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Alan Longmire

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Everything posted by Alan Longmire

  1. Mostly because the bell reducers being cast iron tend to melt off after a while. Plus they require a ginormous hole in the shell you have to pack with wool. "Store bought" flares are 304 stainless with a polished interior, and the really good ones have a inset female thread to eliminate the step where the pipe enters. Bell reducers don't help the airflow because the rather abrupt expansion actually slows down the incoming fuel/air mix, which leads to premature combustion, aka rough idle at low pressure and the occasional flashback into the burner tube. A smooth taper, or even a straight pipe, tends to accelerate the mix a bit and promotes a clear, smoother burn. I run mine with straight pipe. It has more of a hot spot than it did with a flare due to the edge of the pipe acting as a flame holder, but it works fine in my little two-brick forge. You can get away with a lot in the air/fuel path of a blown burner (in fact adding things to increase turbulence is a good thing with them), but venturi burners need a long-ish straight shot with no impediments to the flow. They get enough turbulence from the high-pressure gas jet to do all the mixing, and anything that increases turbulence past that point is a bad thing, performance wise. That's why even the MIG tips you use are important. The tapered tips reduce turbulence at the injection end, which leads to a better mix and a higher velocity downstream. It's a fluid dynamics thing. Don't get me wrong, there are plenty of people using bell reducers in functional forges because they saw a picture of someone doing it and they look like they might do something vaguely necessary, like allow the burner to work outside the forge like a big torch (because of that drop in pressure and velocity that leads to premature ignition). Inside the forge, though, the reducers just don't do anything that's in any way helpful to the system. Those forges work in spite of the reducers rather than because of them, in other words.
  2. Diesel can? I last bought those about eight years ago and they had plain nozzles. Or maybe a surplus jerry can? They are annoying in their own, different way, but they're better than the "safety" nozzles. Or, and this is not recommended, the five gallon plastic jugs turkey fryer oil comes in will stand up to gasoline. Just be sure you label the jug. My dad had a deli in his store when I was growing up, and they went through a lot of deep fryer oil. Dad being the frugal type brought home a couple to use as gas cans for the riding lawn mower and the tractor. It was my job to mow the (five acre) yard. Now, these jugs were always in the same place. Unlabelled. One day I went to gas up the mower and grabbed the first jug, topped off the tank, and set out. I got about 150 feet into the first lap when the mower chugged to a stop. Turned out dad had filled one of the empty jugs with old antifreeze from the tractor and put it with the gas jugs. And a 25-75 blend of gasoline and antifreeze doesn't make a mower engine happy... The field crews at my office solve the problem by just removing the nozzles altogether. But they go through a lot of gas. It is both annoying and ironic that a "safety" feature is so freakin' dangerous.
  3. I sort of answered in your other thread, but I forgot to say the reducers need to go. They are not flares and do nothing for the burner besides make the ends too big. You mold the flare into the lining. It's a 1:12 smooth taper. Eyeball it and it'll be fine. And let the lining cure all the way before you ask about color.
  4. the flame color won't tell you much until the satanite is dry. Once it's cured and you let things heat up, the flame should be pretty much invisible inside the forge. Then you go by the dragon's breath color. If that stays that orange, you're running in serious reduction. That means no scale or decarb worries, but also not as hot as you could be plus a dangerous amount of CO produced. Let it cure all the way and run it wide open, then we'll know what you've got. And welcome aboard!
  5. I amy not always comment, but I too like watching your threads.
  6. Buy a kerosene can and paint it red?
  7. You do have to learn not to flinch when the oil goes FOOM! This is also one of the few times a magnet on a stick is handy.
  8. Yep. All hamon are quench lines, but not all quench lines are hamon.
  9. Looks like a variation of the FAL type C. http://worldbayonets.com/Bayonet_Identification_Guide/fal_page/fal_bayonets_2.html
  10. I like it! And given the things that live in the water near you, not a bad idea. . You could probably sell them, in fact!
  11. No. 5160 will only give you a sharp line at the oil/air junction. Look at the thread called "what is a hamon, anyway" in the next forum up. The mottled look you got was from overheating.
  12. You have to give us some time to look stuff up! Looks like rock wool, or at least Rockwool brand, loses its binder at 250 C and melts at 1000 C, so no good for the main lining. Sorry for the bad news.
  13. I reckon my problem with them is that I was using them at too low a grit and they were just chewing up the steel. That was also before I had a grinder, so everything was filed in. Now I also grind to 220 before moving to hand sanding. Might try the stones again, but only in the higher grits. And the harder stones.
  14. I agree with Daniel about the order of operations. As far as how to determine the temperature, oxide colors are notoriously inaccurate. Any bit of oil, even fingerprints, will throw off the colors. The Tempil company makes crayons that burn off at very precise temperatures. They're not that expensive. https://markal.com/products/tempilstik. Just decide what temperature you want and buy the crayon that corresponds. https://www.amazon.com/TempilĀ°-TS0650-Tempilstik-Temperature-Indicators/dp/B0013L76I4/ref=pd_day0_c_328_4/135-4027940-4541910?_encoding=UTF8&pd_rd_i=B0013L76I4&pd_rd_r=04e66810-aa94-4994-bbcc-fc99839da121&pd_rd_w=O8yNt&pd_rd_wg=atlM6&pf_rd_p=52c44813-ece5-43b5-85d3-aeb14689b184&pf_rd_r=213E3NX5DFK43F9SB9VX&psc=1&refRID=213E3NX5DFK43F9SB9VX, for example. Buy one for 400 degrees as well, you'll want to preheat the spring steel to 400 when you weld it to the tubing. They're easy to search, the name code is the temperature. That is, the one I linked, TS0650, burns off at 650 F. TS0400 burns off at 400 F. Finally, nonmagnetic is 1425 F. Spring steel, assuming it's 5160 leaf spring, has to be about 125 degrees F hotter than nonmagnetic to fully harden. Magnets are not your friend with 5160. If you can't see decalescense, Tempilstik also makes one for 1550 degrees F. TS1550, oddly enough. Edited to add: If you do not preheat the spring and you weld it after HT, it will break at the weld.
  15. Those were all the rage in 2004. The fact that nobody uses them anymore ought to tell you something. In my experience with them, they flat-out suck rocks. They gouge, they wear into the shape you're trying to avoid, and the slurry they leave behind is nasty. They do come in different levels of hardness, as in you can get them that won't wear into the shape you're trying to flatten, but those are the ones that drop a piece of grit that then leaves a deep gouge on your blade. They are decent for finishing fullers, but that's about it. I assume they're good for cleaning up EDM dies, since that's how they're marketed, but I don't like them for blades. Maybe the high grits are better, but the ones between 60 and 220 are crap. If you're worried about snapping them, they're remarkably hard to break. Plus you can make a wooden holder for them quite easily. Are they faster than sandpaper? Not if you include the hand sanding required to clean up after them. Do they last longer? Heck yeah, I bought five of every grit between 60 and 220 in 2004 and I still have all of them!
  16. Every time I get on that site I end up reading until I feel my brain start to ooze out my ears... but it's worth it!
  17. I meant be sure the blisters left on your billet go all the way to the edge of the billet, or you get a section of straight laminate like you can see on the left edge of that sword tip. Not a huge deal, but it can be annoying when you notice only after you think you have an even raindrop pattern.
  18. Watching with interest...
  19. This fits into three different subcategories of "Bowie" unique to the American Civil War period. It's a spearpoint Bowie, which while not necessarily double-edged often were. It's a D-guard Bowie, which while usually iron-hilted do appear in cast brass on rare occasion, and it's a Confederate Bowie, being made at the Memphis Novelty Works (great name for a company that made knives, swords, and pistols, eh?) in Memphis, Tennessee. Not your typical "Bowie" knife, but still a representative of what can be called one. Here's a tablefull of American Civil War Confederate Bowie knives of all types: One could argue they're actually short swords, but it's accepted that they are a legitimate class of the Bowie family.
  20. Feels good, doesn't it? I really like this. Cool project!
  21. He was one of my mentors, and a good friend of the founder of this forum, Don Fogg. Not to mention a larger-than-life bear of a great guy. He is still missed.
  22. Start here, and see how far down this particular rabbit hole you end up. I know I've learned more than I thought possible! https://knifesteelnerds.com/2018/08/20/what-is-powder-metallurgy/
  23. Ah, I get it now. Interesting effect!
  24. Industry does this, it's called sintering. You can get some really interesting properties by squishing together stuff that doesn't naturally alloy, but the results are generally not forgeable. The CPM powder metallurgy steels are in this family, but they are forgeable if you're masochistic enough to try it. The advantage is finer, more evenly distributed carbides when making high-alloy stainless steels. These are designed for stock removal, and forge kind of like granite. There's a lot of interesting stuff about PM steels over at www.knifesteelnerds.com if you're willing to search for it.
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