VaughnT Posted April 4, 2010 Share Posted April 4, 2010 After a long, long time away, I've decided to get back into working metal. Lots has changed since I last pounded iron! Due to space constraints, I'm starting small with knife-making and would like to build a small propane forge for heat-treating. I was thinking about something with a finished chamber measuring 8" by 14". Big enough for the biggest blade I might attempt, but not too big for the majority of small, utilitarian blades I'll be turning out. Is this a good idea if the majority of my work will be one or two blades at a time, and only 1% of those blades being about 12" AOL? If I make a pass-through on the rear wall, could I use this down the road for forging? Is it too much space to heat at a reasonable cost using small propane tanks commonly used for barbeque grills? And, most importantly, can I use this http://www.northerntool.com/shop/tools/product_266859_266859 to fire the forge? It's great for burning weeds and ant hills, and I've used it to anneal a few leaf springs, but how would I go about fastening it to a forge body? Can I simply make a hole and stick the can through to the chamber? Of course, maybe the safest option would be to simply buy one someone a lot smarter than me has for sale..... :D Quote Link to comment Share on other sites More sharing options...
Fe-Wood Posted April 4, 2010 Share Posted April 4, 2010 The chaimber your thinking about is WAY to big for that burner and that burner may not function properly in an inclosed environment such as a forge because of the back pressure produced. I would suggest bying one, for now. Have fun and post pictures....we love pictures :D Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted April 5, 2010 Share Posted April 5, 2010 8" is a fairly good sized forge for a propane knifemakers. You probably need at least two burners. Note that weed burners are not built to be choked and so run way oxidizing that is a BAD thing for blademaking. Burners are pretty simple to build from plumbing parts; especially blown burners that tend to have higher heat outputs but tie you to a power source. I'd suggest more web research to see what folks are commonly using out there. I currently have an aspirated forge, a blown forge and am building a ribbon burner forge, (burner done working on a flux proof forge liner now) Quote Link to comment Share on other sites More sharing options...
VaughnT Posted April 5, 2010 Author Share Posted April 5, 2010 Oh, I just knew it couldn't be easy! I'm keeping my eye open for a cylinder that looks right and will go from there when I get it. What is "...way oxidizing..." and why is it bad for bladesmithing? On a scale of 1-10, how bad is it? What's it doing to the steel? Is it recoverable? Quote Link to comment Share on other sites More sharing options...
pkrankow Posted April 6, 2010 Share Posted April 6, 2010 What is "...way oxidizing..." and why is it bad for bladesmithing? On a scale of 1-10, how bad is it? What's it doing to the steel? Is it recoverable? eleven It removes the carbon from the steel, and causes the steel to turn to scale. Together this makes your part "go away" and what is left has a thick de-carb layer that needs ground away. You want a "neutral" to "slightly oxidizing" atmosphere with a burner that can be choked. Check out http://www.zoellerforge.com/flare.html http://ronreil.abana.org/design1.shtml here's what I use Phil Quote Link to comment Share on other sites More sharing options...
don't tread on me Posted May 6, 2010 Share Posted May 6, 2010 Go to ebay and tipe in blacksmith gas forge. That is where I got mine. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted May 6, 2010 Share Posted May 6, 2010 Well it's a perfectly marvelous way of turning expensive tool steels into cheap heavily pitted mild steels *and* greatly increase the time you have to spend grinding. Almost anything can be recoverable; I can take scale and make wrought iron from it and take wrought iron and make steel from it. Of course you are talking about spending *MANY* *TIMES* as much money on doing so than you can buy good new steel for---but it can be done. If you are interested in bladesmithing it will help greatly to get your forge as well tuned as you can. Saves time, steel, fuel, grinding and finishing media, frustration! Quote Link to comment Share on other sites More sharing options...
VaughnT Posted May 7, 2010 Author Share Posted May 7, 2010 Good news! I appreciate all the input and have ceased using the propane torch to heat the blades. Thankfully, the only time it was used was to straighten the leaf springs so I shouldn't have to worry about ruining anything. And, I've finally come across a steel tube big enough to make something out of. It's a piece of heavy-wall pipe from the local water/sewer company, proving once again that it's good to know people. It measures 8" ID and 28" OAL, with a cut partially through that will yield me a piece approx 15" long. Good enough for knives once I block off the ends. The walls are 1/4" thick, and they said it was weldable steel. With an inch+ of insulating wool and refractory, I'm expecting to get a chamber that's about 5 1/2" in diameter. Two burners? I'm thinking of going with a forced-air system for better temperature control and propane savings. What say ya'll? Quote Link to comment Share on other sites More sharing options...
Sweany Posted May 11, 2010 Share Posted May 11, 2010 Quote Link to comment Share on other sites More sharing options...
VaughnT Posted May 12, 2010 Author Share Posted May 12, 2010 Thanks for the link, Sweany. Read it all the way through and still at a loss. Talked with one guy and he seems to think that the 8" ID will be too small after insulating for proper gas circulation. But, I see a lot of forges with 4" chambers.... Maybe I should just go ahead and buy one that's ready to light! Quote Link to comment Share on other sites More sharing options...
Sweany Posted May 12, 2010 Share Posted May 12, 2010 one of my favorite forges was built out of a mailbox. I cut half the top away and used the remaining bottom as a stock rest. I used an old SS travel cup for the exhaust/pass door in the back. Lined it kwool (the wet kind) and covered the bottom with Blu-ram. it was powered by a 1/2" side arm burner. It wasn't for welding, just small stuff http://www.zoellerforge.com/sidearm.html You just need to size the burner to the forge box. Zoeller has some very good info on his site. The Kiln and Forge Burner book is very informative also. Google,gas forges and spend a bit of time reading up on it. Quote Link to comment Share on other sites More sharing options...
newbladesmith Posted May 12, 2010 Share Posted May 12, 2010 i've seen forges made from old propane tanks, and mine is an old coffee can that is actually perfect for making knives. I found out that if you have it insulated enough it heats to forge welding temp with the rite burner. the burner i use is actually a burns-o-matic blow torch head. It's self lighting and has it's own air feed for an atmospheric forge. The one that i have is designed for mapgas, but i did some research and found out that it worked fine with propane. With the size you're talking about i'd use two of them. one on each side facing opposite directions. one should be in the front and the other should be in the back. hope i helped. Quote Link to comment Share on other sites More sharing options...
Sweany Posted May 13, 2010 Share Posted May 13, 2010 i've seen forges made from old propane tanks, and mine is an old coffee can that is actually perfect for making knives. I found out that if you have it insulated enough it heats to forge welding temp with the rite burner. the burner i use is actually a burns-o-matic blow torch head. It's self lighting and has it's own air feed for an atmospheric forge. The one that i have is designed for mapgas, but i did some research and found out that it worked fine with propane. With the size you're talking about i'd use two of them. one on each side facing opposite directions. one should be in the front and the other should be in the back. hope i helped. That would work for a coffe can, I believe you would be hard pressed to do any serious work in the larger forge with two propane torchs. Quote Link to comment Share on other sites More sharing options...
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