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Dan Hertzson

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  1. I've heard good things about those also. When I purchased my light industrial blower I needed it rated for continuous service, which I doubt the bounce blowers will do. For a hobby smith that is not likely to be an issue.
  2. Also, over here a lot of folks use the helium tanks that are supplied with party balloon kits. They are a little thinner than propane tanks, but a lot safer since they only held an inert gas.
  3. One potential budget source for burner blowers is to contact local HVAC repair shops or scrap yards. Blowers used in the burners for gas fired furnaces and boilers with the same heat output as your burner design (say 150-250 MBH) should be able to work. Note: not the furnace fans for distributing the air, the combustion blowers. As a bonus, the newer ones may also have speed controls, though you will have to play with the controller board a bit. These can sometimes be available very cheap from a scrapper or HVAC repair shop where they are discarding the unit due to a cracked heat exchanger... Years ago I got a great radial centrifugal blower from a liquidator for $25. I use one of these in my shop (now $575, but around $350 when I bought it years ago). It supplies more than enough air for two or three forges:
  4. There are a wide variety of castable refractories as well as a variety of refractory insulation blanket. How well they will work for making a forge for pattern welded billets varies quite a bit depending on what you chose and, to some extent, whether you use flux. For the typical borax fluxed billet it is important to have a refractory surface that is resistant to the molten glassy material that the flux creates. Usually that is a high alumina castable. I like Kastolite 30 because it is a high alumina insulating castable material that has a heat transfer coefficient almost as good as insulating firebrick. I like a 3/4" thick cast liner made out of this material, though you can get away with 1/2" if you do a good job casting and you have the correct refractory blanket. It is easy to mix too much water into the castable, which should be mixed to a consistency where if you form a handful into a small ball and toss it gently up above your hand it stays together. Too little water and it will break apart quickly. Too much and it won't even form a good ball. Then it should be packed into a form with removable sides... Note: refractory cement is not the same thing as castable refractory. Refractory cement is make for mortaring bricks together (like Satanite). If it is rated for 3000 deg. F it can be used (applied in very thin layers like paint till you build up at least 1/8" thickness), but in my experience cracks pretty easily and has limited to no flux resistance. The refractory blanket comes in different flavors as well. My recommendation would be for a 2" thick layer of 2600 degree blanket at 8# density. You can use (2) 1" layers if that is what you have. Also note: not all insulating (soft) firebrick is the same either. I used some rated for 2300 deg. F on my first forge and melted them with the flame from my burner. Try to keep the flame (which is in excess of 3000 deg. F) from directly impacting the forge liner unless you have a castable rated appropriately. Tangential burner orientation is a good idea to keep the flame dwelling inside the forge as long as possible (for maximum heat transfer) and to avoid having the flame directly hitting your stock. The tips of these flames usually have a bunch of superheated uncombined air which will increase scale production on your stock surface.
  5. Could be the safety integral to the new tanks. Try detaching the regulator (first closing the tank valve of course) then reattaching the regulator and before opening the tank valve, closing the regulator fully. Slowly open the regulator after opening the tank valve when going to relight. Another possibility is that you may have an obstruction in your gas orifice. How to clean that varies depending on type of burner. Good luck and be safe.
  6. I have had good success cutting grooves in soft brick using a drill press (this may also work for ceramic board). You can set the table at an angle and use a stop to keep the groove straight. You can either make up a custom cutter, or just use an old drill bit. If you grind it with a radius on the bottom you won't get those sharp corners that may be crack initiation points for your insulation. In any case, please use a respirator while cutting this stuff.
  7. Joel, Sorry, can't really answer that. I think it may have to do with a number of factors, like type of compensation in your controller, length of wire, temperature of the room... I've always just taken the easy route and used the proper thermocouple wire the manufacturer recommends.
  8. Also worth noting that the two wires from your thermocouple, if properly selected, need to be connected to the correct terminals on the controller so the compensation that Brian notes is effective. You probably are aware of this already, but worth mentioning. The wires should be labeled.
  9. If accuracy is important to you, you should consider using thermocouple wire between the thermocouple and controller, not normal copper wire.
  10. @Brian Dougherty Sorry, I thought that modern SSR allowed fast enough response to provide modulating heating load allowing better system tuning. I built a heat treat oven that was only around 8 x 6 x 14 with salvaged coils from an old duct heater, mercury contactors, and an older, programmable, PID controller. Pulled over 40 A at 220V and was still able to maintain stability without hysteresis at temperatures between 400 and 1500 deg. F. Been a very long time since my System Control classes (over 40 years), but thanks for brining some of it back.
  11. Brian, Sounds like you are talking about the PID constants for the feedback loop. I would expect most decent controllers would have the capability to manually set those to tune to equipment design or have autotune. Certainly the ones I've used have that capability (of course I built most of mine from old lab controllers from Kodak that I picked up for a song from a liquidator (1/4 DIN Honeywell and West programmable units). Somewhere I even have an algorithm for tuning a PID heating system that gets things close with only a couple of iterations. Really wasn't that hard to do.
  12. Perhaps a section of heavy wall 3" pipe set in through the top of the vertical forge will help (will need a new port for the vent). It will scale away with time, but may help spread the heat out better. Does a 200 deg temperature difference really affect things that much?
  13. I have some silicon bronze that was sourced from discarded survey markers like the one in the photo below. It forged pretty well, hot, though it was important to keep it just barely in the dull red range. I heated to dull red and forged till it stopped moving, then repeated. Picture to the right are items made from one of these markers. Lovely material once you get used to it. All punching was done hot. Brass is completely different, at least the stuff I got. There I did the anneal and quench route. Still has a tendency to work harden and crack if you aren't careful.
  14. A discolored band in locations that may have had previous chipping. Evidence of later brittle breakage, typically at poorly repaired edges, that pull away even more of the parent hard face.
  15. I love my Fisher, and they are certainly fine anvils. However the edge chipping on both of those look like it might be the result of someone attempting to add weld to the edges where they had previously been damaged, and having the area repaired embrittled and prone to further spalling. Since you have been using a similar anvil, you should know if this is the case, for the one on loan at least. If it is, I certainly wouldn't be offering top dollar for the marketplace anvil.
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