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spamonkey8

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Everything posted by spamonkey8

  1. Here, this works great: Dump some carbon powder onto the stain, and heat it all to a few thousand degrees and the carbon will reduce the rust to iron, then you can put out the smoldering embers your house has become and bask in the glow of a beautifullt de-rusted patch of melted carpet!
  2. Hehe, oh to have a job as easy as joining two little pieces of metal like that That's not what I was getting ready to do, I just grabbed something steel and tried to get the basics down before I borked up my whole project. I haven't tried brazing with fuel/air, I was told that even mapp is "sorta able" to braze light stuff, but I'll give it a try. For now, I've come to the conclusion that some brazing will be just fine, but the parts I'm joining are attached closely to some plastic that would melt if I took the time to use air/fuel.
  3. use a low reaction most of the static-pressure rise in the stator[/u single-stage I think that this is likely not too difficult of a question, though explained in esoteric terms. You have to think about what you're doing a little more. There are people on this forum who know the answer. I'm sure of it. I'd venture to say that there's a possibility that those who do know the answer may not remember exactly the definition of all the terms you used. If a person isn't currently working with this particular field of fliud mechanics, they might have forgotten some of the vocab from Fan Design 101 and need a tiny refresher. Even if they don't know what you're talking about, having more explanation will not only invite the insight of someone who can offer a different perspective, but it will make this forum a better resource for someone who is searching through old threads for an answer. And even if it is on your homework, you would do well to approach it as a student who wants to learn and needs a hint instead of one who just wants an answer to put down. Remember that you're the one who wants help here, and you're only alienating the people whose expertise you need by not giving them every opportunity to help you. I'm sorry if I seem to be taking this out of proportion, but like many people, I see this sort of thing far too much.
  4. Yeah, way back I had a half-psychotic chem teacher who taught us about gun powder and did an 'experiment' involving sodium metal and water. Yep. The teacher gave us all goggles and dunked a sizeable chunk of sodium in a beaker. None of us knew what was going to happen, and we all jumped. A smartass in the class asked her what variables she was measuring in the 'experiment' were and she scrambled to think of the education value...
  5. This isn't perfect, but if you have the option, you can put it in a sealed container and heat it to just under boiling, then measure the gas output. I think a beaker with a large stopper and a little bit of glass tubing going to an inverted graduated cylindar filled with water. The gas would leave and bubble up to the top of the cylindar and you can measure its volume under controlled temperature and pressure. This would measure all dissolved gasses, and you will get a little water vapor, but you can use a condenser to get that out I think (run it through copper tubing under ice water for an easy way). It also occurred to me you'd have to measure the volume inside the tubing. Like I said, this may not be feasible, and some test strips may be the thing for you.
  6. I'm teaching myself with scrap pieces of steel, for example the cheap little steel covers for PCI slots. I suspect that these may be plated/alloyed with something, though, as I have never known them to rust. At the time, I wasn't using any welding rods and was just trying to weld them without it, but I need to give that a try. I found that the one time when both pieces started to melt, I couldn't get the two beads of molten steel to merge and stick together. The other time I might have just needed to crank the fuel and match the flame with O2. I've had great results (even with stainless steel) brazing common metals with fluxed bronze. I guess this comes down to bead envy, I just can't get the perfect weld bead an arc welder can supply...sigh... Any air/fuel torch won't provide the heat necessary to melt steel, and even if it could, it would be way too hard to work with given that the secondary flame would warp the metal (not a very concentrated heat) and it would be too hard to keep the metal hot. The Torch (My research for a torch to learn on and use on a few small projects, you can skip this unless you're in the market. Just wanted to pass on a little knowledge to those interested ) I'm using a relatively cheap ($50 incl two tanks) entry-level Bernzomatic Oxy-MAPP (stabilized liquified methyl-acetylene and propadiene) or Oxy/Propane torch that uses disposable cylindars. It eats O2 like a mofo (rated 8-24 min. run time depending on application, lasts 1/40 as long as fuel tank), and the O2 costs about $8/tank, but it's very portable and good to learn on. You can compare that with small oxy/acetylene torches like a common Tote Torch (at least $300). The regulator knobs are on the tank fixtures, which is a slight inconvenience, I suppose, but as far as safety and portability it can't be beat. Just read the instructions and keep the flame at least 3/4 in. to avoid flashback. It doesn't come with gloves, welding goggles or a face mask, but those should factor into your purchase. MAPP burns a couple hundred degrees F hotter than propane in air, but in oxygen, it burns 700 degrees hotter, just shy of acetylene, though with a hotter secondary flame, which, I'm told, can warp metal. Also, when the oxygen is limited or it's not well mixed with air, MAPP produces a lot of soot that will float around and get stuff messy. Fortunately, this only happens when the oxygen tank runs dry or when you have just started it and haven't hit the O2. Count on $70 plus O2, and keep that air/gas torch around for jobs that don't require oxy/fuel. Bottom line, the torch is cheap, safer, very portable, and effective for moderate use. I fought with the price of the O2, but if you consider the $240 price difference with an oxy/acetylene kit, you can buy 30 tanks of oxygen to even it out. All in all, I'm pretty happy with it. Edit: http://www.bernzomatic.com/bernzomatic/consumer/jhtml/productDetail.jhtml?attributeId=BMBZOPA000006&productId=BM019614
  7. I've been teaching myself to use my new torch, and I've got brazing and cutting, mainly because I've known how to solder for so long. I have a really simple question I hope someone can help with. When I try to weld steel, it either just gets red hot and does nothing or it sparks and acts like I'm trying to cut it. Is there some trick I'm missing to get it to flow together and produce a nice clean bead at the joint like I see all the time, or are those made with an arc welder? Thanks!
  8. I don't necessarily need lower voltage, I just need more current. I guess what I'm looking at is any way other than a transformer to up the current.
  9. I also saw some proof dealing with an infinite cycle of integration. It's been years, but it has something to do with how (n-1)! would be expressed as an integral... I'm too tired for math...
  10. I've been toying around and I had an idea. I have a transformer that can supply 26VAC/15A. If I run this through a bridge rectifier, I get about 24VDC (this rectifier drops about 2V). I have two of these handy little rectifiers that can handle 25A at 50PIV max. For my application, I need electricity much as it is supplied with an arc welder, low voltage (about 2V) and high current (the more the better). Here's the question: Hooking two loads to a source of power in series allows the max current to flow whilst splitting the voltage (in the simplest case). What happens when I wire two rectifiers in series? I have confirmed that the voltage is split between the two, and I know that if I wire both rectifiers' DC outputs in parallel, the fact that they are in series doesn't matter, and only half of each rectifier is actually used, thus giving me the 24V. The question is this, how much current could I safely draw from each rectifier at 12V given they are both connected to separate but equal loads. (no pun intended) I've included a simple drawing for visualization (ignore that the outputs are in parallel). I'm a bit over my head, thanks for your time and expertise everyone!
  11. I found this a while ago, it seems perfect: http://www.overclockers.com/tips1054/
  12. Sorry, I solved my own problem. As it is, the secondary *will not* supply any more than ~7.7 amperes. If the max current the given wire can handle is ~7.7Amps from one end to the other (52V) and there is a center tap to give you 26V, there is no way to draw more current. Granted, the lower impedance of the shorter coil will allow you a bit higher current, but not double. If I cut the insulation off the side and find where the center tap is, I can cut the coil wire and solder separate leads to give me two separate secondaries supplying 26V and 7.7A each (technically more, as I said above). I can then choose to wire the two in series for 52V 7.7A or in parallel for 26V 15.4A. Thanks for the help in working through this!
  13. Yeah, but as far as efficiency, how much would be lost with heat? Also, could I do something to get 26 volts at double the current?
  14. But that's the point, isn't it? The gamma function has much broader applications than expressions of factorials, and all he wanted was that.
  15. Don't forget [math]\[n! = \int_0^{\infty} x^n e^{-x} \,dx\] [/math]
  16. Ethane's just a little bit of oxygen away from ethanol, and that's the most important part of the pub.
  17. hehe, this was in stargate once: Jack: Hey, could you finish this phrase: up, down, charmed, (7-letter word) DJ: Strange Jack: Yeah, thanks for trying DJ: No, the answer is--::hung up on::
  18. god, as always, e=mc2 gets the votes simply because people recognize it better
  19. Definitely search. I'm either looking for help or looking for the topics I'm passionate about and I can contribute with.
  20. As long as I've got a way out, I'm ok for as long as I can take it. And as long as a certain someone in my life can get it too. And my dog... But that's it! maybe my cat...
  21. It's tough to find one party to put complete faith/support in. In my opinion, the only way to think for yourself is to find parts of parties to support.
  22. Stargate: SG-1 needs a little more representation here! Give the dying series its last hurrah
  23. Oh a whim, I punched in some letters on the side of the unit, and it was made by Ten Pao. The part number isn't listed on the site, but it's TOU543001F0, just for reference.
  24. Douglas's got it. It was from the amp/sub cabinet to a 4.1 system that came packaged. I hooked 120VAC to the red/white and the secondaries were 52 volts between the yellow & orange with the black being the center tap for 26. Whew, I was thinking backwards I saw the three cords and without thinking jumped to ac and a ground for some reason. I just would like to know one thing. How could I find out how much current it can deliver? As far as the system goes, it will take 720W max, 400 RMS. This thing weighs a good 7 or 8 pounds at least...
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