Tuesday, March 06, 2012

You Can't Always Get...

...what you WANT
(But if you try some times...)

(This posting an echo from Bloom to Bar)

This is a look at what happened yesterday in the forge.
If you check back to yesterday's posting. You will see that the concept I had come up with was to take one of the smaller, more compact looking blooms and layer it up on to a carbon steel core. The intent was to preserve the ragged edge into the finished object.

The bloom I chose for this was the one from Smelt 14 - at Dan Nickel's 'Folly at the Forge' event. (Black Rock Forge - Traverse City MI, February 2006. The story of that smelt is an interesting tale of endurance, it was 20 bellow F when we started!) The piece was a fragment at 485 gm off a much larger bloom. As we had forged down the full bloom to bars at the event, I knew the material was a 'nice workable iron' (from my notes).

As it was about fist size to start, it easily fit inside my two burner propane forge to pre-heat. This allowed me to bring the core up to temperature more slowly. Also allowed this process to take place while I was getting my main coal forge set up and started. All the actual forge work was done in the hotter coal fire.
(Note that I have altered this image in an attempt to get it closer to the actual colours you would have seen. The camera 'sees' down into the infra-red differently than the human eye does. The actual colour would have been a 'bright orange'.)
This is the end result of the initial flattening stage. I worked the raw bloom starting at a welding heat. I took two heats working with the hand hammer, concentrating mainly on the flatter of the rectangular sides. Then I took several heats on the air hammer, again starting with welding each time. The action there was primarily to draw the rectangle down to a wide and thin flat bar.
Here you can see the results after being cooled and cut into two fairly equal pieces. The loss from bloom to this stage (as you can see) was down to 394 gms

Thats a total loss of 91 gm, or about 20%.
The metal at this point still had some fissures in it, especially along one edge. If I was really trying to make a solid working bar, I would have collapsed the bloom into a square cross section, allowing me to work all four of the edge surfaces (instead of just concentrating on two). I would have undertook at least one more weld series. My estimate is that the total loss would have been closer to 25 %

The two bloom iron plates were roughly 1 3/4 inch wide x 3 3/4 long x 1/4 thick. I took a piece of standard 1045 middle carbon spring steel (new leaf spring) and placed it as a core. A working handle was MIG welded to the spring. I then tack welded the three pieces together at the far end. You can see that the central cut end of the bloom plates was placed at the far end.
(I normally wire together my starting layers. Also I like to weld from the far end back towards my body. Just habits!)
At this point there was a total of 643 gms of material, the stack was roughly 3/4 inch thick.You can see that the spring was a bit wider, at 1 3/4 inch. I left the plates all even on the 'cleaner' edge of the bloom pieces. (Remember a ragged effect was my initial goal.)

The finished result.
This billet is roughly 8 inches long (with the more or less pointed end) x 1 3/4 at the base x 3/8 thick. I have given it a fast surface clean on the high speed sander. Although there are certain to be some flaw lines, generally the surfaces are welded fairly tight.

Although this billet will certainly work up into a potentially quite nice blade, it is not quite 'what I need'.

Back to the pile for another attempt...

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February 15 - May 15, 2012 : Supported by a Crafts Projects - Creation and Development Grant

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