Mycelium Posted January 17, 2019 Share Posted January 17, 2019 Greetings! I come to y'all in the hopes that someone can help me trouble shoot my gas forge. I've been building myself this forge so I am not as reliant on hauling propane out to my local makerspace which has a lovely forced air forge but getting propane to it is a PITA when all I want to do is heat treat. I've just been doing the curing burn on my refractory cement bottom and have run into some trouble getting the forge hot. For refrac curing purposes this is kind of helpful but I'd actually like to use this thing to heat treat and possibly forge at some point. The design I worked off can be found here. Yes I know, its a youtube video and there is an inherent risk to working off designs on youtube. The design seemed simple enough that I was pretty confident it would work but maybe I am missing some glaringly obvious flaw. Here is a picture of the forge running earlier today. Forge details: The body is a standard 20lb propane bottle. It is insulated with 2" of Kaowool that I rigidized and then coated with stove refractory cement for additional durability. I pour about 1" of URC 4U Uni-cast 3000 (a bronze foundry a friend worked at was moving so I got it for cheap) on the bottom. I allowed this to dry for two days at about 19-20C. Burner details: 0.6mm (0.025") MIG tips threaded and loctited (565) into a 1/8" iron pipe that is T'd and connected to the propane line. The 1/8 pipe ends are MIG welded shut. The air intakes are 1.5" to 3/4" bell reducers with simple sheet metal flaps for air control. Where the 1/8" propane line passes into the bell reducers is also MIG welded xxxx (all welds and loctite'd areas have been leak tested). The propane would leave the MIG tips right about where the reducer comes down to 3/4" so about 2" from the mouth of the reducer. The flame is shot down 3/4" wide by 6" long pipe nipples which then flare out to 1" by means of another reducer fitting that I have pushed back into the kaowool. I am using a 0-30PSI high pressure propane regulator and am pretty much at sea level. I can get the burners to jet (can vary them from consistent jetting to periodic sputtering) however by the time they get down into the body of the forge they seem to be putting out fairly long tongues of flame. Ranging from very yellow orange to a mix of blue orange depending on how I fiddle with the air intake and fuel pressure. Problem 1: Not hot enough. I don't have a probe so the way I'm gauging how hot its getting is simply by sticking a piece of scrap steel in there and watching for a colour change. I let the forge run for about ten minutes with fire bricks (pretty sure they are the soft variety) across the front/back (more or less how the forge appears in the picture above). Then lay a 1/4" wide by 1/8" thick by 4" long piece of scrap steel in there. I gave it a solid fifteen minutes and at most I get some bluing on the scrap. Not getting anywhere close to non-magnetic. I figure I'm loosing too much heat out the front/back (the fire bricks don't totally close off the openings) and through the tubes that hold the burners. In attempting to address this I ran into a different problem. Problem 2: Burners going out As I said above I though I was loosing too much heat so I grab some scrap kaowool wool (I was keeping it in the yard where I thought it would be safe from moisture but it seems I was wrong so its sopping wet. Not sure if that's a problem?) I have left over. I squish some kaowool around the rim of the front/back to act as insulation gaskets around the fire bricks and stuff some between the burner tubes and the pipes acting as mounts to reduce heat loss. Now with all these holes plugged I relight the forge with no issues and I go to close up both ends. The burners run for about 2 minutes before going out. They'd go out silently. No sputtering no cracking. I relight them and try again to the same result. I try this at low pressure (5PSI) and high pressure (25PSI) all to the same result. This suggests that the burners are using up all their oxygen? Which I guess suggests that I have effectively insulated the areas where I was previously loosing heat? At this point I was loosing daylight so I wasn't able to carry out further tests to see if I could really get the forge up to heat. In addition I suspect that although my kaowool "gaskets" appear to be working the water boiling out of the is presumably acting as a heat sink to some degree. I'm somewhat at a loss for how to proceed in an effective manner. Advice would be appreciated Quote Link to comment Share on other sites More sharing options...
Frosty Posted January 17, 2019 Share Posted January 17, 2019 Have you contacted the guy who made the video? He's the guy who came up with this after all. It's too light out to tell what the flames look like in the pics and I can't tell much from your description of how you built the burners. A well tuned forge should bring that steel to yellow in under a minute give or take. I don't make linear burners though I expect someone who does will speak up. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted January 17, 2019 Share Posted January 17, 2019 It is a little hard to see clearly from the photo, but it appears that the cross pipe is too low in the reducers for MIG contact tips to be placed properly; the holes should touch the lip of their openings in order for there to be enough room for 1-1/2" long tips not to be within the mixing tube? Quote Link to comment Share on other sites More sharing options...
Mycelium Posted January 17, 2019 Author Share Posted January 17, 2019 Frosty: Its very hard to actually get hold of people on youtube. The best you can hope for is that they see your comment on their video there is now way to DM any more. At least so far as I can tell. I'll grab some clearer photos of the flames once the sun starts to go down today. Mikey: For clarification, by mixing tube you mean the pipe nipples that the flame is shot down? If that is what you mean the MIG tips aren't projecting down into the mixing pipe. I busted out my calipers to check exactly where they are in the reducer fitting. The opening in the MIG tip sits 43.23mm (1.701969) from the 1.5" end of the reducer (air intake) and 17.46mm (0.6874016") from the 3/4" end of the reducer. give or take a mm or two. The reducer fitting itself is 64.73mm in length (2.54"). Here are some better photos of the burners. Firebrick addendum: I did a little investigation and believe the firebricks I have are actually these. Given that they are described as high density I presume they are in fact hard firebrick not soft so that probably isn't helping. I'll have to figure out where to get some soft ones. So far two of the stove supply stores I've called have been surprised that there is more than one kind of firebrick out there :l Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted January 17, 2019 Share Posted January 17, 2019 I think Frosty is gently suggesting that asking people to troubleshoot someone else's designs is going towards consultancy... As for fire brick: ceramic supply places may have had soft firebrick for kilns. Wood stoves require hard firebrick for wear purposes. Quote Link to comment Share on other sites More sharing options...
Frosty Posted January 17, 2019 Share Posted January 17, 2019 Nicely said Thomas, close but no cigar though. We troubleshoot other people's designs all the time and were I to be curmudgeonly direct I'd say that design IS the problem. However I'm not a linear burner guy and I don't build jet ejectors like Mike does either. We need better information to be able to render meaningful answers. If you picked a set of proven plans and followed them it'd be a piece of cake. We've seen about every mistake possible made on the plans posted here so we often only need a glimpse to point to the specific problem. someone else's designs are a different matter completely. Check with HVAC service or supply companies for light insulating firebrick. Heavy/high density brick is a major heat sink and poor insulation. Presently Morgan Thermal ceramics, K-26 IFB (Insulating Fire Brick) is about the best I know of. It'll take more heat than we usually generate in our forges, it's good insulation and it's pretty immune to forge welding fluxes. If you're not interested in what I find really poor burner design about these particular ones feel free to skip the following. That particular build has too many single failure points. First as Mike points out the final fuel supply tube is welded WAY too deeply in the intake bell. It shows me the person who made the video doesn't understand jet positioning. That deep would only be appropriate if you were drilling the jet orifice. Drilling and tapping for a mig contact tip puts the jet WAY too deep. Commercial linear burner jets are WAY back away from the throat. The throat being the narrowest point between the intake bell and mixing tube. End of the pipe nipple in our general case. The next single failure point is welding all the fuel supply lines together, how many welds do you have to get perfect to get this thing to work? All of them? Can you adjust the nipple that connects to the gas hoes? Nope, shot in the foot there too. Don't weld the fuel lines! It's not like they're structural nor do they need to be: air, water, anything tight. Set screws have worked beautifully for Ron Reil and folks who build his burners for at least the 30 years I've known him. That way if a jet is a little off, just loosen the screw and move it a little till it's working then tighten it a bit more than snug. If you don't weld the T to the final nipples you can move it up or down to get it out of the way of forge temps and more importantly as a trip hazard. The last about welding things together like that, you can't fix any of it. It's take it apart salvage what isn't welded, toss the rest and start over. Single point failures are like that, ONE thing goes wrong and the whole sheebang is junk. It's like getting a flat tire and having to buy a new car. Personally I use 1/4" copper tubing, (refrigerator tubing sold most anywhere, even big boxes) for my final fuel supplies. They are soft enough to move simply by bending them gently IF you leave enough extra. They don't much care how hot they'll get when you shut down. Chimney effect will burn rubber hoses and may lead to a future failure in the B-A-D way. If you like Linear burners, look up Ron Reil's plans on the ABANA site or Larry Zoeler's plans Larry also has a good version of the "Side Arm". There are more than one good burner design with plans posted here as well. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted January 17, 2019 Share Posted January 17, 2019 The new photos show the MIG tips to be in the right place; I stand corrected. Not that they are in the best place, but they are as good as they can be positioned from a cross pipe. Quote Link to comment Share on other sites More sharing options...
Irondragon Forge ClayWorks Posted January 18, 2019 Share Posted January 18, 2019 Welcome to IFI... Don't be upset if your links get removed due to violation of TOS. I suggest reading this thread to get the best out of the forum. READ THIS FIRST Quote Link to comment Share on other sites More sharing options...
swedefiddle Posted January 18, 2019 Share Posted January 18, 2019 Happy New Year Myc, Send me a PM or come to VIBA Blacksmith Shop. Lots of helping knowledge in your own town. Neil Quote Link to comment Share on other sites More sharing options...
Mycelium Posted January 18, 2019 Author Share Posted January 18, 2019 ThomasPowers - Our sole local pottery supply place would seem to have some. Thank you for the reminder. I always forget about them. Frosty - Oh I know its not the greatest design. I put it together before I realized there was better stuff out there. Getting the rest of the forge finished up got pushed onto the back burner for awhile and I'm just getting back to it now. I figure I'd see if I could make what I have work before I reconsider re-building the burners. Knowing the flaws in the design is rather instructive though. I will say that despite what it appears in the photo my fuel line is positioned well out of the way of any chimney affected areas but I will certainly look into some copper tubing. Having only had the time to skim Ron Reil's website thus far I think I might actually be able to salvage the reducer fittings should it come down to a rebuild. It'll mean some extra time with an angle grinder but I suspect do-able. Failing that black iron fittings are mercifully cheap. Either way thank you for the referral, very helpful. Unfortunately today got busy and I was unable to get better photographs of my burners flames. Mikey98118 - Indeed. I am considering my options in that regard. Irondragon Forge & Clay - No worries, every forum is different. I see that I shouldn't have @'d people but I'm not clear on how my links violate the TOS. The read this first document doesn't seem to mention anything about linking out to pages external to the forum. swedefiddle - I have sent you a message. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted January 19, 2019 Share Posted January 19, 2019 If you look carefully at the MIG tip section of Ron Reil's site, and follow my directions there, your burners can be made very hot indeed. Quote Link to comment Share on other sites More sharing options...
Frosty Posted January 19, 2019 Share Posted January 19, 2019 Your links were to commercial sites and nobody gets to advertise on Iforge without paying to. Don't sweat it, just part of the learning curve. You're going to fit right in here. Frosty The Lucky. 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.