Andy98 Posted January 13, 2017 Share Posted January 13, 2017 Hi, I'm in the contemplation stage of a forced air natural gas burner. Typically when I see forced air burners (and NG ones) people use 2-3" pipe. I believe most people do that using the argument that you need a higher volume of flow, and thus larger pipe. I'm getting stuck on that line of reasoning. Here is my logical argument: I am essentially trying to replace my 1/2" T burner with a NG forced air burner. Lets assume that my T burner is producing 30000 BTUs (just to anchor the math - I believe that is almost the top end of where I operate it). 30K BTUs = 11.6 cuft/hr of propane, and will need 24:1 air:fuel by volume for a stoichiometric burn. That means a total of 290 cuft of gas/hr for my T burner. 30K BTUS = 28 cu/t/hr of NG, and will need 9.7:1 air:fuel by volume for a stoichimetric burn. That means a total of 299 cuft of gas/hr for my theoretical NG burner. I know that the gas/fuel mixture inside my T burner *must be* atmospheric, or slightly below atmospheric - so it's not like it's "packing in" the volume and benefiting from that. I need a blower volume than 300 cuft/hr or 5 cuft/min. I'm cheating and assuming that the blower is pushing all of this (even though only the air is going through the blower - the NG is being injected afterwards and thus contributes probably to some backpressure on the blower....) I understand and accept that the larger pipe will have lower flow resistance. The blower I am planning to use is a furnace draft inducer. I don't have a spec sheet for it, unfortunately, but it seems to move a heck of a lot of air - I find it hard to believe that it couldn't push 5 CFM through 1/2" pipe, or even 1" pipe if necessary. If I do a bunch of hacky math using sketchy online calculators, then I calculate that 3ft of 1/2" black pipe will give me less than .3in-h20 of static pressure loss at these velocities, and inferring from other blower data that might bring the 100cfm down to maybe 50cfm, still well above the 5cfm I'll need. That diverges a lot from the 2" and 2.5" pipes I see people using, so I'm of course worried I have lots of things wrong. Does anyone have any comment or suggestion here? Where and what am I missing? Has anyone made/used a small diameter pipe blown burner? Thanks! Link to comment Share on other sites More sharing options...
Mikey98118 Posted January 20, 2017 Share Posted January 20, 2017 Or you could use computer fans, but then you will miss out on the thrill of way over powering the burner with a noisy expensive fan, and then dumping most of that air out a movable vent. Not to mention that your equipment would become easily portable with a little motorcycle style battery running it all day long on a demonstration site...but hey; who wants to go the same and sensible way, when we can just follow the thundering heard, right? Link to comment Share on other sites More sharing options...
Mikey98118 Posted January 21, 2017 Share Posted January 21, 2017 that should read "... the sane and sensible..." Link to comment Share on other sites More sharing options...
Andy98 Posted January 24, 2017 Author Share Posted January 24, 2017 On January 20, 2017 at 4:41 PM, Mikey98118 said: Or you could use computer fans I didn't realize that they would work! I think I saw you mention them in the burner thread, but I thought that was just to induce a swirl. I assumed they must not get enough flow, and that for sure they weren't build to deal with any kind of back pressure. Is sizing just a trial and error kind of thing? I dont believe I've ever seen a performance rating - just a physical size rating. Link to comment Share on other sites More sharing options...
Andy98 Posted January 24, 2017 Author Share Posted January 24, 2017 Wow - I see now they do carry cfm ratings, but no performance curves. Any suggestions on how much I should derate their cfm? I'm looking at a 70cfm 120mm fan with pwm speed control, for all of $8. That seems...too easy. I suppose (wonder) if I needed to I could stack them like tubine stages... Link to comment Share on other sites More sharing options...
Mikey98118 Posted January 26, 2017 Share Posted January 26, 2017 If it proves to be too easy you only got eight bucks in it... Link to comment Share on other sites More sharing options...
Latticino Posted January 26, 2017 Share Posted January 26, 2017 By all means test it out if you have the inclination. Nothing is better than an empirical test for proving a concept. Not sure of where you are getting your BTUH data from for burner operation, but assuming your calculations are correct I believe that you may have the following issues with the proposed design: Typically I select burner blowers for high pressure/low airflow operation as the standard commercial ventauri mixers have some backpressure at the mixing chamber. With a simpler mixer (straight tube gas side inlet) you will likely have less loss in the mixing chamber, but there will still be wall friction and burner outlet friction. I believe that the computer pancake fans are optimized for high flowrate and low static pressure. Though I don't have a fan curve for them I wouldn't be at all surprised to learn that at full airflow they only exert 0.1" WG of external static. The key reason for getting a fan curve is to see whether the fan will give enough static at the proposed reduced airflow, or just stall out. 5 CFM in a 1/2" OD mixing chamber has the fluid velocity at around 3,667 ft./min at standard conditions. This equates to a duct friction loss of 97" WG in each equivalent 100' of duct. While I know you don't anticipate a long duct length (by this calculation 3' of the 1/2" pipe would be 3" of static loss, so I think you may have missed an order of magnitude somewhere) you need to be aware that any elbows or rapid changes of duct diameter will equate to a fairly significant equivalent length (as will the entry condition for the fan and exit condition for the burner). A single 90 degree elbow can be more than 15' of equivalent length. For this example that is almost 14" WG for an elbow alone. Note that a 1" mixing chamber is much better (2.7 "WG for each 100'), but that is still relying on your estimate of 30 MBH burner output. Placing computer fans in series (your turbine configuration) will theoretically maintain the flowrate while increasing the external static pressure available. In practice turbulent effects and fan speed controls makes putting fans in series rather problematic. My suggestion would be to pipe up your forced air burner in 1" pipe, right up to the forge inlet. At the end of the mixing chamber I would recommend some kind of a burner outlet (multi port burner block, flame retention ring, 1 x 3/4" reducer...) to provide a clear velocity transition at the burner exit to allow you to tune burner operation easily while limiting precombustion in the mixing chamber. You certainly can try a pancake fan, but keep that centrifugal draft inducer fan around if it doesn't work (I assume it is a centrifugal fan you are talking about, not one of those cheap, inline paddle wheel draft inducers that get put onto furnace flues). Good luck and please post your results. Remember your residential pressure natural gas line is typically quite low pressure (0.25 psi), so long runs of natural gas will have to be larger diameter than your relatively high pressure propane. On 1/13/2017 at 11:49 AM, Andy98 said: Has anyone made/used a small diameter pipe blown burner? By the way, yes I have made a couple of 3/4" mixing chamber blown burners (for glass furnace pilots), but those used industrial ventauri mixers and air provided by the same large high pressure blower that I was using for my main furnace burner. Kind of a different application. May try to pipe one up for a paint-can forge sometime, but will likely use a small Dayton squirrel cage blower. Link to comment Share on other sites More sharing options...
Mikey98118 Posted January 26, 2017 Share Posted January 26, 2017 Good stuff there, Latticino. Link to comment Share on other sites More sharing options...
Andy98 Posted January 29, 2017 Author Share Posted January 29, 2017 On 1/26/2017 at 11:53 AM, Latticino said: Not sure of where you are getting your BTUH data from for burner operation, but assuming your calculations are correct Hi - thank you very much for your reply. Lots of stuff in there to address (plus I have a week of additional calculations and research done). I arrived at the BTUH using the BTU calculator referenced off Ron Reil's site - it's working off orifice size and input PSI to calculate BTUH. The same spreadsheet also estimates propane consumption in hours, and that seemed to line up approximately enough with my real world results. I then proceeded to round up to help ensure that I had the necessary headroom. On 1/26/2017 at 11:53 AM, Latticino said: by this calculation 3' of the 1/2" pipe would be 3" of static loss, so I think you may have missed an order of magnitude somewhere No doubt I did. I was working with a really first-principles calculator scrounging all around the net for input values. I found a better calculator, intended for HVAC (here: http://bry-air.com/resources/utilities/static-pressure-calculator/) that gives me results closer to yours. I'm now calculating that 2' of duct carrying 7 cfm (I've upped my volume a bit) will present: .08 inH20 (1.98 mmH20) @1" nominal. .28 inH20 (7 mmH20) @ 3/4" nominal. 1.22 inH20 (31 mmH20) @ 1/2" nominal. ...plus, as you indicate, additional static pressure amounts for bends, constrictions, etc. The mm units are there because that's how computer fans are rated. More below... On 1/26/2017 at 11:53 AM, Latticino said: I believe that the computer pancake fans are optimized for high flowrate and low static pressure. Yes - so what I've uncovered is that there are (now) two classes of computer fans being sold - some optimized for high volume/low-pressure, and others optimized for static pressure. Unsurprisingly, the high static pressure fans are called "Static Pressure Fans" and the highest rated one I could find in 120mm size has a static pressure rating of 7mmH20 (0.27inH20) and 100cfm. This a $35 fan, not the $8 fan. Bonus is that it's IP67 rated. I found one that went to 10mm in 140mm size. Both are PWM variable speed, and 12VDC. The manufacturer for these fans is here: http://noctua.at/en/products/fan So it looks like right off the bat I'd need to go to 1" for sure, but it seems at 1" it might actually work - by those numbers at least. Next thing I looked into was the NG supply. My NG supply piping would look like this: Gas Company Regulator -=> 1" black pipe, approx 30' + 6 elbows and 2 T's -=> Reducer to 5' of 1/2" copper -=> 3/8" quick connect -=> 10' 3/8 flexible BBQ hose -=> Burner. Unfortunately, I haven't found a good reference for calculating the NG flow. If I approximate by pretending that the 5' of 1/2" copper + 3/8" quick connect + 10' of 3/8" BBQ hose is equal to 15' of .3" ID duct, then that same calculator tells me I'll drop 2inH20 (0.07psi). That seems suspiciously low to me. Any thoughts on this calculation? I imagine that there will actually be some amount of suction on the NG outlet inside the burner as well, which should a bit? On 1/26/2017 at 11:53 AM, Latticino said: I assume it is a centrifugal fan you are talking about, not one of those cheap, inline paddle wheel draft inducers that get put onto furnace flues ...actually I am talking about one of those cheap, inline paddle wheel draft inducers. It was free, so I'm not out anything - will it not be up to the task? Thanks again for all information and the time taken to respond. I'm not 100% convinced I'll proceed with this yet, by the way. The biggest obstacle is that I'm cheap, and the 10' NG hose ain't. At full price for that hose alone, I'm looking at a 2-3 year payback with the meager amount of forge time I get. If I do proceed, I will certainly update with results. Link to comment Share on other sites More sharing options...
timgunn1962 Posted January 29, 2017 Share Posted January 29, 2017 The first thing to understand about fans is that you will very rarely get the information you want about them unless you are paying top dollar. It's the curve you want to be looking at. The CFM value quoted is almost always the flow at Zero pressure differential. Where quoted, the static pressure is the pressure against a closed discharge (zero flow). You need to know what happens between these 2 points. I think I'd be looking at radial blowers, rather than axial fans, since they generally have higher static pressures and lower headline flowrates. http://media.digikey.com/pdf/Data Sheets/Sunon PDFs/Maglev Catalog.pdf seems to have some actual curves. Axial fans are near the front and the radial blowers are near the back. I have no idea what the prices are like. Link to comment Share on other sites More sharing options...
Andy98 Posted January 30, 2017 Author Share Posted January 30, 2017 20 hours ago, timgunn1962 said: It's the curve you want to be looking at. The CFM value quoted is almost always the flow at Zero pressure differential. Where quoted, the static pressure is the pressure against a closed discharge (zero flow). You need to know what happens between these 2 points. Understood. See below the next quote. 20 hours ago, timgunn1962 said: I think I'd be looking at radial blowers, rather than axial fans, since they generally have higher static pressures and lower headline flowrates. http://media.digikey.com/pdf/Data Sheets/Sunon PDFs/Maglev Catalog.pdf seems to have some actual curves. Axial fans are near the front and the radial blowers are near the back. I have no idea what the prices are like. Great link! Their products are competitive - randomly picking a blower model #PMB1297PYB1-AY it looks like they are around the same prices ($30-40) as the other fan I mentioned above. At 7cfm, it'll handle .8inH20 which means it'll work for 3/4" and 1" but not 1/2". The fan I mention above would only work at 1" pipe sizes. Regarding the fan curves: If I look at the ones provided by that Sunon link, it looks like (for their fans at least) you can almost just treat them as linear and then round down a bit. So with the .27inH20 and 100cfm fan I mentioned in my previous post, it seems somewhat likely at .08inH20 it'll do something a little under 30cfm, well above the 7cfm I need. So - apparently there are options! Actually digikey is fantastic - makes sense that they have full spec sheets. Some other options: 7cfm at 1.1 inH20, for $28. 7cfm at .7 inH20 for $25 7cfm at 3.7 inH20 for $45 ...seems like lots of choices from our friends in the electronics industry. That last one might actually work with a 1/2" burner. Downside of these blowers is that they are not variable speed as far as I can tell, so they'll need gates. Link to comment Share on other sites More sharing options...
Mikey98118 Posted January 30, 2017 Share Posted January 30, 2017 Good stuff, guys. Link to comment Share on other sites More sharing options...
stockmaker Posted January 30, 2017 Share Posted January 30, 2017 I noticed these fans are DC, 8V - 12V rated. I am not 100% sure about this, but I would expect the fan to change speed somewhat as the voltage was reduced or increased. You may have variable speed when coupled to a variable DC power supply. Link to comment Share on other sites More sharing options...
timgunn1962 Posted January 30, 2017 Share Posted January 30, 2017 Run on variable speed, fans follow the "fan laws", perhaps unsurprisingly. On a fixed system (one where there is no adjustable throttling): Flow varies with the speed. Pressure varies with the square of the speed. Power absorbed varies with the cube of the speed. It may also be worth mentioning that flow through a fixed jet varies as the square root of the pressure difference across it, at least for the sort of pressures we tend to get involved with. It stops being true when the speed through the jet reaches the local speed of sound (choked flow), which usually happens somewhere in the region of 30 PSI for Propane. I've seen posts in the past where the poster seems to have assumed that halving the pressure halves the flow. This tends not to be the case in reality. Link to comment Share on other sites More sharing options...
Andy98 Posted February 5, 2017 Author Share Posted February 5, 2017 On 1/26/2017 at 11:53 AM, Latticino said: I would recommend some kind of a burner outlet (multi port burner block, flame retention ring, 1 x 3/4" reducer...) to provide a clear velocity transition at the burner exit to allow you to tune burner operation easily while limiting precombustion in the mixing chamber Ok, so I'm now starting to process what you said here and it leads me to few questions: Are there any design guidelines for the mixing tube? I am aware of the guidance for naturally aspirated burners, but I don't know if they apply to forced air, and to forced air with natural gas in particular. How would I diagnose inadequate pre-combustion mixing? Regarding the outlet: I'm not prepared to make a ribbon burner (I don't think my small forge would accommodate it, but mostly I am looking to avoid buying a bag of refractory). I can easily do the 1" to 3/4" transition. Should I consider making a small manifold and having 2 or 3 small (1/2") burners? I'm inclined at the moment to try and keep it simple (ok, I'm inclined to overthink and overbuild it, but I'm disciplined enough to keep it simple...) What is a good design flame speed to shoot for? I know people usually say 1ft/sec for NG, but from here I see that at high temperatures it can get to ~ft/sec. At 2ft/min even 1" pipe at (say) at low end operation of 2cfm should keep me above the flame speed...? Also, I went and checked out the eclipse engineering guide you posted a while back. Using (abusing) the orifice table, it tells me that a 3/8" orifice at 1"wc will yield 270cfh (4.5cfm). If I pretend that is comparable to my 10' long 3/8" BBQ hose with closer to 7"wc NG (yes, lots of approximation) it suggests a fuel BTU potential of 240,000 BTU. I have trouble accepting this number (and have no practical experience to validate it) but it's encouraging! Link to comment Share on other sites More sharing options...
Latticino Posted February 5, 2017 Share Posted February 5, 2017 I am not aware of any design guidelines for the mixing tube configuration for forced air burners. I believe that there are too many variables for potential configuration to set them, but in my mind the only drawbacks for a mixing tube that is too long is the potential to "stall out" your low pressure gas entry by requiring too much static pressure to overcome the friction of the mixing tube and the backpressure of the burner outlet. I use commercial burner components currently, Inadequate precombustion mixing is not the issue. The issue is the potential for combustion in your mixing chamber. Believe me you will know if that is occurring. It will be loud and quite scary. The mixing tube will also get hot. Manifolds can be difficult to balance. Typically some sort of valving is needed to properly balance the multiple outlets. I prefer to minimize any potential leaks after the air and gas have been mixed (like valves with packing). Initially I would stick with a single burner if possible. I have no information on flame speed other than you need to strive for a stable flame. The stable flame should be burning just at the burner entrance to your forge, and not either lifting into the forge or burning back into the mixing chamber. I am not planning on performing the calculations to validate the proposed equivalence between the orifice and long tube run. It is certainly possible that there is one, but you will need to do some rather tricky calculations to confirm it (Reynolds numbers and the like). My residential pressure forge uses a 1" hard piped NG line, for what that is worth, but the line runs at 1.5" underground for some 100' to the main gas house regulator.. Link to comment Share on other sites More sharing options...
ThomasPowers Posted February 5, 2017 Share Posted February 5, 2017 When I was building my first one at a SOFA workshop around 15+ years ago they were advocating a right angle bend in the pipe to mix the propane and air better. In that burner the gas came in at that bend from the outside and the jet had two holes to the sides. Link to comment Share on other sites More sharing options...
Andy98 Posted February 5, 2017 Author Share Posted February 5, 2017 4 hours ago, Latticino said: am not planning on performing the calculations to validate the proposed equivalence between the orifice and long tube run Hi - Sorry if it seemed I was trying to offload work. That wasn't my intention - I am just looking for additional "gut checks" on NG supply being sufficient. As you are no doubt aware, for every "I built a NG Forge" post out there on the internet, there are 100 posts stating that residential NG can't work. I'm sensitive about the NG supply since I know my feed is not ideal (being at the end of a 3/8" BBQ line...). Thanks as always for your comments! I'm hoping I can get some of this build done during the winter months here, but I will post further once progress is made however long that takes... Link to comment Share on other sites More sharing options...
Latticino Posted February 6, 2017 Share Posted February 6, 2017 On 1/29/2017 at 4:08 PM, Andy98 said: The biggest obstacle is that I'm cheap, and the 10' NG hose ain't. Why use hose and quick connects at all? Hard pipe right up to your burner connection with 1" schedule 40. If you need to be able to move it put in an isolation valve (full port) and downstream union. Make the final size reduction inside the burner body where you can adjust the orifice size iteratively to match your blower output to the maximum pressure you develop with the gas. Since you are developing your own burner design you had better expect to do some testing and optimization. With low pressure gas supply, my policy is to get as much into the forge area as possible. Can always turn it down, but if you don't have enough you are out of luck. 3 hours ago, Andy98 said: As you are no doubt aware, for every "I built a NG Forge" post out there on the internet, there are 100 posts stating that residential NG can't work. Residential pressure natural gas forges definitely can work, as I have built several at this point. I am still struggling with getting my multiport burner to work up to my standards, but have successfully forged and even forge welded in the existing unit. Link to comment Share on other sites More sharing options...
Andy98 Posted February 6, 2017 Author Share Posted February 6, 2017 8 hours ago, Latticino said: Why use hose and quick connects at all? Hard pipe right up to your burner connection with 1" schedule 40 I do my forging in my extremely small, big-city back yard. To get the 1" line back there I'd need/want a gas fitter to do it and there would need to be an external wall penetration and I'm not quite ready to make that kind of an investment yet. Perversely, the more serious I get about this hobby, the more likely it is that I'll end up relocating where I forge (i.e., not in the backyard at all). I could also get shut down by an annoyed neighbor pretty easily, based on the local bylaws (as I read them at least). I'm prepared to have to tinker, and I'm also prepared for this to fail - although I will be disappointed. I figure that I need less than $20 worth of black pipe and fittings to get a test run going (using the BBQ hose that is actually connected to my grill). If that works, then I'm happy to invest more. If it doesn't work then I ruminate and possibly go back to propane. I am putting a lot of energy into resisting the temptation to just experiment on burners instead of actually forging. On that topic, I'm at a loss as to how I can actually measure the effectiveness of my burner? Other than "will it weld" what kinds of tests can/should I do? Link to comment Share on other sites More sharing options...
Andy98 Posted February 18, 2017 Author Share Posted February 18, 2017 Ok, some measurements now: 1) The draft inducer (not the computer fan): I measured it, using a makeshift poly tube manometer, at 1"WC when full blocked. 2) When connected to approx 5' of 4" flexible plastic duct line, which will not be the final install, it was able to move approx 26cfm of air. 3) With my NG connection, the 10' 3/8" BBQ hose with nothing connected to it will expel approx 6.3 cfm of natural gas. That's 378 cuft/hr, and if I assume 1000 BTU/cuft then that's should be 378,000 BTU. So with a target of approx 40000 BTUs, and thus a need for 0.6cfm of NG and 6 cfm of air, I seem to have a 4.5x margin on the air supply and a 9.45x margin on the gas side. So I feel like this has a pretty good chance of working. Also, even running full out at 378k btu, I'd only be burning $1/hr of NG. Link to comment Share on other sites More sharing options...
Hammerfall Posted February 21, 2017 Share Posted February 21, 2017 Tag for progress info. Link to comment Share on other sites More sharing options...
Andy98 Posted February 23, 2017 Author Share Posted February 23, 2017 Ok, so more info (forgive me, I'm using this as a multiplatform notepad to some extent): I've built the burner very simply: 3/4" black pipe T 3/4" x 6" black pipe nipple as mixer tube NG goes in drop/bottom of the T (3/4 to 1/2" bushing, 1/2" x 2" nipple, 1/2" to 3/8" flare full port ball valve) Air goes in the run of the T (3/4 x close nipple, 3/4 to 1.5" PVC bushing, 1.5"x2" PVC reducer) Basically, the most controversial thing above is that I've decided to just try going 3/4" for the whole assembly rather than using a larger diameter and reducing it as a nozzle (e.g.,going from a 1" or 2" down to a 3/4" nozzle). I did look into the flow-resistance of 1" to 3/4" black-pipe reducer, and the few bits of reference material I could find implied that the reducer itself was equivalent to around 10-20x the downstream diameter (10x3/4"=7.5") which means the reducer looked like it was going to add more back pressure than just having the whole short length at 3/4". So I decided I'd give it a try. Cheap parts, why not. I've also chosen a relatively short mixing tube (at 6"). This follows the T-burner guidance of 8D, plus I figure there'll be enough turbulence in the T to mix it well (who knows?). I put it all together and gave an airflow test with my draft inducer. Using my highly calibrated plastic garbage bag, I appear to be getting around16cfm. Still above my target. I did a crude pressure drop measurement using my plastic tube manometer, and it looks like I'm like my 3/4" pipe arrangement creates >0.25inH20 of pressure head. Seems ok. Interestingly, I am measuring almost no pressure drop between the fan outlet and the inside of the T. Again, these are really crude measurements. In contemplating how to get the blower hooked up to the burner, I started looking into some axial fans (like regular PC fans) rather than blowers. The benefit being that I could simply stick one of these into the 2" PVC reducer, rather than having to duct it in. It also means I have less weight to support, and the burner assembly becomes more portable. That turns out to be a goldmine - still using the 7cfm desired flow to make this list comparable to the one from my previous post: 7cfm @ 1.1inH20, $16 (NMB: 1611RL-04W-B80-B00) 7cfm @ 0.8inH20, $14.58 (Mechatronics Fan Group: MD4028V12B-RSR) 7cfm @ 0.6inH20, $17 (NMB: 04028DA-12Q-AA-F0) 7cfm @ 0.7inH20, $19 (Sunon: PF38281B2-000U-A99) 7cfm @ 0.8inH20, $19(NMB: 04028DA-12R-AU-F0) Since I don't trust my pressure measurements, I'd probably look at the first one. Link to comment Share on other sites More sharing options...
Andy98 Posted February 28, 2017 Author Share Posted February 28, 2017 Due to unseasonably warm weather, I was able to find 15 minutes today to give this burner a test run: It definitely seems to work. This video was take about 20 seconds after it was lit for the first time. I didn't spend much/any effort trying to tune it. The NG valve is not very open (it's a ball valve, turned maybe 20 degrees (with 90 degrees of total travel). My observations: It's odd to me that I do not see an actual flame cone. It seems to have gotten a lot of the forge wall to an orange heat faster than my propane burner. There seems to be a cool spot where the gas is hitting the sidewall, rather than a hot spot. I guess that means the gas isn't actually burning when it hits that wall, but I don't understand why the ceiling of the forge is hot along that same line. I believe some of the behavior will change when the forge is actually fully hot. I'd love to hear other's observations. I take this as a pretty positive test. Based on this, I'm thinking of buying one of the CPU fans (this one) so I can get rid of the draft inducer. Thoughts and comments are very welcome. Link to comment Share on other sites More sharing options...
WoodnMetalGuy Posted February 28, 2017 Share Posted February 28, 2017 I wonder if you'd have better control with a regulator in the feed rather than trying to control the gas with a partially opened ball valve. And an unrelated question - what's up with all the funnels hanging on the fence in the background? -- Dave Link to comment Share on other sites More sharing options...
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