[Alan Longmire]

I spent a fun day yesterday at the shop of Lord Possum himself, Larry Harley, attempting to do a crucible smelt by reducing a rich (~70%) magnetite ore in a closed crucible with some charcoal fines for carbon and a pinch of vanadium for kicks.

All was going well until we saw what we though was melted flux from years of buildup dripping slowly from around the door of Harley's large horizontal forge. We were running VERY hot, an estimated 2600-2900 degrees F. At the one hour mark, we thought about pulling the crucible, but decided to leave it in for another half hour to be sure. At 1 hour 15 minutes, I was talking with one of the other guys who always seem to magically appear when the forge is running when we heard a loud "Oh, SH!T! Turn off the gas!" from Harley. We turned to see the whole 500 gram charge pouring out the front of the forge and puddling on the shop floor, igniting the various bits of stuff to found in that oh-so-not-clean shop.

We thought at first that the crucible had melted or cracked, but upon opening up we saw the crucible was fine, but the forge lining had melted enough so the the crucible turned over. The molten charge promptly ate the kaowool lid and turned into a puddle of black slag with a few little prills of steel within.

We had a fun four hours, but as with so many things involving the quest for steel, had nothing to show at the end.

Anybody got a clue if we even did this right? We were NOT trying to make wootz, just to reduce ore into steel. 500 grams of or, 110 grams of charcoal, a pinch of ferrovanadium powder in a neutral atmosphere forge. We've done it successfully with magnetite sand, and almost got it once with the ore we used this time. I think it was molten steel until the wool cap melted into it and it spilled. I'll post a pic or two of the lead-in soon, but there are no pics of the aftermath as we were too discouraged. We're trying it again in two weeks...

[Alan Longmire]

As promised, three pictures of the non-event:

Darth Possum and Cody (who brought the ore) roasting the big chunks to break them down into powder:



Front view of the forge at heat shortly before the first flux started dripping out:



And finally, a back view of the forge about 20 minutes before disaster struck. There seems to be some sort of mountain troll watching in the background:

[Greg Thomas Obach]

i think you had it... just spilled it.. or at very least it should have clumped up into a sponge ?

i'm having the same kind of day
after reading so much bout seax twist core stuff, i tried some forgewelding today in my gas forge ( not something i do, as i weld inna coal forge ) so i put her on up to 10 psi.. some air and couple minutes later... it looks kinda cold in there... 15 psi... and couple minutes later i pull out the rod i welded the billet to...... look in there... scooped up the crumbles of what was the billet... runnin just a tad on the high... the next two billets came out ok... but that first kicked me in the can... it was an oldy file and 15n20... man, i was savin that file for something good... those darned firey beards..

nice shop !

[Skip Williams]

Hey Alan,
'tis good to see that the mountain troll is still trolling around.

What do you mean by a rich ~70% ore. Is that 70% Fe or 70% Magnetite with a bunch of sand in it?

[Alan Longmire]

Howdy, Skip!

It's Cranberry Magnetite, massive crystalline magnetite of around 70% Fe with the other 30% being natural flux-type crap. Quartz and other silicates, metamorphosed apatite (just a smidge) and stuff like that. I REALLY want to try it in a bloomery or better yet a catalan forge, but Harley and I are a little short of funds to do so at the moment. He had the crucible and a freshly-filled 250 gallon propane tank, so there we were...

[Christopher Price]

Jeff and I smelted some Cranberry in a crucible just fine, and got a wootzy pattern out of it (though I think he threw in some other ingredients when I wasn't watching). For this kind of work I can't reccomend highly enough the Pringle Disposable Furnace (soft-sided edition) design, vs. the forging furnace. Good luck. And I haven't forgotton my need for a field trip to load up on that ore.

[Skip Williams]

Alan Longmire, on 08 February 2010 - 06:10 PM, said:

with the other 30% being natural flux-type crap.

So there is the answer. The common black slag, fayalite, is about 70% FeO and 30% SiO₂. Oh, let me turn that around the other way, the 30% natural flux type crap (silica mostly) combines with 70% of the FeO to make a black fayalitic slag. You can't do much to improve the yield except to remove the silica. Bust the ore up and refine it with a magnet. That should work better.

BTW the archaeology videos you posted were great!

This post has been edited by Skip Williams: 08 February 2010 - 06:43 PM

[Alan Longmire]

Thanks Chris, I was hoping you'd chime in since I knew you and Jeff had done it with this ore. I told Lord Possum about the Pringlerii Softsides Rapidsmelt Mark II, but he didn't go for it for reasons known only to him.

And thanks Skip! We did employ magnetic separation. I have come to believe what really happened was the the kaowool "lid" on the crucible melted. In fact, that's the only explanation that makes sense, as now that I think about it the volume of goo that ran out of the forge was greater by far than the volume of raw ingredients we put in.

The previous time we tried a crucible smelt with this ore I did get a small puck of steel, but in that instance we had added some crushed oyster shell to the ore as flux and no charcoal for carbon, counting on the graphite crucible and a reducing atmosphere for carbon uptake. Since this ore is self-fluxing (we didn't realize that at the time) we got one quart of black fayalite glass with a little olivine atop a five-ounce puck of steel.

Next time we'll leave the lid off and add more charcoal to compensate.

[Dee]

just the mere thought of molten gooey metal all over my workshop floor is enough to stop me sleeping for the next few nights.

im glad that no one was hurt .. apart from the metal that is.

R.I.P. dear steel.

[Skip Williams]

yeah,
I'm hoping to hear from Jeff about which magic ingredients he and Chris put in the crucible. There is a pretty wide temperature valley in the graph of oyster shell, iron oxide, and silica mixtures where you can get a nice liquid slag. I'm guessing about equal weights of CaO and silica.

That did sound like a pretty dangerous way to make your selves some steel toed shoes.

This post has been edited by Skip Williams: 09 February 2010 - 05:54 PM

[Jeff Pringle]

It was the Cranberry ore mixed with Masabi taconite, both brought by Chris. I don't remember doing anything special with the other ingredients so it was most likely a cup of graphite and half a cup of CaCO3. If I was trying to anticipate the different chemistry of the taconite compared to my usual magnetite I would have thrown some pumice in there too, but I probably figured on adjusting slag viscosity during the smelt if things were too gummy
Smelting slag melts kaowool instantly, kiln shelves quickly, firebricks slowly.

[Alan Longmire]

Thanks, Jeff. We have all the above, and may try a few different mixes next time.

The hard part is getting started early enough. Harley insists on watching "Riders of the Silver Screen" on Saturday mornings...

[Christopher Price]

My only remaining question, Jeff, is how much ore went in with those other ingredients?

[Jeff Pringle]

Wasn't it three or four of those Cranberry rocks? Probably two cups of the taconite, more or less - that container was full when you brought it, so if you still have that kicking around you could see how much we used....

[Christopher Price]

Burned the rest up in Visalia. But thanks... I think I was hip-deep in trying to fold some bloom while you were busy loading the crucible. I'd always meant to ask you just what went in there.

[Alan Longmire]

Well, we gave it another shot yesterday after modifying the forge a bit, and had a little more success yet still did not achieve steel. We erred on the side of caution and pulled the crucible too soon, with the result that the Kg of ore we carefully powdered is now a solid rock again, complete with crystals, but is still not steel.

Next time we are going to use green glass in a pathetic attempt to get the @$%@#$%@!@% impurities to float out, leaving steel below the slag cap. Harley is determined to figure out how to reduce this ore in a crucible, since we have an unlimited supply of the ore but no time or money to run a stack furnace. I'm leaning towards sacrificing my nice dry roll of wool and a firebrick to make a Pringelrii smelt-o-matic if I rip the burner out of the little vertical forge...Harley is, however, determined to do it with the current setup.

More pics to come later than now.

[Christopher Price]

All I can reccomend, is heat and plenty of it, a way to check the crucible (easier if the top is open vs. wedged in that little horozontal forge) and patience. Get yerself up to Baltimore in 2 weeks and watch the master at work in person. That alone is probably worth the drive.

[Rogerrr]

Alan Longmire, on 09 February 2010 - 09:17 AM, said:

I told Lord Possum about the Pringlerii Softsides Rapidsmelt Mark II, but he didn't go for it for reasons known only to him.

Just for the record I'd like to point out that one of the reasons I joined this forum is to figure out what the Pringlerii Softsides Rapidsmelt Mark II is.
Now that I finally saw the photo I must state humbly that it is vastly superior to my WingAss Model 1a disposable furnace -- although the WingAss 1a does have the cool psuedo X-ray feature.

This post has been edited by Rogerrr: 19 March 2010 - 10:54 AM