Andrew Golabek

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About Andrew Golabek

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    Ontario
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    Mountain biking, Chemistry

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  1. It is definitely not because of the incorrect forging temperatures, but rather the high alloy content
  2. I’m going to either remelt this one and add some mild steel as the carbon content seems too high (it starts to crumble quite easily) or just start from other materials, as the hardness at temp is very high. Other options are; make some new tongs and be very patient forging it out ( I don’t have a press/power hammer) i was attempting to hot cut it in half, and a corner just came off.
  3. When I start forging it into a billet should I forge it making the top and bottom the ends of the billet, or should I forge it from the sides? I was thinking from the sides since it has one side which is not very smooth due to a piece of trapped charcoal and if one way is preferable, why?
  4. I spark tested it today, and polished up the bottom face to check if there is any visible porosity. Unfortunately my camera didn’t focus well during the spark test, but I’ll describe it; The sparks were dark red, and very short without any visible branching. I compared it to o1, and mild steel which both sparked xxxxxxx a lot more. Then compared to a high speed steel drill bit, which had quite similar sparks however the crucible steel had slightly shorter ones, and less. current thoughts are; due to the saw blades and drill bits used to make the steel, and the other scrap metal/forge scale, it has a relatively high tungsten and molybdenum content, and a medium carbon content. Perhaps the carbon content is slightly low but I’m not sure since it was mostly high carbon steel as input and it was melted under reducing conditions the whole time with a thick layer of charcoal covering, and glass.
  5. Today I was successful at melting down some old bandsaw blades, and drill bits along with some old pieces from knife testing, in my propane furnace! Got a small lump of steel, have yet to check it in anyway for carbon, but this is the first step! Any suggestions on how to proceed? Keep in mind I do not have a forging press or power hammer.
  6. I didn’t use a degasser, I followed some of the recommendations in the ASTM copper alloys handbook for casting bronze alloys with tin. Some of the most important things I make sure of -the sand must have the proper moisture content, just enough to lend the mold strength, but not enough to cause water and subsequent hydrogen and oxygen porosity -I use ground charcoal for deoxygenation, you can’t add too much. -better results may be obtained if it is the second time melting a piece of freshly alloyed metal (the first time from many small pieces seems to have more porosity) not sure if this is 100% true, but it might be. -cast quite hot, I think around 1100c, when you touch the surface of the bronze it should be shiny and very liquid not viscous and not with an oxide layer. This is very key to casting thin items. -I’ve also tried degassing with a green stick of pine. Not sure how this works but the handbook mentions it and it seems to work. -sprue and gate must be properly formed, follow the guidelines in the handbook, later I can update the exact measurements of mine. Here’s a picture of one mold half. 75 grit silica with 10% bentonite looking to get some 125-150 grit to add in as well for next casting
  7. My latest knife has 13% tin, and 0.1% I think of zirconium added. The zirconium is a grain refiner for this type of copper alloy, and also increases hardness. my casting process has also improved quite a bit, there is zero visible porosity on the last knife.
  8. That last nozzle reminds me of one used for flame emission spectroscopy
  9. I think you are underestimating the material, it is hard enough that it won’t roll that far back unless it was exceedingly thin
  10. I took a few passes along the blade, the total width of the hardened area is approx 5mm I think, past that point I don’t think there is much benefit as the hardness of the cutting edge is what makes the largest performance improvement
  11. Yeah, i measured the density of the bronze as I cast it, to help me get an idea of the amount to melt for the casting, it was approx 8.7g/cm3 which is quite higher than steel between 7.7-8g/cm cubed. Testing recently revealed I didn't harden the edges sufficiently as it rolled in one spot, so I made a better jig for hammering them, and now it is much better. I'll attach a picture once I take some
  12. So far, my foundry has survived in nearly the same shape as it was when i started aside from some discolouration due to some silly experiments. I've successfully cast about 10 items so far ranging from 1lb to 4lb melts of classic bronze. The highest verified temperature I've achieved was approx 1400c during some experiments with ceramic it survived perfectly intact, which isn't a large surprise given the max temp rating of 3200f. Now onto its downfalls. There is a lot of larger grit in this refractory, no doubt giving extra strength, but mixing, and casting it without too much water by hand can be difficult. I couldn't find instructions for it online in regards to curing or water content, so just went with what seemed appropriate, as you add water to it, at a certain point it will become much easier to mix, and if there is any vibration it will act liquid. I think that is the ideal amount. Any higher, and from what I was told by the foundry supply is that it may not come out as strong. It sets like cement in approx 24 hours. The surface finish can vary depending on how well it was done from glassy smooth to very gritty with air bubbles on the surface. Firing it can be done relatively quickly once it has been dried with a low flame.
  13. It seems that lead was deliberately added in the past to help the castings flow better into narrow sections. tin had to be mined separately and it was alloyed to make the classic bronze
  14. Search up Neil Burridge, I believe he does the closest work to ancient methods, for European bronze replicas. Swords are cast, cleaned up, annealed, edges are cold forged, and the spine is hardened by hammering, and some bending. One problem with many of the ancient bronze alloys is the lead that was commonly added makes it hot-short.