High-temp, disposable material

[dragonorb13]

I'm trying to liquify some steel/iron to flux out the crap in it. The problem, naturally, is that high-temp ceramics are bloody expensive, and I could only find three places that wouldn't charge my entire left leg for a specified shape, interior size, and thermal survivability... and they still wanted knee down. To top it off, the material wasn't in any way disposable or reusable.

 

What I need is a material that is either fairly cheap to produce (like Plaster of Paris cheap) or I can break down with relative ease to reuse (as in smash it to dust, reconstitute it with water, shape, let it dry kind of ease of reuse). It needs to be able to survive temps of 3500F or better (wiggle room, I know must steels and iron cap out around 2750 degrees), though +/- 250F is acceptable, if nobody can give me my target. I would LIKE for it to be easy to destroy (like smash it with a 3 pound hand sledge sort of easy to destroy).

 

I was thinking of just using firebrick, but I have no idea of how to make it, and the 'tutorials' I could find were... lacking in precision. I have the will, the ingenuity and the sheer lack of anything better to do to get it done, I just need some ideas.

 

Thanks!

[ThomasPowers]

Firebrick won't hack those temps; I see you don't mention safety in there either.

 

I'm afraid you are asking for easily available 24 carat gold for $5 an ounce.

 

Also WHAT COUNTRY ARE YOU IN?

[dragonorb13]

Firebrick won't hack those temps; I see you don't mention safety in there either.

 

I'm afraid you are asking for easily available 24 carat gold for $5 an ounce.

 

Also WHAT COUNTRY ARE YOU IN?

Well, I'm in the US. Specifically, New Mexico. As a little bit of a quantifier, if I can reuse the material, price isn't relavant to the discussion. It's only relevant if I can't reuse it. I'm more than willing to invest in something that I can use over and over.

 

As to safety, I'm in a desert with few trees and fewer scrub plants in the area. Starting a wild fire in this particular spot (yeah, I know Arizona and NM have have had a few fire issues the last couple years, just not where I'm at) is extrodinarilly unlikely. Especially since I'll be using someone else's oven. As to the safety of the material, good point... non-toxic IS kind of a must in this situation. I'd be more than happy with ceramics, but the only ceramics I know how to make are the kind you make by firing clay, and i KNOW that won't stand up.

 

EDIT: When I say "someone else's oven" I mean that they have all the relevant permits, etc, and safety equipment for malfunction in place.

[ThomasPowers]

I myself live in New Mexico and fire danger is always a concern!

 

Safety was mainly in reference to dealing with molten metal; expecially at molten steel temps---a drop of sweat can kill you when working with molten metal.  Many refractories are notorious for not liking temperature swings; having a crucible crack while you are manipulating it can be more excitement than one could wish.

 

Can you go into more detail in what you hope to accomplish?  Melting Blister steel to make Crucible steel helps; melting regular steel will probably *add* impurities unless you have the tech to prevent it. 

 

May I commend to you a search on making wootz steel; as the crucible discussions will be very apropo to your goals.  If you are really gung ho Dr Feuerbach's thesis "Crucible Steel in Central Asia" has a lot of information on their crucibles and reuse of old ones as grog in making new ones. (I recall from "Steelmaking Before Bessemer, Vol 2 Crucible Steel" that Huntsman had many difficulties getting refractories to withstand molten steel; luckily we have a couple of centuries more experience nowadays!)

 

If you are ever in my neck of the desert let me know as I can lend you a copy of her thesis on disk.

[Rich Hale]

Safety is such and inconvenience at times. But one thing that I like to keep uppermost in my conscious thoughts is simply this,,,,

Almost every shop, that does no have a rare odd lightening strike or flood etc. is perfectly safe until the one added factor steps in,,,,Us. WE in wotever way that happens create a situation that causes something unsafe to occur. WE can usually say later, things like: I did not think it would happen,,I did not see this coming, I thought this place was safe....you get the point. All of the safety equipment and warning labels are likely created from incidents that someone caused. 

You mentioned a fire as unlikely to happen due to your location. I think about working a long career as a city firefighter and the ways fire spread. the pain I have seen in peoples eyes, and the Really high percentage of those calls that simply would not have happened if people were not involved. Sounds simplistic I know. 

Molten metals are not only a surrounding area fire hazard, they are able to seek and find flesh and destroy it rapidly...Forever. 

Melting it is a part of the problem. Handling it is a huge deal. Moving from one container to another,,,And as you have asked about,,wot to contain it in along the way. 

For me,,,,I use quite a bit of steel that has to meet strict guidelines for my work. It comes with spec sheets that define the contents. For lesser needs for that quality I rely on steels that I know in a past life have met similar testing.

I wonder wot you will actually find as and end product if you invest a lot of your shop time in this direction? Will yoiu be able to clean up 

Will you truly eliminate and truly eliminate unwanted items in the steel? If it starts out with a carbon content will it lose any of it? wot about other wanted ingredients? Will they remain?  Do you want them to?

Maybe a great project for you,,,,,It would not get any more of my time,,, :)

[dragonorb13]

Well, Thomas, quite frankly, you just hit the nail on the head... me and a friend of mine want to experiment with making crucible steel. Predominately, yes, I will be adding impurities (carbon), but I also intend to remove other stuff. I don't need to handle it in the sense of container transference. Once it's heated to temp long enough to melt the iron/steel, i intend to let it cool and then remove the settled slag from the cooled metal.

 

As to the use I intent to put this to, bladess. Knives, axes, swords, yatta yatta. Weaponry of all sorts that need an edge. Don't really think a mace needs crucible steel. Which neck of the desert are you in, Thomas?

[ThomasPowers]

Socorro and Santa Teresa depending.

 

I would heartily take any suggestions Ric Furrer may make on melting steel!  Also search on anything on the web that Al Pendray has written.  (When they demonstrated at Quad-State---separate years---I made sure to be their "helper"...)

[Frank Turley]

What about dross, sparks, flux?

[ThomasPowers]

I was more worried about what gasses the molten steel will absorb and then evolve during cooling.

 

But if you want some real wrought iron as a "starter"  I have a bunch!  (given that the 13 is not indicative of age...)

[JNewman]

Firebrick won't hack those temps; I see you don't mention safety in there either.

 

I'm afraid you are asking for easily available 24 carat gold for $5 an ounce.

 

Also WHAT COUNTRY ARE YOU IN?

Depends on the firebrick.  The electric arc furnace in the steel foundry I used to work on was lined with firebrick. 

 

I know nothing about making wootz but typically steel that will be cast is melted in crucibles or lined furnace and then cast in sand moulds or investment moulds which are often backed up with sand.   Letting the metal freeze in your (expensive)  crucible is a sure way to destroy it. 

[ThomasPowers]

I think he will be teeming it as per the old days; and so casting ingots that will be heavily worked afterwards.

 

With large enough pours he can make use of piping and crystallization to force impurities into areas to be removed and discarded.

[dragonorb13]

Actually, the plan was to use a semi-sealed container (the lid fits down fairly firmly, but isn't actually sealed on so that gasses get out, but limits how much gets in) for the melting process. The slag migrates down, with the addition of silicons as flux. I was originally hoping for some kind of ceramics, but the high temp ceramics require industrial equipment. I'd planned a narrow cylinder, so that it comes out similar to round bar stock, and just lop the slag end off.

 

I was planning it this way so as to avoid the necessity of worrying about 1) casting it (as pointed out, exceedingly dangerous) or gasses permeating the metal (annoying). I know it will take longer to heat, due to the need to let everything settle, but the advantage being that it can simply leave it in the oven until it cools completely, negating a lot of the danger to body.

 

The reason for wanting something at least semi-disposable is to allow it to be destroyed and (preferably) reused, such as fire-brick, which I know is made with chunks of firebrick (I wonder where the first firebrick came from, if firebrick is made from firebrick fragments o.o).

 

Mr. Newman, would you happen to know the composition, in roughish proportions, of the firebrick they used to line the arc furnace? (not expecting it, just inquiring)

 

Also, what does teeming mean, in this context? I doubt you mean in the same why you would with, say, trout in a river. And thanks for the great resources!

[ThomasPowers]

Teeming:

 

http://www.picturesheffield.com/frontend.php?keywords=Ref_No_increment;EQUALS;y00352&pos=2&action=zoom

 

And yes it was a test to see how deep your research currently was.  Traditionally in Sheffield, crucible steel was teemed producing fairly small ingots that then were worked to refine the grain. They went on doing this for an amazing number of years after the introduction of the Bessemer process and even more "modern" processes.

[dragonorb13]

Actually, either the Norse or some group the Norse were trading with (or raiding occasionally) were producing crucible steel around 800-100 AD (http://en.wikipedia.org/wiki/Ulfberht). And while I'm not looking to reproduce the blades, necessarily, I do want to reproduce the system for making the steel, though I'm more than happy to use somewhat more modern materials in constructing the stages leading to it. I'm also willing, until I can get my own furnace system operational (yes, fire hazard IS my primary concern with this particular issue... I have no way to contain temps in the range of 3K at the moment), someone else more modern furnace.

 

If you wouldn't mind directing me to information on how to do it, I'm always open to new ideas. Especially since I haven't started this process yet. I've found plenty of things on "what" it is, but I tend to understand something better when I know how it works than just what the process does.

[ThomasPowers]

There is some possibility that the folks in Central Asia were melting blooms to get crucible steel.  Have you given any thought to running a bloomery?

[dragonorb13]

Looking at the pictures and designs, this looks fairly close to the model I was planing to use. The only difference I see is that the one I was originally planning to use had the 'chimney' somewhat more closed off (not completely, but fairly close) to retain the heat better, and used two sets of bellows to force-feed oxygen.

 

I say it this way, because the half dozen pictures and the couple of explinations of the theory I found readily all indicated the chimney to be fairly open to allow the (char)coal or other fuels to draw in oxygen by means of convection... air in forge gets hot, expands, goes up, cools, contracts, draws in cooler air from the bottom, lather, rinse, repeat.

I am a complete amature at this, only having produces a couple of low quality items, so please feel free to correct me if my understanding is flawed, I'm always willing to learn. Infact, I'm more than willing to absorb all knowledge your'e willing to hand out.

 

I haven't had a chance to read the previous articles and authors you directed me to (colledge > hobby, sadly), but I have a 5 day weekend starting tomorrow, so after the programming and troubleshooting homework is completed, those are at the top of the list.

[Metalsmith21]

There is a utube video showing the making of crucible steel, as part of a video coving the ulmbert, and recration of it, though the video name and poster of said video elude me at the moment.

[dragonorb13]

As a side note, Thomas, no, the 13 is NOT age, or even age I started using the account name. It's a reference to something out of a DnD manual. I'm 28, so no need to worry about that. Also, any iron, wrought or otherwise, you're willing to spare next time you're in the area, I'm more than willing to take off your hands. (Just read through the thread a little more in depth, grabbing names from the various posts to look up)

[JeffD]

Use silica sand about 35 mesh and add about 30% by volumn of fire clay such as lincoln fire clay. add water until it is doughy. If it is not sticky enough for your use then add a little bentonite. Just a little. Press it into a steel pot or whatever pot you have. Use an oxyfuel torch to dry out the lining and then make it red hot. Add your material and melt it with the torch.

[Ric Furrer]

The heat to melt is easy to get with coke or charcoal fuel, less so with propane, but possible.

The hottest part f the fire is only a local thing..the heat drops quickly as you move from the air/fuel blending area.

Fire brick are fine, but they will be fused into a single mass most likely..and usable again as they sit...no need to crush them up.

 

I suggest clay graphite crucibles for the melt as they are cheap and work. Size 3 or 4 is good to start.

 

side note...not all crucible steel is wootz, but all wootz is crucible steel.

 

Ric

[dragonorb13]

Awesome! Thanks, both of you! And everyone else that's given me information thus far.

[dragonorb13]

Upon further investigation, the only issue with the graphite crucibles is that, while they are cheap on their own... getting one with a lid, however, is... less cheap. And I'm willing to go through the effort of redoing the crucible every time :D

[ThomasPowers]

ISTR Ric making his own lids with kaowool and refractory gunk.

[Frosty]

You can get a better than Youtube video by downloading the Viking Sword episode Ric did for Nova at the PBS website. He covers most everything you've asked so far and darned well. Heck I'm almost tempted to take a slash at it and I'm not a badesmith guy.

 

Frosty The Lucky.