Jump to content

Recommended Posts

Hello all,

 

I have been making knives for 1.5 yrs and been wanting to step up my game with the heat treat process. I have a home built forge(from a air tank) with 2" kaowool, ridgedizer and refractory cement with 2 "frosty" T burners, a 20psi regulator and it's been fine up to now. I want to make some modification and would like some thought/ideas on my set up. 

Some of the things I want to do is the following:

 

Take my horizontal set up and mount it vertically(I saw someone heat treat like this and liked the idea) the inside of my forge is round and not flat, I believe this would help with my other idea to hang a "baffle" pipe dead center of my forge.

Also I ordered a thermometer with a K coupling that I want to somehow insert into the baffle pipe to get a accurate reading. No idea how to do this as of yet. Not sure what the probes will look like and if any or all will melt lol. I will attach some pictures although they are a little old. Anyone can offer me some thoughts?

20191012_114902.jpg

20191011_163907.jpg

20200707_095325.jpg

Link to post
Share on other sites

That forge is not ideal for heat treatment because the area is so tight and small. Unless you can get a small enough baffle tube in there so as not to restrict the burners, you could probably use it for heating smaller knives up to heat for a quench. The thermocoupler is probably not necessary in such a small space. Just learn to watch for decalescence and recalescence. 

If you were planning on making a new set up specifically for heat treating, I would suggest you use basically the same design, but only use 1 inch of wool and a thin coating of refractory. Make a flat floor and keep ample room inside to allow the burner flames to surround the baffle tube. This will heat it up more uniformly and create an oven-like environment inside the tube. 

 

If you were planning on making a new forge that would double as a working forge for general forging as well as a heat treatment forge, do this:

Use a bigger tank.

Create a larger space inside that will accommodate the baffle tube, like enough to have an 8 inch diameter clear after wool and refractory.

Either bring the T-burners in at an angle off to one side rather than centered straight down, or build yourself a ribbon burner and put it anywhere (top side, doesn't matter)

 

There are posts about building forges and ribbon burners elsewhere on the forum. Do some reading and figure out what you want the forge to do, and pick a design from the many available here that fits your needs.

  • Like 2
Link to post
Share on other sites

I had a forge with a burner like yours( venturi)and went through the same thoughts and made a ribbon burner and can heat treat way better now with it.My main gripe with the pipe burner was uneven heat even with a baffle,tips are just too thin to keep the knife even in a forge with that big difference in temp where flame hits.It can be done,but my problem was in doing it I had to do a bunch of things that made it un enjoyable.I wanted to get an even heat and hold it somewhat,and I found it impossible to do consistantly in my 1st,well it was my 2nd one.Those burners sounded like a jet and you could hear and feel that it was on from far away,and my ribbon is super quiet and super efficient,it runs at 10psi.at the regulator and 5psi at the needle valve.  Are you making a whole new forge?Have you ht'd some blades in there?What steel are you using?Are you going to non mag now?Try a baffle,just stick a pipe thats not galvanized in and see how it works..I lost much time trying to research the "perfect" forge,and found I had to make it myself from exactly where you are.Yours looks neater than mine! I put my burner in the floor ,it swirls heat nicely and my thermo just pokes in there and gives me numbers ,but like Joshua says learn decalescance,I once thought if I get a themocouple=problem solved. Info on Waynes site above has surely helped me,the Kasto-lite and metrikote came from him!

20201008_014214[1].jpg

Link to post
Share on other sites

Don't try and make a forging forge a heat treatment forge. They are different animals. 

 

You will end up with the worst of both worlds. I posted a thread on here about my little heat treat for the 'the jizer' which shows how little you need for a super accurate heat treatment forge. I can hold a couple of degrees with it. I recall the post I made about the forge was made a 'sticky' in one of the forums on here. Not got time to locate the post now, but will dig it out tomorrow for you.

  • Like 1
Link to post
Share on other sites
14 hours ago, John N said:

Don't try and make a forging forge a heat treatment forge. They are different animals. 

I beg to differ. You can use the same forge to do general forging as you use to bring a blade up to quench temp. I used the NC Tools Whisper Daddy for a few years with great success before I purchased my Paragon oven. You just have to learn to vary the propane pressure appropriately for the task at hand and use a baffle tube.
Now if you want a welding forge, that's a whole different animal.

Edited by Joshua States
Link to post
Share on other sites
17 hours ago, John N said:

Don't try and make a forging forge a heat treatment forge. They are different animals. 

 

You will end up with the worst of both worlds. I posted a thread on here about my little heat treat for the 'the jizer' which shows how little you need for a super accurate heat treatment forge. I can hold a couple of degrees with it. I recall the post I made about the forge was made a 'sticky' in one of the forums on here. Not got time to locate the post now, but will dig it out tomorrow for you.

I'll try to find it

Link to post
Share on other sites
8 minutes ago, Ronnie D said:

I'll try to find it

Ok I found it! Question for you.  I thought the baffle tube was to keep the direct flame off the item. Yours has a ton of holes in it. Also I like the idea of isolating the flame with it.

Link to post
Share on other sites

The baffle tube is to even out the heat.  A closed one is great if you can't regulate your forge atmosphere to reducing, since you can toss a chunk of wood in there and have reduction for hours.  If you can tune the forge to reduction, you don't need a solid tube.

Link to post
Share on other sites

Here is the tube I used. It's 3x3 and I drilled two 1/4" holes through one side and fit two pieces of round rod into them, then welded them in place. This allowed me to put the blade in the tube, spine down, and have it stay that way.

 

Heat tube.JPG

 

It fit right in the front door and the back door closed it off.

 

Heat tube (2).JPG

  • Like 1
Link to post
Share on other sites
23 hours ago, Joshua States said:

I beg to differ. You can use the same forge to do general forging as you use to bring a blade up to quench temp. I used the NC Tools Whisper Daddy for a few years with great success before I purchased my Paragon oven. You just have to learn to vary the propane pressure appropriately for the task at hand and use a baffle tube.
Now if you want a welding forge, that's a whole different animal.

Not sure what a whisper daddy is and honestly a little scared to Google it lol 

16 hours ago, Joshua States said:

Here is the tube I used. It's 3x3 and I drilled two 1/4" holes through one side and fit two pieces of round rod into them, then welded them in place. This allowed me to put the blade in the tube, spine down, and have it stay that way.

 

Heat tube.JPG

 

It fit right in the front door and the back door closed it off.

 

Heat tube (2).JPG

This is kind of what I'm thinking

Link to post
Share on other sites
19 hours ago, Alan Longmire said:

The baffle tube is to even out the heat.  A closed one is great if you can't regulate your forge atmosphere to reducing, since you can toss a chunk of wood in there and have reduction for hours.  If you can tune the forge to reduction, you don't need a solid tube.

Ok I have read in a few places now about either wood or coal in the forge/baffle tube. Could you explain to me what this does?

Link to post
Share on other sites

If your tube has one end closed, a piece of wood, coal, coke, or charcoal pushed to the far end will consume all the oxygen in the tube.  What this means for your steel is there will be no scale formation, no decarb, and an easy cleanup after hardening.  

Same thing if your forge is running in reduction, that means all available oxygen is consumed.  If you do that with a gas forge, though, be aware you'll be pumping out huge amounts of carbon monoxide and ventilate accordingly.

Link to post
Share on other sites
1 hour ago, Alan Longmire said:

If your tube has one end closed, a piece of wood, coal, coke, or charcoal pushed to the far end will consume all the oxygen in the tube.  What this means for your steel is there will be no scale formation, no decarb, and an easy cleanup after hardening.  

Same thing if your forge is running in reduction, that means all available oxygen is consumed.  If you do that with a gas forge, though, be aware you'll be pumping out huge amounts of carbon monoxide and ventilate accordingly.

Thank you sir. Just got done welding a tube up. I ended up putting a piece of plate with a hole for my tube across the front. But thinking about it it will probably get really hot so I may need to cut that part off.

Link to post
Share on other sites

Ronnie, a whisper daddy for is made by NC tools.  They're another general blacksmithing gas forge with three burners entering at the top of a square box.  They're also a little on the pricey side and you should be able to build yourself something better for a lot less.  My heat treating forge is built in a large mailbox.

 

Doug

  • Like 1
Link to post
Share on other sites
1 hour ago, Ronnie D said:

I ended up putting a piece of plate with a hole for my tube across the front

 

Just remember that the T burner (or any venturi burner) needs enough open door for exhaust to run well.  With your burner position at top dead center you're going to have a hot spot right in the middle of the tube.  Once it's been running for ten minutes or so it'll get bigger, and since you'll be running it at around 1550 degrees (which is a lot harder than you'd think), the hot spot will even out to be around six or eight inches long.  To get a longer even heat the burner has to come in either parallel to the tube from one end or at a tangent from the side (or top or bottom) so that the flame swirls around the tube rather than blasts directly on it.  

 

Not a huge deal for the average knife, you'll just have to slide it in and out while it heats up.  In my coal forge with a tube I'm limited to a ten inch hot spot, since that's the length of the firepot. The tube itself is 18 inches or so.  I've successfully done a 14" blade in there with a lot of sliding around to get even heat.  In my mini-gasser I can do up to a foot, but it involves a lot of sliding through the hot spot.    I've known guys to do 27" katana blades in a 4" hot spot with a LOT of sliding back and forth.  I now have a 54" HT forge.  Just need to make some swords for it! :)

  • Like 1
Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...