Forge damage?



http://www.panix.com/~alvinj/furnace.jpg
That's not set up to be a forge it's set up to get as even of heat as I can for heat treating knife blades.      Regular fire bricks cost me 75c each and the insulated fire bricks cost me $2.45 each. They were the lightest to be had there/then.
Inside, on the floor, where you can't see, are two insulated fire bricks and simply surrounded by the ordinary fire-place-liner bricks to form the floor.
The insulated fire bricks are light weight almost like styrofoam. :)
No kidding on this, I did this and even showed it to others a couple times... picked up an insulated fire brick with my bare hand with one face of it glowing orange-yellow and turned that face toward myself and felt like I was going to singe my eyebrows. ;)
The first time fired it up after switching to the insulated fire bricks from the old ordinary fire place liner bricks I "almost melted" (non blacksmith ok?;) the O1 kitchen utility knife blade I was trying to heat treat. Not only was it much faster but so bright in there I missed seeing the arrest point and blew right past it. :) (i always heat treat at night)
I was using the same size of flame as before... since then cut it back to 1/4(?) and need to experiment with even cutting it back somemore.
I'd really like to see configurations of insulated fire bricks that are considered good forges by their user! So some day I could copy it. That's the thing about bricks you just re-configure as needed.
I melted and poured in four different melts, 315 pounds of lead using those bricks then put it back the way it is in the picture.
The first few years I was heat treating, that stack of fire bricks took on a dozen different configurations. :)
Alvin in AZ (dogs, beer, ribsteaks cooked over wood;) ps- still working on the spark testing... stalling for a known sample of something in between 1035 to 1060. pps- all I have are 4140 and 5160
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That's what I'm talking about! I have just the tan bricks... So the insulated brick makes that big a difference in the interior heat? Guess I'll have to source some.

I keep playing with different designs than the one I have and I keep coming back to the original design. I would like to work out a double chamber system for heat treating where the torch flame travels to the end of the first and is bounced into a second chamber for lower more even heats
I'm with you on the working at night thing. I start in the late afternoon. Last night I was working it till it was almost too dark to see the rest of yard. You get an entirely different relationship with the forge and work after the sun goes down. Very nice!

So the HC spikes are a known 1030 anyway. Not close enough? I keep coming up with different samples of stuff. Been working a leaf spring lately and it seems to be pretty much the same thing as the cement/rail clips we were discussing. Which leads me to believe it's 5160 (shrug)? found another big heavy piece of railroad castoff the other day. shaped kind of like a splitting wedge with some extra details added on. Can't imagine what its used for.
Greyangel
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Ask your current supplier - they might be willing to order you a box. If no luck, check for "refractory materials" in the yellow pages. Any pottery supply will also have them.
Depending on how narrowly you define local, you should be able to get them locally. However, the good part about them if you actually can't find any locally is that they are lightweight to ship.
Web searching on insulating firebrick (or IFB) will result in various sources online. They may not be a good deal (alvinj reported a local price of $2.45, these are more expensive at $63 for 25 bricks, plus the shipping). But it's one source as an example, anyway.
http://store.ceramicstoreinc.com/fiincaof25.html
Those are 2300F bricks, there are others available up to 2600F (might be only one supplier for IFB at that temp - came across a page describing it as a novel process extending the IFB temp range from previous limit of 2500F, so 2500F is probably available from several suppliers). All should work fine for forging steel, and lower temp rating is probably cheaper.
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Cool! Thanks for the site info. They're a bit pricy but I notice they sell by the brick too. I don't think I'll need more that ten or so of them.

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GA, You are using a big ass torch tip in open air now, right? Your idea of "baffles and chambers" is not needed. You need to think differently about forges. Think of the interior of a forge as very even, controllable, volume of heat energy. When you use a heat source in open air it is nearly impossible to control the atmosphere surrounding the steel you are working with. Even if you can manage an even heat on the entire knife blank the steel is probably suffering a lot of undesired oxidation. Think of a knife makers forge as a box with a 6"w x5"h x 10"l interior holding an even, non oxidizing, volume of gases at 2300?f. You really don't want the torch or burner directly impinging on the steel. You can do this with brick but the most efficient way to do this is with fiber blanket insulation like "Kaowool" The downside of refractory brick (hard or soft) is that, while very durable and heat resistant, it is also a VERY poor insulator. This means that it requires a lot of BTU's to get it hot, and to KEEP it hot. Every brick you put in a forge will be acting as a heat magnet.
There is really no comparing brick to thermal fiber insulators (like Kao-Wool) These materials reflect almost all of the heat energy and absorb almost none. Put 2"- 3" in a sheet metal tube and it will get to welding heat in 15 minutes and the outer surface temp will only be about 500?f. The forge will also be stone cold in and hour or two. The downside of fiber is that it is very susceptible to abrasion. In my mind a good gas forge will use as much blanket as is practical with some brick or castable refractory to toughen up high wear areas like doors and floors Using an expensive liquid coating like ITC100 on hard brick is pretty much a waste of money unless you are trying to hold molten metal, like in an iron cupola. ITC100 encapsulates and slightly toughens the surface of the fiber insul. It is also resistant to welding flux which, btw eats through fiber like gasoline through styrofoam.
Greyangel, there is no such thing as cheating when it comes to using tools. It's how you use them mate. A better description of the flatter would be to think of a hammer about 1-1/2" square one face flared to 3" square with the other left plain.
Good luck, GG
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Thats about the gist of it ;)

Actually I'm working up to something about 36 inches long...

Read several designs. Shooting for a Riel setup in the near future. Kind of curious though, I think it is Dan Fogg who has the design for the upright tube chamber that he passes the steel all the way through it and only gets about 6 or 8 inches of actual forge heat on the steel at a time? This would seem to cause problems with the heat soaking off the ends but then I've seen his work and he's doing what he does very well.

Less fuel would be good.

Understood. Ron Riels reciepe calls for coating the entire inner surface with ITC. A round chamber will also circulate the heat better than sqare brick.

plain.
I was joking ;). Actually I thought to myself "what a wonderful idea!" I have a left over piece of railroad rail without the top rail that I cut off my rail anvil and got to thinking that a piece of that with webbing forming the part you hammer on and the footing cut down to shape would make an excellent flatter.
GA
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Hey GA, Weld a longish handle parallel with the web of the rail section and that should make a usable flatter. The face of the tool should be, well.......FLAT.
36" long forge? That's huge. keep in mind the more voulume the more burners/fuel you will need. I have a huge commercial brick pile forced air forge with 5 burner ports, 500k BTU's. It's great if you want to heat 30" of 2" square bar but for most work it is an absolute waste of energy. A small frax forge will do 90% of the work I do and costs very little to run.
GG
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glen wrote:

And smooth. Every imperfection in the surface will be faithfully transfered to the work.

Three feet of box? You're gonna need more Fire. Think about another burner for the back half.
Charly
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I was thinking on using it like a punch for more control. Might do one of each to see what works best for me.

I expect to build up to this for swords but it's not necessary for smaller items. NEVER 2" sqare stock. Long and low and narrow would be appropriate. Too much work to start with material that oversized. Actually I was thinking on building tubular segments out of refractory lined with Kaowool with maybe brick for an exoskeleton. Do it in two brick lengths that can be fitted together or capped off depending on the immediate need? All it needs is a quick connect for the desired number of torches and an insulated plug for the back end. I'm also thinking on a fairly easy tear down since I don't have a proper shop.
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Howard Clark used to start with 3/4" round because that's all he could get -real- L6 (4370) in was rounds.
Alvin in AZ
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Hell, 3/4 round would be the next best thing to flat stock for a knife or sword man with a forge. Now Railroad scrap, now thats work! ;)
Greyangel

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I don't know, but figure, that work is going to get a lot easier when you get your new, hotter forge going. ;)
What I need to figure out is a way to take rounds and laser cut or EDM(?) them into nice, clean, thin (3/32") flats. If I felt sure about that part I could get some steel I've always wanted to make pocket knife blades from-> F2! :)
F2 tool steel: 1.25% C (minimum) 0.25% Mn and Si (nice and low:) 3.50% W and either 0.30% Mo or 0.30% Cr
Fracture grain size = #10 looks kind of like flint when it breaks. :)
O7 tool steel is another that I'd like to get but haven't found in rounds or anything else. :/
Alvin in AZ
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That would be good.

What's EDM? I hear Admiral Steel will lazer blanks out for you. Normally they want a CAD file to feed the machine but simple flats should be a punch and go operation.

Interesting mix. Enough Mn and Si to make it machineable? Sounds like one of those alloys you have to have a digitally controlled kiln to harden and temper.

One of the things that I noticed while researching steel is that the market seems to supply very specific metal types and sizes. I'm betting if you were a corporate buyer with a mass production volume in mind you could get just about anything you wanted though. With the corporate production model these days I'm betting a really sharp person with a big bankroll could make a good business picking up leftover stock for dirt cheap and warehousing it for resale in smaller quantities. We have a real problem where I work trying to get electronic components in small quantities. Most suppliers want to sell minimum buys of 10 or 20 thousand units. Now if you could set yourself up to buy them in those quantities and then resell them to the low end customers you'd have a booming business. Then there are the businesses that are frantically dumping the contents of their warehouses to reduce their inventory value for tax purposes. Aught to be a way to use that kind of craziness.
GA
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It's been done. One of them is called DigiKey, and another is Mouser, and there are many others.
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Electrical discharge machining? Heck I don't know. :/

What I should do is inquire locally about lazer machining and surface grinding and after getting some prices go from there?

Sure enough. :)

Nope. :) Nothing about F2 or F3 is for easy-machining it's all about taking and holding a fine edge for "Finishing cuts". WC and HSS has pretty much taken over that role now. It's still used as wire drawing dies tho and that's why it's still available in rounds.

That's one reason I want some... I can heat treat it myself. F2 and F3 are "water hardening". F3 is F2 plus 0.75% Cr for deeper hardening (more hardenability).
O7 would be a good one for me too. :)
I dreamed about getting some W7 but figured I'd never see any and all of a sudden a guy in Colorado had some for sale aka- 50100-B. The -B part is a modification and in this case it means added V.
So I have gotten one "dream steel", so I can't complain really. :)

Yep, and there are outfits that specialize in certain extra high quality steels in what they call "small batches". ;)
I could prob'ly make do with what they consider "free samples". :)
Alvin in AZ
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OK, don't know a thing about it.

Thats just about the exact opposite of what I do. I go shopping on the internet and then start calling the local sources. I find a big difference between the two though. I went looking for a hand held propane torch based on the web expected to pay about 50 bucks for a basic model. I went to Home Depot and found the same thing for about 20. 50 bucks got me an Oxygen/Mapp gas unit. I went calling around Machine shops to get a quote for milling the top off my Railroad anvil and most folks wanted two to three hundred dollars and one guy told me he wouldn't even touch used rail. Said it would be too unpredictable. Fortunately I found a friend of a friend who works in a machine shop and he did it for me at lunch time for free. 3/16 off the top got me a great flat work surface for knife working. Still want to find a way to slice a piece of rail into flats for swords (one that wouldn't require a rediculus amount of work).

So why can't you forge it flat and cut it up into blanks?

But you need to convice them that you are project engineer and get them to send it to a business address ;) Ever develop your con skills? It's amazing what businesses will give you if they think it fits into their sales plan.
GA
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I don't forge and for pocket knife blades, they really are better if the tang is machined. I've filed my share by hand and they are "ok" but not as good as they could be.

Hmmm... :)
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You've got the hard part already. It'd just be a matter of drawing it out flat, then you could cut to length and grind the rest. A file and then a belt sander does a great job of taking a nasty forged surface and giving you nice clean flat stock. Finish up the shaping with the grinder. Or not...

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I didn't just mean flat tho I can get both sides really flat.
Flat -and- parallel is another story. ;) The tang is so small and the blade so long that any play or ill-fit is amplified.
I've filed quite a few but really tho they would have been better if I'da had the right thickness metal to start with. The blade needs to be .001 to .002" thicker than the spring.
I've filed down factory blades and springs and that can actually improve their side to side fit sometimes. Up to a point.
But if the thinning is substantial then my sloppy methods will begin to show itself in a sorry looking/feeling fit. Forging would need too much I figure.
And in the case of F2 if I could get it lazer "sliced" that would still be plenty of work getting it fitted etc.
I've about give up on F2 anyway, I've figured out how to use the ends off of power hacksaw blades and F2 prob'ly can't beat that stuff anyway. :)
It's just a dream is all, F2 and O7 would be fun to have and use. :)
Alvin in AZ
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Hmm, guess I'd need a picture.

So we talking about a folder?

I figure you gotta live as long as you have projects left to do :)

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