Sam Salvati Posted December 24, 2007 Share Posted December 24, 2007 Would this work? 1" thick inswool/kaowool coated with satanite refractory all around the inside, burner port at one end, with a fire brick in fornt of the flame to disperse/baffle the heat, with the blades never extending over the firebrick and flame itself. ID is 10 inches, would this be suitable for heating blades nice and even to the proper temperature? I would use just the PSI valve to control the heat with a thermocouple to measure how hot inside it is and control it from there. I know it wouldn't be as good as salts or an electric oven or kiln, a bit oxidysing, maybe a bit uneven heat but much more ideal than using just the forge. Quote Link to comment Share on other sites More sharing options...
habu68 Posted December 24, 2007 Share Posted December 24, 2007 here is a link to a heat treating company and a stainless steel bag that they use to keep oxygen form de-carbonizing parts http://www.nabertherm.com/produkte/waermebehandlung/waermebehandlung2_englisch.pdf you might find some ideas there. Check out pages 8 and 9 Quote Link to comment Share on other sites More sharing options...
RainsFire Posted December 24, 2007 Share Posted December 24, 2007 seems kinda deep with alot of wasted space, unless the blade is proportionate to a smaller blade.. but I'm assuming it is a full length-28in +/- so ya.. Don-fogg has a controlled propane heat treating furnace, but I cant remember what it looked like. wouldn't the blueprint for the tube furnace or whatever it was where the burner blasted down the length of the forge instead of through the side work relatively well also? anyway, nice rough design! Quote Link to comment Share on other sites More sharing options...
John Martin Posted December 24, 2007 Share Posted December 24, 2007 Why not make the furnace smaller so that it needs less heat and you waste less propane/natural gas/energy. Anyhow, it's a nice design. What would you use for a shell to put the kaowool in? Quote Link to comment Share on other sites More sharing options...
RainsFire Posted December 24, 2007 Share Posted December 24, 2007 exactly what I was thinking^^ I have a feeling he would just lay the kaowool in place to be held down by the refractory(which you might want to do without if possible). Refractories are usually more just as a protection from flux, and I have found kaolwool to distribute and achieve heat faster than firebrick and satanite refractory. cool stuff man. you might also want multiple burners too..I dont know how you would engineer that, but ya.. more heat disperesed. Quote Link to comment Share on other sites More sharing options...
RainsFire Posted December 25, 2007 Share Posted December 25, 2007 yes well, theres the dillema.. even your design will have a hot spot near the rear of the furnace.. that fire brick will absorb alot of the heat, and the entry (front) will be a considerable ammount cooler. really, you need more than one burner to disperse the heat more evenly. As you've said, you do not want to heat with the flame, but it is nearly un-avoidable with this sort of system. If you had a seperate air heating furnace that circulated the heat through the box at high temps, thats different.. but highly un-efficient, and you could just as easily be using salts.. seriously check out Don foggs.. I'll root around for the picture. Quote Link to comment Share on other sites More sharing options...
welder19 Posted December 25, 2007 Share Posted December 25, 2007 How about like this, please excuse the rough drawing, I just sketched it up real quick in paint, I think it would heat more evenly but 2 burners might be better. welder19 Quote Link to comment Share on other sites More sharing options...
drogo Posted December 25, 2007 Share Posted December 25, 2007 why use a forge burner at all. if you are just trying to back temper(heat treat) why not use a burner for a gas grill. they cost less than making a burner and give off a large eaven heat. just my .02 Quote Link to comment Share on other sites More sharing options...
Ian Posted December 26, 2007 Share Posted December 26, 2007 Why not make an electric heat treating oven? In fact I thought a lot of knife makers used a normal domestic oven to heat treat? If you can get the guts of one a simple kiln type box around lightweight refractory bricks would work well IMO. The refractory bricks are much better than the standard refractory in a cooker so it would probably get a lot hotter too, but remain 'dialable'. I've seen designs somewhere for a really nice electric furnace on the net. Think it was one of the british knife forums. Quote Link to comment Share on other sites More sharing options...
welder19 Posted December 26, 2007 Share Posted December 26, 2007 I don't know as though a grill burner would give the heat needed here but you could actually make a burner similar to them but much more high performance, you could make it the appropriate length for you "oven" and have it put out a lot more heat, larger holes more gas and more air. You could definitely get a more even heat with that style burner, as far as them being cheaper.....that I guess depends on where you shop and how much you can scavenge up, I've build somwhere around 8-10 propane burners and have yet to spend a dime....not trying to brag or rub it in anyone's face. just making the point that if you srounge around enough you can do almost anything with very little or no $. welder19 Quote Link to comment Share on other sites More sharing options...
case Posted December 26, 2007 Share Posted December 26, 2007 British Blades :: Custom Knives - How to Build a Heat-Treat Furnace - Page 1 here you go. Quote Link to comment Share on other sites More sharing options...
HWooldridge Posted December 26, 2007 Share Posted December 26, 2007 Have you thought about a salt bath for both quenching and tempering? I'm told the results are very repeatable and reliable with almost no decarb issues. Quote Link to comment Share on other sites More sharing options...
Ian Posted December 26, 2007 Share Posted December 26, 2007 Thanks for posting that Case, exactly the one I was thinking of :D Quote Link to comment Share on other sites More sharing options...
dragonflySmithy Posted April 27, 2008 Share Posted April 27, 2008 One thing that you could do to help controll the build up of scale is to put a choke plate on the buner and run a slightly rich flame. For the little bit of scale that will form you can get most of it off by soaking it in white vinagar for a few days. then take it out and rinse it off with lots of water and a 3M pad ie green scruby. Quote Link to comment Share on other sites More sharing options...
simonsch Posted September 27, 2009 Share Posted September 27, 2009 Hello, I am an new member of your community. Started as blacksmith demonstration for an museum for 1 day last april. So, I hope to learn a lot of knowlets about forging. Best regards, Simonsch Quote Link to comment Share on other sites More sharing options...
Frosty Posted September 27, 2009 Share Posted September 27, 2009 Welcome aboard Simonsch, glad to have you. The blacksmithing bug can get you pretty easy alright, a one exposure infection is not uncommon. It's okay though, you're in good company, most of us here are addicted to blacksmithing, I have been since I was a kid and there are no signs I'm getting over it. Anyway, there is plenty of good reading here, check out the getting started and lessons in blacksmithing in the "Blueprints" section. They'll help you get a shop set up and provide some good exercises to help you learn the craft. Frosty Quote Link to comment Share on other sites More sharing options...
pkrankow Posted September 28, 2009 Share Posted September 28, 2009 I was going to suggest something like an electric pottery kiln, but that heat treat furnace design Case suggested is much nicer. I was poking about on the linked website, BCS - Budget Casting Supply, and the prices look reasonable, but will cost more than your gas set up. Good luck. Phil Quote Link to comment Share on other sites More sharing options...
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