# Torch For Fire Brick Forge



## Seffers93 (Aug 14, 2020)

Hey everyone! I've posted this to a couple forums just trying to get as much info as I can.

I'm gathering supplies to set up shop in our new home at the end of the month. I've gathered everything on my list except a torch for the forge. 

I ordered 10 insulated fire bricks. I don't plan on using all of them. Just wanted extra in case I ruin my first attempt. But I need something bigger than the 2-Bricks I've been seeing.. something a little longer and wider for cleaver styles. (I'll be using 1084 for now)

So I doubt the average less-than-5000BTU torch from Home Depot would work unless I used more than one. I found this at my local store though..









20,000 BTU Utility Propane Torch MT450C-3 - The Home Depot


The self-lighting Mag-Torch MT450 utility torch is a versatile torch useful for a multitude of jobs around the yard. This torch can eliminate weeds without the use or need of chemicals. The 36 in. L reach



www.homedepot.com





Does anyone have any knowledge as to why this would or wouldn't work? I know it's crazy long but I'm okay with that. I'm somewhat of a worry-wart so I'd prefer to have the tank further from the flame anyway lol. 

Any insight helps. Thanks!


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## HSC /// Knives (Aug 14, 2020)

I can't speak about this one, but consider the Harbor Freight weed burner. Tai Goo showed me how to use it and I've used it for 200+ knives. It does require a large diameter opening however. It has very good flame control


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## inferno (Aug 14, 2020)

ive been using this one here. sievert 335002 its about half way down. its *43,5kW*.


https://sievert.se/wp-content/uploads/2017/01/Sievert-Promatic_ENG.pdf


normally i use maybe 2 bar on the regulator and and maybe half volume on the handle knob. so maybe 10kW or similar. you dont need more than that for regular kitchen knives. but the longer they get the more juice you need. because the knives will cool off. when i made my sword i cranked everything up to max.

i made a thread about my cheap lowtech setup.





low tech HT friendly steels?


is the second lower bulge to the right the bainite bulge?? i'm thinking bainite katanas, bainite :) the magic steel. bainite nakiris. :)




www.kitchenknifeforums.com


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## inferno (Aug 14, 2020)

20000BTU is 5,8kW, i'd say you want at least twice as many BTU. you can always turn it down.


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## Tim Rowland (Aug 14, 2020)

I know it is slightly more money than rigging together a weed burner but it would certainly save you some headache and time to just buy a burner with regulator from a known blacksmith supply like the one below:






Mathewson Metals


Mathewson Metals offers blackmithing classes in Eatonville, WA as well as quality blacksmithing forges, propane forge burners, tools, and blacksmithing supplies that deliver professional results at affordable prices.




mathewsonmetals.com


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## inferno (Aug 14, 2020)

yeah its probably better to buy a real forge burner.
only reason i use what i use is that i got half of the stuff for free.


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## HSC /// Knives (Aug 14, 2020)

Tim Rowland said:


> I know it is slightly more money than rigging together a weed burner but it would certainly save you some headache and time to just buy a burner with regulator from a known blacksmith supply like the one below:
> 
> 
> 
> ...


What is the regulator and what does it do?


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## inferno (Aug 14, 2020)

the regulator regulates the gas pressure coming out of the gas tank so its always the same pressure.
usually the big propane tanks start at 8 bar or similar. and after you use up the gas it goes down.
also heat/cold will affect the pressure. usually you dont want the 8 bar. you want between 2 and 4 bar.
the regulator pretty much lets you use 2 bar until the tank is finished.
the "volume knobs" on some burners are not regulators. they only restrict flow. but not pressure.


here you can see how the pressure in the tank changes with temp, look at the graph.


https://sievert.se/wp-content/uploads/2017/01/Sievert-Regulators_ENG.pdf


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## Seffers93 (Aug 14, 2020)

Thanks for the replies everyone. I'm going to take your advice and buy a burner meant for forges. Makes a lot more sense to go that route if my budget allows for it.


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## HSC /// Knives (Aug 14, 2020)

inferno said:


> the regulator regulates the gas pressure coming out of the gas tank so its always the same pressure.
> usually the big propane tanks start at 8 bar or similar. and after you use up the gas it goes down.
> also heat/cold will affect the pressure. usually you dont want the 8 bar. you want between 2 and 4 bar.
> the regulator pretty much lets you use 2 bar until the tank is finished.
> ...


OK very good thank you for that and I read through the explanation

So my question is ...what is the relevancy in this application for a blade Smith Forge? I’m not seeing the need for regulating pressure

I used to own a twin burner custom-made Forge by Russ Moody with hybrid burners and regulator

The way I’m reading and understanding this is these burners require a regulator to perform well

i’m not often advocating harbor freight goods or the wrong tool for the job. But this is a case where I know it works and I am using it


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## inferno (Aug 14, 2020)

Seffers93 said:


> Thanks for the replies everyone. I'm going to take your advice and buy a burner meant for forges. Makes a lot more sense to go that route if my budget allows for it.



get a regulator for it too. check the specs. without a reg you will be burning a lot of gas. 
make sure the regulator can handle the flow/power the burner needs so its not a camping stove reg or similar. 
the one i run from sievert is used for their 150kW burners so i know it can handle the juice. 150kW is a lot of power.


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## inferno (Aug 14, 2020)

HSC /// Knives said:


> OK very good thank you for that and I read through the explanation
> 
> So my question is ...what is the relevancy in this application for a blade Smith Forge? I’m not seeing the need for regulating pressure
> 
> ...



1 basically when it says the burners can only handle 2 bar. it will probably create a turbulent flow above that. and that means you are just burning a lot of gas that the burner cant really burn. so money wasted.

3 all burners needs regulators to perform well over a length of time. otherwise the pressure in the tank will dictate everything, and that gets lower and lower the more of it you burn so.

4 yeah you can run almost any burner straight of the tank, no problem, but is it money efficient? probably not. also as we can see the pressure in the tank varies with temp.

at 25C we have 9-10 bar. and at 10C we have 5 bars. maybe its better to simply have 2 bars no matter what?


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## HSC /// Knives (Aug 14, 2020)

inferno said:


> 1 basically when it says the burners can only handle 2 bar. it will probably create a turbulent flow above that. and that means you are just burning a lot of gas that the burner cant really burn. so money wasted.
> 
> 3 all burners needs regulators to perform well over a length of time. otherwise the pressure in the tank will dictate everything, and that gets lower and lower the more of it you burn so.
> 
> ...


Appreciate the education. Certainly the right burner and regulator combination is the right investment long-term

however FWIW I still maintain the harbor freight weed burner is quite suitable and I’ve been using it for 2 1/2 years trouble free.


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## inferno (Aug 14, 2020)

i dont question that. i mean you just turn up the knob if you need more juice. 

my sievert 0-4 bar regulator was around 110€. i could have gotten a fixed 2 bar for like 30-35€, but then i can never cram out more juice than that. 
for me i think its worth it. i have to travel quite far to get more gas so i want it to last as long as possible. and sometimes i'm out in -10C and sometimes its 25C outside. but with the regulator i always get the same result no matter what. it also doesn't care if the tank is full or almost empty.


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## inferno (Aug 14, 2020)

for me it cost around 60-80€ to fill a 12kg propane bottle, so i feel its worth it. i just do this as a hobby so a tank last quite long for me.

with my burner/handle and reg combo in my extremely inefficient forge (no real insulation) i can heat a carbon blade to temp in around 20-30 seconds.
bada bing, bada boom, done. ymmv.


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## lowercasebill (Aug 15, 2020)

Red dragon / flame engineering sells a 500,000 btu torch. I have one sounds like a jet engine. Use it to burn weed. Grass was dry when i set the neighbors yard on fire


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## gregfisk (Aug 15, 2020)

There are several YouTube videos that show you how to build your own burner and they are not hard to build. I built mine by following one of the videos and it works perfectly. I did buy a regulator which was also spec’d in the video I followed. You need a larger one than are used for your typical bbq. Do a quick search and get a pro burner at a fraction of buying one prebuilt. Harbeer (HSC) uses his HF weed burner to great effect so that’s also an economical way to go.


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## birdsfan (Aug 15, 2020)

You all are gonna end up making me build a forge! This is too interesting not to try


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## birdsfan (Aug 15, 2020)

Tim, that one you posted appears to come with a regulator. right?


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## gregfisk (Aug 15, 2020)

Here’s a picture of my home built forge with the burner I built installed. These are typical of what you’ll see on YouTube.


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## gregfisk (Aug 15, 2020)

Here’s the forge if you’re interested


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## Seffers93 (Aug 15, 2020)

gregfisk said:


> Here’s the forge if you’re interested



Thanks for the tips! And I’ll probably build a forge very similar to this. Is there a big difference between placing the burner on top as opposed to the side? Or would it be fine to just go with whatever works better for the setup? I’ve seen burners on top and also at the side angled slightly backward and up.


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## gregfisk (Aug 16, 2020)

Seffers93 said:


> Thanks for the tips! And I’ll probably build a forge very similar to this. Is there a big difference between placing the burner on top as opposed to the side? Or would it be fine to just go with whatever works better for the setup? I’ve seen burners on top and also at the side angled slightly backward and up.


I don’t think it makes a lot of difference. The YouTube video I got the idea from had the burner coming in from the side and had an extended frame to hold it. I ran it through the top simply because it takes up less room. And I’d seen other designs done that way so I figured it would be okay. The burner and the forge both work great and the cost was very reasonable.


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## birdsfan (Aug 16, 2020)

How long a blade can your forge effectively handle, Greg? Do you have to move it around a lot for even heating?


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## HSC /// Knives (Aug 16, 2020)

gregfisk said:


> I don’t think it makes a lot of difference. The YouTube video I got the idea from had the burner coming in from the side and had an extended frame to hold it. I ran it through the top simply because it takes up less room. And I’d seen other designs done that way so I figured it would be okay. The burner and the forge both work great and the cost was very reasonable.


maybe I can get you to make me a ribbon burner forge with PID control....


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## Tim Rowland (Aug 16, 2020)

birdsfan said:


> Tim, that one you posted appears to come with a regulator. right?



Correct. It does come with regulator


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## gregfisk (Aug 16, 2020)

birdsfan said:


> How long a blade can your forge effectively handle, Greg? Do you have to move it around a lot for even heating?


The opening is 13.5”L x 2”H x 3.5”W. The back is open so you are not limited by the length inside. Even so I would think that you wouldn’t want to heat treat anything too much longer than that and try and keep it evenly heated. I have used 1095 and 15n20 so far. Both of those steels do not require long soak times so I never put the knife down while I’m heating it up. It doesn’t take more than a few minutes. I move it back and forth until it’s evenly heated to non magnetic and the correct color.


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## gregfisk (Aug 16, 2020)

HSC /// Knives said:


> maybe I can get you to make me a ribbon burner forge with PID control....


I have considered building an electric heat treat oven a couple of times now but just can’t bring myself to take the plunge. It’s a lot more complicated than the one I built but I do really want to own one. The main reason is I would like to do other types of more difficult steels including stainless and for consistency sake it makes a lot of sense. If I decide to build one Harbeer I may be willing to build two.


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## Jesse Killion (Aug 21, 2020)

One thing to keep in mind with burners is they need to be sized to the forge. If you are building a 2 brick forge, a 3/4" burner will be way too much. Atlas Knife makes a small burner that works quite well for smaller forges. You could also contact them with dimensions on your forge size and they should be able to let you know if the burner is the right size for you.


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## Seffers93 (Aug 21, 2020)

Jesse Killion said:


> One thing to keep in mind with burners is they need to be sized to the forge. If you are building a 2 brick forge, a 3/4" burner will be way too much. Atlas Knife makes a small burner that works quite well for smaller forges. You could also contact them with dimensions on your forge size and they should be able to let you know if the burner is the right size for you.



Good call Jesse! I'll have ten bricks to work with. I plan on building something with a hole about 14 inches deep and six inches wide. I'd like to make a couple cleavers after a while! Hopefully I'll be able to heat it!


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## Jesse Killion (Aug 21, 2020)

That is gonna use up some propane for sure. That's quite an area to heat up. How often do you plan to make cleavers? If it's only once in a while it might not be a bad idea to make a 2 brick forge and a large forge and only use the larger one when you absolutely need to, propane can get expensive fast. Just food for thought.


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## Seffers93 (Aug 21, 2020)

Jesse Killion said:


> That is gonna use up some propane for sure. That's quite an area to heat up. How often do you plan to make cleavers? If it's only once in a while it might not be a bad idea to make a 2 brick forge and a large forge and only use the larger one when you absolutely need to, propane can get expensive fast. Just food for thought.



I guess I probably won’t be making cleavers too often. I had only planned on a few.. I hadn’t even thought about making two forges! That’s a great idea! Thanks for the tip!


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## inferno (Aug 21, 2020)

the nice thing when working with block shaped pieces is that you can have the chamber any height/width/depth you want. you simply enlarge it when needed for the project. its the volume that will dictate the power needed. however i dont even let my whole "forge" heat up evenly, i simply put the blade in the flame and try to somewhat contain the flame. it works too. very well actually.

if you look at most "knifemaker" electrical furnaces like evenheat/paragon and such they are usually only 3kw for a chamber thats about as big as i make mine. but i have 15x the heating power. thats why it takes less than a minute to heat a blade for me vs an evenheat. 

also most industrial furnaces have like 20-50kW is for the same volume that an evenheat would have. and there is a good reason for that. time is money. 

if you can limit the volume of the chamber when needed, you get a higher power density. and everything goes faster. and gets cheaper.


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