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I Forge Iron

Just got my first forge


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Hi guys, I am very excited I just got my first forge. I lit it for the first time yesterday but have to admit I dont know much about what I am doing. But it did raise quite a few questions.


Can I feed this thing too much propane to be dangerous. I realize you only want the fire so big so that may be the limiter.

You'll notice the 2" pipe nipple about 8" out of the main insulated body. The welding tip propane nozzle sticks about 4" in from the far end. So concievably the burn could happen half in the nipple. Should'nt you want the welding tip nozzle to inject the propane into the insulated body?

This is setup with a hose to attach a blower. The previous owner never used one. For grins I gave it a trickle of shop air and WOOOSH it was like a jet engine and everything glowed orange. It was getting air for about 20 seconds and even in that time the 2" nipple was already bubbling the paint because it was non insulated. This again leads me to believe the air and fuel mix should be injected as close into the insulated body as possible. What do you think?

Instead of a seperate electric blower, has anybody tried to just hook up shop air with a reg or a metered orifice? It would make it smaller and simpler.

Using injected air would allow you to use less fuel for the same OP temp due to more complete burn correct? Is there any reason not to?

Just thinking out loud about stuff here, what do you guys think?

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So I have read that to adjust a forge you want to make it as loud as possible. I am thinking that is adjusting the air for a given amount of propane. So how much propane do you use? Obviously you want to keep the fire in the forge, but other than that is it simply 'hot enough to do what you need to do'?

More gas will use it up faster, and less would take longer to heat or warm up. So is this just a balancing act to make it work for you?

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Welcome aboard Snowplow glad to have you. If you'll put your general location in your header you might be pleasantly surprised to discover how many of us live within visiting distance.

I can't say for sure but this looks like it was put together by someone who didn't really know what s/he was doing. There are two basic types of gas burners, gun or blown and naturally aspirated. Guns are the easiest to put together and tune but to increase or decrease the fire you need to adjust both air and fuel. Naturally aspirated induction burners use the gas jet to induce air into the device, they're trickier to build and tune but all you need to do is turn the psi on the gas up or down to adjust heat.

I see a number of basic mistakes in your burner, there are WAY too many elbows in it, like ANY. One elbow between the gas jet and the forge is all that really helps. Burning gas doesn't like going around corners and the turbulence helps mix the air and fuel. for best performance in a gun it's best to introduce the fuel into the blower intake, you can buy blowers designed for this.

My thing is naturally aspirated burners, I prefer the ejector type but won't go into details now, so I'll move on to tuning yours. First YES it makes an imperative difference to get the air fuel ratio correct, for propane neutral is 17.5:1 but to limit scaling a little rich is better though it will produce CO. All fires will produce CO while depleting oxy so ventilate! No, putting the fuel jet close to the forge is NOT a good thing, air and propane don't mix easily so it needs time blowing down a tube to mix. A gun burner lets you put it well back or in the blower making guns superior in mixing category.

I don't know if your burner as it's set up even can be adjusted properly but I can't tell from the pics. They can be tuned visually though so if you're good at tweeking you can get it as good as it'll get. First, forget the loud roar bit, sure it will be loud but the loudest possible is BS. What you want is a clean flame entering the forge chamber. The primary flame is the bright blue center, if it's a cone or smooth blunt cone that's good. The secondary flame is the clearer blue flame surrounding the primary and you don't want any color but clearish blue, orange, yellow, etc. is bad, it's either too rich or it's mis aimed in the tube. Lastly seeing as this is a blacksmith forge and you don't want scaling (excessive oxidization) of the steel/iron you want it a LITTLE rich. The easiest way to tell visually is by the dragon's breath, this is the flame exiting the forge door, if it's blue it's a little lean or neutral so increase the fuel a LITTLE so the dragon's breath has a little orange or pink in it.

Remember, even a perfectly tuned gas forge is going to produce CO (Carbon Monoxide) and is BAD to breath so use good ventilation and I MEAN GOOD. a breeze across naturally aspirated burners can cause sputtering but that's better than taking a dirt nap. Never NEVER use a propane forge in a basement! Propane is heavier than air and WILL settle in low spots to await a spark to blow you all over the neighbor's place.

I think I've probably rambled long enough, I've covered the basics and hope I haven't made them more confusing than they are. Please feel free to ask questions this stuff is entirely too dangerous to play with unless you have an idea how it works.

Frosty The Lucky.

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Thanks Frosty! I can easily eliminate the extra bends. Do you have a preferable burner to model mine after? I see lots of different ones on the site. Any idea which would lend itself to work best with this type of forge?

One stupid question before I go; what keeps the flame from traveling back into the fuel jet and into the hose?

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