MattBower

Great! Sorry if this is a dumb question, but who's Patrick, and how do we get him to come help us out with this decarb issue?

Yikes. You got my attention with that.

I asked a metallurgist with lots of heat treating experience to pop over here and see if he can help us sort this out. I don't know if he'll find the time or not. Quenchcrack might be able to help, but he hasn't been around these parts for quite a while. (Bob, you out there? Everything OK?)

OK, Thomas, point made. My mistake. I've never broken one open, and I don't know why I assumed they were white CI. Gray it is. Nevertheless, my point was that ASOs are made of a brittle form of CI, which is a very different thing from ductile iron. And I don't think there's anything inaccurate in that claim.

At least we're only saying good things. Oops, sorry! I know Eric has a bunch of magnetite, and I guess I just assumed you guys used his.

RTFT, folks.

Slightly too simplistic. There are several types of cast iron. The typical ASO is white cast iron, which is brittle stuff and makes a ****** anvil. Ductile iron is white iron in which the graphite inclusions have been spheroidized by the addition of magnesium to the melt shortly before it's poured. It approaches steel in strength, toughness and hardness, and can make good anvils. It can be quenched and tempered, and Quenchcrack (Bob Nichols) told me of a ductile iron alloy that's RC 60 in the as-cast condition. Several brands of fairly well-respected new production anvils are cast in ductile iron, including TFS. I think they don't go out of their way to publicize this because smiths have such a knee-jerk negative reaction to the mention of cast iron, without realizing that not all cast irons are created equal.

Thanks for that detailed discussion, Frank. And yes, I think a beehive is the same thing as a "cave fire."

OK, interesting stuff on this subject on pages 555-57 of Steel Heat Treatment Handbook, by George Totten and others. It appears that decarb is a lot more complicated than I ever realized.

Grant, I honestly didn't set out to try and contradict you on this. I started Googling around because I believed you, and this was so contrary to all I've ever read/heard that I wanted to read the details straight from Carpenter, so I could have my ducks in a row when I started telling folks that oxidizing atmospheres actually help prevent decarb. But here's what I found in Carpenter's own online glossary: ?

That's really nice. Jump up to a 24 oz. hammer and you'll have a bit more material to work with in spreading out the bit. Nice work on the spike. It doesn't look a darned thing like a pein anymore!

Good point about the mercury, Thomas! I had a gold prospector (and fellow smith -- the same guy who provided the ore for that So-Cal smelt, actually) offer me a bunch of CA magnetite, and I turned him down because I wanted to do it the hard way -- find my own local ore, dig it out, roast it, etc. I'm just dumb like that. Turns out I may actually have given the right answer for entirely different reasons than the ones I was thinking of.

I'm one of the mods over at Paleoplanet. What Chris (Price) did at their So-Cal hammer-in was actually a bloomery smelt of wrought iron; it'd need more processing to become wootz. The bookmark that Phil linked to is a paper written by Greg Obach. He, Jesus Hernandez, Jeff Pringle, Chris Price, Owen Bush, Ric Furrer, and most of the other folks who're crazy enough to make their own steel (a group that I hope to join one of these days) all hang out over at the Bloomers and Buttons forum at Fogg's. Like John said, I don't want to offend anyone by cross-advertising, but this is a very esoteric topic, and that's the only website I've ever found where there are quite a few folks with significant experience in actually doing this stuff -- particularly making wootz.

When I was much younger I did that once to a fire ant nest in the mid-day heat of a North Carolina summer. (I was mowing the yard, the little buggers stung the **** out of my legs, and the gas was handy. I was extremely annoyed with them.) It was just like detonating a tiny, underground fuel-air explosive. It killed the ants very dead, yes (and I hope it was a painful death!). But it also burned up a big patch of yard, and the flame front was headed for the pine trees before I got it out. Since then I've opted for more conventional methods in dealing with these sorts of problems.

Nice job! That's easily one of the nicer homemade anvils I've seen -- horn, hardy hole, the whole bit! And heat treated, too! Awesome! Sam is almost certainly right that you caused the grain to grow by soaking so hot for so long. However, there is a plus side to larger grain size: it increases hardenability (i.e., makes the steel deeper-hardening). With 0.4% carbon and a mass that large, increased hardenability may not have been a bad thing. The downside to large grain is brittleness. But if you deliberately tried chipping the edges and weren't able to do so, I'm guessing it probably isn't too brittle. Update: I just saw the results of your Rockwell test. That's pretty impressive! I would worry that the RC60 spots might be a bit brittle. I've read that some good quality old anvils were that hard, but I'm guessing the heat treat on those was pretty carefully controlled to keep brittleness to a minimum. You might want to be a little careful about those hard spots. Maybe think about tempering them back to mid-50s, unless you're really sure they're OK.

Why is that, exactly?

No offense taken here, Jake. I'm a huge fan of Weygers. His was the first smithing book I bought, and it's still my favorite. His description of the stuff he was required to do with a file as a student is flat-out mind-boggling to me. That's an interesting point you made about the brain acting as a gyroscope, and rotating the work instead of the file. Thanks, for the video, Grant. Looks like I've been doing at least one thing right -- even to the point of indexing the file after each stroke.

Thanks for the suggestions, Frosty. Lots of good ideas, there. The filing horse sounds like a great idea.

Well, remember: equal amounts of 4140 and 1065 will give you a final carbon content of roughly ((40+65)/2=) 52 points carbon, minus decarb losses. 4140 plus 1095 (in equal masses) would give you about 65 points carbon (again, without taking decarb into account). Just something to consider when making your decision.

Not even close to a hundred, Thomas. Like I said, I know a lot more practice is really the key. But practicing bad habits only reinforces them, so I'm trying to learn as many good habits as possible. I've seen filing guides used for tangs, as you mentioned. It had occurred to me to try a similar sort of thing for bevels, but I've never seen it done before and haven't gotten around to trying it myself. I've also seen some nifty filing jigs, like the ones shown here: filing/grinding jig Building something like that might go a long way toward solving the problem in the short term, but then I'd never learn how to do it by hand.

Thanks, Mark. Strangely enough, the straightedge idea has never occurred to me. Good idea! I do use the marker trick, although I probably should stop and re-apply the marker more often. Thanks.

Yeah, I've done the same. What I'm doing now is basically the same thing.

- how is the blade positioned and clamped while filing? Clamped flat on a board, which is in turn clamped to the table of a drill press. (Just as a matter of convenience, not because I need to use the drill press during this process!) - what height in relation to your body is the blade while filing? Mid-torso level. - are you draw filing? Yes. I started with more conventional filing to knock down isolated high spots, but I'm well past that point now. I'll try to provide photos when I get a chance.

I posted this question on another site, but I hope it's OK to post it here, too. I'd like to get input from as many experienced folks as possible. After forging, pretty much all I do on a blade is done with files, stones and sandpaper; in other words, I don't have a belt grinder (and no other power tool I've tried is even close to suitable). I'm still very inexperienced, and one of my biggest problems (a common one, I know) is getting crisp grind lines. Or rather, not getting them! I just seem to have a heck of a time maintaining a consistent angle during draw-filing and sanding. It's especially a problem where blade geometry changes in a way that requires me to change the angle of the file or sanding block -- where the bevel gets wider or narrower, along curved portions of the blade, or where the thickness of the blade changes due to distal taper (which requires me to change the angle of the file or sanding block). If all I had to do was put a forty-five degree bevel on a straight, 1/4" thick bar, I think I could do a half-decent job of that. But the geometry of knife blades really complicated things. On the attached picture, which is a rough representation of a blade I'm working on now, the geometry is changing in multiple dimensions in the area I've circled. I'm having a heck of a time establishing a recognizable "grind" line there, let alone anything remotely crisp. Having said all that: tips? Techniques? Suggestions? Book recommendations? I realize what I really need is practice, but I'd feel better if I had a plan to guide that practice; right now I'm sort of groping around in the dark. For whatever reason, the books I've read all seem to sort of glide over this subject without going into much detail. I dunno; maybe I'm just one of the few who's dumb enough to need help with this.

Both! Seriously, different folks prefer different etchants for different combinations of steels. You'd probably be best-off just experimenting. Ferric chloride is a very common etchant for pattern welded steel, but it's by no means the only one.