Homemade Heat Treat

C

CAlife

Joined
Aug 29, 2005
Messages
191
is there a process and things that you could use to heat treat at home with things you'd find at a home? And without a propane tank preferably as i don't have one. I do have a propane torch but i don't think that'd work.
 
To harden steel you need to heat it up hot enough to become non-magnetic. That is pretty hard to arrange without a lot of heat and some heat resistant insulation. You would probably need to buy a few fire bricks and make a partial enclosure. If you had a mapp gas torch you might create enough heat to get a modest sized blade up to the non-magnetic point. If you had a pistol style hair dryer (or better yet a pistol style paint stripping heat gun) you might be able to build a charcoal forge. It would take engenuity. Once you reached the non-magnetic point you plunge the blade into oil. Some people just use old motor oil or cooking oil. Improvised oil can catch on fire. Your best chance would be with simple carbon steel. Subsequent to hardening you could temper by baking in about a 400 degree oven for an hour or two.

If you want to try only half the process you could use steel files as your material. This steel is already hardened, but up to a level where it is brittle. You will often break a file if you drop it on the floor. If you bake a file in the oven at about 400 degrees for an hour or two it will get tougher and softer. You can grind it into a knife form and it will be in the right hardness range. Look for some old Nicholson brand files. Some of the cheap foreign files may not work.
 
ohh yeah, i've already tried to make a blade, somewhat crude and grinds are horrible but its carbon steel. I could go out and get some stuff but i can't be spending too much money, im on a budget.

Also, how do you get the grinds to looks so good and symmetrical? I know i should be using a sander but is it really as easy as it looks?
 
Pick up a copy of $50 Knife Shop by Wayne Goddard. He has a couple of forge designs in his book for a person on a tight budget. Also fill in your profile and your location so that we can find you a knife maker close by to help you.
 
Not as easy as it looks:D But, it is doable. Try squaring your work up with a file. If you get the steel hot enough that a magnet doesn't stick to it and bury it in ashes or kitty litter it will soften it completely and file, grind and sand better. One thing about simple carbon steels and steel like file steel is that it needs to be quenched quickly. Not stuck in the quench quickly but, once in the quench it needs to cool very rapidly. Old oil is not a good bet for this. Water may be to quick and cause it to crack. Steel like 5160 is not as fussy and is easily obtainable. Many old car and truck springs were this steel. But as many have pointed out you can get 5 foot of good known 5160 steel from http://www.riversidemachine.net/item24119.ctlg for $18 plus shipping. You may be able to get a smaller piece from a spring shop near you.

Here is a short course for a decent first knife blade.

Get decent steel. 5160 is a very good bet.

Grind to shape, use files to make lines even and straight. leave edge about a dime to a nickels thickness. sand to 220 grit. Wrap the paper around a file to help keep flat and straight. Drill any nessecary holes.

Make a very small forge. I suggest you get 2 soft fire bricks and hollow both out so that when you place one on top the other you have a hole and have a hole from the side you can stick your small propane torch nozzle into. Kinda like this only 2 bricks

http://www.anvilfire.com/21centbs/forges/microfrg.htm

Fire up you forge and get your knife blank red hot. Have a magnet attached to something so that you can pull the blank out a bit and place the magnet to the steel to see if it sticks. Once the magnet stops sticking you are at the correct temprature to quench. YOU DON"T want it much hotter. Try to keep it near this temp for about 10 min. After checking one last time to make sure it is above non magnetic, stick it in a can of very warm (hot coffee temprature) transmission fluid. Then wipe off the oil and stick it in the wife"s oven at 375 for a couple hours. Cool it off. Stick it back in the oven for 2 hours and then after cool sand it smooth it and sharpen it.
 
If you're using simple carbon steels like 10xx or 5160, etc. you can do it at home without much equipment. All you need is a BBQ, charcoal, a hair dryer, a magnet, and a quench. It's not the best way to do it but it can be done well this way.
 
well the blade is 1095 steel. I do have wayne goddards book so i will look into that. I will also try to see which methods i can try at heat treating that you have all suggested. Im also planning on getting a belt/ disc sander soon. Hopefully today. Thanks for all your help.
 
also, anyone else have simpler methods of heat treating that a newbie would understand how to do? This hopefully means stuff that is easily gettable at hardware stores and B&M stores and not really specialty items.
 
Read Wayne Goddards book and you will see the simpler methods. He explains them but you have to read the book. It doesn't get any easier than that.
 
It's either that or you pay someone to do the heat treat for you and i dont think you want to spend that much money.
 
The guys have been trying to give you the simple approach. If you had a blacksmith shop the process would be fairly direct. You would hold the blade in the heat of your forge until a magnet would no longer stick to it. Next you would plunge it into an oil like transmission fluid. Then you would stick it in an oven at around 375-400 degrees for an hour or two.

The fundamental problem is that you don't have that forge. You could try and make a big simple forge with a pile of coal and a bellows. That takes a lot of space and is expensive. You could go for the super barbecue approach with a pile of coal/charcoal and a blower (hair dryer). This requires a fair bit of futzing around to get a big enough and hot enough fire without melting the equipment or setting the place on fire. You could do this in a pit with some steel pipe to duct air from your blower to the bottom or your pile of coal. It is a big production, but somewhat simple. You need some good long tongs to work near the extremely hot fire. It will really radiate a lot of heat.

The cleanest small scale approach is to use a small clean high temp torch as your heat source and some serious insulation to keep the heat from escaping. The trick here is that you want insulation that will withstand the extremely high temperature without soaking up much of that heat. You want a very light weight insulation that won't break down up to a couple thousand degrees. Regular bricks and cement either won't take the heat or require a lot of heat to heat them up. Fire brick is almost like foamed plaster in texture. It is very light and requires little heat to warm up its surface. It also does a great job of blocking the flow of heat. If you want to make a little furnace fire brick is what you need to find. I can't think of a Home Depot substitute that would work nearly as well.
 
"You would hold the blade in the heat of your forge until a magnet would no longer stick to it. Next you would plunge it into an oil like transmission fluid."

The problem with not doing your best homework, and doing some basic heat treating study, is that you will end up wasting a lot of your time and NOT ending up with a blade that got hard!
Firstly, almost all simple carbon steels go "non-magnetic" at 1413 degrees, at which temp your carbon has NOT gone into solution!
Your 10XX steels you might get by with 1480-1500 or so, but because of the alloy content of 5160, you'll need to HOLD at 1525 for about 10 minutes!
Then you need the correct SPEED of oil for each of the above examples, and used motor oil AIN'T IT!
Do a little studying first before you waste your time.
Here's a good place to start: http://www.dfoggknives.com/hardening.htm
 
I hardened a kiridashi of 1095 using a mapp gas torch and the kitchen oven and the freezer. It seemed to work ok. I also made a knife from a file w/o softening it first, except the handle so I could drill it. Its a wharncliffe style, but dropping it point first on the concrete driveway didnt break the tip. BTW, I dont recommend this unless you have a good grinder and a lot of time. I did the rough grinding with a bench grinder, then finished w/ a belt sander. The finish grinding took a long time, off and on for about 4-5 hours.
 
Yes, the temp is a bit higher than non magnetic. If he tries to keep it near non magnetic like I suggested in my first reply he will hit the high spot and 5160 will harden in ATF. It is not optimimium at all. But, it will harden. Very few are going to go out and buy all first class stuff to make and harden their first blade. For me just seeing a piece of soft steel get hard and the file skate acrossed it got me going. I used my oxy acetelene torch and ATF. It got hard and it still cuts. Was it the best ? No but, that knife still makes me happy. It helped peak my curiosity and got me fired up. It is not perfect and could be so much better and thats were I headed. It got me curious to find out how and why. So I studied and I read. Now I have real quench oil and a high temp oven with a good control, If I had to wade thru to much stuff I may have gotten bored and went along my way. Now I have a kmg, and etc etc. I read almost every post here and have read most of those in the beginners archive. Yes, he needs to read. But, IMHO there has to be a bit of reward along the way. If he starts to experiment and stays to learn he will. Just my two cents worth. A friend of mine who is a machinist gives some simple blacksmith demonstrations at the local HS. One of the things he does is harden a piece of steel with a torch and some oil. It amazes the ones that are truely interested. Some go on to study and learn more. It is more complicated yes, but you can do a simple job with decent results.

Just my humble opinion. LOL I am anything but humble.
 
I'll chime in here with some hopefully welcome observations.

If you have a propane torch and a soft firebrick, you can probably heat treat the knife laying on the brick. MAPP gas will work better. If the side of the blade is non-magnetic, the edge has most likely reached CT before that point, so you shouldn't have to worry much about soak time with 1095. Get the color even across the blade, make sure that it's non-mag and quench it in your medium. This is not "exact", but it will give you a decent, hardened blade, imo.

Others are right, the Goddard book has all of this info and more.

J.McDonald Knives said:
It's either that or you pay someone to do the heat treat for you and i dont think you want to spend that much money.
Click to expand...

I don't think too many folks will take money to HT carbon steels. I don't know of any, actually. If it were stainless it could be done for relatively little money, so I don't get the point of this reply.
 
There are big time commercial heat treating outfits that have minimum orders that would be expensive to deal with. There is an outfit here in Colorado Springs that has clients like Spyderco that would be over budget for most hobbyists.
 
No doubt that some are expensive, but some are not too painful. Texas Knifemaker's Supply is the first to come to mind.
 
You must log in or register to reply here.
Back
Top