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DWatson
05-25-2011, 06:06 PM
HT oven or forge?



Ok folks help me get a grasp on things here. I am going to need a way to heat treat and am unsure of which way to go. I will be using the simple steels, high carbon, like 1075, 1080, maybe some 1095 or 5160, as these are, as I understand, fairly easy to work with and treat. ( Heat to non magnetic and quench)

I know that I can purchase a ready made oven or forge, but where would the fun be in that? lol.

I dont think I would have to worry much about critical heat temps and soak times with these steels, so a complicated oven, I think would be unecessary.

What I have in mind is building a propane forge, something like Wayne Coe shows, from a freon tank.

Just wondering what other peoples thoughts are on the subject, and if I was on the right track in my way of thinking?

Thanks for any advise.

Justin King
05-25-2011, 06:36 PM
For just heat treating, I would choose a digital controlled oven any day, even for simple steels. I would avoid putting much work into a HT setup that is going to hold you back a year or 2 down the road. Building a digital oven sounds much more complicated than it is, building the sheet metal body and door hinge assembly is often more complicated than the wiring and controller setup.
If you want to forge your blades then a forge makes a bit more sense, and if this is the case then you will have to familiarize yourself with color ranges and judging the temp. from them anyway. Just be prepared for a bit of a learning curve using eyeballs and a magnet. When I was HT'ing in my forge I found that the magnet was more useful for calibrating my eye than for actually telling me when to quench.

Doug Lester
05-25-2011, 08:46 PM
I'm with Justin on this, better heat control makes the process easier and more repeatable reguardless of the steel used. Granted, you can learn to use a forge, especiall if it has the ability to be turned way back and you have a pyrometer to help you out. My heat treating forge, which will also end up being my welding forge one of these days, can run at about 1650 degrees if the needle valve is all but closed off but can go above 2000 degrees if it is opened up wide. So that gives me a bit of controlability when it comes to heat but a dedicated electric heat treating oven would give me even more. That said a gas forge, even without a pyrometer, can be used to heat treat the simpler steels. It's all going to depend on how much you want to invest, which can go beyond the cost of the oven. If I wanted to have something that could handle large knives, I would have to have the garage rewired for a 220 volt circuit. If I wanted to restrict the OAL of the knife to 7-8" then I could look into putting a digital controller on a small kiln that I have.

Doug

DWatson
05-27-2011, 02:47 PM
Thanks guys, gives me something to think about. May just go for a small propane forge for now then go for an oven as I learn more about what I am doing.

Thanks again....Darrell

Wayne Coe
05-27-2011, 04:45 PM
I don't know what happened. I contributed to this thread earlier today but it is not here.
I said: I do all of my heat treating with a gas forge. If you opt for a HT oven you will have a very good piece of equipment for heat treating but no forge.
If you decide to build a forge you will save a lot of money and have a good forge and will be able to do most of your heat treating. If you can afford it get both, if it is one or the other you must decide that you are not going to do any forging and that you are needing to heat treat lots of knives and need the higher quality for that purpose. If you need to do both and money is a consideration I would go with the forge for now.

Leatherface
05-28-2011, 12:00 PM
hey guys

I am wondering

why not combine the 2

I was thinking of making a forge and adding a thermocouple to it to tell me the inside temp...Would this be more a pain than I am thinking or is this feasible?

you can forge at a set temp range, then crank it down a notch or 2 and let it come into heat treat range...with practice you can keep the forge within a few degrees and get a good soak out of it

IIRC Burt Foster does his 52100 and W2 this way

Doug Lester
05-28-2011, 12:06 PM
Dave, that is what a lot of people do. I have a pyrometer rigged to my heat treating forge. I found that I was way off in estimating the temperature that it was operating at. It's going to be there to stay. Now all I have to do is find a unit that reads over 2000 degrees. The thermocouple can handle the heat but the read out max's at that temperature. I should have read the fine print when I bought it.

Doug

DWatson
05-28-2011, 10:34 PM
I don't know what happened. I contributed to this thread earlier today but it is not here.
I said: I do all of my heat treating with a gas forge. If you opt for a HT oven you will have a very good piece of equipment for heat treating but no forge.
If you decide to build a forge you will save a lot of money and have a good forge and will be able to do most of your heat treating. If you can afford it get both, if it is one or the other you must decide that you are not going to do any forging and that you are needing to heat treat lots of knives and need the higher quality for that purpose. If you need to do both and money is a consideration I would go with the forge for now.

LOL, Not to worry Wayne, your sanity is intact. This is also posted on the shop talk thread. I posted it there first and relized it should have been here, so it ended up on two threads. Oh, and by the way, I saw the other post as well and thanks for the advice.

DWatson
05-28-2011, 10:37 PM
hey guys

I am wondering

why not combine the 2

I was thinking of making a forge and adding a thermocouple to it to tell me the inside temp...Would this be more a pain than I am thinking or is this feasible?

you can forge at a set temp range, then crank it down a notch or 2 and let it come into heat treat range...with practice you can keep the forge within a few degrees and get a good soak out of it

IIRC Burt Foster does his 52100 and W2 this way

Dave, the forges over at ellis custom knife works come with a port hole for that very purpose. I think it's a good idea as well, and something to be considered in building one.

HELLGAP
05-29-2011, 01:58 AM
Sorry but after from what ive heard a salt pot is the next best thing to a induction forge process. I would just go build a cheap forge for now and when you can afford it get a salt pot. Kellyw

rob45
05-29-2011, 09:47 AM
Darrell,

Much good advice in this thread. I cannot add much that is new, but merely expand on what has already been said.
There are advantages and disadvantages to each, and for most of us budgetary concerns are always at the forefront.

You have stated the types of steels you wish to use, but there is more to the story than that. Something not yet mentioned is the conditions under which you are forced to work.
Your shop conditions, which you have not discussed, can also influence the decision.

What type of work area do you have available? Basement shop? Backyard? Garage? Pole barn?

Burning fuel needs proper ventilation; electrical requires proper wiring. Is either a problem for you?


Rob

Doug Lester
05-29-2011, 10:40 AM
Salt pots are good tools but like all tools they have their limitations and problems. Especially with gas burners, they get complicated. Not only to you have to rig a controller to cut the gas flow on and off, if you are running it at below the ignition point of the propane, you will also have to rig an igniter to the circuit. They it will have to be monitored closely just in case the igniter doesn't work. Then you have to take steps to insure that it doesn't spew molten salts while it is heating up. You could rig eletric heating cables in the shell of the furnice but then it is less effecient but at least you won't have to worry about it leaking propane all over the shop if the igniter doesn't work.

Doug

DWatson
05-29-2011, 08:58 PM
Darrell,

Much good advice in this thread. I cannot add much that is new, but merely expand on what has already been said.
There are advantages and disadvantages to each, and for most of us budgetary concerns are always at the forefront.

You have stated the types of steels you wish to use, but there is more to the story than that. Something not yet mentioned is the conditions under which you are forced to work.
Your shop conditions, which you have not discussed, can also influence the decision.

What type of work area do you have available? Basement shop? Backyard? Garage? Pole barn?

Burning fuel needs proper ventilation; electrical requires proper wiring. Is either a problem for you?


Rob

I have a building in the back yard, wired for 110 and 220, plenty of ventilation. The only problem I have is, it has wood a floor. When I eventualy get a forge going, I will have to use it outside, or risk burning it down. That really isn't a problem though as I am going to build a roof type shelter on the side for that purpose. I have pics of my shop on the Shop pic thread, http://knifedogs.com/attachment.php?attachmentid=23467&d=1306202117

rob45
05-30-2011, 10:00 AM
I have a building in the back yard, wired for 110 and 220, plenty of ventilation. The only problem I have is, it has wood a floor. When I eventualy get a forge going, I will have to use it outside, or risk burning it down. That really isn't a problem though as I am going to build a roof type shelter on the side for that purpose. I have pics of my shop on the Shop pic thread, http://knifedogs.com/attachment.php?attachmentid=23467&d=1306202117

OK, that helps put things in perspective.

Your conditions are similar to mine.
I have a basement shop where I try to do most of my work, but running a forge down there is a no-no. The floor and walls are concrete, but it has a low ceiling and no fresh air circulation.
I also have a 10x20 shed out back, but it has a wooden floor like yours.
I use the forge outside next to the shed; that is also where I run the casting furnaces.
I used to run the oven in the shed, but now it is used down in the basement.

So it sounds like you don't really have any major obstacles that can't be overcome.

A forge is a good start, and you're going to probably build one at some point anyways as you advance.

Later down the road you may decide to build or purchase an oven for more precision, or because you want to work with other steels. You have the electrical in your shed, but still have the problem of the wood floor.
Moving steel from oven to quench is going to depend on your confidence in your abilities and how much risk you want to take.
A friend of mine covered the floor in the direct "hot work" area with brickpavers. I guess that works for some, but I can't get over the fact that some of that stuff can hold moisture. Not good for immediate contact with something very hot, and not good for long term contact with wooden floor. The biggest problem with that approach, IMO, is the trip hazard.
I took another route- I cut the wood out in the back half of the shed and filled it in with sandy soil. I have no worries if I drop or spill something hot.

Yet another alternative is to move your electrical outlet for the oven on the outside of the shed under the lean-to. Or if the outlet inside is close enough to a window, that may not even be needed.

You'll get it figured out.

By the way, nice pics of your shed.

Good Luck,
Rob

Wayne Coe
05-30-2011, 10:47 AM
You could cover the floor with Backer Board. This is a product that is used in place or over dry wall and is a concrete based product. There are two different kinds, one looks lik concrete and the edges are not a smooth, the other is light tan in color and quite smooth and square. This comes in two different thicknesses. Both can be nailed to the floor and are 4' X 5',l I It has been a while since I have looked at either.

rob45
05-31-2011, 09:57 AM
The backer board that Wayne mentioned may very well work; I don't know enough about its characteristics. But surely it's better than wood.

Been several years since I did a tile job, but I do know it's some heavy stuff!
This is the material that tile layers use under tile. It is used because tile should not be laid directly on the plywood subfloor, as the moisture involved can cause shifting.
If you want to check it out, nearly any "home center" (Lowes, Home Depot, etc.) should have it.

Leatherface
05-31-2011, 12:51 PM
Hey bro

good to see a fellow Carolinian around here...

if I dont build my own, I plan on getting one of those from Ellis...

DWatson
06-01-2011, 02:45 PM
The backer board that Wayne mentioned may very well work; I don't know enough about its characteristics. But surely it's better than wood.

Been several years since I did a tile job, but I do know it's some heavy stuff!
This is the material that tile layers use under tile. It is used because tile should not be laid directly on the plywood subfloor, as the moisture involved can cause shifting.
If you want to check it out, nearly any "home center" (Lowes, Home Depot, etc.) should have it.

Thanks Wayne and Rob, I havent thought about backer board, thats a good idea that I will have to think about.