natenaaron Posted May 27, 2016 Share Posted May 27, 2016 Got the gas plumbed, checked for leaks and installed both 1 inch burners. neither would stay lit no matter what I did. Replaced one of the 1 inch burners with my 3/4 to make sure the flat floor was not the culprit. It fired up. I adjusted the remaining 1 inch so it was further into the lining and it fired up. I ran the forge on both the 3/4 and the 1 inch at the same time and hoooollllyyyyy cow it went to town for about 10 minutes then it was like it lost pressure for some reason. The flame in the 1 inch crawled up the tube and went out, came on went out. The 3/4 remained on. If I turned the 3/4 off the 1 inch stayed on but at reduced pressure. My tank was cool but I would not say it was cold. It is getting toward empty but not empty yet. Could this have caused the drop in pressure? Quote Link to comment Share on other sites More sharing options...
Buzzkill Posted May 27, 2016 Share Posted May 27, 2016 With both a 3/4 and 1 inch burner running I would say that yes, that is most likely the culprit. Mike or Frosty are obviously more well suited to answer the finer points on this, but I believe the 1 inch also needs more space between the end of the burner tube and the first obstruction the flame will hit (opposite wall) in order to function correctly. I had a dual gauge system on mine for a while, like you would see on an oxy/acetylene system, and there is a significant drop in tank pressure well before it gets frost on the outside or feels particularly cold, especially when it's nearly empty. It's also possible that you have some debris from the build that collected in your jet, but my money is on trying to pull too much propane from too small a tank too quickly. Quote Link to comment Share on other sites More sharing options...
natenaaron Posted May 27, 2016 Author Share Posted May 27, 2016 hmmmmm. Do I run each off its own tank? I have 622 cubic inches I want to get to welding temp. Quote Link to comment Share on other sites More sharing options...
Buzzkill Posted May 27, 2016 Share Posted May 27, 2016 Good question, but it may have more than one answer. The first one is it depends on your tank size. If you're using grill sized propane tanks that still may not be enough. When I run a single 3/4 inch T burner on a single BBQ tank for more than a couple hours I can lose pressure. So, if you don't anticipate forging for too long then you can probably get by with individual tanks of that size. I just got a Mr. Heater 2 Tank Hook Up Kit for running my single burner to keep the problem to a minimum. That will allow me to still use a single regulator for both tanks. My guess is if you are running two 3/4 or 1 inch (or a combination of both) you'd need 3 or more of those tanks hooked together for long forging sessions. If you're using 100 lb tanks then 2 of those would probably get you by, but I have no direct experience there and I'm sure someone else out there does. Another simple solution is to place your tanks in a shallow water bath to keep the tank from getting cold so fast. You don't want it deep or you risk the tanks tipping over as they empty, but water should contact the entire bottom of the tank to be effective. A gallon or two of water makes a lot of difference in the tank temperature. Still, with 2 burners of that size you probably want a separate tank for each or 2 tanks linked together. Let us know what works or didn't work. I'm curious in case I decide to build a bigger forge. Quote Link to comment Share on other sites More sharing options...
natenaaron Posted May 28, 2016 Author Share Posted May 28, 2016 I'm running the next size up from BBQ tank. I think 30 pound. I have two of them. I hooked up the full one and it ran a lot better for longer at a much lower pressure. I still don't have a pressure gauge. I will run a longer test tomorrow. I have run it up to temp three times, as I was supposed to, to cure the liner, and letting it slow cool. I have 2 inches of ceramic wool and about 1/2 inch of satanite and the outside is getting screaming hot. The welds around the burner holders blued. I am somewhat concerned about this. That Gas Can in the background was moved before the forge was lit. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted May 28, 2016 Share Posted May 28, 2016 You need to fill the tanks before trying to guess whether low fuel is part of the problem. As propane leaves the tank you creates a refrigeration effect. All there is to counteract that cooling is ambient air temperature being transferred through the cylinder wall. It is the propane itself on the inside of the wall that sucks that heat where its needed. the less propane present in the tank the less area of transmission. If it is part of your problem, then you need more fuel to give more wall area to gather more heat faster from more ambient air; simple, yes? This is where most guys go off the track; you don't want to get a big tank, because several small tanks will give you about TWICE THE WALL AREA; and they are easier for most guys to deal with; just gang them together Quote Link to comment Share on other sites More sharing options...
natenaaron Posted May 28, 2016 Author Share Posted May 28, 2016 Then that is what I will do. Quote Link to comment Share on other sites More sharing options...
Frosty Posted May 28, 2016 Share Posted May 28, 2016 Nate: Step back and look at your forge end on. now visualize which direction the vortex generated by each burner is traveling. Now imagine both vortices in the same cylinder at the same time. See the problem? Issue 2. One properly tuned 1" NA burner will bring 600-700 cu/in to welding temperature. Is there something about the chamber's shape that makes it need 150% max burner? Believe it or not the larger the home built NA burner the more susceptible to back pressure it is. I can't speak for one of Mike's but most are. Put your tank in a wash tub of warm water and it'll maintain enough pressure to run both burners even caked in ice. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
natenaaron Posted June 8, 2016 Author Share Posted June 8, 2016 On 5/28/2016 at 9:55 PM, Frosty said: Nate: Step back and look at your forge end on. now visualize which direction the vortex generated by each burner is traveling. Now imagine both vortices in the same cylinder at the same time. See the problem? I guess I am not understanding. The flames are not directly aiming at each other. I'm really tired so please forgive the ignorance. I am thinking this was a bad experiment and will need to be recified when I get some more Satanite. It sure gets hot in there though. I had a piece of two inch 4140 in it to see how fast it would get it hot. It got above orange in the ten minutes before I lost pressure. I removed the steel then so nothing was in the way. The way I read the burner to volume thread was a 3/4 inch heated 300-350 square inches to welding temp, and other threads varied. A 1 inch heated 600 square inches IIRC. I have 620ish. On one of my other threads you said I could turn the pressure down if there was too much burner. In my head this registered as it is better to have too much burner than too little because too much can be turned down. Was this wrong? Quote Link to comment Share on other sites More sharing options...
Will428 Posted May 31, 2019 Share Posted May 31, 2019 You sound just like me. What size jet are you using. Also what regulator. I was using 1 in pipe with a .035 originally. I was also using a 0-30 psi regulator cheap from Amazon. I went down to .030 and the difference is amazing. I will be setting up everything later today. Only ran briefly yesterday but I think the regulator does not like little back pressure. Having the smaller jet sprays faster down the tube and uses less fuel.and obviously causes more pressure in the line. Quote Link to comment Share on other sites More sharing options...
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