along with my wind powered ball mill I built with a ceiling fan. If I get enough wind it should be done in a week or two.
Right now I'm hoping to try and set off some courser thermite mix with a brazing torch my godfather has tomorrow at his house, but will see due to time, me and my friends have a lot of things planned. Since he is an adult, however, and knows more than me then hopefully all will turn out well and I can know if I'm making it right.
Anyways, see you around on this forum, all fingers attached.
I'll admit, I started making ferric (iron) chloride today instead of the iron oxide I was intending. I'll have to talk to my dad (a chemist) about that one tomorrow... at least I have the making of powdered aluminum down. Now that I think of it, I'm not sure why I believed one internet comment on using bleach anyway without talking to my dad. At least the search taught me about chlorine bombs--good info to have you know. (in a safe location, mind)
If I get nominated for the Darwin award, then so be it. As some people say, when you die all you can take is your knowledge with you, so if that is the case then I learned a heck of a lot of chemistry today.
It was advice - an attempt to point out (sarcastically, admittedly) that this guy has no clue what's going on or potentially going to go on if he by chance gets this right. On multiple posts, he has demonstrated a lack of basic knowledge on what's going on.
The advice again: Don't do it! Work your way up and get a thorough understanding of what the heck you're playing with.
People have attempted logic, referred him to videos, explained that he says he's trying do won't work, he says he's being "safe" but was attempting to blow his house up (aluminum dust) and performing chemical reactions he didn't understand until after the fact. How is any of this being "safe".
Sometimes, some people deserve insults (well, maybe not "deserve", but "invite"). Maybe the right combination will wake him up before he causes serious damage to something, or worse, someone.
I'm almost expecting him to say he'll have water and some dirt to put out the fire if it gets out of control. (pi'd - in case you didn't know, you don't put out a thermite fire, you let it burn itself out, although "let" isn't necessarily the right word.)
The point of all this unsolicited advice isn't that he "shouldn't do it", but that despite "saying" he's being safe, he has demonstrated that he does not have the background knowledge to know how to be "safe", or what might not be safe.
It's not that he "shouldn't do this", but more, he needs to understand more before he does it, and we don't want to see him hurt, in the news for burning a hole through the garage floor.
John R. said...
Sometimes, some people deserve insults. Maybe the right combination will wake him up before he causes serious damage to something, or someone.
He doesn't deserve to be insulted, any more than you do. You simply decided that it was your duty to do so, which it isn't. If you gave the kid non-insulting advice, and he ignores it, that's his business. But don't act like a jerk and then try to justify yourself, because I'm sure that when you were his age you were the same way in some area of your own life.
Forgive me if I have seemed argumentative, and too serious. I just feel strongly about the dangers of DIY chemistry.
My main message was quite simple.
I feel the Parallax Forums are NOT about doing dangerous activities. In fact, one should receive such training hands on with experienced people in a well controlled environment.
I could go on and on about why a 'digitally-controlled thermite engine' is highly never likely to be successful.
I can point you toward engine technologies that are more worthwhile to investigate.
But, the main thing is the nature of the topic!
There are other young people that are on this forum as signed in members or just visitors. One might not make a mistake, but you may never hear about the other guy that read your postings and 'went for it' with bad results.
The beauty of micro-controllers is that electronics has gotten down to low-voltage DC. We can be educational at a distance because screw ups are reasonably small.
Youth will always find a way to explore danger. I certainly did, and lucked out.
When I was learning electronics at twelve years of age, we used tubes and 350 volts was not uncommon. Inside a TV, that would go up to thousands of volts. And 'Scientific American', in it own lapse of awareness would publish articles like "How to make an X-ray machine" in 'The Amateur Scientist". Kids would jump in and copy the designs - some got serious radiation burns. Others just got zapped with a shock. And other might set the house afire. I just made a few X-rays and developed the results in my home darkroom.
Others of us sorted out all sort of suppliers of chemicals. It used to be that you could get just about anything by paying cash through the mails. More disasters in the making - some made explosives, others made drugs. Where do you think 'hippies' got their LSD? That ended with a lot of people hurt - some directly, other's from car wrecks under the influence, other's from having to cope with a loved one that was no longer oneself.
But the inspiration for all of this was always the same. Someone has published a 'show and tell' piece that inspired others to try the same.
Please, not here.
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Ain't gadetry a wonderful thing?
aka G. Herzog [noparse][[/noparse] 黃鶴 ] in Taiwan
Post Edited (Loopy Byteloose) : 7/31/2010 11:40:41 AM GMT
My brother in law lost the tips of his fingers in high school when some DIY chemistry blew up on him.
pi'd, make sure you wear a dust mask while griding metals. Fine dust can get into your lungs, but I'm not sure how good your body would be at getting it out.
pi'd said...
I respect what you have to say pjv, and my parents do know what's going on. Earlier today I had to stop grinding aluminum in the house due to the powder in the air, so it is currently running outside filtering the fine particles I need through water and blowing the air out with a fan. Perhaps I'll show a picture tomorrow, along with my wind powered ball mill I built with a ceiling fan. If I get enough wind it should be done in a week or two.
How easy is it to remediate your house completely of the dust?· You are exposing yourself and everyone within living quarters of the dust.· I was also reading about the elements of a dust explosion on Osha's website.· I work at a company that sells chemicals.· I was getting sick when we had the windows closed and I've been to the doctor over 21 times and they can't tell me what was wrong with me.· We also had workers come to legally dispose of the chemicals and they had to leave because they were throwing up.· For years our chemicals were legal and then one day the zoning changed and we had to get rid of a lot of them.· There were an unusual number of workers at one of these fortune 500 companies we sell to come down with brain cancer and they couldn't figure it out.
What are the long term health effects of exposure to aluminum powder (uncoated)?
LUNG EFFECTS: No conclusions can be drawn regarding the possible long-term effects of aluminum on the lungs. Historically, several cases of scarring of lung tissue (pulmonary fibrosis) have been observed following prolonged or repeated occupational exposure to certain types of aluminum dust, either a molten pellet variety or stamped aluminum powder (also called pyro powder). Pulmonary fibrosis is a potentially serious lung disease which, in severe cases, may lead to death. Airborne dust concentrations required to produce the effects were not well documented and there was exposure to other chemicals at the same time. Some reviewers have concluded that the lung effects may have been related to a mineral oil-based lubricant historically used to treat pyro powders in Germany and the United Kingdom. Pulmonary fibrosis has not been observed following more recent occupational exposures to coarser granulated aluminum dust, manufactured from melted aluminum, aluminum pigment flake or pyro powders treated with stearin.
Reduced lung function, consistent with chronic airflow limitation, has been observed in aluminum production workers although the cause has not been determined and exposures to many different airborne substances occur in this industry.
One case of injury to the lower lung (pulmonary alveolar proteinosis) has been reported in a worker employed as an aluminum grinder. This disease may or may not be reversible. No details of the level of exposure were reported. Similar effects have been observed in experimental animals. However, no conclusions can be drawn based on this limited information.
NEUROLOGICAL EFFECTS: A link between exposure to aluminum or aluminum compounds and Alzheimer's disease or other neurological diseases has been suggested. This link was suggested because of severe neurological effects which have been observed in patients receiving dialysis treatment (with dialysis fluids containing aluminum); effects seen in animals exposed to aluminum using non-occupational routes of exposure; case reports of neurological effects in individual workers; and findings of elevated aluminum levels in the brains of patients with neurological diseases. At present, whether or not this association is a true effect is controversial and findings are inconsistent. Recent reviewers have concluded that the evidence is inadequate to establish a link between occupational exposure to aluminum and specific effects on the nervous system or Alzheimer's disease, in normal, healthy workers. One reviewer has concluded that there is a likely connection between long-term occupational exposure to aluminum and a specific effect, impaired co-ordination, but not other toxic effects on the nervous system or Alzheimer's disease.
One case of brain disease (encephalopathy) involving convulsions, as well as pulmonary fibrosis, was observed in a worker occupationally exposed to aluminum flake powder. These effects were not observed in another 53 workers similarly exposed. In another study, follow-up of 2 employees who had been diagnosed with fibrosis, following exposure to pyro powder in the 1930's and 1940's, revealed that one had developed a brain disorder (dementia with motor disturbances). No firm conclusions can be drawn based on these limited findings.
I think we can probably agree that pi'd's posts suggest that he hasn't learned enough to do this safely, and therefore that there is a very real chance of it ending badly.
That may not be the reality - maybe he is better at this, more well-informed, and more well-supported than his posts suggest, but we have no way of knowing that.
In light of that, as responsible adults we should be saying "don't do this", and in fact that's exactly what I'm saying. Don't do this.
If it does end badly, I don't want someone to say "there's the forum guys who told him how to ignite the stuff". I want someone to say "there's the forum guys who warned him about the dangers".
As a side comment, the stuff about being part of a crowd that wants people to wear crash helmets to bed is a bit out to lunch, I think. Surely no-one here wants anything like that, but there is a LOT of space between giving a warning to a 16 year old who admits he hasn't done his research before trying to make and ignite thermite, on the one hand, and wanting people to wear crash helmets to bed on the other hand. I fly high power rockets, and have a Low Explosive User's Permit, and I'm all in favor of doing interesting but potentially dangerous things, after properly educating yourself and taking the commonsense precautions. It doesn't sound to me as though that's the situation here, though. I don't see anything remotely resembling the "people shouldn't do things that might be dangerous" argument here. Not even close. This is way over on the other end of the spectrum.
Pi'd - perhaps you're able to do this safely. Can you see, looking back at your posts, why it looks from our point of view like you can't?
I see that you've made quite a few posts to these forums already, and I think that you deserve some benefit of the doubt because of that (if these had been your first posts, I think I'd have made some comments far more sarcastic than any you did get here). But a better first question on this topic would have looked more like "I'm interested in learning to work with thermite. What kind of tips can you give me on making it, and on safely using it?". Maybe you would have still gotten sarcastic responses, but you would have earned polite ones.
Post Edited (sylvie369) : 7/31/2010 1:42:10 PM GMT
What kept me safe as a kid was lack of money to do these things.· There was a guy who wrote a book on how to make your own rocket engines.· He would cook popcorn in the oven with the oven door open and bake rocket engines at the same time.· The popcorn would pop and he would eat it with one hand while he held a fire extinguisher in the other hand.· If I could only tell you how dangerous this is except I think he set his kitchen on fire more than once.
Then I grew up and life is about working, making a living, having a family, paying my mortgage, and helping others rather than being cool.
John R. said...
Sometimes, some people deserve insults. Maybe the right combination will wake him up before he causes serious damage to something, or someone.
He doesn't deserve to be insulted, any more than you do. You simply decided that it was your duty to do so, which it isn't. If you gave the kid non-insulting advice, and he ignores it, that's his business. But don't act like a jerk and then try to justify yourself, because I'm sure that when you were his age you were the same way in some area of your own life.
Kevin,
I understand some of the things about aluminum powder in the material safety data sheet and some of the things I don't understand.· I believe this kid doesn't know what he is doing and I bet he doesn't have a class D fire extinguisher either.
It is classified as a hazardous material which you need to have a license for.· He is making it and if it dusts up his whole house then it is possible he has it in quantities that he doesn't have a permit for.
The bottom line is that aluminum powder can be combined with a lot of different powders to create an explosive.
When I was a kid, one in particular was popular (I won't mention it here) and far more easily gotten that iron powder. That particular item was extremely unstable - a slight jar would set it off unexpectedly. In the methods he is using, contamination is an issue. Contaminated powder is a wild card and may detonate due to unknown reactions. The first and foremost precaution in all chemistry is to use as pure ingredients as one can possibly get or to fully assess impurities. All this is beyond a backyard DIYer.
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Ain't gadetry a wonderful thing?
Chuckz I really don't have much yet, but I will. It's in a safe place now and the water is filtering it well.
Loopy--I worry about impurities as well, which is why I'll be adding hydrochloric acid to my supplies of rust to ensure there is no iron left in it. (my dad told me to do that, BTW) Then negate the acidity with baking soda and hope the fact that the rust is made from steel won't affect it's capabilities.
Also, just out of curiosity, why do many of you think a thermite engine isn't possible? And to those of you who think there are better engines out there to use--what? I plan to use it on a military-grade android robot eventually, maybe I'll get a chance to start during college. Prove me wrong and I'll change.
pi'd said...
.... I'll have to talk to my dad (a chemist) about that....
Your father is a chemist and you're wasting your time talking to us?
There are cheap sources of granulated Aluminum perfect for making Thermite available to the general public that require no special shipping restrictions. If you had done your homework, you would have discovered this rather quickly. But obviously you are very inexperienced at (or downright lazy?) doing research of any kind, and this by itself is a clear indication that you are more likely than not to hurt yourself, damage property, or maim an innocent bystander.
I suggest you talk to your father about this before you burn down his house or give everyone around you a stubborn case of lung cancer or something.
25 bucks for 3 lbs ground up aluminum off of ebay, and fe 203 is cheaper but you need more. This means to get started I need 50 bucks...no thank you. I already tried asking multiple paint places in my town about it and they have nothing, it's all pre-mixed.
1) burns to hot. Engine must be made of ceramics
2) burns to quick. can't be controlled to do usefull work
3) can't be put out. If your fuel tank ignites it can not be put out until it burns out.
You are much better off to seperate water into hydrogen and oxegen and modify an engine to burn hydrogen. This is not safe either but would at least work
The only example I've seen of a powder fueled engine was the black powder engine they did on Mythbusters. I don't think the results will encourage further work in the area.
While many recommended the use of refractory ceramics, this ignores the aspect of toughness. Tiny cracks can easily form on the surface of a ceramic and tensile stress can concentrate·at the bottom of the crack, making the local stress as much as 250 times the bulk stress of the material. The crack propagates through the material at supersonic speed and you have catastrophic failure.
That's why we still use metals in jet engines, in spite of having readily available ceramics which have superior high temperature strength. This strength vs. toughness issue is the reason you see martial artists break bricks and cinder blocks, but not metal plates.
You're not the only guy that has a brain wave here and finds out several other Forum members have already considered it and dismissed the idea. From time to time, I have done so as well.
You can look forward to Material Science and Statics and Strengths of Material classes in university. You can even to self-study with Schwamn's Outlines right now. Chemistry is a vast and complicated field. But a good introduction is Linus Pauling's "General Chemistry". I have a copy for bedtime reading. Steel Making and high temperature material science are soul mates. After all if you waste 1% of your energy in the process, your product is costing more than the competitions.
There are exciting things happening with engine design. In particualr, methane as a new fuel.
It looks like Cummins is now converting some of its production to long-haul semi tractors powered by methane. The fuel is far cheaper per mile. The fuel needs a range of engine compression from about 9.5:1 to 12:1, any higher it pre-ignites, any lower it may not easily burn. Autos go up to about 9.5:1 conventionally and work on methane which is fuel injected or has a compressor blowing it in. But conventional diesel engines often are too high a compression ratio and don't have spark ignition.
So there are things to explore, if you really want to follow engine design. Also, it really is all about that Carnot cycle I mentioned. The heat has to properly move through the cycle, not just be a lot of heat.
I suspect the best way to get started is to get a 'junker', remove the engine, and rebuild it. That's how I learned and the guy who taught me never graduated from high school and couldn't read. He learned from his dad, a Model T mechanic.
BTW, the military uses thermite grenades especially for destroying enemy artillery. They are quite handy in that manner and don't make a loud boom that the enemy can hear.
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Ain't gadetry a wonderful thing?
aka G. Herzog [noparse][[/noparse] 黃鶴 ] in Taiwan
Post Edited (Loopy Byteloose) : 8/2/2010 3:04:11 PM GMT
K2 said...
...
Thermite as a propellant for an internal combustion engine may be the worst idea ever proffered on this forum......
I agree!
And if he's been talking this over with his father, the chemist, and his father is letting him go ahead and do it instead of explaining to him why it won't work, then one can only suspect his father has ulterior motives: one less mouth to feed?
I'm finding it really amusing that you have made the assumption I would use it in a rotary engine. In all reality, the only reason I'd need rotary energy is to run a generator, a mild task. I just want thermite for the heat and expansion of gases for the conversion of pneumatic to hydraulic. Hence, using thermite in a car is one of the most pointless ideas brought up in this thread.
I didn't mention a rotary engine or a car. Internal combustion, external combustion, closed cycle, open cycle; doesn't matter. Thermite is neither a propellant nor a fuel. Leave out the iron oxide. Replace it with an appropriate nitrate, chlorate, or perchlorate. Or just leave the matter to the experts while you obtain more education.
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"Let's not bicker and argue about who killed who."
I think that air can be very dangerous and it basically could blow up.· Why don't you study steam locomotives or steam tractors.· I remember that one blew up in Ohio and killed some people.· My neighbor was telling me now they have to have them x-rayed for faults.· These steam engines have a lot of tubes in their boilers.· The engineer can spend all day trying to hammer them out.· They're very old for an age that is long past and I can't imagine what will happen to them in the next 50 years as they will have to be retired because I wouldn't want to stand next to one of them.
I think you need to do some mathematical calculations to figure out heat, volume, pressure, etc.· Then you will have to match it with strength of the parts.
pi'd said...
....I just want thermite for the heat and expansion of gases for the conversion of pneumatic to hydraulic. ....
Though what you propose might seem straightforward, it actually requires a good deal of knowledge in thermodynamics, far beyond just the ideal gas law, to design a system like this for real. Just because you can create something that's really, really hot, does not mean that it's the ideal system for providing useful work.
Consider a solid propellant rocket motor out in the vacuum of space. When it is fired, it produces thrust by doing what? Well, the propellant doesn't just get really, really hot. If that's all the propellant did, there wouldn't be much thrust. Instead you'd just have a heap of molten metal drooling out of the rocket nozzle. Instead, a real rocket propellant, in addition to getting really, really hot, also generates lots of gases, and so it's the heated expansion of those gases that provides the propulsion = does useful work. So, Generated Gases + Heat to Cause Those Gases to Expand = Useful Work.
But now consider your thermite reaction:
Fe2O3 + 2Al → 2Fe + Al2O3 + Lots of Heat
But where are the gases? What's going to expand and do any useful work?
If you tell me that it will be the air in the pneumatic cylinder that is going to expand and do all the work, well, I'd have to say that's a pathetically small number of molecules you're relying on to do the job. And the heat transfer from the burning thermite to the air will not be uniform - so a large percentage of the air volume won't even get that hot and therefore won't expand as much as you'd hope.
Okay, to solve the heat transfer problem, perhaps you'll try to disperse the thermite in the air inside the pneumatic cylinder. Then your problem becomes: how to get enough molecules of Fe2O3 close enough to molecules of Al to even get a reaction? How can you guarantee that the "burn front" will propagate through this air + thermite mixture once you start ignition?
I'm sorry to sound so negative, but you're proposing to play with some dangerous stuff, and your goals, though ambitious and perhaps entirely respectable, lack the background necessary to follow through on such a project. Based on things you've said here, it seems to me that, because of your lack of knowledge, you're simply more likely than not to shoot your eye out, kid.
ElectricAye said...
Consider a solid propellant rocket motor out in the vacuum of space. When it is fired, it produces thrust by doing what? Well, the propellant doesn't just get really, really hot. If that's all the propellant did, there wouldn't be much thrust. Instead you'd just have a heap of molten metal drooling out of the rocket nozzle. Instead, a real rocket propellant, in addition to getting really, really hot, also generates lots of gases, and so it's the heated expansion of those gases that provides the propulsion = does useful work. So, Generated Gases + Heat to Cause Those Gases to Expand = Useful Work.
I haven't played with model rockets for ages.· Every once in a while, we would get one that would just burn all the way through the engine without giving any thrust.· We've also had engines that the ejection timer didn't work as planned or even though we used wadding, it would burn the wadding and the nose or body of the rocket.
I heard the hobby is more regulated now which is why I am not interested as much.
Model Rocket Engines = Regulated
Thermite Engine = should be regulated but they can't regulate something that hasn't happened yet
Interesting, yet again you are making assumptions about what I have planned without me saying a word on how I intend to make it. As one person may have guessed it's related to steam, true. Closed cycle regulated steam pressure to hydraulic power. With my planned design it should have underwater, omni-position and short-term in-fire run time capabilities.
Comments
Right now I'm hoping to try and set off some courser thermite mix with a brazing torch my godfather has tomorrow at his house, but will see due to time, me and my friends have a lot of things planned. Since he is an adult, however, and knows more than me then hopefully all will turn out well and I can know if I'm making it right.
Anyways, see you around on this forum, all fingers attached.
Obviously pi'd has a firm grip on safety and thorough understanding of materials science.
I'll second the nomination for the Darwin award.
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John R.
Click here to see my Nomad Build Log
If I get nominated for the Darwin award, then so be it. As some people say, when you die all you can take is your knowledge with you, so if that is the case then I learned a heck of a lot of chemistry today.
He asked people for their advice, not their insults.
The advice again: Don't do it! Work your way up and get a thorough understanding of what the heck you're playing with.
People have attempted logic, referred him to videos, explained that he says he's trying do won't work, he says he's being "safe" but was attempting to blow his house up (aluminum dust) and performing chemical reactions he didn't understand until after the fact. How is any of this being "safe".
Sometimes, some people deserve insults (well, maybe not "deserve", but "invite"). Maybe the right combination will wake him up before he causes serious damage to something, or worse, someone.
I'm almost expecting him to say he'll have water and some dirt to put out the fire if it gets out of control. (pi'd - in case you didn't know, you don't put out a thermite fire, you let it burn itself out, although "let" isn't necessarily the right word.)
The point of all this unsolicited advice isn't that he "shouldn't do it", but that despite "saying" he's being safe, he has demonstrated that he does not have the background knowledge to know how to be "safe", or what might not be safe.
It's not that he "shouldn't do this", but more, he needs to understand more before he does it, and we don't want to see him hurt, in the news for burning a hole through the garage floor.
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John R.
Click here to see my Nomad Build Log
Post Edited (John R.) : 7/31/2010 8:11:37 AM GMT
He doesn't deserve to be insulted, any more than you do. You simply decided that it was your duty to do so, which it isn't. If you gave the kid non-insulting advice, and he ignores it, that's his business. But don't act like a jerk and then try to justify yourself, because I'm sure that when you were his age you were the same way in some area of your own life.
My main message was quite simple.
I feel the Parallax Forums are NOT about doing dangerous activities. In fact, one should receive such training hands on with experienced people in a well controlled environment.
I could go on and on about why a 'digitally-controlled thermite engine' is highly never likely to be successful.
I can point you toward engine technologies that are more worthwhile to investigate.
But, the main thing is the nature of the topic!
There are other young people that are on this forum as signed in members or just visitors. One might not make a mistake, but you may never hear about the other guy that read your postings and 'went for it' with bad results.
The beauty of micro-controllers is that electronics has gotten down to low-voltage DC. We can be educational at a distance because screw ups are reasonably small.
Youth will always find a way to explore danger. I certainly did, and lucked out.
When I was learning electronics at twelve years of age, we used tubes and 350 volts was not uncommon. Inside a TV, that would go up to thousands of volts. And 'Scientific American', in it own lapse of awareness would publish articles like "How to make an X-ray machine" in 'The Amateur Scientist". Kids would jump in and copy the designs - some got serious radiation burns. Others just got zapped with a shock. And other might set the house afire. I just made a few X-rays and developed the results in my home darkroom.
Others of us sorted out all sort of suppliers of chemicals. It used to be that you could get just about anything by paying cash through the mails. More disasters in the making - some made explosives, others made drugs. Where do you think 'hippies' got their LSD? That ended with a lot of people hurt - some directly, other's from car wrecks under the influence, other's from having to cope with a loved one that was no longer oneself.
But the inspiration for all of this was always the same. Someone has published a 'show and tell' piece that inspired others to try the same.
Please, not here.
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Ain't gadetry a wonderful thing?
aka G. Herzog [noparse][[/noparse] 黃鶴 ] in Taiwan
Post Edited (Loopy Byteloose) : 7/31/2010 11:40:41 AM GMT
pi'd, make sure you wear a dust mask while griding metals. Fine dust can get into your lungs, but I'm not sure how good your body would be at getting it out.
http://www.ccohs.ca/oshanswers/chemicals/chem_profiles/aluminum_powder/health_alu.html#_1_4
What are the long term health effects of exposure to aluminum powder (uncoated)?
LUNG EFFECTS: No conclusions can be drawn regarding the possible long-term effects of aluminum on the lungs. Historically, several cases of scarring of lung tissue (pulmonary fibrosis) have been observed following prolonged or repeated occupational exposure to certain types of aluminum dust, either a molten pellet variety or stamped aluminum powder (also called pyro powder). Pulmonary fibrosis is a potentially serious lung disease which, in severe cases, may lead to death. Airborne dust concentrations required to produce the effects were not well documented and there was exposure to other chemicals at the same time. Some reviewers have concluded that the lung effects may have been related to a mineral oil-based lubricant historically used to treat pyro powders in Germany and the United Kingdom. Pulmonary fibrosis has not been observed following more recent occupational exposures to coarser granulated aluminum dust, manufactured from melted aluminum, aluminum pigment flake or pyro powders treated with stearin.
Reduced lung function, consistent with chronic airflow limitation, has been observed in aluminum production workers although the cause has not been determined and exposures to many different airborne substances occur in this industry.
One case of injury to the lower lung (pulmonary alveolar proteinosis) has been reported in a worker employed as an aluminum grinder. This disease may or may not be reversible. No details of the level of exposure were reported. Similar effects have been observed in experimental animals. However, no conclusions can be drawn based on this limited information.
NEUROLOGICAL EFFECTS: A link between exposure to aluminum or aluminum compounds and Alzheimer's disease or other neurological diseases has been suggested. This link was suggested because of severe neurological effects which have been observed in patients receiving dialysis treatment (with dialysis fluids containing aluminum); effects seen in animals exposed to aluminum using non-occupational routes of exposure; case reports of neurological effects in individual workers; and findings of elevated aluminum levels in the brains of patients with neurological diseases. At present, whether or not this association is a true effect is controversial and findings are inconsistent. Recent reviewers have concluded that the evidence is inadequate to establish a link between occupational exposure to aluminum and specific effects on the nervous system or Alzheimer's disease, in normal, healthy workers. One reviewer has concluded that there is a likely connection between long-term occupational exposure to aluminum and a specific effect, impaired co-ordination, but not other toxic effects on the nervous system or Alzheimer's disease.
One case of brain disease (encephalopathy) involving convulsions, as well as pulmonary fibrosis, was observed in a worker occupationally exposed to aluminum flake powder. These effects were not observed in another 53 workers similarly exposed. In another study, follow-up of 2 employees who had been diagnosed with fibrosis, following exposure to pyro powder in the 1930's and 1940's, revealed that one had developed a brain disorder (dementia with motor disturbances). No firm conclusions can be drawn based on these limited findings.
Post Edited (Chuckz) : 7/31/2010 1:34:18 PM GMT
That may not be the reality - maybe he is better at this, more well-informed, and more well-supported than his posts suggest, but we have no way of knowing that.
In light of that, as responsible adults we should be saying "don't do this", and in fact that's exactly what I'm saying. Don't do this.
If it does end badly, I don't want someone to say "there's the forum guys who told him how to ignite the stuff". I want someone to say "there's the forum guys who warned him about the dangers".
As a side comment, the stuff about being part of a crowd that wants people to wear crash helmets to bed is a bit out to lunch, I think. Surely no-one here wants anything like that, but there is a LOT of space between giving a warning to a 16 year old who admits he hasn't done his research before trying to make and ignite thermite, on the one hand, and wanting people to wear crash helmets to bed on the other hand. I fly high power rockets, and have a Low Explosive User's Permit, and I'm all in favor of doing interesting but potentially dangerous things, after properly educating yourself and taking the commonsense precautions. It doesn't sound to me as though that's the situation here, though. I don't see anything remotely resembling the "people shouldn't do things that might be dangerous" argument here. Not even close. This is way over on the other end of the spectrum.
Pi'd - perhaps you're able to do this safely. Can you see, looking back at your posts, why it looks from our point of view like you can't?
I see that you've made quite a few posts to these forums already, and I think that you deserve some benefit of the doubt because of that (if these had been your first posts, I think I'd have made some comments far more sarcastic than any you did get here). But a better first question on this topic would have looked more like "I'm interested in learning to work with thermite. What kind of tips can you give me on making it, and on safely using it?". Maybe you would have still gotten sarcastic responses, but you would have earned polite ones.
Post Edited (sylvie369) : 7/31/2010 1:42:10 PM GMT
What kept me safe as a kid was lack of money to do these things.· There was a guy who wrote a book on how to make your own rocket engines.· He would cook popcorn in the oven with the oven door open and bake rocket engines at the same time.· The popcorn would pop and he would eat it with one hand while he held a fire extinguisher in the other hand.· If I could only tell you how dangerous this is except I think he set his kitchen on fire more than once.
Then I grew up and life is about working, making a living, having a family, paying my mortgage, and helping others rather than being cool.
Chuck
http://www.jtbaker.com/msds/englishhtml/a2712.htm
I understand some of the things about aluminum powder in the material safety data sheet and some of the things I don't understand.· I believe this kid doesn't know what he is doing and I bet he doesn't have a class D fire extinguisher either.
It is classified as a hazardous material which you need to have a license for.· He is making it and if it dusts up his whole house then it is possible he has it in quantities that he doesn't have a permit for.
Chuck
When I was a kid, one in particular was popular (I won't mention it here) and far more easily gotten that iron powder. That particular item was extremely unstable - a slight jar would set it off unexpectedly. In the methods he is using, contamination is an issue. Contaminated powder is a wild card and may detonate due to unknown reactions. The first and foremost precaution in all chemistry is to use as pure ingredients as one can possibly get or to fully assess impurities. All this is beyond a backyard DIYer.
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Ain't gadetry a wonderful thing?
aka G. Herzog [noparse][[/noparse] 黃鶴 ] in Taiwan
Loopy--I worry about impurities as well, which is why I'll be adding hydrochloric acid to my supplies of rust to ensure there is no iron left in it. (my dad told me to do that, BTW) Then negate the acidity with baking soda and hope the fact that the rust is made from steel won't affect it's capabilities.
Also, just out of curiosity, why do many of you think a thermite engine isn't possible? And to those of you who think there are better engines out there to use--what? I plan to use it on a military-grade android robot eventually, maybe I'll get a chance to start during college. Prove me wrong and I'll change.
Your father is a chemist and you're wasting your time talking to us?
There are cheap sources of granulated Aluminum perfect for making Thermite available to the general public that require no special shipping restrictions. If you had done your homework, you would have discovered this rather quickly. But obviously you are very inexperienced at (or downright lazy?) doing research of any kind, and this by itself is a clear indication that you are more likely than not to hurt yourself, damage property, or maim an innocent bystander.
I suggest you talk to your father about this before you burn down his house or give everyone around you a stubborn case of lung cancer or something.
1) burns to hot. Engine must be made of ceramics
2) burns to quick. can't be controlled to do usefull work
3) can't be put out. If your fuel tank ignites it can not be put out until it burns out.
You are much better off to seperate water into hydrogen and oxegen and modify an engine to burn hydrogen. This is not safe either but would at least work
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Lots of propeller based products in stock at affordable prices.
There's this really nifty concept called a Prototype. It's used by engineers all the time. It dates back maybe thousands of years.
en.wikipedia.org/wiki/Prototype
While many recommended the use of refractory ceramics, this ignores the aspect of toughness. Tiny cracks can easily form on the surface of a ceramic and tensile stress can concentrate·at the bottom of the crack, making the local stress as much as 250 times the bulk stress of the material. The crack propagates through the material at supersonic speed and you have catastrophic failure.
That's why we still use metals in jet engines, in spite of having readily available ceramics which have superior high temperature strength. This strength vs. toughness issue is the reason you see martial artists break bricks and cinder blocks, but not metal plates.
-phar
·
You can look forward to Material Science and Statics and Strengths of Material classes in university. You can even to self-study with Schwamn's Outlines right now. Chemistry is a vast and complicated field. But a good introduction is Linus Pauling's "General Chemistry". I have a copy for bedtime reading. Steel Making and high temperature material science are soul mates. After all if you waste 1% of your energy in the process, your product is costing more than the competitions.
There are exciting things happening with engine design. In particualr, methane as a new fuel.
It looks like Cummins is now converting some of its production to long-haul semi tractors powered by methane. The fuel is far cheaper per mile. The fuel needs a range of engine compression from about 9.5:1 to 12:1, any higher it pre-ignites, any lower it may not easily burn. Autos go up to about 9.5:1 conventionally and work on methane which is fuel injected or has a compressor blowing it in. But conventional diesel engines often are too high a compression ratio and don't have spark ignition.
So there are things to explore, if you really want to follow engine design. Also, it really is all about that Carnot cycle I mentioned. The heat has to properly move through the cycle, not just be a lot of heat.
I suspect the best way to get started is to get a 'junker', remove the engine, and rebuild it. That's how I learned and the guy who taught me never graduated from high school and couldn't read. He learned from his dad, a Model T mechanic.
BTW, the military uses thermite grenades especially for destroying enemy artillery. They are quite handy in that manner and don't make a loud boom that the enemy can hear.
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Ain't gadetry a wonderful thing?
aka G. Herzog [noparse][[/noparse] 黃鶴 ] in Taiwan
Post Edited (Loopy Byteloose) : 8/2/2010 3:04:11 PM GMT
*What's your working fluid? Molten iron? Aluminum oxide? In devising a propulsion chemistry, you might consider gaseous products of combustion.
*Unless it is a rocket engine or a spacecraft you are building, it is foolish to carry both fuel and oxidizer.
Thermite as a propellant for an internal combustion engine may be the worst idea ever proffered on this forum.
Let's be real. Pyrotechnic jollies are your sole quest in this matter.
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"Let's not bicker and argue about who killed who."
I agree!
And if he's been talking this over with his father, the chemist, and his father is letting him go ahead and do it instead of explaining to him why it won't work, then one can only suspect his father has ulterior motives: one less mouth to feed?
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"Let's not bicker and argue about who killed who."
I think you need to do some mathematical calculations to figure out heat, volume, pressure, etc.· Then you will have to match it with strength of the parts.
·
Though what you propose might seem straightforward, it actually requires a good deal of knowledge in thermodynamics, far beyond just the ideal gas law, to design a system like this for real. Just because you can create something that's really, really hot, does not mean that it's the ideal system for providing useful work.
Consider a solid propellant rocket motor out in the vacuum of space. When it is fired, it produces thrust by doing what? Well, the propellant doesn't just get really, really hot. If that's all the propellant did, there wouldn't be much thrust. Instead you'd just have a heap of molten metal drooling out of the rocket nozzle. Instead, a real rocket propellant, in addition to getting really, really hot, also generates lots of gases, and so it's the heated expansion of those gases that provides the propulsion = does useful work. So, Generated Gases + Heat to Cause Those Gases to Expand = Useful Work.
But now consider your thermite reaction:
Fe2O3 + 2Al → 2Fe + Al2O3 + Lots of Heat
But where are the gases? What's going to expand and do any useful work?
If you tell me that it will be the air in the pneumatic cylinder that is going to expand and do all the work, well, I'd have to say that's a pathetically small number of molecules you're relying on to do the job. And the heat transfer from the burning thermite to the air will not be uniform - so a large percentage of the air volume won't even get that hot and therefore won't expand as much as you'd hope.
Okay, to solve the heat transfer problem, perhaps you'll try to disperse the thermite in the air inside the pneumatic cylinder. Then your problem becomes: how to get enough molecules of Fe2O3 close enough to molecules of Al to even get a reaction? How can you guarantee that the "burn front" will propagate through this air + thermite mixture once you start ignition?
I'm sorry to sound so negative, but you're proposing to play with some dangerous stuff, and your goals, though ambitious and perhaps entirely respectable, lack the background necessary to follow through on such a project. Based on things you've said here, it seems to me that, because of your lack of knowledge, you're simply more likely than not to shoot your eye out, kid.
I heard the hobby is more regulated now which is why I am not interested as much.
Model Rocket Engines = Regulated
Thermite Engine = should be regulated but they can't regulate something that hasn't happened yet