Anatomy of a failure, learn from my mistakes, raising
Posted: Thu Mar 06, 2008 4:49 pm
Greetings All-
I can provide pics of any of this needs clarification.
I had always desired to raise a helm (or three) as I liked the control I felt I got from raising smaller items, hot. I had made several small items over the past few years, couters, klapvisors, umbos and the like. I even went so far as to cut some early practice pieces apart to check how the metal had compressed and flowed. I felt I had a firm enough grasp of the concept to move up to a helm this past month.
The largest blank I had raised from had been a 10" circle for a 4" deep umbo. In the past I had drawn the path of the courses and after the initial pass I would typically chase a small wave of metal around in a increasing spiral as I compressed the metal. After the first couple passes I would see how much the major diameter had shrunk as the depth increased after each pass.
All well and good, eh?
So, I decide to raise a fluted round top Norman, 8 inches deep. I started with a 18" diameter blank of 13ga. cold rolled mild. I sunk the center into a dish an inch or so just to help it set on the end of my raising stake. The first pass yielded an increase in depth of 2 inches and a reduction in the diameter of only 1/2 inch, not worried yet. So I make my second pass and the wave starts to form right away, I keep my hammer strikes compressing this down as it forms, aiming at the crown or crest of the wave angled toward the center.
The wave is getting harder to compress, and I am growing tired after a couple hours straight of hammering.
I should have stopped for the day right there.
I forge ahead as I have a deadline to meet. After the third pass it is now 5 inches deep and the diameter is and inch and a half smaller. I switch from working off the end of the raising stake to the ball stake as my thigh is getting pretty beat up from where I support the edge with my leg. Working in smaller diameters had never made this an issue. I even consider putting on my leg harness so I have a cuisse to protect my leg.
As I begin my fourth pass using the ball stake now, the angle of my strikes is now reversed. A few errant strikes into the valley formed behind the wave and I see the metal moves faster. Wow! it went fast, but the wave got very steep as I proceeded to push the wave in a spiral outward. Striking into the valley, instead of the crest, pushing the wave. My tired mind thought I had stumbled upon the secret to raising a helm quickly!
Dumbass.
After the fourth pass, the blank was now 7 inches deep, but the diameter had not changed, in fact it seemed to have grown by a quarter inch. I stopped for the night realizing I had probably messed up, hoping I had caught it in time.
The next day, I got a leather apron to keep from burning my leg and went back to see if I could make this work. I begin a fifth pass, working off the raising stake as originally, not letting the wave build, compressing it as I went around.
No luck, before I reached the edge I tore through. I had intended to mic the helm after shaping to check my thickness, but at this point it was a loss in my mind so I took the beverly and sheared the outer 3 inches off. Suspicion confirmed, I had thinned the material in a ring around my blank three inches in from the edge to a varying thinness of .050 to .090.
But wait, there is more!
After reviewing every image, video and bit of information I had concerning raising a helm. Thank you, Eric Thing, Thaden, Dube, et al. And having believed I understood where I went wrong I thought to begin anew. This time though, I would start with 12ga and I would make a sallet instead! As I love those and that seemed the shape the metal wanted to flow the first time. So I cut out a 28" disc with a point.
Here's were I start mistake number two. I had noticed that Dube had dimpled the whole blank before starting to raise his armet, and Thing had actually sunk the whole of his to a depth of 2 inches before flipping it over and starting to raise. What a time saver?!!
My new improved blank is thicker and larger and a bit unwieldy, so I attempt to try and sink it and really only accomplish a plateau of sorts as the metal around the edges compresses quickly and the metal in the center crowns slightly. Seems more of a waste at this point, so I flip it over and begin my first pass. As I radiate away from the center, the wave, which I am trying to control, grows quicker and taller as I get away from the center to the bunched up edge, I have actually made more work for myself by not starting out flat. I am now suspecting Dube's array of random dimples is merely to ridgidize an otherwise floppy piece of metal in the beginning, and Thing was working on a smaller conical and domed the whole surface evenly. I am also realizing I will not meet my deadline at this rate. So I stop.
I have to punt, and go back to a two piece welded skull to meet my deadline. Do I feel this was wasted time? No, I learned. I will try again later.
If anyone feels they have any insight in to where I went wrong, please let me know.
I can provide pics of any of this needs clarification.
I had always desired to raise a helm (or three) as I liked the control I felt I got from raising smaller items, hot. I had made several small items over the past few years, couters, klapvisors, umbos and the like. I even went so far as to cut some early practice pieces apart to check how the metal had compressed and flowed. I felt I had a firm enough grasp of the concept to move up to a helm this past month.
The largest blank I had raised from had been a 10" circle for a 4" deep umbo. In the past I had drawn the path of the courses and after the initial pass I would typically chase a small wave of metal around in a increasing spiral as I compressed the metal. After the first couple passes I would see how much the major diameter had shrunk as the depth increased after each pass.
All well and good, eh?
So, I decide to raise a fluted round top Norman, 8 inches deep. I started with a 18" diameter blank of 13ga. cold rolled mild. I sunk the center into a dish an inch or so just to help it set on the end of my raising stake. The first pass yielded an increase in depth of 2 inches and a reduction in the diameter of only 1/2 inch, not worried yet. So I make my second pass and the wave starts to form right away, I keep my hammer strikes compressing this down as it forms, aiming at the crown or crest of the wave angled toward the center.
The wave is getting harder to compress, and I am growing tired after a couple hours straight of hammering.
I should have stopped for the day right there.
I forge ahead as I have a deadline to meet. After the third pass it is now 5 inches deep and the diameter is and inch and a half smaller. I switch from working off the end of the raising stake to the ball stake as my thigh is getting pretty beat up from where I support the edge with my leg. Working in smaller diameters had never made this an issue. I even consider putting on my leg harness so I have a cuisse to protect my leg.
As I begin my fourth pass using the ball stake now, the angle of my strikes is now reversed. A few errant strikes into the valley formed behind the wave and I see the metal moves faster. Wow! it went fast, but the wave got very steep as I proceeded to push the wave in a spiral outward. Striking into the valley, instead of the crest, pushing the wave. My tired mind thought I had stumbled upon the secret to raising a helm quickly!
Dumbass.
After the fourth pass, the blank was now 7 inches deep, but the diameter had not changed, in fact it seemed to have grown by a quarter inch. I stopped for the night realizing I had probably messed up, hoping I had caught it in time.
The next day, I got a leather apron to keep from burning my leg and went back to see if I could make this work. I begin a fifth pass, working off the raising stake as originally, not letting the wave build, compressing it as I went around.
No luck, before I reached the edge I tore through. I had intended to mic the helm after shaping to check my thickness, but at this point it was a loss in my mind so I took the beverly and sheared the outer 3 inches off. Suspicion confirmed, I had thinned the material in a ring around my blank three inches in from the edge to a varying thinness of .050 to .090.
But wait, there is more!
After reviewing every image, video and bit of information I had concerning raising a helm. Thank you, Eric Thing, Thaden, Dube, et al. And having believed I understood where I went wrong I thought to begin anew. This time though, I would start with 12ga and I would make a sallet instead! As I love those and that seemed the shape the metal wanted to flow the first time. So I cut out a 28" disc with a point.
Here's were I start mistake number two. I had noticed that Dube had dimpled the whole blank before starting to raise his armet, and Thing had actually sunk the whole of his to a depth of 2 inches before flipping it over and starting to raise. What a time saver?!!
My new improved blank is thicker and larger and a bit unwieldy, so I attempt to try and sink it and really only accomplish a plateau of sorts as the metal around the edges compresses quickly and the metal in the center crowns slightly. Seems more of a waste at this point, so I flip it over and begin my first pass. As I radiate away from the center, the wave, which I am trying to control, grows quicker and taller as I get away from the center to the bunched up edge, I have actually made more work for myself by not starting out flat. I am now suspecting Dube's array of random dimples is merely to ridgidize an otherwise floppy piece of metal in the beginning, and Thing was working on a smaller conical and domed the whole surface evenly. I am also realizing I will not meet my deadline at this rate. So I stop.
I have to punt, and go back to a two piece welded skull to meet my deadline. Do I feel this was wasted time? No, I learned. I will try again later.
If anyone feels they have any insight in to where I went wrong, please let me know.