GabrielDunn Posted October 5, 2012 Share Posted October 5, 2012 Hey guys. Teaching myself blacksmithing. I don't have a mentor. I am just reading this forum/books and watching videos. I was hoping someone who has a propane forge similar to the majestic or diamondback model could shoot a quick youtube video of an ideal flame. Does your flame lick out over the top edge of the forge? Does that mean it's too big? I am not certain if I am using too small of a flame or too large. I just assembled the forge and have no real way to confirm it is operating as it should be. I guess it's my anal nature where propane is concerned to be both cautious and over prepared for operating the forge. Do I want to see a blue flame and a solid looking jet flame? Do i want mostly a yellow flame with just a little blue at the nozzle? I have no basis for comparison. If you can't do a video, a picture or description would be great. Sorry that image is gigantic. First time posting an image. I'll look for a guide. Maybe I need to resize it. Quote Link to comment Share on other sites More sharing options...
Frozenforge Posted October 5, 2012 Share Posted October 5, 2012 It appears by the photo that you have 3/4 inch naturally aspirated burners without any chokes so by changing pressure is your means of flame adjusment. A yellow flame will indicate a fuel rich environment, lack of oxygen which with your setup will be low pressure as the venturi effect isnt strong enough to draw in air for the combustion. As your fuel pressure rises you should see the jet cone start to appear with a greenish color, (still slightly rich), then it will become more blue indicating a neutral flame, (correct ratio of fuel to air). As the pressure rises more it become a purplish blue (lean condition) an excess of oxygen. Sound can be a good indicator as well, a rich condition is much quieter and it will roar more as it leans out. The neutral flame is the hottest And the temperature drops off when going either too lean or rich. The lean or oxidizing flame will cause more scale buildup and even burn the steel due to the excess oxygen reacting with the hot metal. A choke is a means to limit air supply to the burner thus helping to "tune" the combustion I dont have the means to post a video right now but a search on you tube will find something Im sure. If i have made any mistakes please post to help both of us! Im a beginner as well and am sharing what I know which might be relatively little. :o Quote Link to comment Share on other sites More sharing options...
GabrielDunn Posted October 5, 2012 Author Share Posted October 5, 2012 There is another control on the tank to limit the PSi. Monitoring the flame from the controls on top off the unit is a bit more difficult with heat rising and all. So I get the sense I should open those fully and use the PSi control to adjust the flame. You can see it on the propane tank here. Quote Link to comment Share on other sites More sharing options...
Frozenforge Posted October 5, 2012 Share Posted October 5, 2012 Usually the valves by the burners are usually on or off so you can isolate them. What pressure have you been running it at? My forge is also running 2 burners at 3 to 6 psi on the main circuit and around 1/2 psi on the idle circuit to save fuel. Check out Ron Reils website lots of good info,pictures and links. Quote Link to comment Share on other sites More sharing options...
GabrielDunn Posted October 5, 2012 Author Share Posted October 5, 2012 The documentation that came with it said to light it at 15 psi. I lit it at 10 and 15. It blasts out real hot and hard. Im actually afraid it might be too much. If the flame licked out of the forge and up to the jets there may be an issue. I think you're right about the small valves on the top. Again though the guide says he opens them and 1/8 a turn to light, then opens them up more. Maybe thats the end of adjusting them though. Just light it then open them fully and use the PSI valve to regulate the flame. Thanks Quote Link to comment Share on other sites More sharing options...
HWooldridge Posted October 5, 2012 Share Posted October 5, 2012 For most forging work, the inside of the forge should be incandescent yellow-white, i.e., almost too bright to stare at with the naked eye. You wind up wasting energy (both yours and the forge's) if you cannot take a high enough heat to move the metal quickly. Subsequent heats should also be done as fast as possible and a hotter environment will accomplish that. Depending on design and jet size, naturally aspirated burners require pressure to pull in sufficient air so you'll likely need 12-15 lbs. Your burners also look to be a little on the short side so you may not be getting enough mixing before they dump into the box. Many designs have a 90 elbow to assist in mixing and it appears you could add some pipe nipples pretty easily as an experiment. In addition, having the door open is going to let a lot of the heat escape. After a gas forge is initially lit, you are basically just doing a fuel dump into the box with the hope that the mix burns inside and puts the heat where you want it instead of in the atmosphere. I've always felt proper insulation and/or refractory are equally important to the forge's performance as burner design. It looks like your floor may be firebrick and if so, it will take some time to reach adequate forging temps. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted October 5, 2012 Share Posted October 5, 2012 IDEAL FOR WHAT????????????? Ideal for knifemaking is NOT ideal for heavy work in mild steel! You adjust your flame for what you are doing not to some "Ideal" and just leave it. It's like driving "What's the Ideal speed to drive at?" depends a lot on the details. The basics are the flame should heat the interior of the forge while not wasting too much coming out the door. The flame should be reducing, neutral or oxidizing depending on what you want. The forge should reach the heat you need for what you are doing---different for forge welding vs heating and beating high alloy steels that will "cottage cheese" at too high a heat; or working real wrought iron which loves and often requires high heats.. Quote Link to comment Share on other sites More sharing options...
Dave Hammer Posted October 5, 2012 Share Posted October 5, 2012 The flame should be reducing, neutral or oxidizing depending on what you want. What is each environment good for? How do you achieve it? What do they look like? When do you "NOT" want each environment? Quote Link to comment Share on other sites More sharing options...
HWooldridge Posted October 5, 2012 Share Posted October 5, 2012 Unless I was working with something exotic that required special processing consideration, I would always want a neutral to slightly reducing atmosphere and as hot as I could get it. If you are worried about excessively high temps, simply pay attention to the work rather than staring off into space. I can't think of any situation where an oxidizing fire would be desired - but I'm certain someone will come up with one. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted October 5, 2012 Share Posted October 5, 2012 Reducing is characterized by a plume of unburnt and partially burnt propane coming out the exhaust: this is good for knife making or tool making where you want to refrain from decarburizing the surface of the metal you are working. One way to dial it in is to dial the air to the forge to the loudest burn/brightest flame impingement and then back the air off some and/or turn up the fuel some. Note this is "wasting" some of the heat in the fuel *and* produces the most CO of the three. Neutral: best flame for most forge work as you are getting the most heat out of your fuel---total burn; but you are not adding in more O2/Nitrogen than can be used thus cooling down the system some. Dial it in by adjusting gas/air till you get the loudest burn and the brightest flame impingement. If you need more heat in the forge add more gas and then dial the air up till you get back to the loudest burn and the brightest flame impingement. Oxidizing: I try to stay away from this one as I came into forging though bladesmithing. *However* I have used it on purpose to create a rough heavily scaled surface on a dragon I forged---when I hammered the scale off it left a pebbled surface instead of the smooth "as rolled/as hammered" surfaces. Dial to neutral and add more air you will see the flame impingement cool down a bit. Quote Link to comment Share on other sites More sharing options...
GabrielDunn Posted October 6, 2012 Author Share Posted October 6, 2012 Fantastic information! This is what I was looking for. I appreciate all the input. I have all of tomorrow slotted to learning the ins and outs of the forge and learning to finely manage the controls. And now thankfully I have an idea of what to watch and listen for. Cheers. Quote Link to comment Share on other sites More sharing options...
ZIG Posted October 6, 2012 Share Posted October 6, 2012 I have the same Forge as the original poster has shown. Other than mine is a middle access ,straight thru the fire box. I had issues with the way the black iron pipe was letting gas slip In behind the top metal shell. Between the brick And it eventually allowed the brick to come off, due to the top metal warping some. So I relined it And sealed all the brick joints and made sure there wasn't any way gas could get between the top brick and top shell. I really Like This little forge. I only have one issue that I haven't addressed. The way the black pipe And bell reducers are mounted right on top. The adjustment controls. Get so hot that You can't touch them. But after reading yalls replies to the OP's questions. I believe, correct me if I'm messing up. But I need to put, say,? a.nipple in the top , with a 45 fitting and get the controls out from over the top of This rig. But I wasn't sure if that would allow the venturia effect to work as well. Seeing. How there Ain't any damper plates on top of the bell reducers. Where the torch modeled fittings are? Plus with a rubber hose connected directly to those controls. It catches a ton of heat. And I should know better than have a hose that close and above it anyway. So anyone done this to theirs? The black pipe will be on a 45 , but the flow will enter top dead center. On my 2 burner model. I need to put a needle valve idle inline to save fuel. But was gonna wait till I got the hard pipe out from over the forge, so much. So would that degree change effect the pull or mixing of fuel and O2? Or Like someone commented about. , That It may help to allow turbulence within What would be considered the mixing chamber ? Thanks In advance. Quote Link to comment Share on other sites More sharing options...
HWooldridge Posted October 7, 2012 Share Posted October 7, 2012 I have the same Forge as the original poster has shown. Other than mine is a middle access ,straight thru the fire box. I had issues with the way the black iron pipe was letting gas slip In behind the top metal shell. Between the brick And it eventually allowed the brick to come off, due to the top metal warping some. So I relined it And sealed all the brick joints and made sure there wasn't any way gas could get between the top brick and top shell. I really Like This little forge. I only have one issue that I haven't addressed. The way the black pipe And bell reducers are mounted right on top. The adjustment controls. Get so hot that You can't touch them. But after reading yalls replies to the OP's questions. I believe, correct me if I'm messing up. But I need to put, say,? a.nipple in the top , with a 45 fitting and get the controls out from over the top of This rig. But I wasn't sure if that would allow the venturia effect to work as well. Seeing. How there Ain't any damper plates on top of the bell reducers. Where the torch modeled fittings are? Plus with a rubber hose connected directly to those controls. It catches a ton of heat. And I should know better than have a hose that close and above it anyway. So anyone done this to theirs? The black pipe will be on a 45 , but the flow will enter top dead center. On my 2 burner model. I need to put a needle valve idle inline to save fuel. But was gonna wait till I got the hard pipe out from over the forge, so much. So would that degree change effect the pull or mixing of fuel and O2? Or Like someone commented about. , That It may help to allow turbulence within What would be considered the mixing chamber ? Thanks In advance. Try a 90 on top and add a 4-6" nipple so the mix chamber is lengthened. Quote Link to comment Share on other sites More sharing options...
ZIG Posted October 9, 2012 Share Posted October 9, 2012 Try a 90 on top and add a 4-6" nipple so the mix chamber is lengthened. Quote Link to comment Share on other sites More sharing options...
ZIG Posted October 9, 2012 Share Posted October 9, 2012 Were You speaking about adding a 90 to the top of the already 10-12 in Pieces of pipe that came with the forge? Or are you meaning to just 90 outta the top and out 4-6 inches? I just figured by using a 45 And Then add the pipe that came with it. Would kick it out enough? Just wanting to Be clear. Quote Link to comment Share on other sites More sharing options...
HWooldridge Posted October 9, 2012 Share Posted October 9, 2012 Were You speaking about adding a 90 to the top of the already 10-12 in Pieces of pipe that came with the forge? Or are you meaning to just 90 outta the top and out 4-6 inches? I just figured by using a 45 And Then add the pipe that came with it. Would kick it out enough? Just wanting to Be clear. If your forge is piped like the pic on the initial post, remove the bell reducers and add 90's there with a nipple, then reinstall the bell reducers. The reducers will then point parallel to the ground instead of downwards. Quote Link to comment Share on other sites More sharing options...
twcoffey Posted October 9, 2012 Share Posted October 9, 2012 My opinion is that any angle in the flow will affect with the mixng process. Inserting the tubes at an angle is the proper way to do this. Quote Link to comment Share on other sites More sharing options...
ZIG Posted October 11, 2012 Share Posted October 11, 2012 Thanks guys. I got you now. Forgot there was a picture of it on here. That thing gets hot being right over the top of the Forge. I'm gonna build a idle circuit too. With supports ,now That I know what I should do. Appreciate yalls input. Quote Link to comment Share on other sites More sharing options...
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