regulator puzzle

I'm working on hooking up a "weed burner" torch. It came with a good regulator but I want to keep that one for a propane forge, so I'm trying to use one of the ones I've scrounged over the years. I got one plumbed in OK but the flame was real wimpy even when I screwed it in as far as I could. I have another one which is also adjustable by removing a screw-off lid and screwing in/out a flat disc which no doubt bears on a spring. I want to try this one next. But it has 3 ports on it, all of which have been used (they have remnants of pipe dope on all 3 1/4" NPT ports). I figure either there are 2 inputs in parallel and one output, or two outputs in parallel and one input. Parallel ports are useful for putting on a gage to read pressure. I've seen pressure gages on the input side of a regulator which are helpful to know how much propane is left in your tank, and I've also seen them on the output side of a regulator so you can see what your output pressure setting is.
The 3 ports are arranged like a 'T'. The 2 ports which form the crossbar of the 'T' you can actually see through partially. So I'm sure they are in parallel. I don't really know what happens if you hook up a regulator backwards. I'm sure I can figure out whether the single port is input or output by randomly picking one and seeing what happens, but I'm worried something bad might happen.
Anyone have any bright ideas or insights?
Oh yes--another question. Can I use a pressure gage off an old air compressor in a propane setup? Or do I need one that is specifically designed for propane?
Thanks!
Grant Erwin

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1: a pressure gauge on the input from a tank containing liquid propane will tell you approximately what the temperature of the tank is - not a thing about the volume of liquid propane left, until it runs out, and at that point it has run out...
1a: Want to to know how much is in the tank? Use a scale. Or, on a humid day, look at the frost on the tank while it's in use.
2: The most likely use of a 3 port regulator is therefore the commonly seen 2-burner barbeque grill - one in, two out.
3: Your scrounged, scavenenged, and presumably somewhat aged regulators should visit a qualified rebuild shop before being placed in fuel-gas service. Your local propane supplier either does it or knows who does, and probably does not cost all that much. A brand new replacement regulator from the spare parts for grills section of a store doesn't cost all that much. Being too cheap can get expensive.

I might also add that as a homebrewer, I know there are different flavors of propane regulators.
There are low pressure regulators. These are for low output burners and many gas grills and such. I would guess you have one of these.
Then there are high pressure regulators. The original weed burner reg is probably one of these. I've got one on my main burner and it can output 100,000+ BTU. Perfect for bringing 12 gallons of water, wort, or oil _rapidly_ up to temperature.
Deep-fried turkey anyone?
The reg off the weed torcher will probably be dandy for a forge. But then your weed burner will be a-wanting...
Jeff Dantzler Seattle, WA

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outputs
regulator
compressor
propane?
I'm not understanding any of this, so help me out if you can. I've been using weed burners for 20 years (as per code)for preheat on welds, and I even use one every once and a while to burn weeds, but I've never seen or used a weed burner, AKA preheater, with any kind of gage or regulater. They have always hooked up directly to the tank. So, what am I missing?
JTMcC.
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JTMcC writes:
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They use an orifice, not a regulator, like a Bernzomatic torch (think of it as just a giant version). Manifold burners like on a grill or turkey fryer need a regulated feed, not just an orifice.

My torch is a good quality torch. It comes with a 30' hose and a real good regulator. The regulator doesn't say Goss, but it looks just like the Goss regulators hanging on the wall at the welding store that cost $60. That's why I bought this torch in the first place, was as a way to get a good regulator cheap for a propane forge.
I may try it without a regulator.
Grant
Richard J Kinch wrote:
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Well, we use high quality, in fact industrial grade, weed burners all the time, but like I said, never seen one with a regulater. Or 30' hose for that matter. Just what are they intended for? Weed burning?
JTMcC.
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fryer

JTMcC wrote:
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Well, this particular one came out of a roofing supply company, so I'm guessing it was used to lay torch-down roofing material. - GWE

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That would explain the 30' hose! I'd still like to know what they use a regulator for, if any one knows.
JTMcC.
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The regulator allow you to set a consistant pressure at the torch summer and winter. No regulator and you are dependant on the bottle pressure which varies with temperature. For a simple setup you can adjust the torch valve to compensate.
JTMcC wrote:
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Ok I agree its probably over the top and a luxury weed burner. The torch valve will serve to adjust the pressure to some degree and allow the flame size to be adjusted but for this type of application and heating etc you normally have some idea of the flame size you require so the regulator is redundant, you just do it by sight and experience. I have had the problem in the UK of trying to get a propane regulator with outlet gauge which are not common. Found one eventaully. I am using it for a glory hole for glass blowing and want to be able to adjust the pressure to control the flow through a fixed orifice. This controls the mixture and has an effect on glass colours. Some colours respond to a reducing atmosphere and produce a lustre effect others just turn nasty such as certain reds which end up looking like liver. I want to be able to reproduce the pressure from one use to another so I need a regulator and gauge.
JTMcC wrote:
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On Mon, 10 May 2004 21:27:28 GMT, "JTMcC"
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Someone already mentioned it - putting on "torch-down" Modified Roll Roofing. It works like hot melt glue, you heat it either the torch enough to melt the back side (and the top lip of the last run), then flip it over and the two roofing sheets fuse together.
You want some control over the temperature, so you don't light the roof on fire, or don't get a cold joint that leaks when it rains. A regulator keeps the burner output fairly consistent regardless of cylinder fill level or temperature.
--<< Bruce >>--

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Won't
Again, thanks, but I'm well aware of hot roofing, and believe me it's not a precise process. It certainly doesn't call for precise regulation of gas pressure.
JTMcC.
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On Mon, 10 May 2004 20:47:17 +0100, David Billington
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Lots of weed burners here in ag country. I dont think Ive ever seen a regulator on any of them. Just the tank valve and one on the ass end of the torch.
Gunner
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That rifle hanging on the wall of the working-class flat or labourer's cottage is the symbol of democracy. It is our job to see that it stays there.         - George Orwell

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The regulator keeps the propane pressure constant at the torch so once the flame is set, it'll stay that way until the propane's gone or the tank gets so cold that the tank pressure drops below the regulated pressure. The tank gets cold because the conversion of liquid to gas inside it absorbs heat. When the propane gets cold its vapour pressure falls off. We used to use a tank, a hose, and a torch with a valve on it, and no regulator, but had to fiddle a bit with the valve to keep the flame set. Someone mentioned that it was illegal to run without a regulator. Might be true in some areas. Dunno. Also used to defrost the tank with the torch. Maybe I'm lucky to be here.
Dan
Dan

Not only that, but the regulator allows you to run the torch just hot enough without wasting fuel. I think it would be like using a rocket to torch a dandelion without one! Even with a regulator, they go through a 20# propane bottle pretty quick. - GWE
Dan Thomas wrote:
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Grant Erwin wrote:
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BBQ two port hose from one tank ? - seems possible.
I don't recall ever seeing a regulator on a weed burner in Texas. It has been 20 years almost now, but the unit was just a valve and a long hose to a t oat a tank.
Normal burners do use them - in shops around (not CA) there are brown stoves that have large burners in them - but run off low pressure.
Good luck - and be cautious.
Martin
Martin