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The Newbies Arena Are you new to knife making? Here is all the help you will need. |
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#1
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propane furnace tempeture control
hi I'm new here. i can't afford a heat treat furnace, so I was wandering if there was a way I could get precise temperature control with a propane forge.
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#2
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Not super precise, but if you stick to some of the "simpler" steels you can HT pretty easy. 1084 is good, there are others mentioned in the heat treat sticky up top
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#3
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Most propane forges run around 1700+, and most of your common forging steels heat-treat around 1425-1500.... this makes heat-treating in one somewhat tricky, as the thinner sections of the blade (the point) will heat up faster than the thicker sections (the spine), and over-heat if you are not very careful.
The good news is that a dedicated heat-treating forge is not too hard or expensive to build. Here is a very simple, yet very effective design: Yeah, it's a trash can... The can is lined with inswool, the burner comes in from the bottom of the bottom end. The large area and indirect heat allows for the heat to equalize over a large area, and this particular forge could easily handle a 10+" blade. A thermocouple with digital readout is used to read the temperature, which is easily dialed in by adjusting the gas pressure. I'm in the process of making one for myself, but I'm wanting to be able to handle a 30" blade.... __________________ A good friend told me one time about forging "What is there not to like, you get to break all the rules you were told as a kid, don't play with that it is sharp, don't play with fire, and don't beat on that" Wade Holloway See some of my work. |
#4
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If you have a port on the back side of the forge you can stick the point out through it and heat up the back of the blade first and then bring the point into the fire to heat it.
Doug __________________ If you're not making mistakes then you're not trying hard enough |
#5
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You can also use a section of black pipe as an internal "oven". It will block the direct heat from torch and even out the temp nicely preventing the "hot-spot" issues in a lot of forges. Just give it time to come up to even heat before trying it out.
Or....take a section of medium hard fire brick, scoop out to look like a canoe with no ends and use it as you would the pipe for a even heat tunnel. Both are simple tricks. On that trashcan forge......he's burning off zinc oxide around the portal....highly toxic to humans. Not very smart, has been credited with killing a lot of people especially in the WWI trenches in Europe. Basic ingredient for simple mustard gas. Also reports of several modern day knifemakers suffering from similar illness when using galvanized metals during forging process. __________________ Carl Rechsteiner, Bladesmith Georgia Custom Knifemakers Guild, Charter Member Knifemakers Guild, voting member Registered Master Artist - GA Council for the Arts C Rex Custom Knives Blade Show Table 6-H |
#6
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Can you give a little more detail on the trashcan forge if possible?
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#7
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Quote:
This is a very similar design, only larger. Just a large metal cylinder lined with 1" ceramic fiber insulation, a door at one end, with the burner on the bottom of the other end. A hole is drilled about halfway down the length for the thermocouple, which is hooked to a digital readout... and that's about it. This one has a stainless steel rack made from rod to support the blade, but this would only be needed for sword-length blades. This is one thermocouple that would work... I'm still researching these. http://www.omega.com/ppt/pptsc.asp?r...QXL&Nav=tema04 Here is the view from the front... Crex, I have to agree with you, I personally would not use a galvinized body either. __________________ A good friend told me one time about forging "What is there not to like, you get to break all the rules you were told as a kid, don't play with that it is sharp, don't play with fire, and don't beat on that" Wade Holloway See some of my work. Last edited by GHEzell; 08-21-2015 at 08:41 PM. |
#8
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I'd guess it takes a lot of fuel to heat that garbage can.
Quote:
I think what Carl is referring to is "Metal Fume Fever" which is the result of inhalation of fumes. Although it can make you sick with flu-like symptoms, it rarely kills people. https://app.aws.org/technical/facts/FACT-25_2014.pdf Be safe, Dan |
#9
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I stand corrected, thank you Dan.
Safety[edit] As a food additive, zinc oxide is on the U.S. FDA's list of generally recognized as safe, or GRAS, substances.[98] Zinc oxide itself is non-toxic; however it is hazardous to inhale zinc oxide fumes, as generated when zinc or zinc alloys are melted and oxidized at high temperature. This problem occurs while melting brass because the melting point of brass is close to the boiling point of zinc.[99] Exposure to zinc oxide in the air, which also occurs while welding galvanized (zinc plated) steel, can result in a nervous malady called metal fume fever. For this reason, typically galvanized steel is not welded, or the zinc is removed first.[100] It is still accumulative and non reversible. Most of the "Old Timers" in galvanization plants are younger than most of us here, they just look old. As with anything else we might do, if it makes one sick or hurts, our body is telling us "Don't do that!" Just like a finger in a door jam. We inhale a lot of junk stuff in our shops from burning, grinding, welding, chemicals, etc. One reason I do almost all my forging and welding in my open air shop 100 ft. from the house. __________________ Carl Rechsteiner, Bladesmith Georgia Custom Knifemakers Guild, Charter Member Knifemakers Guild, voting member Registered Master Artist - GA Council for the Arts C Rex Custom Knives Blade Show Table 6-H |
Tags |
1084, back, bee, blade, block, build, burner, common, design, digital, easy, fire, forge, forging, handle, heat, heat treat, hot, knife, make, making, post, simple, stainless steel |
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