newbladesmith Posted January 18, 2010 Share Posted January 18, 2010 This is a knife I'm making on commission. It will be my first fully made hand forged blade. A friend of mine saw some of the practice blanks that I was working on and decided that he wanted one. I still have to polish and temper it, put on a handle, and finish making the sheath, but i wanted to put a pic of it up now to get peoples opinions. I'll put a picture up when I'm finished but like i said i wanted opinions on it so far. Also i had to move and my coal forge was a sacrifice i had to make for the move. I'm trying to put together a mini propane forge and i was wondering if i could use refractory cement without the kaowool. I can get my hands on it in my town but I'm on a limited budget and would like to get along without it if i can. Any info would be nice. Thanks. Quote Link to comment Share on other sites More sharing options...
reefera4m Posted January 19, 2010 Share Posted January 19, 2010 Welcome newbladesmith! Nice design and a good start. A couple of thoughts. By tempering i hope you mean the whole heat treating cycle, i.e. 'normalizing', 'hardening/quenching' and finally 'tempering'. Tempering is meant to 'relax' and take away some of the brittleness that might have been created during the hardening/quenching cycle. Tempering alone will just leave you with a soft blade. I wouldn't use refractory cement alone. A 1" layer of ceramic wool will provide a LOT more insulation that a 1" layer of refractory cement. However, coating the ceramic wool with several thin layers of refractory cement has a number of benefits; 1) prevents the ceramic wool fibers from getting into the air (and your lungs), 2) protects the ceramic wool from damage, 3) provides a base for later layers of ITC-100 (a lining clay that reflects heat back into the forge increasing the maximum temperature possible and reducing the time to reach temp. I've attached a MS Word document that provides a list of materials/tools, photos, illustrations and instructions on how to build a small propane forge for between $20 - $40. I've also attached a document on basic heat treating. Keep asking questions, there is lot's of great information here.My linkVenturi Propane Forge.docHeat Treating 101.doc Quote Link to comment Share on other sites More sharing options...
newbladesmith Posted January 19, 2010 Author Share Posted January 19, 2010 i was going to normalize the blade several times. but the heat treating process i was going to use was going to be a bit different. i was intending to clay "temper" it. this is why the spine is curved. because according to all the studying that i have done the clay "tempering" process will make the spine curve up and if you want a straight spine you need to give it a downward curve before you heat and quench it. Thanks for your help. I do know that the wool would insulate it better, and other than the welder i am buying next week and the wool i have all the parts for my forge. i was just wondering if it was possible to use just the cement. What i have is Hercules regular body high heat furnace cement. on the back it says it's acid resistant so i hope that it at least takes a while for my flux to eat through it. I was thinking about giving it a three inch lining and using this extremely small forge, (small coffee can design) until i can get the parts to build a permanent propane forge in whatever shop i can find to use in my area. again thanks for the help and please keep the advice and the opinions on the knife so far coming. i really appreciate all the input. Quote Link to comment Share on other sites More sharing options...
reefera4m Posted January 21, 2010 Share Posted January 21, 2010 i was going to normalize the blade several times. but the heat treating process i was going to use was going to be a bit different. i was intending to clay "temper" it. this is why the spine is curved. because according to all the studying that i have done the clay "tempering" process will make the spine curve up and if you want a straight spine you need to give it a downward curve before you heat and quench it. Thanks for your help. I do know that the wool would insulate it better, and other than the welder i am buying next week and the wool i have all the parts for my forge. i was just wondering if it was possible to use just the cement. What i have is Hercules regular body high heat furnace cement. on the back it says it's acid resistant so i hope that it at least takes a while for my flux to eat through it. I was thinking about giving it a three inch lining and using this extremely small forge, (small coffee can design) until i can get the parts to build a permanent propane forge in whatever shop i can find to use in my area. again thanks for the help and please keep the advice and the opinions on the knife so far coming. i really appreciate all the input. Newbladesmith, Funny you should be using the Hercules brand of furnace cement - that's exactly what I used to cover my ceramic wool. My experience, and others I've read about elsewhere, is that doesn't hold up well when applied in thick layers. This is especially true if you don't dry it slowly using very low heat. What you'll find will happen is that the first time high heat is used any residual moisture left inside the cement will turn to steam and crack it all to pieces. That happed to me the first time I tried it. I ended up thinning the cement with a little water and applying several thin layers, drying each layer thoroughly before applying the next one. The more layers I applied the fewer cracks occured and what cracks did occur I filled in with more cement. Eventually I was able to get a crack free surface. Applying a couple layers of ITC-100 on top of the cement seems to help it stay that way. Quote Link to comment Share on other sites More sharing options...
newbladesmith Posted January 21, 2010 Author Share Posted January 21, 2010 OK. two questions that prove my ignorance. 1. how do you suggest heating the cement, and 2 what is ITC-100 thanks again for the info and advice. I'm probably going to go get the wool on Monday, but i was wondering, if i did use nothing but the cement, and just applied it in thin layers, would that work or would it just crack and fall apart. i am going to use the wool but now I'm just curious. I'm just not curious enough to go through all the labor of doing it just to see that it in fact doesn't work. i was also wondering about sandpaper. i can't find anything over 220 grit around here and i actually wanted to take it up to 3000 grit like one bladesmith i use to know. is there a good, inexpensive website where i could order it? Quote Link to comment Share on other sites More sharing options...
newbladesmith Posted January 21, 2010 Author Share Posted January 21, 2010 oh. one more thing. what should i use to spread the cement. a putty knife or something along those lines, or just put on a rubber glove and use my hand. Quote Link to comment Share on other sites More sharing options...
nonjic Posted January 22, 2010 Share Posted January 22, 2010 if you just use the cement it will take forever to heat up, and the outside of the forge will end up extremely hot! You perhaps need to read up on heat treating a little more. You are confusing some of the basic terms. Tempering is the last bit of the heat treat process, heating to about 200C after you have quenched, to 'relax' the steel. You can put clay on the back of the blade before you quench it, this leaves the back of the knife soft steel. you still need to temper it after quenching. Your photo is to big to see! perhaps re-size it - I would smooth the blade out before you heat treat it, its 10x easier when the steel is still soft! Look forward to seeing it finished! Quote Link to comment Share on other sites More sharing options...
reefera4m Posted January 22, 2010 Share Posted January 22, 2010 OK. two questions that prove my ignorance. 1. how do you suggest heating the cement, and 2 what is ITC-100 thanks again for the info and advice. I'm probably going to go get the wool on Monday, but i was wondering, if i did use nothing but the cement, and just applied it in thin layers, would that work or would it just crack and fall apart. i am going to use the wool but now I'm just curious. I'm just not curious enough to go through all the labor of doing it just to see that it in fact doesn't work. i was also wondering about sandpaper. i can't find anything over 220 grit around here and i actually wanted to take it up to 3000 grit like one bladesmith i use to know. is there a good, inexpensive website where i could order it? To 'dry' the cement I used a heat gun on low (the Wagner brand made for stripping paint). Others use hair dryers. Just go 'low and slow'. ITC-100 is a refractory clay (comes in 1/2 pints) that needs to be quite thin to apply (thinned with plain water). The manufacturer recommends applying with a sprayer but I don't know anyone that does - most, me included, use a small paint brush. ITC-100 reflects heat back into the interior of the forge, helping to increase heat/reduce the time to get to temperature. Using an ITC-100 coating will increase the lifespan of the ceramic wool considerably. This also helps keep the heat from migrating to the forge body - something you'll find important. I believe John N is correct, cement alone won't provide the insulation you'll need to get and keep the forge hot enough. The 3000 degree temperature rating for the cement is the temp that the cement will withstand without burning up - not the 'insulation' value. It would work to a certain degree but I think you'd need at least a 2"-3" thick coating. If you want sandpaper of finer grit try your local auto supply store (O'Reillys/Schucks) carries up to 1000 grit. Specialty autobody stores carry the finer grits. After 1000 grit you're better off using a polishing compound. However, after doing one at 1000 grit, I think you find that a 400 grit finish works better :P Quote Link to comment Share on other sites More sharing options...
newbladesmith Posted January 22, 2010 Author Share Posted January 22, 2010 yeah. i saw that the pic was too big. the problem is that i have absolutely no idea how to re-size it. i don't really know much about computers. just how to use them a little without killing them. i can make chainmaille, sew, cook, make archery equipment, just about anything pre-modern, that i can think of i can figure out how to do, but the whole modern technology computer thing completely escapes me. Quote Link to comment Share on other sites More sharing options...
newbladesmith Posted January 23, 2010 Author Share Posted January 23, 2010 ok. here is the resized pic. soon i'll be putting up a new pic because it dosn't look exactly like this any more. i took 180 grit sand paper to it. made a huge difference, at least to me. Quote Link to comment Share on other sites More sharing options...
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