ForgeMan32 Posted January 31, 2015 Share Posted January 31, 2015 How far should the burner stick past the kaowool Quote Link to comment Share on other sites More sharing options...
timgunn1962 Posted January 31, 2015 Share Posted January 31, 2015 It really depends on the burner, the forge, and what you are doing with it, but as a general rule, it shouldn't. Usually the burner is recessed into the Kaowool and in some cases, the Kaowool and its coating are formed to make a burner flare. Quote Link to comment Share on other sites More sharing options...
Frosty Posted January 31, 2015 Share Posted January 31, 2015 Keep the burner OUT of the fire chamber or it'll just burn right off. Don't insert the burner any farther into the forge liner than you have to. A good kiln wash to harden it and raise it's temperature rating will make the Kaowool last longer. Yeah, kiln wash the entire liner. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
ForgeMan32 Posted January 31, 2015 Author Share Posted January 31, 2015 Ok well that's what I thought also I made a little freon can gas forge. But for some reason I was thinking if the burner was 6 inches away from the work it might not heat it well. I keep trying to post pics but when I try to click FullVersion of ifi on my phone it won't let me and it used to do it. I am not a newbie to forging just gas forges lol. I've always been a coal guy . But if I could just fire up a propane forge I think I would get to forge a lot more often Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted January 31, 2015 Share Posted January 31, 2015 in most of the gas forges I have used in the last 15 years or so you DON'T want the burner flame impinging on the work you heat the forge up and it heats the work more evenly and with less oxidizing. Quote Link to comment Share on other sites More sharing options...
SJS Posted February 5, 2015 Share Posted February 5, 2015 The Arizona Artist Blacksmith Association, has a plans section, there is a gas forge article... They mention that a longer distance between the burner and the wall resulted in better combustion... Its a good read. Quote Link to comment Share on other sites More sharing options...
ForgeMan32 Posted February 6, 2015 Author Share Posted February 6, 2015 Thanks sjs I will read up and I put it all together about two nights ago and did my kiln wash and fired it up for about thirty minutes and believe me I see what you mean it heated steel very well for a small single burner forge. It was glowing orange for sure but. The burner did sputter at low preasure is this normal . As soon as I would turn the regulator up it would smooth out Quote Link to comment Share on other sites More sharing options...
timgunn1962 Posted February 6, 2015 Share Posted February 6, 2015 The burner sputtering at low flow is fairly usual. When the mixture speed in the burner tube is low, the flamefront can move down the mixture faster than the mixture moves up the burner tube. The flamefront runs down the tube until it runs out of mixture, when it goes out. Fresh mixture flows until it reaches the hot chamber, where it ignites and the whole thing happens again. If you do nothing, it will often get worse as the burner tube heats up and the flame speed increases. Flames burn faster at higher temperatures. You will sometimes find the sputtering only starts once the forge is at working temperature. Standard fix is to turn up the pressure, thereby increasing the mixture speed, until the sputtering stops. Quote Link to comment Share on other sites More sharing options...
ForgeMan32 Posted February 7, 2015 Author Share Posted February 7, 2015 Another maybe silly question but I built this small freon bottle forge to get started . But I am thinking of building a bigger gas forge . And here's the question if I put 2 burners in this next one and make it to where I can use only one burner if needed . Will the heat of the forge burn up the burner that's turned off . Or will it melt the burner tube or cone. Just a thought do you need to put kaowool in the one that's off when forging or will it be ok. Quote Link to comment Share on other sites More sharing options...
Frosty Posted February 7, 2015 Share Posted February 7, 2015 That's a good question to ask now. You won't have to learn the hard way or worry needlessly. Kudos sir. There are some things to do to prevent burning up a burner that's not running: #1 is to NOT close the forge up enough to make the off burner an exhaust port. #2. having the burner end back in the liner. #3 block the air intakes on the off burner with a little something non-flammable so it can't act as a chimney. I have copper supply lines on my burners and don't do anything special, the off burners don't get hot enough to worry about. Don't touch one of course but they aren't going to get hot enough to be damaged. There's another thing to think about, a 2 burner forge with only 1 running isn't going to get really HOT is it. There was a reason you put the second burner in it. Yes? <wink> Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
SJS Posted February 8, 2015 Share Posted February 8, 2015 Jerry Hoffman had a design in the "Blacksmiths Journal" that is till available for a modular little gas forge, and you could stack them end for end to do longer heats. The drawings are also available in the book "Shop Drawings for blacksmiths." If you combine all the info from the Arizona article, with the modular concept. You could get a real nice versatile forge. A note about 1 vs 2 burners, the guy who wrote the article said that with the testing they did, a single 1" burner seemed to be more fuel efficient than 2 smaller burners. Other people like multiple burners, just some interesting info to consider... Quote Link to comment Share on other sites More sharing options...
ForgeMan32 Posted February 11, 2015 Author Share Posted February 11, 2015 Well I set forward and bought all the fittings for the burner that arizona artist blacksmith page has and its a 1" tube instead of 3/4" so my forge I'm working on now is a 40 pound grill tank whick all together is like 26" long and same roundness as a regular grill bottle . Do you guys think that a tank that size definetly needs two burners. That page on arizona artist says that one of these types of 1" burners has proven to heat better than 2 of the 3/4" burners so I hate to go way overkill and just waste propane. And is a square body forge serve any better than round or does it just give you more forging space. Quote Link to comment Share on other sites More sharing options...
SJS Posted February 11, 2015 Share Posted February 11, 2015 The article list the forge sizes as 12" diameter by 9" deep with 2" of Kaowool, and then you put doors on it. If you were to use the whole cylinder you would need several burners Quote Link to comment Share on other sites More sharing options...
ForgeMan32 Posted February 12, 2015 Author Share Posted February 12, 2015 So should the burners if I use two be about 5 inches apart from what I've seen that looks to be what most are I Think Quote Link to comment Share on other sites More sharing options...
SJS Posted February 12, 2015 Share Posted February 12, 2015 I would carve the tank down to where the inside volume of the forge was about 1000-1400 cubic inches, and stick adjustable doors on each end. The doors will help with fuel efficiency, you need to vent the forge, but you don't need the ends completely open all the time. Having the burners 5" or 6" apart should be adequate I would guess if you cut it down to about 18" in length. With two 1" burners you might want at least a 40# cylinder or a 100#, if you run both burners off of the same tank I would bet you will freeze up too quickly on a 20# cylinder. I haven't tried the 1" burners yet, so I don't have real experience with this... Quote Link to comment Share on other sites More sharing options...
Frosty Posted February 12, 2015 Share Posted February 12, 2015 Figure 650-700 cu/in for each 1" burner and arrange them accordingly in whatever shape size forge you build. In my experience a 1" burner can freeze up a 20lb. bottle in an hour or two, a pair of 1" burners will freeze up a 20lb. bottle if it's floating in the slack tub in under half an hour. A 40lb. bottle will run one, 1"er for hours easily and 20 mins in the slack tub will take care of it if it gets slushy. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
ForgeMan32 Posted February 12, 2015 Author Share Posted February 12, 2015 Well at the moment I am running a 40lb. Tank but I do have a 100# that I can use if it freezes the 40. I've never been real bright when it comes to figuring volume and stuff like that . The forge im working on now with two laters of kaowool should have a chamber that is 6" round and 16" long. So what's anybody's thoughts on these 1" burners besides me reading that there hotter I haven't seen it or heard anybody say there's a benefit yet. Quote Link to comment Share on other sites More sharing options...
Frosty Posted February 14, 2015 Share Posted February 14, 2015 Do you know how to figure the area of a circle? Pi.r sqared. In the case of a 6" circle first determine r, the radius. 3" Square the radius 3x3=9 multiply by pi, 3.1416 = 28.27 sq/in. that is the area of the pipe forge's cross section. Multiply the cross section area by it's length 16" for the volume 452 cu/in. A well tuned 1" naturally aspirated propane burner will bring approximately 650-700 cu/in to welding heat. The problems you have using 1" burners in your forge isn't so much being way more burner than the volume needs, it's the shape of the chamber. It's long and narrow which causes two serious problems. First firing into a 6" diameter cylinder is going to cause a lot of back pressure fighting against it's ability to draw air. This will seriously degrade it's performance. Second problem if you can get it tuned to burn in the chamber, being uneven heating, the chamber will be very hot close to the burner but temp will drop off quickly as distance increases. Even if you were to use two 3/4" burners there is just too much length to heat evenly. Were I designing a gas forge of those dimensions I'd use four 1/2" naturally aspirated burners if I had to use naturally aspirated burners. By preference I'd use a gun burner system either with four or more 1/2" nozzles. Or a long ribbon burner. I'd probably build the ribbon burner simply because I've never built or used a ribbon burner. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Stefan A. Peschke Posted March 6, 2015 Share Posted March 6, 2015 I'm new to all this stuff. Could you explain what a gun burner is?Thanks,Stefan Quote Link to comment Share on other sites More sharing options...
Frosty Posted March 6, 2015 Share Posted March 6, 2015 Sure, a "gun" burner is supplied with air by a blower, commonly called a "blown burner." Naturally aspirated means literally "breaths in by it's nature".Feel free to ask if you have any other questions. I'm happy to provide answers even if I have to make something up. <wink>Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
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