Iron Bloomery

Dave · 2005-05-18T15:38:52+00:00

Guys, (longtime lurker here) I thought you might be interested in some metalworking content: These photos are from Red Top Mountain State Park's "Hills of Iron"program back in March. We gathered and roasted local limonite, madecharcoal, built the furnace, and forged iron bars. We've done it 3 timesnow, successfully. Batting 1000. I finally got around to making a webpage...no captions, but the imagesare a sorta timeline. I Hope the page is somewhat viewable; I'll answerquestions if'n ya'll got em. Dave Demo smith and Ironmaster, Red Top

D

Dave 21 years ago

Thanks for the feedback and patience; I'm not sure how many hits Bellsouth takes before the Bwidth is exceeded. Meantime I'm leaving the pics up so that, well...."Diffusion of Knowledge" and all that.

Answers to questions... A 55 gal.drum of @ 200lbs of seasoned oak yields about 70 lbs of charcoal. There is a loss to powder and fines in crushing and screening of about 15 lbs. We save this to make "lute"(?)...clay/sand/ash/charcoal powder mix to re-line the furnace. Powder can also be mixed with water and starch or molasses to form briquettes of any size. Or...pyrotechnics!

The active cook time of the barrel is about 3-4 hours. The pics show the different phases of the process...from 15 minutes after lighting up till about an hour, fluffy white/gray steam exhales, which changes to steam/blue smoke. Blue smoke then dominates, rushing out through the holes in the lid (@6 SQ inches) with greater intensity until the gasses ignite. Ignition takes about an hour and a half, plus. At this point, we are Colliers, and we keep the heat to the barrel. It'll roar, and this gas can be piped underneath for more efficiency. After 4 hours or so, I lay on a last charge of wood fuel and cover everything with sheet roofing, seal the holes at the bottom with dirt, and go take a shower. The metal holds the heat in and reduces the burn rate of the fuel so that final cook time is longer. 12-14 hours later the metal covering is removed and any remaining fuel coals are scooped into another drum and sealed. This makes our preheat charcoal, as it is pine we use for fuel, and not as good for smelting.

The stone used to make the furnace is mostly schist taken from 300 feet away, and 30 feet downhill along the lakebed. Using a wheelbarrow, these rocks were EXPENSIVE! there is some local "Corbin Gneiss" as well as Tennessee fieldstone/limestone left over from other park projects. The furnace was first fired using vitrified clay thimbles as liners. Second firing we used refractory gasket rope and 5 gal metal buckets...this was all done on the fly, as I'm a volunteer, and we used what we had. The furnace now has a permanent liner of a product called "Kruzite castable". We formed it using 8 inch and 12 inch sonotubes. We lined it with the aforementioned lute, and that works well to keep molten stuff from adhereing to the walls. The shaft size is 8 inches diameter and 37 inches tall. The tuyere opening is 1-7/8 diameter and 10 inches above the base. This is permanent in kruzite, and allows for modification of sizes/configs. I built it overlarge to be able to "build down" and experiment. Packing clay to raise the base,config the taphole ETC.

Blower motor was found in an RCM'ers junquebox , as well as most other hardware/plumbing. Peephole is local mica sheet and a ring magnet on a tee. Elegant.

I posted 2 pics that should have been on the clunky website to the dropbox:

formatting link

Look for "Bloom.Txt" and "Bloom9011/Bloom8443"

~D

Vote

D

DeepDiver 21 years ago

Hi Dave, nice site. Regarding the bandwidth issue, the problem is not the number of "hits", but rather the quantity of data (measured in bytes) that is downloaded by your visitors. I looked at your site last night (between "bandwith exceeded" errors) and noticed that your large images are very data "heavy" (i.e., they have very large data byte sizes).

To reduce the problems with "bandwidth exceeded" errors, you need to optimize your photos so that they are not so data "heavy". You see, there are two parameters when discussing the size of digital images: there are the pixel dimensions (e.g., 800 x 600) which specify the viewable ("physical") width and height of the image; and there is the data size which specifies the amount of bits of information (measured in bytes, or 8 bits) in the data file that represents the image. (The problem you are experiencing is in this latter category.) Typically, there is a correlation between these two specs: a "physically" larger image (in terms of pixel dimensions) generally requires more data (bytes) to represent the image than does a "physically" smaller image. But there is another relationship between these two parameters: quality which determines how much data is used to convey a particular visual artifact within the image. To express this as a simple equation, you'd have:

dimensions X quality = data size

So there are two ways to reduce the data size of your images (so your web server does not exceed its bandwidth limits): reduce the pixel dimensions or reduce the resolution (or both). Most people like to see larger images, so we'll focus on reducing quality. Here's where the magic happens.

The human eye is an amazing device, but it is not designed to perform quantitative analysis of an image. In other words, it looks at patterns and colors and shapes, but does not individually analyze minute differences in adjoining pixes. So if two adjacent pixels in an image are very close in hue and/or saturation, we can make them identical and the eye won't be able to see the difference. In other words, we've (intelligently) reduced the actual quality of the image (less data), but the subjective quality -- what the eye can perceive -- is undiminished. And that's how image optimization programs work: they first reduce the amount of differences in the pixels of the image (so there is less image data to "describe"), and then they use mathematical algorithyms to further "compress" the data so that even less bytes are used to represent that image. Here's a simple example of a compression technique:

If your image data is: 11111100011110000 You could compress that to: 6x1,3x0,4x1,4x0

That simple example may not look like much of a savings, but the reality is that tremendous data compression can be achieved with these kinds of methods.

Ok, perhaps you don't want to know all the nitty-gritty that goes into digital image data compression. But here's what you should know: by using an image optimization program, you can take an 800 x 600 pixel image that "weighs" over 200,000 bytes, and compress it so that it only requires 20,000 bytes (for example). That will reduce your web server's bandwidth load by

90%. And the optimization programs are so good, that the human eye probably won't see much -- if any -- loss of quality (especially when that image is being viewed on a computer monitor). Of course, the more you compress the image, the more the visual quality of the image is reduced. But you can substantially reduce the data size of an image before it starts to look degraded.

There are a number programs to perform image optimization. I use Adobe Photoshop, but that is (an expensive) professional-grade graphics tool. There are some programs that are free and will do a fine job. Since I don't have a lot of experience with these other free or lower-cost programs, I can't make any recommendations. But people have mentioned IrfanView as a free option.

I hope this helps.

- Michael

Vote

H

Harold and Susan Vordos 21 years ago

mathematical

All too cool, Michael. Thanks.

Harold (who recently downloaded IrfanView)

Vote

J

JohnM 21 years ago

Hey, I got it to download. Pretty cool, and it gives a good idea of the labor value in a piece of iron too.

Hope to see more future successes.

John

Vote

A

alvinj 21 years ago

Vote

D

Dave 21 years ago

Regarding the bandwidth issue, the problem is not the

Michael,

Thanks for the great explanation. I have my camera set to take images at 2048x1736 "fine" quality. That way I have HQ raw images that I burn to disc. I edit the real keepers in Photoshop down to 800x600 or whatever is appropriate. Where I went wrong is in the "save as" step. I usually save quality as 7-9 where I probably should save as 2-5. I've never paid attention as per your explanation to file sizes in relation to quality. I'll definitely experiment now!

Yes, it helped!

~Dave

Vote

Iron Bloomery

Join the Discussion

Didn't find your answer?