I want to upgrade

Discussion in 'Burners and their construction' started by KDM, Feb 18, 2021.

  1. KDM

    KDM Copper

    I've ben melting aluminium quite happily for a couple of years now on charcoal with a speed controlled leaf blower for air.

    That's my furnace:

    Furnace to Scale.JPG

    I think I want a bit more convenience. I think I want to try propane, but it looks comparatively expensive and not the sort of thing you "try". It looks like it needs about £40 for a burner, hose, and reg. Then about another £40 to rent the tank and about another £40 to fill it.
    ...and I don't know how long that will burn.

    So, that's quite a lot of cash and I'm not sure I want THAT much convenience. The other possibility is I have a perfectly good Reillo kerosene burner from a home heating boiler. But it looks like it will produce a monstrous flame and , while I'm fairly competent with my hands, it does frighten me a bit and I think it's too big for my furnace.

    I suppose the questions are:
    - Can I make a burner from one of those weed wands? I've heard tell of it, but never seen it.
    - How many hours burn might I expect to get per kg (or lb) of propane?
    - Can anyone steer me to a modification for a similar kerosene burner for a similar sized furnace?

    Blower and Speed Controller.JPG

    Alternatively, should I just stick with charcoal? I've been using barbecue fuel for the convenience, but it's not beyond me to make my own in a pit. If I go down that road, I'm looking for some advice on blower size. I have a leaf blower with a speed controller. I'm running it at bare minimum speed and I'm getting the feeling that there's still too much air and it's maybe actually cooling the furnace. I've read here about folk getting really good results just with a hairdryer.

    Any pointers to advance me to the next level would be great, please.
     
  2. Your laws may be enough different than the U.S. that we probably need a UK member to offer advice on propane.

    It is easy to make a propane burner, just a piece of pipe with your leaf blower blowing straight through. You only need a side tap a foot or so back from the furnace end with a needle valve on it to admit the propane. No orifice is needed if you have a blower. I use a simple slide gate to limit my air flow but I think you could use a piece of cardboard over the inlet to your leaf blower to starve it for air. It doesn't hurt a blower to be starved for air.

    Charcoal is not a bad fuel, and real wood charcoal will make a lot more heat than briquettes.
     
  3. KDM

    KDM Copper

    With apologies "side tap a foot or so back" probably means something to someone who knows what they're talking about. Needle valve, I get (I'm old enough to know what a carburettor is!)
    I also need to learn when air is and is not required. The propane burners I've seen here don't usually have additional air. I'd just as soon not use my blower (it's very noisy and we have neighbours!)
    I know I'm being thick here, but if you have no orifice, where does the gas come out?
    It does worry me starving the blower of air. There's a definite load on the motor. I hope you're right and it's just my imagination!
    Thanks.
     
  4. rocco

    rocco Silver

    I agree with everything Andy has said, and forget about the weed burner, it's a waste of time and money. Next to charcoal, a forced air propane burner is BY FAR the easiest type of burner to build, a blower with an appropriately sized pipe for the combustion air, regulator, valve and hose for the propane along with a fitting to connect the hose to the blower tube, that's it.

    By side tap, he just means some sort of fitting in the side of the blower pipe through which the fuel is introduced into the air stream. On my first burner, it was simply a hole drilled into the side of the blower pipe with a short piece of 6mm steel tube soldered into the hole, the propane hose was secured to the tube with a hose clamp.

    Natural aspirated propane burners i.e. those without a blower, rely on the venturi effect to draw air into the burner and the venturi is "powered" by a high velocity jet of propane, a fairly small orifice is needed for the propane to create that high velocity, on my current burner that orifice is a mig welder tip. The most common type of naturally aspirated burner is what's often called a Reil burner, google "Reil burner" and you'll find lots of example and info. BTW, naturally aspirated burners are also very noisy, nothing to be gained on that front.
     
    Last edited: Feb 18, 2021
  5. KDM

    KDM Copper

    Only one question "forced air". Does that simply mean I need to force air with a blower? The reason I ask is that it looks like the "simplest" burners have air drawn in by venturi.

    Comment on weed burners noted, thanks! (Damn, it looked like an easy option!)

    Right. LIGHTBULB! That's the difference between a tap and a tapping. For me a "tap" is something I can turn on and off: like a valve. A "tapping" is a hole with a pipe sticking out. Thank you.
     
  6. rocco

    rocco Silver

    Forced air = blower
    Not that building a verturi style burner is complicated but in terms of ease of construction, forced air is the easiest
     
  7. No, when you starve a blower you unload it. It will run faster and draw less amperage.

    A side tap is just a hole drilled and tapped in the side of the burner pipe. You just let propane in the side tap and blow it into the furnace.

    You need an orifice if you're going to induce air instead of force it in.
     
  8. I see Rocco answered, sorry for the double posting.

    A 1-1/2" pipe would be plenty, probably a 1" pipe would work fine. So all you need is a little valve, a ball valve or gate valve will work but a needle valve is a bit nicer. Then you use a ball valve to shut off so you leave the needle valve set. once you have propane to the burner area all you need is a pipe with a side opening, valve in that opening, and blower hooked to the pipe.

    Induction burners are easy to build but you do have to tune them. They roar but not as much as a leaf blower in my opinion.

    I heard that in Australia you can't just hook propane up to your homemade burner. Not sure if that's true but you do need to make sure you're not breaking the law.

    Here's my furnace operating on propane. I have a second side tapping for used motor oil. It runs through a piece of brake tubing to the end of the burner pipe. You can see the ball valve for it is off. I have a simple gate (yellow blade) in the pipe to limit air.



    The first minute or so of this video shows me lighting my furnace on propane to warm up for oil. I don't use newspaper any more, I just lay a lit match on the floor of the furnace.

     
  9. One more if you don't mind. When I first started I built an induction propane burner. I made a video of the very first time I lit it. I was nervous. It simply has a plug in the end of the pipe drilled with a propane inlet, a MIG tip outlet, and a gauge in a side tapping. Then there are big holes around the pipe with a sleeve to control the air. The MIG tip has to extend past the holes or very close to past. My plug was a solid piece of steel I drilled and tapped and used a set screw to hold it so the MIG tip would extend in far enough. I used it for a long time until I decided to use used motor oil. My motor oil is in a tank with 10 psi air forcing it out, otherwise it is a drip burner.



    I still start with propane and get the furnace hot before admitting oil. The oil takes a lot more air, burns cleanly, and gets my furnace hotter.
     
  10. rocco

    rocco Silver

    I have no idea what the laws are regarding that here in Canada but I'm quite sure I wouldn't have any problems with law enforcement unless of course my burner blew something up or burnt something down.
     
  11. Tobho Mott

    Tobho Mott Gold Banner Member

    I'm not sure what the law says but Bill Jurgenson's foundry here in Canada was totally above board, not someone's secret backyard project. He ran his furnace on a simple diy forced air propane burner for years, safe as long as it's not left running unsupervised. It wasn't the cops or the FD that made him upgrade to meet the requirements for certification at great expense, it was his propane supplier when he asked for a bigger tank. Nobody is going to bother you if you're hooking up a little bbq tank or two, unless maybe you have problem neighbours. Working in the evenings after the neighbours have all gone inside for the day kept me under the radar for years, and tbat's when I was running my big oil furnace with the drip burner and screaming shop vac blower.

    No orifice means the gas just dumps into the burner tube through a (comparatively) big drilled hole rather than a tiny jet that has to be aimed properly. This means you can use a lower pressure propane regulator. FWIW I hardly ever use oil or diesel anymore ever since I built my smaller furnace, so now I usually run about 5 or 6 psi using a 0-10 psi propane regulator I took off a cheap fryer stand kit, and a hair dryer is all I need for a blower. Melt times are much faster and I don't think it's any louder than a venturi burner. But plenty of people do use those, and they're not all that complicated either.

    Jeff
     
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  12. Peedee

    Peedee Silver

    The law in the UK is shady regarding home made LPG burners, technicaly there shouldn't be any issues as it's not a 'fixed' device or attached to the home (or business) so essentially it's no different to a store bought BBQ. Any GasSafe engineer worth his salt wouldn't sign off on an LPG burner that was home built, nor should he have to as it's a portable unit, but then you are using a non-conformant home built product on your property... Don't over think it, you sound intelligent enough to know what is safe and what is not.

    Of course when things go wrong the insurers will clutch at anything to not pay out. Just make sure things don't go wrong! (Common sense, don't melt inside, well away from the house etc)

    We are very lucky in the fact the NHS don't really care how you blew yourself up ;)
     
  13. FishbonzWV

    FishbonzWV Silver Banner Member

    Here's my weed burner mod. I use it on both of my furnaces, A6 and A10 sizes.
    Propane orifice inserted in the end of the wand.
    Burner1-horz.jpg Burner2-horz.jpg
    Couple of years later, added a blower.
    Burner4.JPG
     
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