I am trying to type this on my phone, hopefully it will work. The first problem was I went to melt down some scrap bronze and it wouldn't melt. My furnace never had a problem melting bronze before and I had melted some brass a month ago and had no problems. But after 2 1/2 hours I gave it up. So after some research I came to the belief that it needed a flare at the end of the burner. Now I don't think that, I think the problem was the combination of jet size and regulator pressure. The original plans I used called for a 1/8" jet and using a barbecue regulator (well under 1 psi). I hooked up a 0-20 psi regulator and it did finally did melt the bronze but it also completely melted the flare I had welded to the end burner pipe (1"). The problem is with a 1/8" jet the regulator doesn't have the fine adjustment at 1 psi or less. So now I am completely rebuilding my burner, something that I have wanted to do for a while but my question is what size jet for what pressure regulator? I have seen people on the internet running 0.035", (mig welder tip) at 30 psi, is this better? Seems like it requires better fittings and one would run out of propane sooner. But these are minor issues if this combination works better.
You'll need to provide some additional information about your burner, like tube diameter, length, inlet size etc. BBQ regulators typically won't cut it. Assuming you have a naturally aspirated venturi type LP burner, you need the LP gas to have very high velocity to make the "ejector" work and draw enough air, thus the .035" mig orifice. There are many subtle variations but here's a picture of a typical Reil style burner and dimensions. A flare is only needed to make the burner perform outside the furnace. It is not needed or wanted when installed in the furnace. Best, Kelly
My simple pipe burners with a mig orifice have worked well for me.. I do use an acetylene regulator, and just dial up enough pressure till it works. My simplistic approach is certainty not for everyone. Maybe just for simple minded people like myself . Mix and match, 4 pipe burners | The Home Foundry
I'm sorry I didn't explain myself very well, it's a forced air propane burner It uses a 1" pipe, 8" long and "T" where the the gas is feed in using a 3/16" pipe that has the 1/8" hole for a jet in it. The other side of the T is connected to the fan, I'll post a picture but I can't do it until this weekend.
if you have a forced air burner and cant get it to melt your problems are much more limited, first it sounds like your regulator is not big enough, High Flow you can use an Acetylene regulator or something like this https://www.oleoacresfarriersupply.com/products/details/full_propane now there are several other possibilities 1) your jet maybe partially clogged , if you did not use fuel grade hose and are using standard air hose, this is your issue, propane will dissolve air hose and chunks will break off and Clog the jet, 2) your tanks to regulator connection maybe regulating your flow details here https://www.crossroadsowners.com/forums/f12/propane-tank-connector-colors-16116.html ) get a plane brass POL one you can look through, no flow restriction 3) if you are using a standard BBQ 20Lb tank the OPD (Overflow prevention device) maybe restricting your Flow ( This is pretty unlikely in a straight forward setup, but if you try to manifold together two or more tanks this will defiantly happen ) ask me how I know V/r HT1 P.S 1 inch pipe is pretty small for a burner , but your furnace maybe small "shrug"
For regulators, and valves, go here: http://www.cajunshoppe.com/regulator.htm I have one of them. I have a dual fuel burner. The waste oil feed is the copper tube, and the propane feed is the 1/4 inch iron pipe. The propane feed just dumps the propane into the burner. I use a five gallon shop vac with a hardware store dimmer control for air. This thing would melt my furnace if I cranked it up. I find the key to this kind of burner is to get plenty of fuel in there and feed it enough air. It uses a one inch iron pipe. Richard
I tried to use a propane BBQ grill regulator the first time I lit my 1" pipe forced air "Moya" burner. With a hair dryer plugged into a dimmer switch and turned way down almost off I was just barely able to get it to stay lit, but if I so much as touched the dimmer switch it would go out. The Moya is a style gravity fed drip injection waste oil burner that works exactly like Rasper's Hot Shot, so the propane is really only meant for preheating the furnace. I have a larger version of the same burner for my (now) medium sized furnace. but I use the 1" exclusively as a propane burner in my small furnace as well, where a bronze melt takes more like 20 minutes. But I absolutely had to get a higher pressure adjustable regulator for mine. It came off a fryer stand. There's no pressure gauge on it but the regulator is rated 0-10psi. Still pretty low pressure compared to a lot of regulators people here are using, I think. With my burner and furnace, to light it I start with the hair dryer on real low. I only open the regulator up about halfway (~5psi presumably), open the ball valve to let the gas get blown into the furnace, and then I crank the hair dryer blower up to full blast and fine tune the propane dial from there by eye and ear from there. <1psi didn't cut it for me, no way. What were you doing differently when you melted brass and bronze before? Jeff
Thanks all for the responses, here is a couple of pictures to help explain my setup. If this worked, that's the setup including the bronze pieces in question. This is a old picture when I was working on the motor (removed) but it shows how simply the gas line goes into the burner. This is the the piece that sits inside the "T". The end is plugged with a large set screw and it just has a 1/8" hole in the side. I built this something like 15 years ago and it has work well over that time, usually takes about a hour to melt bronze or brass. The plans came from a self published book that came with a course I took, and I do think it's emphasis was low cost. I am rebuilding the entire burner and have gone up to a 1 1/4" pipe and will bring the gas in from the bottom. This is what I got so far. As for the jet I do plan on using a mig tip but drilled out, but to what size for how much pressure? Is it better to run higher pressure with a smaller jet size, which seems like it would be "harder" on the system as to leaks and things like that but maybe it burns better? I don't know, is there even a rule of thumb for jet size to pressure ratio?
It looks to me that you are complicating things. With an adequate blower (I suspect your blower does not provide enough air. I use a 5 gallon shop vac. run at a slightly reduced speed) you just need to dump propane into that Tee fitting and adjust the flow of gas with the ball valve, and the flow of air with one of three things: a waste gate, a gate to obstruct the air flow, or an electrical control. (I use an ordinary household light dimmer. It works well with the universal motor of the shop vac. I don't know about with an induction motor.) It doesn't require much regulator pressure. I generally set it at about five pounds. I adjust the gas and the air to get a good neutral flame with the furnace roaring. The burner you are making should not take anywhere near an hour to melt a pot of bronze. I melt a #8 pot in twenty minutes using either waste oil or propane. Here are a few photographs: I made this blower from a David Gingery plan using sheet metal. It has a one-half horse motor. It did not provide enough air. I now use it to cool my stick welder, which went from an annoying ten percent duty cycle to somewhere close to 100%. Richard
