Frosty Posted July 8, 2023 Share Posted July 8, 2023 Increasing the surface area exposed to ambient air will prolong the time propane will stay above vapor temp. Increasing the area in the tank does nothing except maybe increase the chance the tank will tip over and start squirting liquid propane through the burner. This is a B A D thing. 100lb tanks can be had for reasonable at yard, garage, etc. sales. Just look them over carefully for damage and the date on the inspection tag. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted July 8, 2023 Share Posted July 8, 2023 I agree with with this man's application being as safe an answer as there is likely to come along. I also agree that safety codes must be followed. However, I doubt that the code applies to this particular case, because the heat source is controlled. Furthermore, I paid for a copy of the code twenty years ago, and this subject was not mentioned in it then; I doubt that it is now. Quote Link to comment Share on other sites More sharing options...
Candidquality Posted July 9, 2023 Share Posted July 9, 2023 Not trying to stir the pot, 100% with buying the proper size tank, and more importantly, buying the right size burner. Just had a passing thought. Appreciate the confirmation it would not make any real difference tipping the tank (excluding the danger). One more way we know it would not help. Quote Link to comment Share on other sites More sharing options...
George N. M. Posted July 9, 2023 Share Posted July 9, 2023 FYI, with my modified Sandia forge I have had 20# tanks "freeze" up but have never had the problem with 30# tanks and larger. A full 30# tank is about all I can carry around. You would think when any size tank is getting low the cooling vs. mass of liquid remaining would result in the liquid dropping below vapor tempertature but I have not seen that happen. "By hammer and hand all arts do stand." Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted July 10, 2023 Share Posted July 10, 2023 4 hours ago, Candidquality said: Appreciate the confirmation it would not make any real difference tipping the tank (excluding the danger). One more way we know it would not help. No, it would not help at all. An important factor is how fast you use propane out of a given tank, versus the tank's size. Another factor is how cold ambient air surrounding the tank is, because it is heat from that air that is being transferred through the cylinder wall to raise the temperature of the liquid propane. Finally, as the tank becomes seriously depleted the amount of liquid propane that is contacting the cylinder wall becomes less and less; giving the same result as a shrinking cylinder would; less heat transfer from the ambient air. Quote Link to comment Share on other sites More sharing options...
BeaverNZ Posted October 16, 2023 Share Posted October 16, 2023 On 7/16/2020 at 9:29 AM, BeaverNZ said: Well I am getting well along with my bottle warmers for my two 45Kg cyl, Just an update with my bottle freezing or pressure drop due to the bottles getting very cold I have found so far I havent needed to use the fish tank heaters though the bottles do get alot of condensation showing where the gas level is when the level is high enough. the extra surface area outside the water tank and the better heat transfer of the water to the bottle is working well. another plus for putting the bottles in the liquid is if you have the water level at 330mm deep with these bottles they float at that level so the felt weight of the bottles is the remaining amount of gas. Quote Link to comment Share on other sites More sharing options...
Absinthe Posted May 18 Share Posted May 18 I am using a 2 burner vevor forge with 20# propane tanks like one might use with a gas grill or patio heater. Once the tank gets down to a certain point the outside lower 1/4 of it frost's and eventually the pressure noticeably drops. I have some thoughts, and have received some suggestions. 1. Use larger tank like 100# or at least 30# The cost of a tank seems pretty high, and the idea of schlepping the bigger tanks to get filled in my Prius make me feel as though, this may not be an immediate option. Besides, I currently have 3 tanks dedicated to forge use, and one other available if needs be, since we really only use it for our patio heater at Thanksgiving. So this is a maybe someday, but not right now. 2. Put the tank in a water bath I have done similar with canned air. It is messy, and I fear when the weather cools it will be more trouble than it is worth. Now that I am refilling rather than exchanging tanks, I am also not wanting to rust or otherwise damage tanks any sooner than necessary. 3. Use a bucket warmer "band heater" (like an electric blanket but made for buckets) I currently don't really have any electricity at the forge. I am also reluctant to have an active heat source associated with a propane tank. It seems wrong and potentially dangerous. 4. Use a wye or tee to connect 2 or more tanks should reduce the speed of the flow similarly to a larger tank. This sounds good in an intuitive sort of way. I don't know for sure but it sounds like a good idea. I'd love to hear from someone doing this successfully. Even with the suggested hardware configuration. Other ideas would be helpful or information/experiences about these would be cool too. Quote Link to comment Share on other sites More sharing options...
Frosty Posted May 18 Share Posted May 18 What's happening is the boiling propane. . . Yes, boiling it is liquified in the tank and when you draw gas the pressure drop causes the liquid to evaporate and even a small forge burner draws fast enough the liquid boils. Which drops the pressure until the liquid starts to turn to slush and it has to sublimate rather than boil so pressure drops to what sublimation will support. The liquid evaporates at the surface of course which remails the same in a cylinder, Heat input on the other hand is via conduction through the tank. As the tank level goes down so does the contact area so the LPG can not maintain temperature. So, yes, two tanks have more surface area in contact with the tank and double the surface area for evaporation. Combined this means pressure in the tanks falls slower due to the greater LPG surface area. AND the LPG is in contact with more of the tank surface to absorb heat. When it starts getting cool or I have to plug in two magnetic engine heaters to keep my 100lb. tank from slushing up. Anymore I have the shop closed down before that point and it's pretty useless if you don't have power. Before it got so it wouldn't hold water I used a wooden whisky barrel half as a slack tub at demos a couple bungi cords to prevent a 20lb. tank from rolling over on it's side I used to float it. Cold enough to form ice on the surface the water still prevents the LPG from slushing up in the tank. It's also a great way to keep your soda cold on a hot day. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
George N. M. Posted May 18 Share Posted May 18 A full 30# tank is about the most I can schlepp around and I roll it on its end when I can. I let the guy at the propane place lift it into the car for me. If you have a 100# tank or larger you may be able to get the tank refilled in place by the local propane supplier. Back in my geologist days I sat on an oil drilling rig in North Dakota for the month of January. It never broke zero degrees the whole month I was there. We had a problem because the temperature was so low and with the cooling from releasing pressure for the heater in our trailer the propane tanks kept freezing up. We wrapped electrical heat tape around them and then wrapped the tanks and the heat tape with fiberglass insulation. We didn't blow up but I'm not sure I would do the same today. GNM Quote Link to comment Share on other sites More sharing options...
Frosty Posted May 19 Share Posted May 19 I can roll my 100lb tank onto the pickup truck as the shop is on fill at the right level. Unloading it is downhill and the guys at Suburban Propane just swap out tanks so all mine, 20, 40 and 100 have current inspection stamps. From the pickup to the grade is downhill about 1'" so I slide it back off the gate and when it tips I keep the momentum going and stand it up. Then it's hand truck time. The 40s I can get in and out of the truck, even carry one for a ways but the hand truck is RIGHT THERE! I've taken the 100 to demos when there were a couple of us using two forges. The first time we grunted it out and back in, the next time I put my engine hoist in the pickup and haven't had to grunt the tank or my anvils since, sometimes I even take my swage block. The engine hoist is maybe my best ever garage sale buy and the Mrs. was MAKING the old man sell so I got it for next to nothing. Win WIN! Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
BillyBones Posted May 19 Share Posted May 19 When i used propane i ran 3, 20# tanks connected together. Worked quite well to prevent the freezing. Quote Link to comment Share on other sites More sharing options...
Buzzkill Posted May 20 Share Posted May 20 On 5/18/2024 at 1:45 PM, Absinthe said: I'd love to hear from someone doing this successfully. Even with the suggested hardware configuration. I use a 2 tank hookup kit from Mr. Heater (F273737). To that I added a propane regulator to control the pressure of the supply line to my burner. I've used that setup for several years now with no major complaints. Quote Link to comment Share on other sites More sharing options...
JHCC Posted May 20 Share Posted May 20 I've got the same setup, but I've been having trouble with the hose and have had to resort to only connecting one tank at a time. I should probably check to see if there's a stuck valve or something. Quote Link to comment Share on other sites More sharing options...
Frosty Posted May 20 Share Posted May 20 It's been a while since this has come up so it's a good time to go over one of the main causes for a loss of flow in hoses, fittings, etc. Propane is a mixture of lighter fractions from a cracking facility or a gas well and it's not "filtered" unless it's pretty dirty. Propane leaves a waxy residue on surfaces it flows over which can restrict flow or even block it through small orifices like the gas jet in a propane burner. I believe there are safe solvents to clean soluble materials like rubber and plastics, I think Mike knows maybe. Your brass and steel fittings can be cleaned with an acetone soak, valves are a maybe, it depends on what the seats are made of. Regulators are a NO! Solvents are B A D for the diaphragm, even if they don't dissolve they tend to soften and stretch. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted May 21 Share Posted May 21 6 hours ago, Frosty said: I believe there are safe solvents to clean soluble materials like rubber and plastics, I think Mike knows maybe. I would not employ a hotter solvent than rubbing alcohol for hoses. Mineral spirits are probably okay for plastics. Beyond this, it is critical to know what plastic is being discussed, before trying to chose a cleaning agent that is safe. 6 hours ago, Frosty said: I believe there are safe solvents to clean soluble materials like rubber and plastics, I think Mike knows maybe. I would not employer a hotter solvent than rubbing alcohol for hoses. Quote Link to comment Share on other sites More sharing options...
tinkertim Posted May 21 Share Posted May 21 Isopropyl Alcohol was what was specified for cleaning the large rubber rollers in our broadcast reel-to-reel video recorders, back in the day. It is the most rubber-safe solvent I know of, and removed the build-up of iron-oxide from the videotape without damaging the rubber rollers. The wrong solvents would cause the roller surfaces to crack and go brittle. I always keep some for delicate cleaning (as well as a little Toluene for brutal cleaning!!!) Quote Link to comment Share on other sites More sharing options...
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