nthe10ring Posted May 8, 2008 Share Posted May 8, 2008 For those of you that use the small BBQ size propane tanks, about how long of burn time are you getting. I have a vertical forge -with blown burner . If im forging at about 1 to 2 lbs of pressure it usually starts to get low and freeze up after about 3 hours, not usually 3 hours at one time, but over several days. Gonna put tank in water filled tub and see if I can nurse it along till completely empty. Just wondering what the most anyone is getting and any tips in their use. thanks Jerry Quote Link to comment Share on other sites More sharing options...
Frosty Posted May 8, 2008 Share Posted May 8, 2008 Floating the tank in the slack tub will prevent freeze up. Just make darned sure it stays upright. You do NOT want liquid propane squirting into your hot forge! Better yet buy a larger tank, a 40lb will go quite a while before freezing and a 100lb will go till nearly empty without freezing. Frosty Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted May 8, 2008 Share Posted May 8, 2008 Pressure is pretty meaningless without flow rate; ie 2# pressure on a 6" pipe is a lot different from 2# pressure on a 6 micron pipe. On my blown, single burner gasser I get around 6 hours per tank and I don't usually have freeze issues, of course ambient can be a bit warm out here and humidity low so you don't get a good frost ring to judge by. On my two burner aspirated gasser I generally get 8 hours per tank. Quote Link to comment Share on other sites More sharing options...
Awalker Posted May 8, 2008 Share Posted May 8, 2008 So, you assume TP that he is running a 6" orifice in his forge as opposed to the standard #72- 1/16" orifice. I'd agree that it is no as much information as is needed to do the calculation easily but since with the orifice size and pressure you can figure out how many gallons (or BTUs, whatever you are comfortable with) he is using, then if he gave you the pressure and gallons, then you can figure out the orifice size. The only variable that is under question is if he is throttling the LP between the reg and the orifice. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted May 9, 2008 Share Posted May 9, 2008 Awalker; there is *NO* *STANDARD* *ORIFICE* for blown burners unless you cite a particular design of burner and then none of the other types of burner will probably use the same one. I have seen 1/4" pipe used, pipe plugged and opposing holes drilled, needle valves into open pipe, etc. Blown burners area heck of a lot less persnickity about how you dump gas into them than aspirated ones are. I can't tell what he is using; can you tell me what my blown burner uses? If you can we can finally get the Amazing Randi's cash! Shoot I didn't even mention that many gas gauges can be off by as much as 50% at low pressures so unless they have been calibrated against a standard their values are not very good for comparison. What they are useful for is that when you figure out what your set-up works well at on your guage you can get back close to it easily. Quote Link to comment Share on other sites More sharing options...
dragonflySmithy Posted May 9, 2008 Share Posted May 9, 2008 My main forge is using 2 3/4 in side arm burners with a .35-.30(don't remember) mig tip. For nomal forging I run it at 5-7psi. While doing normal stuff I get about 8hrs of play time off of a 30lb tank. Forge welding I run it at about 10 psi but I don't run it that long like that. Just enough to get the job done. Quote Link to comment Share on other sites More sharing options...
nthe10ring Posted May 9, 2008 Author Share Posted May 9, 2008 Im running a blown burner with 1 1/4 reducer to 1 inch pipe going into the forge ( fogg type vertical forge ). Im usually running about 2 pounds on the 0 to 30 regulator with my needle valve about half open. It just seems like Im not getting anywhere near the time I should. Im using the 10 ft hose and 0-30 regulator i got from Darren Ellis. Jerry Quote Link to comment Share on other sites More sharing options...
Alwin Posted May 9, 2008 Share Posted May 9, 2008 I have been very happy with my nc tool whisperbaby. I've had it for about 5 years now, and still go about 15 hours on a twenty lb. tank. It used to be about 17hrs. I can work on long pieces using the door in the back of the forge, and it has plenty of room to work on multiple smaller items. It is also very portable which makes it an ideal demo forge. Quote Link to comment Share on other sites More sharing options...
metalmaster1766 Posted May 9, 2008 Share Posted May 9, 2008 i dont use a blown burner in my forge, but i do use a blown burner in my large foundry furnace, i think its a 1.5" burner pipe, .25" orifice for the gas at about the same pressure you use, 1-2 psi i can run mine for about 8-10 hours, i have set it in a shallow pan of water to keep from frosting up, i also have an old waterbed heat i was gonna try next time i need to run the furnace for that long, not sure if it will work or not Ron Quote Link to comment Share on other sites More sharing options...
Pault17 Posted May 9, 2008 Share Posted May 9, 2008 my helium tank forge, using a Rex price shortly model, on a BBQ tank gets about 16 to 17 hours. that is running at 4 to 5 psi through a regulator I bought from Larry Zoeller I have had a cold tank but never a frosted one, even when running at 10 psi Quote Link to comment Share on other sites More sharing options...
Awalker Posted May 9, 2008 Share Posted May 9, 2008 I'd be curious to have a poll to see what size orifice every one is using for blown and atmospheric burners. From what I have seen here the atmospheric guys are using from #72 to #62 and not manually throttling the orifice. The blown burner guys are using any where from 1/16" to 1/4" and are manually throttling the orifice, and so don't really know what their orifice size is. You can, in theory figure the orifice size with the pressure and total btus consumed over time. You are right about the gages though. After years of calibrating and using very accurate gages (.25% )I tend to forget that not everybody has them. Back to one of the original problems with the tank freezing is that the withdrawl rate is too high. One way around that is to manifold two tanks toether, and you have then increased by a factor of 2 the amount of gas you can take out with freezing and can then empty both tanks. TP, after re-reading my first post it sounds a bit facetious and was not meant that way. I was simply stating that it could be figured out and that pressure is not meaningless. Pressure is one of the three factors that are needed in calculating btus consumed, the other two being orifice size and time. Without all three you cannot calculate btus consumed, but with pressure, time and total btus, you can calculate orifice (but like you said you need accuracey in your readings). Andy Quote Link to comment Share on other sites More sharing options...
nthe10ring Posted May 9, 2008 Author Share Posted May 9, 2008 Just a thought here, where are u guys getting the tanks filled at, I usually do the replacement thing at the local Home Depot. Just wondered if there was a difference if you took it to the gas place. Really convenient though where I get it now, can do it 24/7. Jerry Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted May 9, 2008 Share Posted May 9, 2008 OTOH the gas place is is a lot cheaper for me and getting a good relationship with a local supplier can really help. I bought a 100# tank for $25 at the local implement auction and my local propane supplier tested the tank and replaced the valve with a brand new one for another $25 and they will let me drop it off and then come back later when it's filled. They liked my tyranasaurous wrench too. Quote Link to comment Share on other sites More sharing options...
Frosty Posted May 9, 2008 Share Posted May 9, 2008 There have been numerous attempts to catalog and coorelate fuel rates, burner types, forge sizes, temps and such over the years but there are so many variables it hasn't resulted in meaningful number as yet. If someone wants to work out a useful Dbase we'll be better served listing the variables so that person can build one. Besides, orifice size, forge volume, liner type, there's altitude, humidity and barometric pressure on a given day. Frosty Quote Link to comment Share on other sites More sharing options...
Finnr Posted May 9, 2008 Share Posted May 9, 2008 Frosty said:" Besides, orifice size, forge volume, liner type, there's altitude, humidity and barometric pressure on a given day." Also what color socks you are wearing and which way the wind's blowing. Finnr Quote Link to comment Share on other sites More sharing options...
Awalker Posted May 9, 2008 Share Posted May 9, 2008 Tyranasaurus wrench??? I'd like to see that if you wouldn't mind. Quote Link to comment Share on other sites More sharing options...
arftist Posted May 13, 2008 Share Posted May 13, 2008 I use a 3/8 black iron tee, with two valves on my johnson #122 gas forge. The 122 requires 1gal/hr for the first 1/2 hr to warm up and then 1/2 gal/hr for forging.(info from Johnson) Having these two valves allows me to change an empty tank while the forge is running. Quote Link to comment Share on other sites More sharing options...
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