Greenhorn questions

[Archer Here]

I have a few questions for you guys. I am finally starting to get in line here. I got my forge, which is a combination of fire brick, stacked with an opening in the back, for my new propane torch, which puts out a huge powerful flame. Ok now:

When should steel be demagnetized? Is it only demagnetized when it’s red hot, or is it suppose to be demagnetized even after it’s cooled? I got my blade (which is leaf spring steel, but not sure what type it is, which is why I’m just trying to get it above the temperature to demagnetize it), I believe up to 1600 degrees, because it was the color of bright orange (not red or white). And by the way it took about 3 minutes to get it to this color.

I checked it with a magnet, after I let it air cool. Was that a mistake or should I have quenched it first?

What was the thin smooth flaky stuff on my knife after it cooled? It kind of was crackly all over, and was able to be rubbed off. Not all of it, but most of it.

Next question is Knife Guards: How do you cut out a clean hole in the center of the steel to slide up the handle of the blade? I was thinking about drilling it out and then taking my large file and cleaning it up that way, or can somebody tell me an easier way?

Archer Out

 

[Keith_H]

It will only be non-magnetic at red hot in the austenite range which is starts around 1400 I think so a little higher than this at 1550 would be good. The normalizing is fine, especially if you forged it, In which case in which case it is good to do it up 2 or 3 times. The scale on the blade is oxidization, that is why foil makes for a cleaner knife. Your method of filing the hole would be good, like this http://www.bladeforums.com/forums/showpost.php?p=5538044&postcount=35 . A milling machine would be easier.

 

[bikermikearchery]

By chance did you read any of these.
http://www.knivesby.com/knifemaking.html
Some good stuff there. I think I can say I have read everything on that link and most of it many times. Keep it bookmarked. you will still have many questions, but you'll have a lot of knowledge also.

 

[Archer Here]

Great. Thanks for you input guys.

 

[Stacy E. Apelt - Bladesmith]

Reading the stickies at the top of this forum and a book or two will help you get a better understanding of the process.

The non-magnetic point is the curie point where the atoms rearrange themselves into austenite,and thus become non-magnetic. In cooling down slowly, they go back to the way they were (more or less), and are magnetic again. If cooled rapidly, in quenching, they will hopefully get locked into martensite and that is what makes a knife hard and sharp.

The stuff on the blade is caused by the surface of the metal (and any oils and such in and on it) burning in the high heat. It makes scale. This should be brushed off and then the blade soaked in vinegar overnight to dissolve the rest. It can be sanded off, but dissolving it first will make sanding easier.