Snakes the Clown Posted December 20, 2008 Share Posted December 20, 2008 (edited) Hello everybody! A little background on myself: I have been working in my dad's welding shop for the past 9 years, and have been welding for 7 of them (since I was 13). Blacksmithing and forge work represents the more enjoyable aspects of this line of work and I hope to have my first gas forge running in the new year, funded by Christmas money. The main line of questions I have at this point relates to the volume of my forge and the type of burner needed to get up to welding temperatures. My idea, at this point, is taking a 9 inch dia. piece of 1/8th wall pipe, 12 inches long. I plan on welding an 1/8 inch thick end cap, and usinging 2, 1-inch layers of kaowool at the end and to layer the sides, plus a refractory coating. According to my calculations this will leave me with an internal volume of approxamatly 196.25 cubic inches (minus the piece of kiln shelf or fire brick which goes into the bottom. Question one: which burner would be suitable to heat this to welding temps and would it still be useable for general forging? EDIT: I want to make a burner which is powered by the pressure of the gas for the gas/air mixture process (venturi?), as I would prefer not to have to depend on an electric motor. Question two: I've read that the exhaust to input ratio is 7:1. How is the input determined? As I understand things currently, the input would be the 2-inch burner holder. Or would it be the area of the burner nozzle itself? Going with the 2-inch input, my 5-inch opening falls just short of the 7:1, probably a little bit more than I realize due to the variability of the thickness of the refractory lining, but in either case should not fall short by much more than a square inch too small. How crucial is the 7:1 ratio, will too big/too small cause the forge to loose efficiency? I have a fair amount of wiggle room when it comes to dimensions, so I could easily increase the diameter pipe used. Whew. It just seems to keep going doesn't it? Well thanks for reading so far, I hope you keep up, because I can certainly use all the help I can get. The second line of questioning I have regards the opperation of a propane forge inside a shop. I read somewhere that opperating a propane forge inside a building is illegal in North America. Is this true? If it is not, then what precautions can be taken, in particular to avoid carbon monoxide poisoning? My dad owns a fairly large shop with a large adjacent bay. Is it possible to negate the dangers of CO poisoning through airflow alone, given a large enough volume of the shop space, or is venting to the outside a necessity? Anyway, that's it for now, I appreciate you're time spent reading this long (and possibly confusing) post. Any and all advice welcome! Edited December 20, 2008 by Snakes the Clown Adding info Quote Link to comment Share on other sites More sharing options...
Frosty Posted December 20, 2008 Share Posted December 20, 2008 Welcome aboard Snakes the Clown. The forge you describe is going to be of limited use judging by the shape I'd say you want to make blades. It's also going to be a bit problematic to get an even heat in such a long narrow volume. A more regular shape of the same volume would be over gunned with a single 3/4" naturally aspirated / venturi (though a venturi has absolutely nothing to do with one of these) or atmospheric (to use the more common names) burner. Distribution of the heat is important and to get an even heat in a volume that long and narrow you'd probably need to build two or even three small, 1/2" maybe burners and the smaller the diameter the burner the harder it is to get tuned. I'd suggest you build your forge from 12" dia. SS stove pipe as long as you need. Line it with 2 wraps of 1" 8oz. Kaowool, Insulwool, etc. Use a 3,000f kiln shelf for the floor and coat the whole thing with ITC-100. Assuming you go with the 12" length this will give you a volume of approx. 600 cu/in. which is near perfect for two 3/4" naturally aspirated burners which are easy to tune. It's the most popular size for the general smithing crowd so there's lots of info about building, tuning and trouble shooting this size. Don't worry about the intake to exhaust ratio, you can simply open the door a little more if back pressure is too great. The rule of thumb burner diameter to volume ratio is 1 ea 3/4" burner to every 350 cu/in volume. A properly built and tuned burner will reach welding heat in this ratio depending on some variables like altitude, humidity and ambient temp. And yes, you must provide proper ventilation or CO will be a problem, possibly fatally so. Whoever told you North America outlawed a gas burning appliances inside a building was making it up. That or my Viking range was sold to me illegally! There are however some pretty strict regulations about using a HOME MADE gas fired appliance almost anywhere so be very careful when the fire martial or insurance agent is visiting. Lastly if you'll click on "User CP" at the top of the page and edit your profile to show your location you'll find folk living close enough to visit. Nothing will get you up to speed faster than having someone show you how to hold your tongue when you do a thing. Frosty Quote Link to comment Share on other sites More sharing options...
Snakes the Clown Posted December 20, 2008 Author Share Posted December 20, 2008 Many thanks! So I know I'm up to speed here, I have a piece of 12" dia pipe with an over all length of 14" to account for the two layers of Kaowool at the back. Inside diameter would be 8" then. And the whole thing runs on two 3/4" burners now. Excellent! I am researching info on the EZ Burner right now, I will be sure to post any more questions I have. Quote Link to comment Share on other sites More sharing options...
Frosty Posted December 20, 2008 Share Posted December 20, 2008 You're very welcome. Sounds like you have the idea. While you're checking out Ron's EZ burners take a look at the Side Arm and my "T" burners. You can find pics and description of mine by searching IFI with "T" Jet burner. Larry Zoeller sells forges, kits, Modified Side Arm burners, kits, parts, supplies, etc. for reasonable. Zoeller Forge Home Page Gas Forge parts, Atmospheric Burners, and Blacksmithing Jay Hays also sells forges, kits, burners, etc. Jay Hayes C.J. Products Inc. Phone: (304) 269-6111 (10 AM -10 PM EST) 100 Christmas Place New Email: jay@hrea.coop Weston, WV 26452 My only association with these fine folk is building forges, burners, etc. Frosty Quote Link to comment Share on other sites More sharing options...
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