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I Forge Iron


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Everything posted by jbin

  1. Stay below 1375F when silver brass goes bad it is real ugly ;) Nickel silver/Sterling is a fairly well behaved combo. You can take it up to the point where the sterling begins to shine for a liquid phase bond. This is a reject piece of brass sterling because of the blemishes from not getting all the cuts to the surface. http://www.iforgeiron.com/gallery/image/37827-img-2088/
  2. jbin

    IMG 2088

    © James Binnion 2013

  3. Matt, nice looking bolster on that knife. If you are going to only be working with copper alloys in your mokume you really don't need a temperature controlled kiln, just an eagle eye and keep moving the stack around in the forge to try to keep the heat even. It can also help to turn your burner down some :)
  4. Thank you, I think it just takes being so stubborn that when you run into a wall in your way you just get up and take another run at it again and again till you figure out how to make it work :-)
  5. FWIW there are two types of copper nickel alloys Nickel Silvers and Cupro Nickels. Cupro Nickel alloys are those where nickel is the main alloying component after copper and there are fairly small amounts of other elements in the alloy. Nickel Silvers are those where the main alloying component after copper is nickel but closely followed by zinc in percentage. You will have a XXXX of a time finding much in the way of cupro nickel sheet in the quantities we would buy. Nickel silvers are more available. mostly C75200 Cu65,Ni18,Zn balance http://www.copper.org/resources/properties/db/basic-search.php?uns-search=C75200&submit-single-alloys=Display. If someone truly has a nickel sensitization that causes contact dermatitis "nickel allergy" stacking order will not matter they will still end up reacting to it.

 Nickel and silver don't like each other if you take pure silver and pure nickel and melt them in a crucible you will observe that the silver will melt first and all the nickel will be floating on the surface of the melt. As you increase the heat the nickel will eventually melt but they will not mix you will have a layer of molten nickel floating on top of the molten silver. If you allow it to cool it will end up with the nickel and silver segregated with the nickel on top and the silver on the bottom. Once you add copper to the mix the dynamics change and you will get some alloying of the nickel into the silver but it still will be a two phase alloy ( at room temperature there will be two different crystals in the alloy rather than a homogenous mix of all components) where one phase is mostly silver with some copper and a tiny amount of nickel the second phase will be mostly copper with the rest of the nickel in it and a small amount of silver. The combination of nickel silver and ether sterling or fine silver will work quite well if you are forge welding your mokume.
  6. The ring in the original post is my work. It is 14k palladium white gold and sterling silver. Credit has been added to the starting post, we would have corrected this sooner had we known.
  7. So I heard from Jerry that there was a conversation about forge welding copper over here. Yes you can forge weld copper, it needs to be kept clean and in a strong reducing atmosphere while heating. It can be tricky as the oxygen in the air will cause the bond to fail if it gets too much exposure. This is why it is easier to make the weld in a mokume type of fixture. Also the more deformation (spreading) of the bonding surface you can get on the first strike the better your chances of a successful bond. It is not an easy weld but having a big power hammer will make it easier. As for welding definitions, forge welding, mokume, pattern welding (damascus) are all solid state welding. TIG, Stick, torch etc are all liquid phase welding. Both types are true welding, but there are metallurgical differences in the crystal structures resulting from the joining.
  8. There are many ways to skin a cat. As long as you are satisfied with small billets his technique works just fine (BTW he is very good at what he does). In this video he in effect is using sterling silver to act as a "solder" by heating the stack to the point where the sterling just begins to melt and fusing the billet. There are several potential drawbacks to the torch fired method but it definitely works on small scale. More complex methods are needed for larger pieces and some alloy combination's. There is also a very steep learning curve for torch firing. If you lose a little copper alloy billet no big deal but if you want to use precious metals the cost of failure can climb rapidly so extra effort and special tools and such for insuring a reliable bond is well worth the effort. A typical small billet that I work on in gold & silver it is 1.75" x 0.625 x 0.75" and is somewhere between $3000 and $8000 in materials. In that video if that is a precious metal billet he has likely has 3-4 times that amount of money in materials there. You don't want an oops with that kind of investment.
  9. jbin

    Mokume Gane

    Yes I have made pieces of sheet in the 7-10" diameter range. It is a lot of hammering by hand but if you have a 25lb little giant or small air hammer with clean dies you can do it much faster. The sheet for this teapot was hand forged, now I have a couple of small power hammers, much better :-) The biggest problem is getting even, thickness (.040) sheet . I found that a air planishing hammer is an excellent tool to follow the power hammer with. It allows for a much smoother final sheet. I am not a fan of nickle silver or cupro nickel alloys as they are a bear to move, very stiff. I also have had some problems with hot cracking of nickel silver while forging. Copper nickel alloys are better if you can get a hold of them as there is little or no zinc in them where the nickel silvers have a a fair amount of zinc which makes for trickier hot forging. I am glad you like the rings, my favorite clients are other crafts folk. Jim
  10. jbin

    Mokume Gane

    Yes and no, Yes it is "just" carving with a bur that gives that texture but No I manipulate the hell out of that material to get it to the point where I carve it, as that is a seamless band that started out as a flat laminate stack.
  11. jbin

    Mokume Gane

    Actually there are two separate issues, Annealing and Cooling rate from annealing temperature. Pure copper along many other metals do not require any particular cooling rate when quenching from annealing temperature. Air, water oil it doesn't matter one bit. Some metals like steel, sterling silver, red golds etc care a little bit or a lot about how you cool them. But the annealing or re-crystallization itself is taken care of by the heat and the time at heat. The question is whether you will harden them during cooling by the improper cooling rate.
  12. 304L or 304 forges much hotter than you will be used to. Minimum forging temperature is 1700 F 926 C and it is very stiff down that low. Upper forging temps are in the 2200 F 1204 C range. Even at high temps it is not easy to work. 304L is the low carbon version and would be preferred but if you keep it above 1700 F and quench it before it has a chance to cool from that temp you will not need the properties that the low carbon variety provides. It has to do with chromium carbides that form at lower temps and cause loss of strength and corrosion resistance. But if you heat the whole item to 1750 F and quench you will break down the chromium carbides and return it to its original state. Heavy forging scale can be removed by electro-striping the work in a bath of citric acid with the work hooked up to a 12 volt DC source (battery charger) as the anode (+) and a cathode plate of stainless or even mild steel hooked up to the (-) pole.
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