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I Forge Iron


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    Bay Area, California


  • Location
    Bay Area, California

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  1. There is a railway behind our company, and one day, when I was taking a walk, they performed a thermite weld on the track. I decided I needed a long break and stayed to watch. Anybody interested in more details can ask, but I had a couple of interesting observations. First, most of the time taken for the weld was used to preheat the track. They used a huge gasoline engine blown torch and got it good and hot. I think they were running it for at least half an hour. The gasoline engine ran a compressor which aspirated the burner. Second, the thermite burn was very controlled. I have seen thermite demonstrations, and the rail welding was nothing like it. There were essentially no sparks or flashes, and just a thin wisp of smoke emanating from the reaction vessel. This was surprising to me, and they must have been using a mixture with some sort of moderator in it. Third, I walked by after they were done and looked at the discards. The sprue was huge. This is apparently necessary so that the junk stratifies at the top. The top of the sprue was ragged and porous. They used a magnesia thimble which was very robust. Still it was cracked. I could salvage a few pieces, but I didn't know what to do with them. They probably would have been better than firebricks for cast iron welds. The crew spent a lot of time grinding. They used huge conical wheels and a gasoline powered grinder. When the wheels were used up, they would throw it on the side of the tracks and chuck up another one. I have no doubt that this process would work for welding together a makeshift anvil, but may be too involved for any but the most dedicated tinkerers.
  2. Wow, Jennifer. Looking real good. Makes me want one.
  3. I use separate tags made out of aluminum and stamp those. The links are copper. Kind of like a blacksmith's keychain.
  4. Make sure that the length of the cut is not that long. That is the reason for having a slightly convex edge on the hot cut. Remember, focus the force into a small point. If you are trying to cut a 1" line in that leaf spring, you probably won't be able to hit it hard enough to make much headway. Once you establish a groove, progress will get better.
  5. Hi Mike. I just happened on your post by chance. Thank you for these valuable insights. I did a web search with new terms inspired by your post and found this: https://www.researchgate.net/publication/310651238_The_Zinc_Issue_in_the_Utilization_of_Waste_Tires_Pyrolysis It states that the char, which I observed as nice clean coke, actually contained 4.6% zinc by weight. In a fire with an excess of oxygen, most of this stays in the ash, and ends up as a solid pollutant to be later leached into the water supply, or something like that. Under rich conditions, it can volatilize as zinc vapor due to reduction of zinc oxide. Anyway, I didn't get sick, thank goodness. Interestingly enough, I ran into the guy who suggested this idea to me. He is in the forklift battery recycling business now. The tire waste has long since been depleted, and now forewarned, I will steer clear of any more of it.
  6. What were you cutting, JHCC? I had an accident with a cutting wheel when I was cutting a piece of steel that was too thick. It is almost impossible to hold the tool straight in the kerf. The disk shattered, and a piece struck my finger. Somehow, it got around the guard. Fortunately, I had a face shield, safety glasses, leather apron and thick gloves, so it only hurt a lot. When I was in metal shop, the teacher wouldn't allow students to wear hats or gloves around rotating machinery. He had a special exception for blacksmiths. We could wear gloves and/or hats, and I think that you are safer with gloves when doing that risky stuff with the angle grinder. I don't mean wear gloves around the lathe. The teacher also allowed the blacksmiths to wear gloves around the machine tools, but I noticed that none of us ever put their gloved hands anywhere the rotating spindles. We usually kept them in our pockets or behind our backs, and took the gloves off even to touch a switch or handle.
  7. I'm a little suspicious of that IR thermometer. Get a small piece of cast iron and place it on a chip of hard firebrick. That is a much better indicator of forge temperature for now. If it doesn't melt, you're a little cold. Also, pull those doors shut a bit. If you want to weld high carbon steel, don't use leaf springs. Many of them are not simple alloys. Do a spark test. Instead, start with a file, sandwiched in a folded piece of mild steel. Try using an old garage sale file like a Nicholson or Simonds. Some A-36 (modern mild steel) has a difficult time welding to itself. Also, do a stick test with two coathangers. You cannot miss that little sticky feel. I have to get things just right in my propane forge. It is kind of iffy.
  8. evfreek

    Cutting tools

    What kind of tool holder do you have? This lathe originally has a lantern tool post and Armstrong holders. The hole in the end is pretty small. If you are really tight or pressed for time, you can stuff the appropriate sized broken drill into the hole, and grind to a cutter shape. The fellow who did the doors on the building did this. He made custom door hardware for over 30 doors with a couple of broken drill bits.
  9. I looked extensively at Craigslist and EBay, but only found expensive new rings. I've never seen these at garage sales. Then, at a storage unit clean out, I finally succeeded. They were seized and brittle, but I managed to break a couple out. They spark tested as cast iron, so that's good. They seemed a little hard, but a file will cut them. The third ring groove had a wavy thing and two thin springy rings which sparked as spring steel. I guess I can repurpose the pistons as pistonium as soon as I get a foundry setup working. Thank you for the suggestions. I'll report back on how well they work, but I have seen good results reported from the web.
  10. Wow. I overhauled an engine once, and just threw the old ones away. I don't have any friends who do this now, since the engines last so much longer. For now, I'm going to just use old pieces. But I will forge a tiny pair of tongs to feed the pieces since pliers don't work well and aren't safe.
  11. Hi. Using the technique I mentioned earlier, I was able to successfully weld a broken cast iron C-clamp. I used a small oxy propane torch and cast iron welding flux. The weld had no porosity. Oxy propane has a porosity problem with steel welding due to the heat being in the wrong part of the flame. But, there was a problem. EBay had 3/8" cast iron welding rod, but I was afraid it was too thick. That turned out to be correct. I found a cracked piece of cast iron pipe and hacksaw a 3/8 x1/4" rod from it. I couldn't get enough heat, so I ended up cutting it in half lengthwise and welding the two pieces together. This took a long time, but it worked great. I found out that piston rings aren't cheap! Hopefully I'll find some at a garage sale.
  12. Hi Sascha. I just saw a demo at the California Blacksmith Association spring conference. Mark Aspery was giving it. He said you could purchase "Cherry Heat" hardening powder from Pieh Tool. I don't know if you can find this in Germany. Indeed, there was a sharp crack when Mark swung the piece into water for a rapid quench. Then, he showed how it skated a file. I think that the crack is an indication of two key factors for successful application of the agent. First, a smooth and completely fused coverage showing that the surface hit the active temperature and that there was enough to both treat and protect the surface from decarburization. Second, contraction of the freezing shell combined with expansion of martensite being formed would contribute to the crack noise. Of course, he showed how a file skated after the piece cooled, but the crack was much more graphic. Nobody disputed that the surface was hard after the familiar skating noise from the file. Have fun. I haven't had much luck with those dumb homemade pastes like sugar, salt and flour. I think that those are for pack hardening, which requires quite a bit more patience and fuel.
  13. Hi. I've got plenty of the Ni-99 rod. I meant the cast iron torch rod, like Cronatron 22. Detroit torch has some on their web site, $39 for 5 sticks, sold out.
  14. Hi. I remember seeing a post somewhere about making your own cast iron welding rod in a forge with a mold with triangular channels in it. I cannot seem to find it now. It was only of passing academic interest when I saw it earlier, but now is more interesting, since I performed a seemingly successful experiment with a cut out from a broken street drain cover. Commercially available rod is hard to fine. There is someone on Ebay selling for a high price, but admittedly it is less than the alternative (fiddly cut with a hacksaw). Does anybody remember anything like this?
  15. Report on forge. The forge has been working OK for the past 2+ years. Not great. It is not as hot as I would like, but still hot enough for forging (the metal gets that sweaty look in the hot spot). No forge welding, though. If it had a door, it probably would hit forge welding temperatures. My homemade rigidizer has been OK, but not great. It has started to crack off the front of the forge. I did precoat the wool with rigidizer, and it is running outside, so I am not too worried about fibers. It is out in the rain and ice, and has withstood some abuse, as well as some beginners working in it. All in all, I am satisfied with it. It may be time for a little repair and renovation, though. Last night's forging session was good, but it was raining before and during the session. The rain froze last night, so this is also hard on the forge. If I get a couple of more years out of it, I'll be satisfied.
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