[TheForge] Problems with propane burner

[Jerry Frost]

----- Original Message -----
From: "Marc Godbout" <marc@ironringforge.com>

>
> It's not a tight bend, though. A 90* bend in rigid conduit has, I'm
> guessing, a 5" radius to it. It's a very wide sweep. But your point on
> back pressure is a good place to start. Anything other than straight is,
> well, not straight.
>

How long is the tube straight before it begins the sweep? You might try
giving it 8" of straight tube before it hits the 90*. This should allow good
induction and give the mix a head of steam before it makes the bend.

>
> Ah, but I'm using a cross fitting (four joints). So I've got two 1 1/4"
> intakes. The propane supply is through a 1/8 nipple through a hole
> drilled in a 1 1/4" plug. I was able to plug one opening up completely
> and saw no difference in performance at the low end. It did affect high
> end, though.
>

Ah indeed! Good, I wasn't able to get a cross for mine and had to drill the
"T" for the supply. Using a pipe nipple though leads me to another thought
and that's the distance between the jet and the tube's throat. I use 1/8"
lamp rod so it's adjustable. Lamp rod and 1/8" pipe are the same thread but
the pipe is tapered where the lamp rod isn't. When you tap a fitting for
lamp rod you have to creep through with the pipe tap or the lamp rod will
wobble, making alignment almost impossible. When I tap the hole I only go
till the lamp rod will just pass, this means making 1/4 turns with the tap
wrench, backing it out and trying the lamp rod till it goes. I also use a
locknut to help hold it straight and lock it in position.

If you can block one intake port without effecting performance you're
feeding it way too little, try either chasing the 0.035" to 0.040" or try a
0.045" mig tip.

>
> This I don't know. Because of the bend, it's difficult to see how well
> the jet is aimed. I did drill the hole through the plug while the plug
> was installed on the cross to maybe compensate for any junky threads.
> But I've got no more machining tools than a drill press and simple
> woodworking squares. It is something to investigate, though.
>

Something that'll help is assembling as much as possible before you drill. I
have a lathe but but before I drill I assemble the "T", bushing, tube and
make match marks so I can reassemble it later and have it as aligned as
possible. Still, the first one I made before I had the lathe set up and had
good luck assembling it all first.

>
>
> Yeah, but I want it all and a place to put it :-) My existing forge
> idles at a nice, little purr, so I've been spoiled. Besides the sound
> difference, the heat output at idle on that forge is very much reduced.
> I might be able to forge at that low temp, but I doubt it. On this new
> burner, at its lowest setting, it's quite easy to forge at that heat. So
> I'm pretty sure I'm spending more energy than the other.
>

Ayup I agree you can get better performance. I can turn mine down to where
it maintains in the very low orange.

>

>
> Way back, when I was experimenting, I tried to 45* elbows and straight
> nipples. That was horrible. The flame started in the first elbow. But I
> used threaded fittings and I think the first elbow provided the step
> needed to hold the flame. A welded pipe setup would probably have worked
> well. A friend of mine (and yours, too, by the way - Ralph) has such an
> arrangement on his forges and they seem to work well. So that's an
> option. But if such a tight bend works, why wouldn't my wide sweep? I
> dunno.
>

I always use street ells to minimize turbulence, weld ells are much better.

Ralph's burners use a more conventional configuration for the air intake,
he's slotted the pipe behind the jet and uses a sleeve to control air
intake. This is the basic commercial configuration simply because it works
better than most. Drawing intake air through either a single or double
intake "T" is used commercially to develope high volume vacuum. Basically
we're making suckers instead of blowers. Regardless, there's a surplus of
performance in either configuration that allows us to make excellent burners
for a few bucks.

Also, Ralph's tube is straight for a goodly distance before it hits the
bends.

Lastly I could certainly be wrong about wider turns being better than
tighter ones. Smooth could well be much more important than radius.

>
 >
> > Lastly, how completely are you closing your forge up? If you're not
allowing
> > enough opening for exhaust gasses to escape you're really building back
> > pressure and inhibiting your burner performance.
>
> I think this may well be the biggest issue. When you said backpressure,
> I immediately thought of this. While it wasn't closed up tight, may have
> had only 1" wide "crescent" on each end. I was curing the forge and had
> the doors completely in front and back to cure them, too.
>
> I think the first thing to try would be to put the doors in their normal
> resting place. That will leave a 4" X 8" opening in each end. Another
> cheap thing would be to try a straight 10" length of 1" nipple instead
> of my conduit bend.
>

I agree, try opening the doors, then a straight nipple. 8-9" unless you have
the 10" laying around, longer isn't necessarily better.

Most importantly, only change one thing at a time, if you change several
it's easy to lose track of or not even know about a change in performance.
Keeping notes can be handy too.

> Thanks for the feedback.
>
> -Marc
>
>
> --
> Marc Godbout
> http://www.ironringforge.com
>


My pleasure Marc.

Jerry
------------------------
If it ain't forged
it ain't real.
Wrought iron is.
The FrostWorks

Meadow Lakes, AK.