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Doug Ayen
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I felt this was worthy of moving up to its own post. Sometimes I feel like I've been cast as the villian in movie, especially when I'm trying to get someone to make changes on equipment they manage and I don't have access to.

The scene is the dark, dank depths of a datacenter, the Clueless User is inside a cage, as only she has the clearance to physically enter and make changes to the systems in question. Outside the cage, the BOFH and his tame manager stand around a crash cart managing the systems the User is trying to connect to.

Bofh “Gnu Gateway” Psystar: It tags the packets onto its vlan. It does this whenever it is told.

Clueless: NetEng... my manager will raise hell if this isn’t fixed. Whatever threats will motivate you, she’ll issue them.

Bofh: It tags the packets onto its vlan or else it hoses the database again.

[to his manager, Precious]

Bofh: Yes, it will, Precious, won't it? It will hose the database!

Clueless: Okay... okay... okay. NetEng, if you fix my mistake, I won't - I won't ask my boss to yell at your boss again, I promise. See, my Manager is a real important woman... I guess you already know that. (User finally tags the packets on the vlan interface)

Bofh: Now it routes the packets to the firewall.

Clueless: Please! Please I don’t wanna get fired! Just fix the problem, I don’t wanna get fired, please!

Bofh: It routes the packets to the firewall.

Clueless Luser: I wanna escalate to my Manager! Please I wanna see my...

Bofh: Route the fucking packets to the firewall!

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Windy night out there. Here's a sample of the wind in the trees and chimes.

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fluidized bed closed loop heat treat setup

The suggested size of aluminum media is 90um/4mils aluminum oxide = 180 grit. 50-lb buckets of the stuff is about $1/lb, plus shipping. Probably can source locally from one of the major industrial suppliers as blasting media.

Recirculatory setup, basically a tube (old oxy tank?) in a kiln with a feed pipe at the bottom, diffuser plate, intake at top (filtered?), with a circulatory blower (high temp capable, can a high-temp exhaust fan take 300F? Rig up a speed-controlled router and build a simple one?) and gas (nitrogen) injector.

should build proof of concept, room temp, out of PVC and a blower.


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Studying up on fluidized bed dynamics, because I think this might be the answer to the horribly dangerous molten salt pot heat treat setups. Came across the following in a whitepaper on the subject, talking about how to determine if you have just the right air flow for maximum fluidization without causing bubbling or ejecta: "Finally, in the heat transfer method, the variation of the wall heat transfer coefficient is measured as the gas velocity increases. The point where the heat transfer coefficient increases drastically is the onset of fluidization or the minimum fluidization velocity point. This method, however, is too expensive and requires a good experimental setup to measure the heat transfer data under steady-state conditions." Since the whole point of what I'd like to do involves heat transfer, I wonder if a few highly-accurate thermocouples, a flow-meter, and some accurate logging would work. Probably not, but it might be worth fiddling with compared to the other methods.

How do you measure the brightness of a polished metal surface?

During a recent knifemaker symposium, the topic of stainless damascus came up with the stated problem that nobody really knows which high carbon stainless steels (HCSS) have the greatest contrast. In fact, the expert said in his opinion it was just easier to mix in either non-stainless (D2, L6) or non-high-carbon stainless (305, 315, 420, etc) and accept the inconsistency in the final product. What I would like to do is take a sample of each common HCSS (ats34, bg42, 440c, sv30v, etc), say 20mmx20mm, heat treat, polish to a standard grit, probably .5 micron(A5, 1500 grit ANSI) and then measure the brightness, or reflectivity of the surface, then etch with some standard etchants and see what that shows.  The problem is, I'm not sure what to use to do the measurement. Back when I did typesetting, we used a reflectance densitometer to do something similar, but I'm not finding the right tool. Any suggestions? Ideally, what I'd want is a calibrated light source aimed to reflect off the surface at a specific angle and hit a photoreceiver that can measure how much of that light is being received. The comparative numbers should give a better idea of what existing HCSS would have the highest contrasts, and given the metalurgical analysis of the respective steels, might suggest alloy formulations to try for an even higher contrast. Just don't know what the tool would be to do that measurement.

I'm about ready to start my next batch of blister steel. I use a metal retort in which I place hammered thin pieces of wrought iron, this batch a mix of 130 year old old bridge trusses, colonial era safe armor, some heavy (2" thick) wrought iron chain from the 19th century, and some old wrought iron nails of unknown provenance.

I made a larger retort to replace the one I melted last year, black iron pipe with one end welded closed except for the mandatory (MANDATORY!!!1!one!)  weep hole, and the other closed with a cap lubed  with nuclear grade high temperature nickel anti-seize. After a few days in the wood stove, getting that cap off is painful.

To turn the wrought iron into blister steel I'll pack the wrought iron with a mix of powdered wood charcoal, bone charcoal, and this year I thinking about adding a phosphorus source to the mix. Lay in the wood stove, build fire, let soak until a sample piece, when hardened, breaks cleanly and shows a good grain structure. If a cross section polish and acid etch shows an even shine, you're good to go. This usually takes me with my setup about 48 hours, usually broken up into multiple sessions as I only run my wood stove occasionally.

I'm thinking of adding the phosphorus because metallurgical analysis of ancient blades shows that the hardening and embrittlement agent in their steel was as often phosphorus or other materials nowadays considered contaminants as it was carbon. This was true from the start of the iron age until the 17th century, when ferrous metallurgy really got its start. It’s not too surprising — pretty much any element in the same area as carbon can be used to harden steel — nitrogen, boron, silicon, even aluminum are used as hardening agents in modern steel, and phosphorus is right next to them in the periodic table.

I'm thinking this would probably result in steel of a different shade when etched, and that would add additional contrast in pattern welded blades. It wonder if some of the effects seen in migration era pattern welded blades mentioned in the sagas and surviving literature were created by the deliberate use of steels with different carburizing agents or accidental (but convenient) contaminants.

The first thing that comes to mind for an easily accessible and cheap source of phosphorus would be matchbooks (there’s phosphorus in the strike strips, not in the match itself, except for strike anywhere matches), but mom said never to play with matches -- any other ideas? I'd prefer to avoid mail order.

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Years ago, I made a seax blade from homemade iron and steel, but never could find a handle style I liked. After studying an article on the geometric proportions of medieval swords, I decided to try my hand at it, not really feeling like going out to the forge today. Instead, I spent a few hours designing according to the same proportions as many early pattern welded swords. The next time someone asks me how hard can it be to design a knife, I think I'll show them this effort. The blade and handle material (mammoth molar) are the images at the top. All the thin lines are different reference geometrical shapes. I think I like this one. What do you think?

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Pics of swords and rapiers up on LJ, along with some commentary.

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I braved the cold, unheated shop (temperature: 16F) and put in a couple of hours of grinding on the cleaver after work. I did the profiling, beveling, and shaped the tang. I finally gave up for the evening when frozen fingers (despite the searing heat grinding generates, enough that, as you can see on the tang, it hits "blue" temps ~540F) made control difficult and grinding dangerous. Also, I need to adjust the rotary platen on the grinder, and my fingers were sticking to the metal, the wrench, the cleaver . . .  

The body is 270-year-old colonial-era wrought iron from an old safe, not a very high quality of wrought iron, so there's lots of flaws and imperfections in the body, which are those little squiggles and dark spots on the blade. That said, I'm really liking the pattern that's starting to come out with grinding. I forged thick and ground thin, so there should be lots of figuring in the body when I've got it polished and etched.
2 Photos - View album

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Some photos of a knife I'm working on. Wrought iron body, high carbon steel edge. This shows the process from raw materials to the as-forged state, all ready for final grinding and heat treatment.
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