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I Forge Iron

Andrew Golabek

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Posts posted by Andrew Golabek

  1. Looking back I think the carbon content was way too high, and the mishmash of alloying elements made it nearly impossible to forge. My next attempt will be with much cleaner starting material. I’d guess this one was almost in the cast iron range, some pieces that had crumbled  were easily melted at forge welding temperature 

    On 6/30/2019 at 3:29 PM, DanielC said:

    High alloy crucible steel is properly forged all the time. For instance stainless crucible steel with really high Cr content. Typically those flavors have other alloys such as nickle in them as well.

    If it wasnt incorrect forging temps, what is your estimated carbon content and what temps was this forged at?

    And why the definitive statement if this is your first attempt?

    Because I had tried a wide range of forging temperatures, annealing and normalizing etc. I’m guessing over 1.7% carbon

  2. Hey guys, been a long time since I’ve posted, thought some might be interested in one of my latest little projects. My dad was throwing away a worn out chainsaw chain (too worn to be resharpened). I decided to try and forge it into a knife.

    first step I simply took the worn dirty chain, and wrapped it in thin steel wire to keep it in one piece. I proceeded to forge weld it, and folded it until I was happy with how solid the billet felt. No cleaning of the steel was required, however a high temperature and proper atmosphere were absolutely necessary, especially at the beginning as it was tricky to stick. Anyways, here’s the finished piece and some progress pictures. Altogether only a couple of hours and gives me some confidence in my forge welding. 
     

    Tempered at 350f, considering the steel was likely lower carbon, and the feel during sharpening etc I would put the hardness at a maximum of 56-58.

     

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  3. 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.

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  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. 

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  5. 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

     

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  6. 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

  7. 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. 

  8. 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.

  9. Nearly done, only final polish for the handle and oiling is left.

    brought it to the forest to test chop some bushes and stuff, works pretty well, I’m going to make a video in a little while showing what it can do.

    -the weight is 1.23kg or 2.71 lbs

    -the point of balance is 5.25 inches from the guard now or 13.3cm.

    -maximum width of the blade is 43mm.

     

     

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