gas forge question?

B

BLADECARVER

Joined
Apr 8, 2007
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172
i was thinking on building a small gas forge and heat treating myself. i have some simple and maybe stupid questions be easy on me:D. when the first timer starts using a forge. well i will get straight to the point. how do you correctly use a forge? i almost hesitate to ask this question for fear of looking stupid:( but here it goes i have been reading alot on building the forge and have noticed that the forges do vary in the location of the burner some mount on top , some mount on the side, ect. is the concept that you want the blade being heated directly in the flame path? below the flame path?
 
You want the blade to heat evenly, which I would assume means you want to keep it out of the flame. I'm a bit hazy on how the blade is oriented inside the furnace... do you just lie it down in there, or do you have to keep it standing or...?
 
The flame should enter the forge about 1/3 from the back, and be angled about 15 degrees toward the front. It should be at a tangent to the forge lining , so it swirls around the sides, not blowing into the center. The blade will be heated from all sides that way. The temperature can be read by a type K thermocouple hooked to a cheap PID. The PID can be hooked to a solenoid valve to control the temperature if you want to go that far ( recommended). A blown forge is better than a venturi burner, but either one will work fine.If you are going to use a solenoid, you would be best to make the blown forge.

There have been several threads in the past year about controllers for a forge.
The stickies and sites like Don Fogg's, Kevin Cashen's,Darren Ellis' and Indian George's have great forge building info. Darren Ellis has all the supplies you will ever need:
http://forgegallery.elliscustomknifeworks.com/

Making a forge should be a simple job. If it seems complex, just study the idea some more and ask questions. Once you understand the operation of a forge, and how the flame is made and controlled, it should be an easy build.
Stacy
 
It should be rotated as needed to get an even heating, but flat is OK for forging, edge down for usual for HT.
Stacy
 
i understand edge down how is that achieved properly do you use a rack of some kind to keep the blade standing on edge?
 
i was thinking on using one of those portable air tanks like the ones you fill and keep around to blow up tires ect would that tank be usable as a start for a forge tank?
 
Do a search for a "freon tank forge" it would be the same as using the portable air tank for a forge body but you can probably get one for free from a HVAC business.
 
i think i understand the thermocouple and pid, but where does the solenoid come into play how is it hooked up ect?
 
The solenoid is installed where the gas comes in to the burner. Usually it is just before the main shut-off valve. It turns the gas on and off (controlled by the PID) and thus regulates the temperature.
Stacy
 
will the solenoid re-ignite the gas also what i mean to say is will it shut the gas off completely or just regulate the flow of propane, if it shuts off the flow what reignites the burner?
 
You have two posts going at the same time on this - confusing. -More details on other post.
In a simple one stage control:
The forge will heat up to the set temperature with the valve open. It will close when the PID detects the set temp. The flame will completely go out. When the temp drops a bit the PID will open the valve and the gas will flow into the hot chamber. It ignites with a little woof almost immediately. You could hook up a small pilot flame just outside the back door of the forge, but it really isn't needed.

In a two stage control (Basically, you just add another needle valve as a by-pass) the flame never goes out, it just cycles from high to low. This is a much better system (ask Fred Rowe), and costs very little more to set up. With a little selective ebay shopping, the whole setup, including PID, thermocouple,solenoid, piping and valves, and the fan controls, can be set up for $100-150
Stacy
 
TheLaxPlayer said:
When you put a blade in the forge does it matter if it's laying flat or on it's edge?
Click to expand...

After some experamenting and time you will learn were your forges 'hot' spots (faster) and 'slower' (more evenly heating) are.

Here is a pic of just horseshoes inside an NC Whisper-Momma , back-door forge.

Just a note, the left (as your looking at it) burner is jetted smaller, to be hotter at altitude, the right is hotter as shown at 5280' .

The pic is not that good, but shows the color of the shoes under the burners.

Just included this as I think it helps me understand my own forge and gives me more options banging blades.


2burnerforgeheatdis30per.jpg
 
Party stores go thru helium, and they toss the tanks, same size as freon and you dont have to worry about cutting the tank open. Check with your local party store, they probably have several helium tanks ready for the dumpster.
 
The absoloute best reccomendation I could poosibly give anyone considering making and using a forge is to find someone with one that you could watch use, and maybe even use a bit yourself. Find a hammer in or gathering and attend. Propane, while relatively easy to control, if you're careful, is nonetheless a powerful fuel, and shouldn't be underestimated.

Also, the design considerations are rediculously variable, and seeing a forge or two in operation is incredibly valuable experience if you're going to be building one.
 
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