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I Forge Iron

Gas Forge Tuning?

Scary Mc

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I'm starting this thread here as I think it might get a few more hits than in the forge section. Feel free to move it if I've done a bad, bad thing.
I've had my old Mankel Farrier for a few weeks now and have gone through about 15-gallons of propane banging away on metal, mild steel, stainless, and copper.
I'm wondering of I am adjusting my forge to get the most heat out of it, or if I could adjust things a bit better. I've searched the web and have tried to search this forum to no avail and am wondering if there is a good thread, ect. that might explain how to best adjust the forge. What color should the dragon's breath be, how much should I open the propane valve on the forge, blower aperature, ect.

Ideas, threads, insults?

Thanks for your time,


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Good Morning,

1- What kind of burner does it have? Atmospheric or Blower motor
2- Does the burner go through the top, center??
3- What is the forge lined with? Kao wool? Refractory? Fire-Brick? ?????
4- What propane pressure are you running it at?
5- What is the tip/gas jet diameter?
6- Does the propane bottle freeze after over 1/2 hour of use??
7- How much restriction is there in the front and back doors?
8- Is the flame blue or yellow?
9- Who is near you that can give you advice. Difficult to do through a computor.

Just a start of the questions!!!

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You tune your forge for the work planned. At every fuel pressure there is a corresponding amount of air to get the burn *you* want. Neutral is usually best for most smithing though I have used an extremely oxidizing atmosphere to put a rough "skin" on a dragon I was forging---had to remove the very thick scale leaving the rough steel it created.

For knifemaking I often run a bit reducing to lower scaling and decarburization---however this also increases CO production so VENTILATE! (I have 2 10'x10' roll up doors on opposite sides of the shop along the general wind direction *AND* a 1'x30' ceiling vent and open eaves!) Reducing will have a bit of unburnt gas in the exhaust plume that will burn as it hit open air. Too much and you are throwing away gas (and money).

Blown burners are generally easy to tune. Set a fuel rate (pressure) and then add air until you get the noisiest burn---that's generally neutral then you can add or subtract a bit of air to get what you want if you don't want it neutral. Note that neutral should also be the hottest so if you look at the refractory opposite the burner when it glows the brightest it's neutral---better for kaowool as it heats/cools fast when adjusting compared to a hard firebrick.

Atmospheric are a bit trickier; but the better burners are easier to tune that the not so good ones. Atmospheric burners generally have some sort of choke plate that adjusts how much air the burner can draw in. (some that don't have a choke can be adjusted by adding a strip of tape or aluminum foil to cover part of the open end (the COLD END)
You use the same stuff to judge the burn as with a blown burner.

Note that most forges will need tweaking again after they come up to full heat and if you do not use a regulator they will need tweaking as the pressure in the bottle changes---use a regulator!!!!!

If you are working large stock or a lot of pieces you may want to turn the fuel up and adjust the burn to put a lot of heat in the forge. If you are working small delicate or very few items you might turn it down a bit---it is quite possible to MELT steel in a gas forge if you are not careful! (When I relined my blown forge, the gas pressure that worked fine for the previous runs now was too hot and melted a piece that was left in too long...)

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