kogatana

evfreek, Yes I meant quenching. It seems you have observed something very similar to what I have. Part of my piece was also silvery, it got dark covered with scale after I put it back into the fire. The spark test: I'm not expert, but by comparing the sparks on the hard end with those from other part, it is striking that the sparks on the hard part are totally different: the end of the sparks appeared somehow like many snow crystals, while on the other parts, nothing special, the bright rays were more like shooting stars: bright curved lines with no sparkling at the end. Bridgeport I have cut the hard part (one low quality hacksaw blade just lost all its teeth in the operation!), and thus had access to bare steel in the thickness of my piece. The bare steel was still very hard, so it was more than a crust. However my piece was quite thin (<1/8"), so maybe the whole thickness got "burned" as you said... But are you sure we can "burn" steel in a similar fashion as we can burn a dough crust?? Ludo

It might be scale indeed, but I have cut about 1 inch of the cracked hard part, and when grinding the cut it is still hard. Why is scale so hard?

How can a part of a piece of mild steel becomes hard without me tempering it?? More details: I took that piece of mild steel from an old metal fence in a farm. I believe it is mild steel, and very mild for that because it bends veery easily, is cut with my hack saw very easily and a file bites in it like teeth in butter. Now I make a nice hot charcoal fire, put there my 1" by 1/4" section of material, and taking it out after some time I notice that it looks as if it had melted. I do not pay much attention, though I'm a bit surprised since I've got red hot steel or iron before but never melted iron. Maybe this was only a partial melt, on the surface. Back home (I do not forge at home, I'd bother the neighbours), I want to get rid of that ugly end on my small knife. It is then that I notice that it is very very hard, definitely much harder than the remaining of the knife (and it is the side opposite to the edge). I do a spark test, and well, definitely the sparks are way different at that end compared to other parts of the knife. It rings differently also. I haven't quenched any part of the knife yet. Could it be that some carbon went into the material when it was hotter that usual and made a small area a high carbon steel? Otherwise how come did it become so hard? Ludo

Now if I get a piece of very rusty and pitted iron that I want to forge: will the rust burn in the fire? Or do I need to have a really clean surface prior to heat? Ludo

Thank you all. Thomas, I'm just trying to first understand what's flux and how to use it. That's the textbook and IForgeIron part. Next is to put into practice the information gathered which will be another story. I plan to forge weld to make a small knife or woodworking tool. Ludo

Have you ever tried a forge welding using sand as a flux? I'm just reading in the book "forging" from J. Jernberg that this is possible, and that borax is a substitute for flux. Interesting anyway. What act as a flux in the sand, is it silica? Ludo PS: I read further, and you might be interested to know that borax can be heated red hot (I believe you put it in a pan on a stove) and left to cool. It become vitrous and have almost all of its water gone. In the form of powder, that "dry" borax won't boil when heated in the forge and will remain more easily on the pieces to weld.

Thomas, interesting! I'd be interested to know where you got your iron ore and to read you if you have posted your experiences with the smelting. Could you post a link to the company's web you mention?

Woody, does mild steel only bend without breaking when repeatedly bent? On the picture of my first post of this thread, you see a 1mm deep saw mark: without first sawing the bar, it would not break after 5 solid minutes of repeated bending. To make sure of the metal, I'll try the quenching and file method. Thomas, yes, 20 years is not old. And I also tend to think that what I've got is the result of a mix of various irons and steels. Bruce, I've just noticed you are from the UK. Here is a picture of wrought iron bars (that I'm sure it is WI), from a bridge made in the 19th century in Japan, from british iron. The picture was taken in the shop of a plane blade maker in Miki-city Japan. Steel and iron from England is widely used by Japanese woodworking tool makers. Also, an anchor and the chain, from unknown origin, also wrought iron and from another Japanese toolmaker.

Thomas, I'll try that. Let me find some nitric acid... I'll keep you all updated. Ludo

Woody, the piece come from an old fence, used now to build a shelter for chickens. According to my stepfather who owns both the chickens and the fence, it is some 20years old. I will try to do something out of that bar. Thomas and evfreek, you seem to confirm my first idea that it is not wrough iron indeed. evfreek, I like the idea of observing the crystals of the metal following the hints you provide, in Japan there is a quaterly about woodworking and tools that regularly shows pictures of various steels' crystalin structure used for toolmaking. Pictures are taken with just a simple optical microscope. By the way, what should I do with the rust? Put it as is in the forge's fire after some rough cleaning with a wire brush? Ludo

I have found a source of what I believe is iron, now what kind of iron, I would need your help. Can we have an idea of the iron (or more generally the steel) by looking at the way it rusts: is there any particular rusting pattern for a given iron/steel? Now if we break the piece, by repeated back and forth movements, and observe the fracture, I'm sure we can tell something about the iron/steel. Not a precise metalurgical analysis sure, but maybe a rough idea of the metal, and how it would look like when etched for example Recently I watched a show about an archeological metalurgist who uses a microscope to identify the crystaline structure of an iron/steel and then date it. Here are 2 pictures. One shows the rust, with pits as deep as about 1/16" or 2mm. The other is a close up on the break, and the sawn area. Is this what one call wrought iron? I think I can say no, I've seen broken wrought iron and it looked more fibrous than this. Ludo

Bonjour de Taiwan, Louise A forge made entirely out of brick is surely possible to build. On my small forge based on a BBQ, I use bricks, see: forge_brick_30.JPG (image) You could easily build a similar small forge only with bricks. As for stones, I'd be carefull on which one to use (or wouldn't use any at all at least not anywhere near the heat) as they might explode due to the heat. For the bricks, I haven't had any problem. Comment aimez-vous la France? Ludo

I'll check the exact nature of that coal tonight (it's the morning now in Taiwan), will break a piece or two and take close-ups. I haven't got clinker for sure. The little amount of what I thought was burnt out coal that I've thrown away, I can still take it back to the fire! It's not gone yet.

Should the coal burn completely, reducing itself to ash? I have never got ash with the coal. So maybe I've thrown away some (not much) coal that could still be burnt! What is clinker exactly? Does it look as if chunks of coal had melted together? If so, I didn't see this in my forge. Ludo

The article is online. Link to the pictures: View of the blower (air admission has since then changed). FirstBlow_30.JPG (image) Combustible and partial view of the new air admission (I hope you could identify what type of coal I'm using). Forge_w_coal_30.JPG (image) Latest configuration: forge_brick_30.JPG (image) Ludo

Gary, Ed, Don, I think the best way to document this conversation is to describe my forge... on my just created one day old blog. I've posted some pictures here: At last blacksmithing Maybe you'll need to wait 10mn before what I'm writing now on the blog is published and available on the web. Ludo

Now that I started to hammer, I've been contaminated with the virus "blacksmithobacilus hammergus"! But... I have been struggling to keep my coal burning since my first attempt 3 weeks ago (I'm at my 3rd sunday of blacksmithing only). It works very fine at the begining, I first light a fire with charcoal, then add fresh coal. It will provide me a nice heat. But after some time, the fire will die, even with a constant blowing and adding new coal. Yesterday sunday, I restarted 3 times my fire (same process: small wood fire, then add charcoal then coal). So... Should I remove burnt coal and if so, how do I know it has to be removed? Is it when the fire dies? Also, I remember seeing a japanese blacksmith rinsing his combustible but don't remember what kind it was (charcoal, coke or coal). Should I rinse coal to get rid of its dust? Ludo

From that post, I think I will not use the pipe I've found. You both confirm that. Black iron maybe cheap but I have no idea where to find it in Taiwan! Thanks Ludo

I have found this pipe, and I wonder if I can use it as the air admission pipe for my forge. I have doubts because it might be covered with zinc, and I know from IFI's safety notes that zinc is not good for one's lungs. If it is covered with zinc, can I still use it for the above mentioned purpose, or should I grind the zinc away (as I started to do, see the pictures) or should I reserve the pipe for anything but heat related tasks? Thanks Ludo

Here is my mini RR anvil, can't compare it with other real anvil (I haven't tried any), but for small work this should be good enough to begin with. And in Taiwan, it's probably more difficult to find an anvil than anywhere in the states! Yes, it does seems to rebound a lot, it rings with a high pitch. I plan to drill a hardy hole. Ludo

By the way, I've asked Google books why I couldn't access to the books from Taiwan. They answered my mail in 36hrs and explained it is for copyrights reasons. Until they are sure the books are free of copyrights outside the US, they will not authorize their access. Ludo

6011, 6013 and 7018... what is this, was I going to ask. Then I've just found out this interesting page: http://www.clovisusd.k12.ca.us/agcenter/arc_welding.htm All is explained. The first 2 numbers for example refer to the tensil strength of the rod (ex 7018 has a tensil strenght of 70000lbs/in^2), ... Thank you for those answers, now I'll need to figure out what is available in Taiwan. Ludo

Arc welding is inexpensive, easy to use, and I'm still wondering which welding solution I'll invest in. One of my concern is the electrodes. What are they made of? Can we forge the welding? Will any residue, or the welding itself pollute the piece being forged (if for example we need to weld a chain or other pieces of metal together before forging)? Ludo

Intersting topic! You can read more about arc blow and how to avoid it here: http://archive.metalformingmagazine.com/2001/05/Lincoln.pdf A coil fed by AC current at 50 or 60Hz will not make an electromagnet, because the magnetic field is changing direction all the time and cancels itself in average. With the very high DC currents used in welding, yes, you can create non negligeable magnetic fields. Ludo

About the "edit" right of the author of a message: could we have a message that would be editable within a limited period of time only, and after that limit, and for the sake of the intelligibility of a thread, the message couldn't be modified? If one realizes ones message is not correctly formulated, one will modify it within few days. It wouldn't make sense to change ones message after others' answered that particular message. If the feature is not available, it should be invented. I forgot who said this: "Your freedom stops where the other's starts." Applied here, one is not free to alter the IFI community's freedom to have an integral and undamaged access to the knowledge database. Ludo