Caleb Harris Posted October 23, 2013 Share Posted October 23, 2013 I'd like to try my hand at forge welding (possibly in the form of a hawk) but I'm not sure my forge will get up to heat. The forge I have I built off a tutorial by Chris Anderson and it does get to a bright yellow hot. Thing is, from what I've heard (please correct me if I'm wrong) welding temperature is about 1800 Fahrenheit or so, and I have no idea how to convert color to number. I've seen a couple heat charts, but they seem to vary a bit and I'm not sure which is best. So are there any reliable charts that I can compare to temporarily (that is until I get used to knowing right off the bat what color = what temperature)? Trying to make each knife just a little better than the last Link to comment Share on other sites More sharing options...
jake cleland Posted October 23, 2013 Share Posted October 23, 2013 short answer: no. how your eye perceives incandescent colour is different from how it perceives hue. that said, bright yellow is about what you're looking for, with the flux bubbling and dancing on the surface like melting butter, and you can get a good indication by using a piece of steel wire - touch it to the fluxed steel in the forge when you think it's hot enough, and when you feel it stick just from contact, you know you're in the ballpark. after that you need experience to know how long to soak, whether to go hotter, etc... Jake Cleland - Skye Knives www.knifemaker.co.uk "We can't solve problems by using the same kind of thinking we used when we created them." "Everything should be made as simple as possible, but not simpler." "Two things are infinite: the universe and human stupidity; and I'm not sure about the the universe." Albert Einstein Link to comment Share on other sites More sharing options...
GEzell Posted October 23, 2013 Share Posted October 23, 2013 Interesting fact: the higher the carbon content of the steel, the lower the temperature needed to weld it together. Heat the steel up to a dull red and add flux (20 mule team borax works good), you want a good coat of melted flux over the surface. When it reaches a bright yellow heat, take it to the anvil and hammer it together. Work fast, but not hasty. Expect red hot flux to go flying, wear a leather glove on your tongs hand and a leather apron if possible. Don't worry about using too much force, just go over the entire surface to be welded, starting in the middle and working outwards. When it drops down to a red heat, wire brush it, re-flux it, and put it back into the forge to heat back up. Repeat. Repeat again, and this time strike it along the seam to see how well it is holding together, hitting a weld 'on edge' will quickly let you know if the weld was successful or not. If it is holding together well, at this point no more flux is needed, but it is advisable to work the welded section at welding temperatures from here on out. After you are finished forging, give it a few normalizing cycles to get the grain back down to size. George Ezell, bladesmith" How much useful knowledge is lost by the scattered forms in which it is ushered to the world! How many solitary students spend half their lives in making discoveries which had been perfected a century before their time, for want of a condensed exhibition of what is known."Buffonview some of my work RelicForge on facebook Link to comment Share on other sites More sharing options...
Freya W. Ward Posted October 23, 2013 Share Posted October 23, 2013 Never judge forge temp via unprotected eye. Especially when trying to weld, When I'm forging I wear shade 2 welding glasses which makes the color of the forge even at welding temp register at a dull orange. What Jake said about the flux bubbling is what I find to be the most reliable judge, after that's it all comes down to experiance. I'd like to respectfully disagree with George about the gloves though, I've had more times than I'm willing to count, a glob of hot flux getting lodged under the glove next to my skin, if I'm not wearing gloves, it may pop me in the arm or hand, but usually bounces off. Tight fitting gloves and a long sleeve shirt that you're willing to ruin is much less unpleasant. I do love my welding apron though... <a href="http://darkfireforge.mymiddleearth.com/darkfire-forge/">Darkfire Forge</a> Link to comment Share on other sites More sharing options...
Caleb Harris Posted October 23, 2013 Author Share Posted October 23, 2013 What sort of project should I do for practice? I've got 02 steel (gift from another smith), low-carbon nail from the 1800s that'd make a good spine, and lots of old dull files. Trying to make each knife just a little better than the last Link to comment Share on other sites More sharing options...
Alan Longmire Posted October 23, 2013 Share Posted October 23, 2013 (edited) If you want to find out if it will get hot enough to weld a hawk, use mild steel from the hardware store with a piece of file in the middle. Grind them all clean first, wire them together, flux at a low red heat, then let 'em sit in the forge until you're sure it's hot all the way to the middle. If it's hot enough for the file to start throwing a spark every so often you're golden. That means you're getting almost hot enough to weld wrought iron. If it doesn't ever get hot enough for the file to throw a spark you can still possibly weld high carbon to low carbon. The key is as George said, firm taps at first. If you haul off and whang it hard you'll just blow the flux all over the place and make the layers slide across each other, shearing the weld as it happens. Last weekend at Bowie's hammer-in I was not sure the forge I was using would get hot enough to weld mild-to-mild, since that welding temp is a couple hundred degrees hotter than high carbon (again see George above). A hawk head is a big hunk of steel to get hot all at once, and when it was clear the forge was putting out all it could do it was just bright yellow. I like to be able to melt steel in a forge, and while this one clearly wasn't going to allow that to happen it did get just hot enough for the 1018-to-1018 weld to work. The 1084 to 1018 weld is never a problem, you can do that at a low yellow if your steels are clean enough. As mentioned above, the flux should look like molten honey on hot bread before you even think of trying to weld. Finally, if the forge atmosphere is too oxidizing you may have trouble welding even if the heat is there. Borax fluxes by scavenging oxygen from the surface of the steel and keeping the scale liquid. If there's too much oxygen in the forge the borax gets exhausted before it's hot enough to weld. Unfortunately the only way to figure that out is to try it and see. If your forge really makes a LOT of scale that's a clue it's too oxidizing, but it may still work. Leave the O2 and the nails for future projects after you've developed more skills. For that matter, I wouldn't try to weld with the O2 myself. High alloy tool steels are very finicky indeed, especially if mixed with simple steels. Edited to add: If your simple sandwich of mild/file/mild works, you will have a nice chunk of sanmai to make a blade from! Edited October 23, 2013 by Alan Longmire Link to comment Share on other sites More sharing options...
Caleb Harris Posted October 23, 2013 Author Share Posted October 23, 2013 Thank you!! I'll try that out! Trying to make each knife just a little better than the last Link to comment Share on other sites More sharing options...
Caleb Harris Posted October 23, 2013 Author Share Posted October 23, 2013 If you want to find out if it will get hot enough to weld a hawk, use mild steel from the hardware store with a piece of file in the middle. Grind them all clean first, wire them together, flux at a low red heat, then let 'em sit in the forge until you're sure it's hot all the way to the middle. If it's hot enough for the file to start throwing a spark every so often you're golden. That means you're getting almost hot enough to weld wrought iron. If it doesn't ever get hot enough for the file to throw a spark you can still possibly weld high carbon to low carbon. The key is as George said, firm taps at first. If you haul off and whang it hard you'll just blow the flux all over the place and make the layers slide across each other, shearing the weld as it happens. Last weekend at Bowie's hammer-in I was not sure the forge I was using would get hot enough to weld mild-to-mild, since that welding temp is a couple hundred degrees hotter than high carbon (again see George above). A hawk head is a big hunk of steel to get hot all at once, and when it was clear the forge was putting out all it could do it was just bright yellow. I like to be able to melt steel in a forge, and while this one clearly wasn't going to allow that to happen it did get just hot enough for the 1018-to-1018 weld to work. The 1084 to 1018 weld is never a problem, you can do that at a low yellow if your steels are clean enough. As mentioned above, the flux should look like molten honey on hot bread before you even think of trying to weld. Finally, if the forge atmosphere is too oxidizing you may have trouble welding even if the heat is there. Borax fluxes by scavenging oxygen from the surface of the steel and keeping the scale liquid. If there's too much oxygen in the forge the borax gets exhausted before it's hot enough to weld. Unfortunately the only way to figure that out is to try it and see. If your forge really makes a LOT of scale that's a clue it's too oxidizing, but it may still work. Leave the O2 and the nails for future projects after you've developed more skills. For that matter, I wouldn't try to weld with the O2 myself. High alloy tool steels are very finicky indeed, especially if mixed with simple steels. Edited to add: If your simple sandwich of mild/file/mild works, you will have a nice chunk of sanmai to make a blade from! Oh, and mild steel, would RR spikes count as mild? They're around .3-.4% carbon. What percentages define "mild"? Trying to make each knife just a little better than the last Link to comment Share on other sites More sharing options...
Freya W. Ward Posted October 23, 2013 Share Posted October 23, 2013 Real mild steel is a member of the 10xx series. 1018 is roughly .18% carbon. <a href="http://darkfireforge.mymiddleearth.com/darkfire-forge/">Darkfire Forge</a> Link to comment Share on other sites More sharing options...
Alan Longmire Posted October 23, 2013 Share Posted October 23, 2013 "mild" is usually less than 0.3%, usually defined as 1020, 1018, or A36. Spikes have a good bit of silicon and copper added for toughness and corrosion resistance, so they are techically a low-alloy steel, but they will work. Just make sure they are the same size and shape as the file part you use. Billets work best when all the parts are the same size in all ways except thickness. Link to comment Share on other sites More sharing options...
Alan Longmire Posted October 23, 2013 Share Posted October 23, 2013 Oh yes, and if you want to make a sanmai blade out of it, let the softer steel be thinner than the core steel. If you try it you'll see why. Link to comment Share on other sites More sharing options...
Caleb Harris Posted October 24, 2013 Author Share Posted October 24, 2013 Well, I just spent the last few hours trying to weld some rebar to an old file. Either too many impurities in the rebar, or I'm not hot enough. I'll try again once I get some better mild. Trying to make each knife just a little better than the last Link to comment Share on other sites More sharing options...
Caleb Harris Posted October 24, 2013 Author Share Posted October 24, 2013 Could you confirm the following? Clean up the flat billets and wire them together. Start heating up in forge and once I get to a red, brush off impurities and flux. Heat up to welding temp and give firm taps to set the weld. Trying to make each knife just a little better than the last Link to comment Share on other sites More sharing options...
Alan Longmire Posted October 24, 2013 Share Posted October 24, 2013 Flux at red before scale forms, then no need to brush. Link to comment Share on other sites More sharing options...
Caleb Harris Posted October 24, 2013 Author Share Posted October 24, 2013 Flux at red before scale forms, then no need to brush. OH ok. Thanks. Trying to make each knife just a little better than the last Link to comment Share on other sites More sharing options...
Caleb Harris Posted October 24, 2013 Author Share Posted October 24, 2013 And is there a more reliable way to hold the steel than wire? Would folding the soft over the hard, work? Trying to make each knife just a little better than the last Link to comment Share on other sites More sharing options...
Ondřej Borský Posted October 24, 2013 Share Posted October 24, 2013 I usually weld the ends together using an electrode welder. But when I started, I used wires... I always welded the tip, and when that was done, wires were no longer needed... Link to comment Share on other sites More sharing options...
Caleb Harris Posted October 25, 2013 Author Share Posted October 25, 2013 VICTORY!! I wired it up and followed Ondrej's advice. The bar is only about five inches long, and one piece of mild just failed, but the other piece of mild and the high stuck, and the last inch or two has been successfully welded. Thank you all so much!! This has been my first successful weld! Trying to make each knife just a little better than the last Link to comment Share on other sites More sharing options...
GEzell Posted October 28, 2013 Share Posted October 28, 2013 Here you go... George Ezell, bladesmith" How much useful knowledge is lost by the scattered forms in which it is ushered to the world! How many solitary students spend half their lives in making discoveries which had been perfected a century before their time, for want of a condensed exhibition of what is known."Buffonview some of my work RelicForge on facebook Link to comment Share on other sites More sharing options...
Doug Lester Posted October 28, 2013 Share Posted October 28, 2013 The only problem that I have with those charts is than ambient lighting will effect them. I have never seen red in my steel at my forge. It's always some shade of orange until it reaches yellow and it's different on a bright day than a cloudy day. Let the steel tell you when it's ready. Doug HELP...I'm a twenty year old trapped in the body of an old man!!! Link to comment Share on other sites More sharing options...
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