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C. Renzi

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About C. Renzi

  • Birthday 03/20/1983

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  • Gender
    Male
  • Location
    Italy
  • Interests
    Bladesmithing.<br />Molecular biology.<br />General curiosa.
  1. Here you will find all kinds of thermite and their energy yield. Sorry but I don't have the time to check them right now. Keep in mind that copper fumes are nasty.
  2. I saw this link in one of the other threads: http://www.foundry.ray-vin.com/k-bond/k-bond.htm. This stuff is interesting, but I fear the materials required for its making are not as common here as in the US, so I'm planning to substitute some of the components: silica sand -> silica sand (duh) Bentone 34 -> ground kitty litter Indopol L-100 BP -> any polybutane lubricant Isopropyl alcohol -> Methanol (as per recipe) I'm hoping this will be easier to use than solid investments...
  3. So, that would mean adding 1/8 to the total weight og the thermite charge... I'll try with steel scraps from a hardware shop, which should be fine enough to melt straight away. I've taken a look at your star chamber furnace Bennett: looks quite ingenious, but I think I'll start with something simpler. Will the heat from a coke furnace be enough to prepare the mold for the thermite pour?
  4. Just a question while I'm preparing a better mold for my next experiment: first, do you mix some steel bits or shavings in the thermite? The heat dissipated from the reaction is quite impressive and I'm sure that there is more than enough left to melt additional metal, it's just I don't know how much I can put in the mix...
  5. Here we go... I suppose you have had one of those days when you feel quite lazy but you still want to do something? And of course you skip a passage or two thinking "What the hell, at least it's going to be fun..." So, instead of making a proper mould you just cram some refractory cement in a box, place it under the "crucible" (unadulterated flower pot) and light its thermite charge, hoping that it won't turn into an horrible mess... Guess what? I got an horrible mess. Plus I think I have breathed some of the cement, I hope it's not too carcinogenic...
  6. Nice sample. Well the slag should be aluminum oxide, its properties are quite interesting (from what I can see on wikipedia). I just realized that I placed the thermite on a brick I found in a yard, so the bubbles are probably due for the most part ho the humidity of the brick itself. I will have to heat the crucible and the mould thoroughly to avoid that and possibly an explosion. Next on this thread: small scale experiment with a lot more thermite and a rough mould. That is, if it dries...
  7. The magnet test has revealed that the fragments are indeed magnetic. Love it when stuff works. Now, how do I get rid of the "Luflee" effect?
  8. For this batch I used a 8/3 iron oxide/aluminum ratio; I used a sieve to select the smallest particles of aluminum. I put the thermite in an oven at 250° C (480° F) for an hour to eliminate humidity; then I placed a spoonful on a brick and lit it with three sparklers. This time there was a bigger flare, and about half of the mixture went off. It burned neatly and left this... iron turd (look down ) Its consistency is quite surprising: it's extremely light and brittle, as it has so many bubbles inside it resembles a milkshake. Still, I think it's iron, so I'm gonna call this just half a failure... I think some more time in the oven will do the trick, as it will reduce the residual water in the thermite. As usual, feel free to comment.
  9. Uhm... Which is it? 8:3 or 4:1? I have to go by weight since my aluminum is quite bulky... Argh. If only aluminum powder wasn't so damn expensive around here... At least the oxide is quite fine and cheap. Nah it's just for a figurine, nothing fancy. Maybe, if this works, I'll cast some serious steel, but that's for the future. Again, thanks for the help, I'll post the progress here.
  10. Ok I made my first batch of thermite. I used Bayer 120 red oxide powder, which is, to the best of my knowledge, red iron oxide (Fe2O3). I mixed this compound with aluminum scraps I got from a mechanical shop. These scraps are similar to minuscule apple peels: they have a lot of surface for the iron oxide to bind to so they should be ok. I used an iron oxide/aluminum ratio of 3, that is, 30 g of iron oxide and 10 of aluminum. I placed a spoonful the mixture on a steel plate and lit it with a sparkler, one of those toy fireworks: I managed to obtain a small flare, and a little ball of iron welded to the plate, but the reaction stopped before completion. So 1) I didn't pack the thermite 2) I didn't bother to wash the aluminum scraps, which maybe are too big or too dirty or both. Could you give me your opinions?
  11. Good thinking, I didn't realize flower pots were stackable... The additional pot will also act as a wall should the first one break. So fire clay is a viable material for the mould? I bought some from a bricolage store, but unfortunately I don't know its composition... I hope it holds, I used it for a little propane foundry and it did ok. I was planning to get the bubbles out of the investment using a vacuum claner and a tupperware box; I think it should be enough for this project, but do you have any pointers? Thanks for the help, guys! Little by little this is becoming feasible!
  12. Well, I'm trying to rig up something quick and easy, and thermite seem a lot less complicated than a cupola furnace. My little coke thingie can barely soften steel, let alone melt it, so when I saw those guys weld the rails I thought it would be an excellent, albeit expensive way to produce melt iron quickly. I do not intend to melt an iron object to produce this figurine of mine, I'll just calculate the amount of iron oxide I need from the weight of the wax model. Nice! And somewhat comforting... Refractory is indeed my principal worry: I was planning to use a ceramic plant pot fot a kiln and refractory mortar for the mold, err... investment. This is a first run so I'm thinking disposable, there's no need for things to last; I just need them not to fall apart during the pour. I drew the general schematic for this experiment; it's pretty basic, please feel free to criticize it. The orange stuff is the thermite.
  13. Hello there, it's been a while... Some time ago I ran into a description of a railroad welding that used thermite (or thermit); the process was intriguing and it stuck in my mind. Now I found myself thinking about making a small figurine and I was wondering if it would be feasible to use homemade thermite to do a little lost wax casting. May I have your opinion? Thanks
  14. Ok, I bought the metal for the frame and the jack has just arrived. I'll show the results In a while.
  15. Thanks. From what I can tell reading the forums there it would seem that the dreaded eBay.co.uk has some jacks to offer, including a 35 ton beast. Definitely worth looking, I just hope shipping fee won't surpass the price of the item. I might be able to make this little thing after all. Thanks again.
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