edge9001 Posted September 20, 2010 Share Posted September 20, 2010 ok I have my gasser I got a few month ago. its doing something I find possibly bad. sorry for the blurred picture if you look at this picture the area around the door and the weld where the burner tube connects to the forger body were both glowing a nice pretty red. also last night when I had it going good i started seeing sparks come out of the hole, similar to what is deswcribed as steel being at welding heat. the problem is I had nothing in the forge at the time. today i went out and pulled my burner and there was scale trying to clog my burner as well as the out side of my forge as a nice coat red of surface rust, today, that wasn't there before I lit the forge last night. my forge has the koawool(or some ceramic wool) and no hard coat yet. to help with visualizations ive included a picture of my forge plans. thes designs can also be good for anyone who is looking to build there own. the builder of my forge added the doors and closed in the back. the back has what looks like terracotta tile on the back wall, and no insulation on the door and only 1 inch of kaolwool. any advice guys? Quote Link to comment Share on other sites More sharing options...
kcrucible Posted September 20, 2010 Share Posted September 20, 2010 I'd say that you don't have a large enough exhaust for the amount of gas and air that you're pumping in. If the doors and burner inlet aren't airtight, all of that heat is trying to escape from the cracks, and heating up your metal shell. If they WERE airtight, then the pressure would increase and shoot out in a very hot jet through your tiny exhaust. Basically, I wouldn't be closing down that flap door unless you've got the air cranked WAAAAY back... maintaining heat, not at full burn. Quote Link to comment Share on other sites More sharing options...
edge9001 Posted September 20, 2010 Author Share Posted September 20, 2010 the door is bolted on, I'm considering removing it alltogether, or possibly opening up the back to give me some pass through capabilities. if your right than one of those should solve my problem Quote Link to comment Share on other sites More sharing options...
pkrankow Posted September 20, 2010 Share Posted September 20, 2010 Put an extra inch of insulation on the inside, line the door, and make a back door that has a pass-thru and get to work! If you put a brick in the bottom you can leave the 1 inch under the brick and not add a second inch there if you choose. Adding the inch under the brick will help some Phil Quote Link to comment Share on other sites More sharing options...
RandyScott Posted September 20, 2010 Share Posted September 20, 2010 Tim, I agree with kcrucible.. I think your exhaust openings are too small. If I read your post correctly, the only opening you have is the one shown in the photo. I believe the rule of thumb is the exhaust opening is at least or not less than seven times the area of the burner. The schematic was for a 2" burner or 3.14 square inches. Per the rule of thumb you will need at least 22 square inches to properly ventilate the forge. I just completed a Freon tank forge build and fabricated 2 half inch Porter style burners for a total area of .40 square inches. I have a rear opening, 1" x 2.5", and a front opening, 2.875" x 2.5" (kinda horseshoe shaped). I reckon the openings are about 8+ square inches total. Of course, my burners are aspirated vs. blown, but I have no back pressure problems nor getting it hot. At 5 psi, the dragon will reach out and lick your hand. Randy Quote Link to comment Share on other sites More sharing options...
edge9001 Posted September 20, 2010 Author Share Posted September 20, 2010 Tim, I agree with kcrucible.. I think your exhaust openings are too small. If I read your post correctly, the only opening you have is the one shown in the photo. I believe the rule of thumb is the exhaust opening is at least or not less than seven times the area of the burner. The schematic was for a 2" burner or 3.14 square inches. Per the rule of thumb you will need at least 22 square inches to properly ventilate the forge. I just completed a Freon tank forge build and fabricated 2 half inch Porter style burners for a total area of .40 square inches. I have a rear opening, 1" x 2.5", and a front opening, 2.875" x 2.5" (kinda horseshoe shaped). I reckon the openings are about 8+ square inches total. Of course, my burners are aspirated vs. blown, but I have no back pressure problems nor getting it hot. At 5 psi, the dragon will reach out and lick your hand. Randy yes my forge has two openings, one being the front door, the top half of the door opens, when it's closed only the 2inchx3inch opening. the second opening is around the burner, there is approximatly a 1/4 inch gap around the burner and the tube that is welded onto the forge body. the scale inside my burner is what is worrying me. am I burning up my burner? since I didn't build the forge I don't want to have to rebuild part of it untill I truely have to if I can. Quote Link to comment Share on other sites More sharing options...
ciladog Posted September 21, 2010 Share Posted September 21, 2010 It sounds to me like the back pressure in the forge is causing the flame to burn inside your burner and not inside the forge. So instead of your burner staying relatively cool as it should, it is turning your flame holder and burner tube red hot. Once this starts to happen, the air coming in from the burner is causing lots of scale to form on the flame holder and it is sloughing off. You can usually tell when this starts to happen because when it does, the forge gets louder Quote Link to comment Share on other sites More sharing options...
RandyScott Posted September 21, 2010 Share Posted September 21, 2010 Tim, I checked the schematic which specified the flameholder is at the end of the burner tube. Due to the heat involved, there will be oxidation of the pipe. How much is dependent upon how hot it gets. If the flame is burning inside the burner tube prior to the flame catcher, then there will be greater oxidation. If the burner tube is inserted into the forge, especially deep enough for the end to be in the forge chamber and exposed to the full forge temp, yes there will be more oxidation. Additionally, if that were to happen, the red hot burner tube would ignite the gas/air fuel mixture deep in the tube prior to the flameholder. If there is insufficient exhaust vents, i.e., too small or too small for a high pressure/volume fan, then the back pressure could cause the flame front to move back into your burner tube. In an unrestricted exhaust flow scenario, i.e., top half door open, an insufficient air flow, i.e.,not enough pressure or flow would also cause the flame front to move back up into the burner. Try this test: fire it up at night and see if, and how much, the burner tube becomes red. I used BP nipples for my burner tubes and nozzles. The nozzles do get red and are oxidizing. I consider the nozzles to be sacrificial and will replace periodically as needed. Additionally, my burners are mounted so that the end of the burner tube is even with the freon tank shell, the nozzle is an additional inch into the two inch Kaowool lining so it is never within the actual forge chamber. The portion of the burner tube where the nozzle is mounted has blue oxide scale due to heat. Therefore it never gets over about 700 degrees just one inch behind the end of the tube. Those are my thoughts.. hope it helps. Randy Quote Link to comment Share on other sites More sharing options...
sfDuck Posted October 16, 2010 Share Posted October 16, 2010 Make a doorframe for the back and add a door made of a double row of chain. The chain keeps the heat in the exhaust out and room to move a 10 foot pole through it Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.