Is building a propane forge really that simple?

D

Danimal6513

Joined
Apr 16, 2013
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Alright, so I've been screwing around with my homemade charcoal forge for a couple weeks now and i can tell that forging is going to stay with me, but I've been getting increasingly frustrated with the whole charcoal deal. I've made some of my own, but i just can't keep up. An afternoon of work splitting wood and burning in a 10 gallon metal container. makes enough coal for about 2 hours of forging, and I can't co bigger than that because I live in an urban area.
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My very first railroad spike knife :D

So anyways, I got to researching building propane forges/ burners on the internet, and i was surprised at how easy it looked. These are the plans I would like to follow. http://makingcustomknives.com/building-a-gas-forge-burner/ I just want some input from someone who knows what they're talking about before I go and blow up my garage haha. Are these good plans? do you know of any better ones out there? I chose these because of the simple tools required. I don't have welding equipment or anything like that. Just pretty basic stuff, but me and my dad are pretty handy. Also what's a rough estimate on how many hours of forging i could expect from a 20 gallon propane tank? Thanks
 
Yep cept I've used black pipe fittings instead of brass and don't run a flare. You will save 50% or more by going to a plumbing supply store instead of Lowe's.
 
I concur. It's really quite simple. The most important things are: that the fuel jet be centered, that the jet orifice be the right size (57 should work, as per plans), and that you have both a regulator and shutoff valve.

As Will says, black fittings for the fuel supply may even be preferable- they cost less and are more durable.

The sidearm burners work even better, they are still a venturi design, and Ron Reil talks a lot about them on his site. Parts can be bought from Zoeller forge, as the reducing tee you would need can be hard to find off the shelf. They are no harder really to build.

But heck, build this one, it will work fine. I'm still running one of the early Reil burners I built years ago. It's great for a small blade forge.
 
What kind of regulator will i need exactly, and how much do you think the regulator and shut off valve will cost? I did a google search for those parts but they're all over the spectrum. Should i just talk to someone at a local welding supply store and explain my setup to get the exact parts i need?
 
I paid approx $65.00 for mine locally in Canada. A BBQ regulator won't allow enough pressure. They're about 1/2 that in the states, or less. 0-15PSI is what is recommended in the tutorials, but mine is 0-30psi. I haven't been able to run mine yet, but from what others have posted I can't recall anyone going over 10psi. Double check your fittings. My tanks are POL, and the line is 1/4"npt.
 
I wrote down all the parts listed, went to three different hardware stores, and came back with everything I needed, except the time to put it all together.
 
When I was starting out, I assumed that venturi forges were simpler than fan/blown forges because there were fewer moving parts. Then I went to a few classes where they had forges made from a stack of firebrick and a hair dryer for a fan, and nationally known smiths were welding damascus billets.
I built mine almost ten years ago from a 10 gal propane tank- one layer of Kaowool (Cheap and insulates well) and an inner layer of Durablanket (reflects heat, thus raising the effective temp well into comfortable welding temps).
No orifice, will run at most any gas pressure since that's not a factor in controlling the flame.
I used a sacrificial firebrick floor, but have yet to replace it though I do a fair amount of welding still.
Stupid simple, long lasting, very effective.
Feel free to PM me if you'd like photos or details.
Andy G.
 
I didn't post yesterday, because the discussion was mostly about venturi burners.
I highly recommend a blown burner. It is about as simple as it gets as far as building one. There is no orifice to position, adjust, etc. The flame can be easily balanced for atmosphere, and flame size with just a twist of a knob. Converting a blown forge to PID control later on is also very simple.

The biggest advantage of a blown burner is that it can run at virtually any temperature the gas supply will allow. It can run at .5PSI with a tiny flame that barely warms the chamber, up to a jet exhaust size flame that will melt your steel. A venturi burner has to run at a fairly high flow rate to draw the air in. Most will start to sputter out at around 3-4PSI (1500-1600F, depends on your forge). HT soaks are a bit tricky with a venturi, but a piece of cake with a blown burner.

On building a forge:
1) Saving money isn't cost effective on the liner materials. Get 2" regular Kaowool or use 2 layers of 1" High-Z wool, satanite, and ITC-100. The 1" insulboard is good for forge ends and replaceable floors.

2) Get a proper regulator and a 10' hose. Use "quick-connect" propane fittings to hook it to the forge. That way, you can switch the tank to other forges or devices with ease. A 0-15PSI regulator and gauge is needed. 0-30PSI is also common.

3) If at all possible, use a blower that is made to power a forge. Most folks recommend a blower with 50-150 CFM, depending on the forge size and use. Forge blowers are longer lasting and have better static pressure than just any old squirrel cage blower. If you can't afford one now, that is OK, just use what you can get. You can always change the blower later on. Using a shop-vac or leaf blower is just plain crazy....get some sort of real blower.

4) The shell can be nearly anything from an old propane tank to a piece of stove pipe. Most folks use an 18" length piece of 10" pipe. Shoot for a chamber size of 4-6" diameter and 16" length for a good general use forge.

5) Make the forge "well made". Take your time and do all the steps fully. Short cuts or rushing things will make the forge not last as long or work as well.

6) If at all possible, put a floor in the forge of a shelf liner ( thin firebrick), or a refractory like bubble alumina or Mizzou. The floor is where the forge takes a beating....especially if you plan on welding in it.

7) Add a TC and ceramic sheath with a simple PID reading device to monitor the temp. This will cost about $50. It can later be changed to a PID controlled forge for around an extra $50-70.
8) Put on sturdy legs, or make a cradle for the forge. Nothing is worse than a forge that moves around in use.

9) Put the forge on a HF welder cart or a rolling shop cart. That way the whole assembly ( including propane tank) can be rolled away when not needed. The tongs and other supplies will store on the shelves below the forge for easy access when needed. -
http://www.harborfreight.com/welding-cart-90305.html http://www.harborfreight.com/16-inch-x-30-inch-steel-service-cart-5107.html


10) - Places like High Temp Tools and Refractory sell all the supplies needed to build a good forge - http://www.hightemptools.com/supplies-mainpage.html
Expect to spend $100-150 for building a GOOD forge. Adding temperature reading and control can run an extra $100 or so, but can be added later. I would build in the TC sheath when making the forge, though. A well built forge will last many, many years of heavy use, and can be easily sold if no longer needed.

TIP:
For doing HT in a forge, use a piece of 2" stainless pipe. This pipe is called a muffle. Put the blade in the pipe with just the end of the tang reachable by your tongs. Put the pipe in the middle of the forge. The flames will heat the pipe and the pipe will heat the blade. You will avoid overheating the edge or tip this way. When doing steels that require a soak time, like O-1 and 1095, this is about the only way to go when using a forge for HT.
 
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To add to Stacy's post: in Canada, the materials cost me about $400.00 to make a PID forge. I did a google search for refractories, and found a local supplier who sells in small quantities right from their warehouse. I saved a lot on shipping, and the prices were quite reasonable. I bought extra when I was there and have enough material for a tempering oven, and an electric heat treat oven as well. The two burners cost me about $150.00 for the parts with the valves. I got the PID controls from Auberins. Great service from them. Prices were way better than expected. I have two out of date propane tanks for the forge body. No cost.
 
What stacy said... plus..
I put mine on a 200# shop cart instead. The top is already level, plenty of room underneath for bottle, and easy to use the handle as a tool rest, etc. They can be had for as little as $20 on sale at HF and the red finish is surprisingly durable...

A venturi burner of the proper size can reach forging heat easily. I have a 3/4" burner using a diverter y with a 1/8" npt pipe and cap with a 3/64" hole as the orifice. I use a set screw to slide it in and out of the rear of the burner, and change its relation to the air inlet which is choked. The 3/4" pipe screws directly into a 1 1/4" reducer which is welded to the top cover of the forge and blows through a hole in my bricks. (Mine is a hard brick design.) At 10psi I can get steel hot enough that a jet of air will spark it off... I can pull the orifice back and drop to 1-2 psi while choked up and have a nice low heat. Temperature control is relatively easy. I designed my burner after making three other plans found on the web and found it to be a good performer with a lot of control. The main chamber is 4"x4.5"x12.)". It is open front and rear and I can stack bricks up to make the chamber larger if I need to though the temp will be lower obviously.
Altogether I have about $125 in the setup including the cart, bricks, steel for the frame and box its in, regulator, hose and cart...
A blown forge is the best way, venturi is the least expensive. I love my forge but am in the process of building a larger 2 burner blown forge with PID control. It is the way to go in the long run but the venturi got me started...
If the picture cooperates and attaches, this is before the diverter y and had drilled carb holes...
You can build the zoeller improved sidearm as well. The key is a strainer y as opposed to the diverter y.
 
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Yes building a propane forge is easy if you have the right tools to do the job, a welder and chop saw makes things really easy:p I have mine more less ready to be lined and will only need to pick up the hoses and regs for my burner. Mine was built from scrap, grabbed an old propane tank from the dump, scavenged an old BBQ frame for a base from a friend that was throwing it out, and made the framework to mount the tank to the BBQ frame from an old laundry sink frame. I was fortunate enough to have a burner given to me by a member here, but I can't remember his name:o It is really embarrassing because I truly appreciated the gift.

Everything has been put on hold for some time now due to renos and elbow problems. I saw my surgeon last week and he said at least 8 more weeks till I can use a knife, let alone make one:( I think in the next couple of weeks I might dig out the forge and get to work lining it. I think the most expensive part of my forge build was buying a small wire feed welder, but it was worth it. I have used it for other things since and my brother loves having it at his place and uses it constantly.
 
Bladsmith- Can you sticky that post, or is it already there? Great summary!
As Lucy says, one advantage of venturi forges is that they are more efficient. My blown forge is plumbed right into the shop propane, but if you're running on tanks, a venturi forge won't tend to freeze propane bottles as fast.
One more thing- I like my forge much better with Plistix refractory cement painted on the inside- no bits of mineral wool floating around the shop, and it really boosts the effective heat output by reflecting all the IR into the work piece. (not sure if that's the correct description, but that's kinda what it does.)
Have fun!
 
I have built 7 blown forges between mine and ones for my students. They really are that easy

-Page
 
elementfe said:
Bladsmith- Can you sticky that post........
Click to expand...

It has been added to the forge building sticky. I also edited the post to correct a few things and added the below tip -
http://www.bladeforums.com/forums/showthread.php/782574-PID-CONTROL-FORGE-Salt-Pots-and-more

TIP:
For doing HT in a forge, use a piece of 2" stainless pipe. This pipe is called a muffle. Put the blade in the pipe with just the end of the tang reachable by your tongs. Put the pipe in the middle of the forge. The flames will heat the pipe and the pipe will heat the blade. You will avoid overheating the edge or tip this way. When doing steels that require a soak time, like O-1 and 1095, this is about the only way to go when using a forge for HT.
 
bladsmth said:
TIP:
For doing HT in a forge, use a piece of 2" stainless pipe. This pipe is called a muffle. Put the blade in the pipe with just the end of the tang reachable by your tongs. Put the pipe in the middle of the forge. The flames will heat the pipe and the pipe will heat the blade. You will avoid overheating the edge or tip this way. When doing steels that require a soak time, like O-1 and 1095, this is about the only way to go when using a forge for HT.
Click to expand...

I figured this one out the hard way. :)
 
I actually did some 440c a couple years ago in the propane forge, in a stainless box with a small opening at one end- kept some wood chips in there to absorb some of the oxygen.
I don't recommend it, but most of the blades actually tested pretty well. It was an Experience.
 
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