Tell us about yourself!

Complete Your Profile
  • jpfalt commented on darbinorvar's instructable How to Bend PVC & Make Incredible Shapes11 months ago
    How to Bend PVC & Make Incredible Shapes

    Could you steam the pipe from the interior with a wallpaper steamer as heat source?

    View Instructable »
  • jpfalt commented on brichtl's instructable Laser Engrave Metal1 year ago
    Laser Engrave Metal

    What power levels and travel speeds did you use for the engraving?

    View Instructable »
  • jpfalt commented on hobbyman's instructable Strengthening a 3D Printed Part1 year ago
    Strengthening a 3D Printed Part

    If I'm doing reinforced parts I use both methods 1 and 3 on the same part. Method 1 makes the ABS uniform strength in all directions and method 3 adds additional strength in whatever dimension the fiber strands run.Something I will do in addition if I want a smoother surface after fiberglass or kevlar reinforcement is to pain the part with ABS dissolved in acetone to build an additional layer of plastic for sanding and finishing. I use a small glass jar about 2/3 full of acetone and add the ABS printing filament until the solution starts to thicken. Then I just paint it over the surface and it fuses to the part.

    View Instructable »
  • jpfalt commented on aridbennett's instructable Self Spinning Gyroscope1 year ago
    Self Spinning Gyroscope

    Any thoughts about using a split phase stator and an oscillator to drive the wheel without magnets?

    I have thought that if you set up an equatorial mount, you could use the gyroscope as a 24 hour clock. Very nice work by the way.

    View Instructable »
  • Viking Bearded Axe (Skeggox) From An Old woodsman Axe

    You can prevent the cracking during welding by preheating the steel to 500 deg F. The cracks are caused by rapid cooling of the steel around the weld, which forms martensite which is hard, brittle and expands in size. Martensite usually forms during rapid cooling to below 250 deg F. If the work is above 500 deg, then no martensite. A slow cool afterwards avoids forming martensite as well.An alternative is to do the weld with acetylene, where you preheat the steel with the torch and then do the weld. Again the magic number is about 500 deg F to prevent the forming of martensite.

    View Instructable »
  • jpfalt commented on Xexos's instructable Japanese Style Blade Forging2 years ago
    Japanese Style Blade Forging

    You are right and I have learned something. Pig iron per your sources is high carbon and the forging and folding process appears to serve the purpose of decarburizing the surface layer of the steel. The carbon in the flux appears to be intended to avoid too much decarburization. Interesting and good work.

    View Instructable »
  • jpfalt commented on Xexos's instructable Japanese Style Blade Forging2 years ago
    Japanese Style Blade Forging

    You are right that cast iron has high carbon content. Cast iron is an alloy of iron, carbon and silicon. The silicon causes the carbon to precipitate out in flakes as the cast iron solidifies. If you look at the microstructure it shows areas of low carbon iron, areas of structure called cementitie which have some carbon and zones of nearly pure carbon. If you cut cast iron and rub it, you get carbon rubbing off almost like a pencil mark. However, new refined iron from iron ore, referred to as pig iron has almost no carbon and has very little if any alloying materials present. It is also very difficult to forge as it is hot short and tends to crumble if the temperature is not just right. When finished the Japanese knife blade has somewhere between .85 to 1.15% carbon. This class...

    see more »

    You are right that cast iron has high carbon content. Cast iron is an alloy of iron, carbon and silicon. The silicon causes the carbon to precipitate out in flakes as the cast iron solidifies. If you look at the microstructure it shows areas of low carbon iron, areas of structure called cementitie which have some carbon and zones of nearly pure carbon. If you cut cast iron and rub it, you get carbon rubbing off almost like a pencil mark. However, new refined iron from iron ore, referred to as pig iron has almost no carbon and has very little if any alloying materials present. It is also very difficult to forge as it is hot short and tends to crumble if the temperature is not just right. When finished the Japanese knife blade has somewhere between .85 to 1.15% carbon. This classifies as a W-1 grade of high carbon tool steel. The carbon is added in the form of the willow or hoof charcoal. If you look at the microstructure of the material, you see layers of low carbon iron and layers of high carbon steel with grain structures of mixed bainite and martensite. The martensite is very hard, but brittle and looks like a pile of sewing needles in the microstructure. The bainite is very tough and of medium hardness with a mixed up looking structure. Because of the very thin layers, a fracture in the martensite arrests and stops as soon as it reaches the adjacent iron layer. The quench on the blade is into 98 degree brine. Occasionally the Japanese Katana was quenched by being plunged into a prisoner. The Romans preferred fresh urine from red haired boys. Can you believe that the Roman government taxed urine as an industrial and commercial commodity?To make pig iron forgeable, the refiner goes through a process called puddling, where pure iron is mechanically mixed with slag as it cools. The mixed iron and slag is then hammered or rolled. The result is wrought iron. The slag inclusions make the wrought iron forgeable over a larger temperature range. The downside is that if forged too hot, the wrought iron delaminates at the slag inclusions and can fall apart on the anvil as you hammer it like strands of string in a rope. Traditional wrought iron develops an appearance of wood grain as it corrodes, due to the films of slag stretched through the material during forging. I have two Japanese hammers that have wrought iron cores with high carbon tool steel faces hammer welded to the ends or the wrought iron core. It's neat stuff.

    Actually, you don't need the tatara. If your forge runs hot enough to forge, it is likely hot enough to hammer weld. A coal forge is definitely hot enough, charcoal works and a properly contained propane forge is also plenty hot. What's important is that as you add carbon to iron, the melting temperature of the metal decreases until you get up to about 4% carbon. Also, as the surface of the steel oxidizes, the resulting iron oxide also melts at a lower temperature and squirts out of the joint when it is hammered. In practice, you add a minimum of .75% carbon and a maximum of 1.2%, or the steel will not harden without spontaneously cracking as it cools. To do the weld, you clean the iron, flux it and heat it until the surface of the iron looks a little wet and runny. the color sh...

    see more »

    Actually, you don't need the tatara. If your forge runs hot enough to forge, it is likely hot enough to hammer weld. A coal forge is definitely hot enough, charcoal works and a properly contained propane forge is also plenty hot. What's important is that as you add carbon to iron, the melting temperature of the metal decreases until you get up to about 4% carbon. Also, as the surface of the steel oxidizes, the resulting iron oxide also melts at a lower temperature and squirts out of the joint when it is hammered. In practice, you add a minimum of .75% carbon and a maximum of 1.2%, or the steel will not harden without spontaneously cracking as it cools. To do the weld, you clean the iron, flux it and heat it until the surface of the iron looks a little wet and runny. the color should be orange, going to yellow hot. At this temperature, the iron can still be handled with the tongs and has plenty of strength to stay in one piece. If sparks come off the iron while in the forge, it is too hot, and you are burning the carbon out of the surface of the steel. Then you hammer.

    View Instructable »
  • jpfalt commented on Xexos's instructable Japanese Style Blade Forging2 years ago
    Japanese Style Blade Forging

    A few minor corrections:The starting material for a Japanese traditional knife was smelted iron and had almost no carbon in it. It is roughly the same material as wrought iron or pig iron directly smelted from ore. Carbon had to be added from charcoal to develop a steel alloy. If you add silicon and carbon, you get cast iron.The Japanese used a mixture of finely ground pumice and either willow or hoof charcoal during the folding process. The pumice melts to glass at forging temperature and flows as a liquid flux to prevent the iron surface from oxidizing. The charcoal of willow or hoof is nearly pure carbon and ash free and goes into the iron surface to make the carbon steel.The folding of the steel did two things. The carbon on the surface of the iron and the low carbon iron unde...

    see more »

    A few minor corrections:The starting material for a Japanese traditional knife was smelted iron and had almost no carbon in it. It is roughly the same material as wrought iron or pig iron directly smelted from ore. Carbon had to be added from charcoal to develop a steel alloy. If you add silicon and carbon, you get cast iron.The Japanese used a mixture of finely ground pumice and either willow or hoof charcoal during the folding process. The pumice melts to glass at forging temperature and flows as a liquid flux to prevent the iron surface from oxidizing. The charcoal of willow or hoof is nearly pure carbon and ash free and goes into the iron surface to make the carbon steel.The folding of the steel did two things. The carbon on the surface of the iron and the low carbon iron underneath stretch out into thinner layers. As you add more folds, the layers thin further and the carbon from the charcoal dissolves and diffuses in the iron to make a more uniform steel composition. The thinning and folding also makes defect size in the original iron smaller. The defect size is limited to the thickness of a single layer of iron in the fold. If there was a defect in the original iron and there was no folding, the defect is a significant location where the tool can break. With 8 folds, the defect is stretched out and thinned to be 1/256 th the thickness of the knife and is much less likely to cause a break.The end result is something with the hardness of the steel and the toughness of the original iron. You can chop a red brick in two without damaging the edge of the blade.I worked several years with a metallurgist who studied these blades and have made a few forge welded blades myself. As a point of interest, the Scandinavians made similar forge welds, but used sea salt instead of pumice as the flux. You can get enough heat with a charcoal forge to do welding, but an atmosphere controlled forge makes it easier. Most of mine were done using a coal fired forge.

    View Instructable »
  • jpfalt commented on Tuan_Hoang's instructable Weapons from nail and scrap metal2 years ago
    Weapons from nail and scrap metal

    NOW I CAN ARM MY BEANIE BABIES!!!THE WORLD IS MINE!MUWAA-HAA-HAA!

    View Instructable »
  • How I destroyed our dinning table.

    Lots of suppliers have iron-on veneer. Rockler, Woodcrafters, and others.Just lay the veneer on the surface and iron with a clothes iron. The veneer has hot melt glue on the back and is much too easy to use for most serious DIYers. Then stain and finish.

    View Instructable »