I made a two brick forge

[SamHarper]

Well, dang it, I think I tempered my knife too hot. I bought an oven thermometer and used it to get my toaster oven to 400ºF, but apparently, it got a lot hotter. Some of my knife turned purple. What do y'all think? Do y'all think this knife is going to be too soft? Should I redo it or just finish it like it is? I'm a little concerned about grain growth if I do it again. Should I be worried about that?

[Gunnyart]

I copied the soup can forge idea from youtube and scaled it up a bit . My dad gave me an old anvil and now I just need one of ya'll master knife crafters to teach me how to make my own knives. I'm not planning to sell knives I just want to make my own for the fun of it.
I'll post a pic of my forge tomorrow.

[SamHarper]

I copied the soup can forge idea from youtube and scaled it up a bit.

The tomato can forge? :-) I thought about doing that but didn't know where to be refractory cement.

My dad gave me an old anvil and now I just need one of ya'll master knife crafters to teach me how to make my own knives.

I learned by reading forums and watching YouTube videos. I also got a book called The Complete Bladesmith. I haven't forged a knife yet. I tried forging one out of a railroad spike, but it was more difficult than YouTube made it look. I just use the stock removal method.

[Kevin Smith]

Here you go.

http://www.hightemptools.com/

[Bjankowski]

Good job Sam; you'll find the more you get into knife making you'll come up with ideas for jigs, clamps, drill press and other resources to help you in the process.

In knife making you have to thinks on your feets.

[SamHarper]

Thanks for the link, Kevin.

So no opinion on whether I should re heat treat this knife? Last night, I was googling around to see what other people did in this situation, and one person said it's possible to get a little purple from the residual oil left on the blade after quenching. I tried rubbing it with my thumb, and most of the purple came off, and it's yellow underneath, so I'm thinking maybe it's okay. What do you think?

Here's a before and after picture.

[JP Weld]

Nice!

[akey]

Are you just doing 1 temper cycle? I usually do 2 and after the second one my knives are typically more gold in appearance than your picture. Are you using a thermometer that stays in the oven? If so, you should be able to monitor the swings in temperature as the oven cycles on and off. You want to make sure that whatever temperature you are aiming for is at the very top of that cycle.

[SamHarper]

I only did one cycle with this knife because I wasn't sure whether I should re-harden it and start over or not.

I had the thermometer in the oven to get it to the temperature I wanted (400ºF), but I took it out to put the knife in there.

I seem to have better luck with my big oven, but it sure does seem like a waste of energy to heat up that big oven for just one knife. I thought about maybe heat treating multiple knives at once, but I'm not sure how that would work either since the oil would get hotter and hotter with each knife I quenched. And I don't want to leave a hardened knife sitting around waiting for other knives to get hardened several hours later because I've heard of them cracking and stuff while just sitting around. What to do, what to do. . .

[SamHarper]

Maybe on my next knife, I'll try tempering it with the blow torch.

[akey]

I think the kitchen oven with a thermometer sitting next to the knife is your best bet in the long run. My experience in knife making so far is I find the best success when I use methods that are easily predictable and repeatable. I know that is not always possible when working within the budget I have but when talking about using your oven, I think you are not really using as much electricity as you think. Below is a table from the Consumer Guide to Home Energy Savings.


Appliance

Temperature

Time

Energy

Cost

Electric Oven 350 1 hour 2.0 kWh $.16
Electric Convection Oven 325 45 minutes 1.39 kWh $.11
Gas Oven 350 1 hour .112 therm $.07
Electric Frying Pan 420 1 hour .9 kWh $.07
Toaster Oven 425 50 minutes .95 kWh $.08
Electric Crockpot 200 7 hour .7 kWh $.06
Microwave Oven "High" 15 minutes .36 kWh $.03

So, I temper my knives for 2 hours at 400 degrees, twice. That means I am probably spending around 75 cents. When you take in to account that I can easily control this and repeat it, as well as do other stuff while the oven is doing all the work, it is well worth 75 cents to me.

[SamHarper]

Thanks for providing that information, Akey. I feel a whole lot better now. I'll just use the oven.

I decided not to reharden this knife. I'm going to give it one more tempering cycle, then finish it out.

[Gunnyart]

Here is my soup can forge. The refractory material was 50/50 mix of play sand and plaster of Paris.

I used the nail in the picture to forge the knife. It looked nice enough for my first attempt but would not hold an edge.

[SamHarper]

That's pretty cool. At least you got some practice forging. According to a book I'm reading, nails don't have enough carbon to really get hard.

[LeanMachine]

Hey sam if you haven't hardened the bowie by the time you come to canton, I have a friend that is a knife smith that would probably help you out. Do a google search for Tommy Gann knives and you will get an idea of his skill set.