brian Posted March 19, 2008 Share Posted March 19, 2008 Hello Folks, Just finished my gas forge and fired her up for the first time.Used a 9kg gas bottle for the body and an old fan from a Volkswagen motor. No jets used, just a 1/2 inch gate valve to control the gas and 1 1/2 inch valve for the air flow.Once I got the mixture right ( after scaring myself a few times ) it heated steel up to white heat running at about 2-3 psi with the gas tap just open, think I'll put a valve off an oxy torch on it for finer gas control and a solenoid shut off valve in case the power fails to the blower. :confused:Can't remember how to put photo's here so I've put them in the gallery section. Quote Link to comment Share on other sites More sharing options...
Glenn Posted March 19, 2008 Share Posted March 19, 2008 Posting images on IForgeIron ---> click here Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted March 19, 2008 Share Posted March 19, 2008 I've used acetylene regulators on the gas side of things---as long as they are rated for propane as the seals can be trashed if it's not rated. A regulator is handy to keep the flow fairly constant as the gas in the bottle level changes. Welcome to the dark side and watch the Dragon's Breath! Quote Link to comment Share on other sites More sharing options...
hidn45 Posted March 19, 2008 Share Posted March 19, 2008 Nice looking setup, Brian. Speaking of dragon's breath- I couldn't tell from the pic, but if the generator's still mounted to that VW fan, you ought to hook it up to a little muffin fan under the forge opening to blow the dragon's breath up & away from you. Actually, now you've got me thinkin'- I think I've got an old VW fan still in the shroud, that'd make a great air source for a father & son double forge for our shop..... hmmmm. Good stuff- randy Quote Link to comment Share on other sites More sharing options...
brian Posted March 20, 2008 Author Share Posted March 20, 2008 I've used acetylene regulators on the gas side of things---as long as they are rated for propane as the seals can be trashed if it's not rated. A regulator is handy to keep the flow fairly constant as the gas in the bottle level changes. Welcome to the dark side and watch the Dragon's Breath! Forgot to mention I've got a lpg regulator on the gas bottle,Trouble is it's marked in 50 kPa increments which makes it hard to be sure exactly what pressure the forge is running at.I think I can mount a low pressure guage in the gas line to be more accurate but don't know if this is necessary. Can anyone tell me when it's running at the right air/gas mixture or is it trial and error until I get it right?:confused: Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted March 20, 2008 Share Posted March 20, 2008 First of all pressure gauges are nortorious for being wrong. Your forge doesn't need to run at some set pressure. It needs to run *right* and that is a mixture of things: ambient air pressure, gas pressure, airflow, needed forge temp, size of forge, etc. To tune a blown burner you can start by giving it some gas, lighting it and then adding air until you get the loudest burn and then backing off slightly on the air to get a bit less oxidizing burn if you are working with stuff where scale or decarburization is an issue. Another method is to tune it so that the flame impingement area on the forge is brightest. However if you need the forge hotter you will have to turn up the gas and the air both to get more BTU's into the forge. If you get a setting you like note what that is on your gas guage and air valve and start there next time---may still need tweaking but you start in the area that is right for your forge. Also as the forge heats up you may need to tweak the adjustment again to maintain the correct atmosphere in the forge. Quote Link to comment Share on other sites More sharing options...
brian Posted March 22, 2008 Author Share Posted March 22, 2008 Thank you for your tips Thomas. Still a bit scared of the gas, which is probably a good thing,I guess I'll relax a bit the more I use it. Quote Link to comment Share on other sites More sharing options...
Frosty Posted March 22, 2008 Share Posted March 22, 2008 Brian: While my personal preference runs towards naturally aspirated burners, there's nothing wrong with a gun (blown) burner. When you plumb the mixing tube put at least one 90* bend in it for two good reasons. First it really aids in mixing the air and propane. Propane doesn't like to mix with air and in fact will settle out over time. Though NOT below an explosive ratio! Secondly, it will help prevent back fires, for reasons I don't know the flame front of burning gas doesn't like going around corners. Another excellent method of mixing the prop and air is to introduce the prop at the blower's intake and let the blower vanes mix them. Another thing to think about is where you're going to use your forge. Make absolutely sure your work space is well ventilated. ANY fire will deplete oxy from the atmosphere and introduce combustion byproducts like CO2 and CO. A good hot forge will make nastier things like nitrous oxide (NAO2 ?) and such but it's the CO that'll kill you. Get a CO monitor with an audio and lighted alarm! you may not hear an audio alarm or you might not see the blinking light but having both will double your chances. Do NOT set up propane appliances in a basement! Propane is heavier than air and will settle in low spots just waiting for a spark to blow you into next thursday. Do some research and play safe. This stuff is really fun, if you take some simple precautions. There're few things as satisfying as building and lighting off your very own home made burner. The jet engine roar, the blast of heat, the smell of singed hair. OH be still my beating heart! Frosty Quote Link to comment Share on other sites More sharing options...
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