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View Full Version : Can you use a forge to heat treat?



C Craft
09-13-2010, 11:09 AM
My forge had a catastrophe.

click thumbnails for larger view:
http://i164.photobucket.com/albums/u20/craft5759/th_000_1150.jpg (http://i164.photobucket.com/albums/u20/craft5759/000_1150.jpg)
http://i164.photobucket.com/albums/u20/craft5759/th_000_1147.jpg (http://i164.photobucket.com/albums/u20/craft5759/000_1147.jpg)


It was my own DA fault for not having it fastened to the cart. I ran it into the garage the other night and it jumped off the cart. Busted up the lining and messed up my gauges on top.

When I get it rebuilt I am hoping to use it not only use it as forge but as a heat treatment oven/forge. This PID controller and the thermocouple I have should be able to read the temp and with me monitoring it I should be able to control the temp.
http://i164.photobucket.com/albums/u20/craft5759/th_000_1175.jpg (http://i164.photobucket.com/albums/u20/craft5759/000_1175.jpg)

http://i164.photobucket.com/albums/u20/craft5759/th_000_1173.jpg (http://i164.photobucket.com/albums/u20/craft5759/000_1173.jpg)

I don't have a good pic of the PID but here is one like it, it is a programable PID.
http://cgi.ebay.com/New-DIN-Digital-PID-Temperature-Control-Controller-/320580942271?pt=LH_DefaultDomain_0&hash=item4aa41cf9bf

Constant monitoring would be just for the time being. I don't have them yet but I can get the valves to control the gas flow and the PID will operate them to reguate the flow of propane thru the valve and the temp of the forge at any given time, this would allow for better control of temps.

So here is the questions does anyone out there use a forge as a heat treatment oven?

Is this even a feasible solution for HT on a temporary basis, till I can afford or make HT oven?

If so any advice here on sitting one up?

LRB
09-13-2010, 03:29 PM
Many makers use a forge to HT, but the wise ones only HT the simple steels with them. Go with the 10XX steels, and you will do fine. Steels with chrome and some other alloys require soaking which is best done in an oven.

Leatherface
09-13-2010, 05:25 PM
hey bro

IIRC MS Burt Foster uses a forge to do his soaks in...

If you have really good temp control, I cant really see why you cant HT as well as a soak in a forge

am I incorrect in this?

silver_pilate
09-13-2010, 05:59 PM
For heat treating, I'd recommend a baffle in the forge. Take a piece of stainless pipe of a larger diameter than your blade, and place it in the forge for heat treating. After the forge is stable and up to temp (take the temp reading within the baffle), place you blade it and let it come up to temp. The baffle will distribute the heat better and tends to even out hot spots. Also, it protects the blade from the harsh forge atmosphere, and placing a piece of wood charcoal or something in the back of the baffle to use up the oxygen will allow for a better atmosphere and less scale.

Stainless steels typically heat treat better in an oven with the higher temps and stability needed as well as the long soaks. You really have to protect agaist oxygen at temps needed for stainless.

--nathan

Byron
09-14-2010, 07:22 AM
Yeah, it can be used. It's just not as accurate and you should use it only for simple steels that don't require soaking. I tried Hting some 01 in mines..I don't think it worked as I probably didn't soak it at the correct temp for the 10mins since I had to constantly adjust the gas flow.


Take a piece of stainless pipe of a larger diameter than your blade, and place it in the forge for heat treating.

Would this work for 1 brick forges? I'm sure it would for the smaller knives but the last knife I started working on is about the largest it can handle in width.

Dan Pierson
09-14-2010, 08:37 AM
A PID controlled forge with a muffle (a.k.a. baffle) should work just about as well as an electric oven. Maybe better in some ways because of easier options for atmosphere control. Stacy Apelt has posted a good deal about building one over on bladeforums.

You might get a used copy of "Tool Steel Simplified" and see what the experts have to say about heat treating equipment...

Doug Lester
09-14-2010, 05:36 PM
Just about any steel require some soak time and you can do it in a forge if you have good temperature control. Some just need a little longer soak than others. That said, I would not use a forge for the more complex tool and stainless steels. I know that we had a discussion on heat treating 440C stainless with a forge or torch and yes it can be done, as in others have done it, but it would be done better with better heat control. That's one of the main reasons that I don't use some of the higher alloy air quinching or stainless steels for knifemaking.

Doug Lester

C Craft
09-14-2010, 07:06 PM
Thanks everyone for the replies. I would mainly be using it for now with 1080 and 1095. So taking everyones advice under consideration I will more than likely give it a try! Like I said it will be hopefully only temporay till I can build me a heat treating oven!

Carey Quinn
09-14-2010, 07:48 PM
If you think about it, there have probably been more knives heat treated in some type of forge than have been treated in ovens. That being said, those knives were the more simple steels and not the high alloy super steels that so many makers use today. The use of a muffle or baffle in the forge really evens out the heat and you can see what is going on in the steel as it comes up to temp. You need to hold the knife with tongs so you can keep it off the sides of the pipe and be able to move the blade around so as not to overheat the tip. Pay attention to what is going on and you will do fine.

Just like anything else in knifemaking, it is a learning experience but it ain't brain surgery and you can figure it out as you go along.

Have fun with it and test, test, test,
Carey