Is building a forge a waste of my time/money?

A

Andy Johnston

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Feb 10, 2014
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I just spent the last couple of hours sifting through the stickies on building forges, looking at different designs, taking notes. Then I stumble upon some threads talking about building heat treating ovens, but I didn't see any designs/plans. Since I am planning on going the route of the stock removal method right now would it be more worth my time, energy, and most importantly what little money I have into building myself a heat treating oven? If so has anybody seen any designs/tutorials for ovens that are running on 120 volt power. I saw the thread on turning a toaster oven into a PID controlled tempering oven, but I have not seen anything about a heat treating oven. For all I know it could be the same basic concept too. Any help would be great. Thanks!
 
A heat treating oven is little more than a well insulated and reflective chamber (that can hold AND withstand heat treating temps), with a CONTROLLABLE heating element (again, that can hold and withstand HT temps).

The variables that come into play are chamber material (aka refractory), element type (as well as how it will be powered), and controller (PID).

Grade 23 (good to 2300F) fire brick is probably one of the more common oven/kiln materials. It will be stable at the common temperatures needed for heat treating knives, and it will hold and reflect more heat than a grade 26 or higher.

Kathal or NiChrome wire makes a good element.

As for controllers? There's cheap ones and expensive ones. Some of it depends on if you want programmable functions, ramping/soaking capabilities, etc...
www.auberins.com is a good source for decent PIDs, and the various accessories you need to make them work (Relays, heat sings, thermocouples, etc...)

Now, as for the forge vs. HT oven/kiln question:
A Heat Treat oven is typically a little more precise and controllable than a forge. If your main goal is heat treating, I'd probably opt for the oven over the forge.

As for the 120V oven, it can be done, but it will take a lot longer to come to temp than a 240V oven. If you could make either work, go with 240 and maybe a 3000W element.

Another option you might look into is the "knife dogs" oven at USAKnifemaker.com. IIRC, they start at about $650 to $700 for a basic model.

If you do plan on building one, remember this: The bigger the chamber, the longer it takes to heat, and the harder it is to maintain a steady temp. a 4x6x18 opening is usually pretty adequate, and easy to heat.
 
I don't have the ability to do 240V unfortunately. I'm going to be scrounging and selling stuff for cash as it is or I would just buy one, especially for $650. Most I have seen have been more towards the end of a thousand and up. Still if building one would save me money, and I know it would, I would rather do that. As far as how long it takes to heat up, its not a real big deal to me. I'm not going to be on any kind of strict time line to get knives done as I am just starting. Honestly taking my time with every step is really what I want to do right now. My friend that is starting with me just wants to go go go, but I'll let him do what ever he wants to do. Not my blades anyways. I also wont need a big oven right now anyways. At most I will probably be doing a handful of knives at a time, if that even. Thanks for the info!
 
You could use, with some modifications, a kiln. Often they come up for sale at a low price. You need a protected area that can handle the heat given off from it.
 
How big and how many knives would you say you plan on making in the next 6 months?

To get started, a small (9 -10 brick) propane heated forge might be a good primer to give you an idea of how far you want to take your hobby. With the right torch, forge/ht oven dimensions and pyrometer (Auber instruments as mentioned prev.) and appropriately sized work piece you can get very good temp controls.
 
jwesthurl said:
This is the one I stumbled across while researching the same thing. Pretty detailed instructions.
There is a link to a .pdf on this page
http://www.freewebs.com/knifemaking/heattreatmentfurnace.htm

*edit* My bad, I just saw that you said 110 and I believe this tutorial is for 220. Still a good build, though.
Click to expand...

Whether it's 120V or 240V shouldn't really change how the oven is built, other than the size of his element, power cord, relay, and other electrical components. The wiring will be slightly different, but the body of the oven and the way the element is wired to the controller should be basically the same.
 
I probably will make a dozen or more knives in the next 6 months, or at least Id like to. I am going to try and get the most amount of knives that I can out of the steel that I get. I also think I am going to focus on drop point hunting/skinning knives. I am a fisheries and wildlife major so if I get some decent blades I might be able to, subtly, show them off and see if I get any takers. If that happens I would obviously want to make some more and keep it going, although selling or not I'd ultimately like to make it a life long hobby. It is the only thing so far other than guitar that I have gotten this into and excited about. OH YEAH! Size. Sorry for getting side tracked. I tend to like blades around 3 inches long. 4 is really my max and with a handle I don't think that any will be over 8-9 inches total length. I have a friend that wants a tanto/machete that has a 9 inch blade and a 5 inch handle but that's way out of my skill level right now so I do not think I will need to accommodate a 14 inch blade. Hope that helps give you a little more information.
 
I missed the comment saying that the 240V design could just be used with 120V components, although I guess that should have been obvious. Thanks for the info guys! I'll start a WIP when I have the components and can start working on it.
 
A couple of things about Andy Gascoigne's plans taken from some guys who have built HT ovens using them.

The bolts/studding/allthread through the wall for the element connections may be weak point. There have been some element failures posted on British Blades recently that may be at least partly down to this. Going out through the brick in doubled, twisted Kanthal wire has been the fix tried. On limited information so far, it seems better.

If you can source them, thicker Kanthal A1 for the element(s) seems to help a lot with avoiding element failures.

Use only JM23/K23 IFBs from Morgan Thermal Ceramics. They should be easier to find over there. Over here, they are expensive, hard to find and worth it. They have the best insulation value and lowest mass of any IFB I have tried. As a bonus, they are the easiest to cut and groove.
Where a 220V design can run enough power to live with less-than-optimum IFBs, if you use cheap ones I think you'd really notice the slower heating on 110V and might not be able to reach the higher temperatures needed for some stainless steels.

Pretty much every controller you might come across will run on 100-240V, leaving an upgrade path if you ever have 220V available. If you intend to use the oven for tempering, or for treating stainless steels, I'd strongly advise using a ramp/soak controller. But if you are "only" going to be Austenitizing carbon steels for a while, and have another means of tempering, a cheap basic PID controller will do the job and keep the initial cost down a bit. Stick with a 1/16th DIN-sized controller (48mm x 48mm) to leave the path open for later upgrade.

It's not just a voltage difference between here and there, the whole thinking behind power distribution is slightly different as well: Europe has 230V hot and neutral is at ground potential; probably a better way to distribute power but more likely to kill people than your system. Find and follow a trustworthy wiring schematic from your own part of the world.

Tim
 
If you're really just starting out and haven't yet made any knives then I think building a serious forge or a full-on kiln are both overkill.

If you buy a couple of K23 firebrick (will cost you about $5 each) then you can use two of those bricks and a decent propane torch to make yourself a '2 brick forge'. If you're using a simple steel (1084 or O1) then this small forge will be perfectly sufficient to do heat-treat on your first knives. I wouldn't recommend a forge like that for actual forging as it will be too expensive to run, but for simple heat-treat on your early knives it will be fine.

I see from your other threads that it looks like you bought 1095 for your first steel. That should work fine after heat-treating in a 2 brick forge, you just won't get the extra magic that 1095 has to offer over 1084.

2 fire bricks and a good bernzomatic propane torch will give you a setup that will let you heat-treat your first knives for about $60. You can use a household oven for tempering with no real worries, provided you clean off the quenching oil first.

Between the 2 brick forge and a filing jig (or freehand filing) you can have all the equipment you need to make your first few knives for well less than $200.

I have several knives out in the field with customers that I made with the exact equipment listed above and I've had no complaints about them. They hold an edge well and have held up to a bunch of abuse.

There's no doubt that a real kiln/forge is a useful piece of equipment and will be invaluable once you get really going. But if you're blowing all your cash right now on a kiln then you're going to realize you have no money left over for all the other stuff you'll need. Start out with 'make due' equipment and work up from there, you can make some great knives even with lesser equipment provided you take your time and are patient.

Here's a video I did a while ago showing the heat-treatment of an O1 knife using a 2 brick forge and vegetable oil as the quenchant:
[video=youtube;8bunCG6W6dA]http://www.youtube.com/watch?v=8bunCG6W6dA[/video]
 
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Hey Aaron. I'm not gonna lie I've watched that video probably 20 times or more now :p. Your channel and trollsky custom knives actually were one of the reasons I wanted to get into knife making. I built the filing jig that you had a video for and I have a few files. My friend that's getting into it with me actually bought a belt sander, angle grinder, and a bunch of other things that I told him we didn't need but he works at a hardware store so he got them anyways. I have a toaster oven that someone gave me for free for tempering, which is nice so the fiancee wont get mad at me for using our apartments oven. I think I still would like to build myself a heat treating oven, but I have stuff that I have wanted to sell for a while yet anyways so I can still do that down the road once those are sold. I have been told a couple times now a small forge like this would work with my 1095 it just wont be as hard as 1095 can potentially be. That being said they are my first few knives and I'm just looking for some experience so I might just go ahead and build the 2 brick forge and still use the money I get from selling stuff down the road to make the oven. Thanks for all the advice and thanks for all the videos Aaron they have helped a lot.
 
aarongough, That's a neat 2 brick forge. Do you have any trouble with the propane spitting when you lower the cylinder to horizontal?

Andy Johnston, Get a magnet and test your hot blade. You need to get it a little hotter than non magnetic. Many state a couple of shades redder. If you received your steel as fully spherezoidized you can skip the normalization step. Although normalization is a good step to help with grain refinement.
 
FWIW, the first thing I did before making any knives was to build a NWGS and HT Oven.

But that was just me.... ;)
 
knife to a gunfight said:
FWIW, the first thing I did before making any knives was to build a NWGS and HT Oven.

But that was just me.... ;)
Click to expand...

That's awesome man. I wish I thought like you. :)

I'm with you Andy. Aarons videos are great for the new maker. I know I appreciate them.

The only thing I'd offer... If you do make a two brick forge, consider getting an Atlas venturi burner. I have one for my 2bf and it's great. Get the adjustable regulator to go with it, and if you already have a bbq propane tank you have a good fire breather for about as much as the burnzomatic. I didn't have the recommended t4000 (I think that's the model) torch and tried two pencil tip torches. It worked but it's pretty hard, not to mention unsafe, to juggle all of that. I hold my burner in place with hard fire bricks and it's nice. I need to add a thermocouple to monitor actual temp, but I've had good results with 1084, and I've seemingly done well with 1095 too. I still need to test the 1095 to be sure, but it's definitely hard and the grain is fine for whatever that's worth.
 
I finally found a few places around town that sell refractory bricks, or supposedly do as it is the weekend and they closed and I couldn't check. I would have a forge made monday but I ran across a 23 piece file set for 25 bucks and I couldn't pass it up so I wont be getting a torch just yet. I'm well on my way though.
 
Andy Johnston said:
Hey Aaron. I'm not gonna lie I've watched that video probably 20 times or more now :p. Your channel and trollsky custom knives actually were one of the reasons I wanted to get into knife making. I built the filing jig that you had a video for and I have a few files. My friend that's getting into it with me actually bought a belt sander, angle grinder, and a bunch of other things that I told him we didn't need but he works at a hardware store so he got them anyways. I have a toaster oven that someone gave me for free for tempering, which is nice so the fiancee wont get mad at me for using our apartments oven. I think I still would like to build myself a heat treating oven, but I have stuff that I have wanted to sell for a while yet anyways so I can still do that down the road once those are sold. I have been told a couple times now a small forge like this would work with my 1095 it just wont be as hard as 1095 can potentially be. That being said they are my first few knives and I'm just looking for some experience so I might just go ahead and build the 2 brick forge and still use the money I get from selling stuff down the road to make the oven. Thanks for all the advice and thanks for all the videos Aaron they have helped a lot.
Click to expand...

Glad you've found the videos helpful mate! I think the small forge is a great way to get started! Honestly I reckon you can go a long way with equipment that simple if you stick with carbon steels and are willing to be patient!

Bo T said:
aarongough, That's a neat 2 brick forge. Do you have any trouble with the propane spitting when you lower the cylinder to horizontal?

Andy Johnston, Get a magnet and test your hot blade. You need to get it a little hotter than non magnetic. Many state a couple of shades redder. If you received your steel as fully spherezoidized you can skip the normalization step. Although normalization is a good step to help with grain refinement.
Click to expand...

Can't say I've had any issues with the torch spitting, but I think most of the canisters I've used have been at least partially empty so maybe that's why? The TS4000 torch makes a big difference over the standard torch heads, very glad I had that for use with the forge...

knife to a gunfight said:
FWIW, the first thing I did before making any knives was to build a NWGS and HT Oven.

But that was just me.... ;)
Click to expand...

I tend to want to do that too, but I'll be the first to admit that it gets expensive quick! If money is less of an issue then I think that's a safe route, but as Andy said things were tight I figure keeping it simple to start might be the way to go...

Strigamort said:
That's awesome man. I wish I thought like you. :)

I'm with you Andy. Aarons videos are great for the new maker. I know I appreciate them.

The only thing I'd offer... If you do make a two brick forge, consider getting an Atlas venturi burner. I have one for my 2bf and it's great. Get the adjustable regulator to go with it, and if you already have a bbq propane tank you have a good fire breather for about as much as the burnzomatic. I didn't have the recommended t4000 (I think that's the model) torch and tried two pencil tip torches. It worked but it's pretty hard, not to mention unsafe, to juggle all of that. I hold my burner in place with hard fire bricks and it's nice. I need to add a thermocouple to monitor actual temp, but I've had good results with 1084, and I've seemingly done well with 1095 too. I still need to test the 1095 to be sure, but it's definitely hard and the grain is fine for whatever that's worth.
Click to expand...

The upgraded burner sounds like an interesting idea! I bet that makes the little forge actually useable for actual forging as well, which is always a nice option to have!
 
I would like to get into stainless steels eventually, but that's quite a ways off. Id like to get a few years of practice and research under my belt before I jump into that.
 
aarongough said:
The upgraded burner sounds like an interesting idea! I bet that makes the little forge actually useable for actual forging as well, which is always a nice option to have!
Click to expand...

I can't imagine that it wouldn't get hot enough. At a full 10psi and a partially blocked opening, it gets raging hot with enough dragons breath to singe your eyebrows from a ways away. I burnt the crap out of my finger from getting too close to the port. Didn't even see the flame. Next time I'll do it the right way, in low light.

I can't see myself trying damascus, mostly because I'm not a huge fan of the look, but trying mokume is definitely in my future. Of course I'll need a floor to do it, but that shouldn't be too hard.
 
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