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timgunn

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Everything posted by timgunn

  1. Looks good Collin. I'm not entirely sure about the firebrick splits for a work support: they look like a lot of thermal mass. Whilst the general idea of extra thermal mass to help even out fluctuations is good, the downside is that it slows the response to any adjustments you make to get the temperature right in the first place. You may find it greatly increases the time it takes to get the temperature set. You may not: I don't know and the only way to find out is to try it. I thought I'd mention it as a possibility now just in case it proves to be a problem: removing the
  2. The small diameter bands on the rubber drums need to be run fast. Maximum speed for a 25mm x 25mm (1" x 1") Spiraband is 24000 RPM and they seem to like being close to that speed. Metal removal rate is tediously slow and their life (in minutes) seems no longer (possibly shorter) when run at drill speeds. They are really intended for use in die grinders, though I have used a cheap import trim router to spin them quite successfully. Even at the correct speed, they'll never last well compared to a small wheel attachment on a 2 x 72: a 1" Spiraband is about 3" long so there's 18 tim
  3. Looking at the first pic in post #2, I think you are going to find the flame runs very rich and probably won't reach anything like welding temperature. I do appreciate that there are a ridiculous number of variables and that I could be way off with this, so give it a try and see what actually happens before taking any notice of some random muppet on the interweb. Should you find it does run too rich, my thinking is as follows: The end cap looks like it will significantly reduce the area of the mixer throat available for airflow. Restricting the airflow will tend to make the mixture r
  4. The best of the readily available penetrating goops available over here is "Plus Gas", by some margin.
  5. The appropriate paint will depend on the temperature it will be exposed to. That will depend largely on the insulation provided by the materials used in the build and the temperature you run the forge at. There's also a potential compatibility issue with the Hi Heat paint you have on it already. Some paints don't play well with others. Hi Heat paints "cure" and this can affect things. Safest is probably to use Rustoleum Hi Heat and complete the paint job before curing.
  6. You certainly got something of a bargain there. As Alan noted, the only Tractor Supply fire brick I could find online was the 1 1/4" hard brick from US Stove. There's not much spec on it, either. Easiest thing to do is probably measure and weigh one of yours to see what you've got. Maybe post pics? Do you have any details on the board? The temperature rating is the main thing. If there's no spec or ID, the color can often give some clues. If the board looks like compressed HPS blanket and/or has a similar temperature rating, board ends on a 10" diameter cylinder, 18"-24" long an
  7. The 1/2" should be OK in a small chamber, but it'll probably be a PITA in a big one where it's not stiff enough to hold the curve of the top of the chamber without sagging, particularly when wet with whatever rigidizer/coating you use.. If building a biggish forge, I'd be inclined to find a suitably-sized former and get a couple of wraps well rigidized onto the outside of it before wrapping with more layers of unrigidized blanket and inserting into the shell. My first attempt at doing this was a dismal failure because I couldn't get it off the PVC pipe former. For the second attempt, I wr
  8. I'm pretty sure I picked up a roll of the HTZ for cheap a while ago: 128 kg/M3, 25mm thick (8 lb/cu.ft, 1"). It was pretty much indistinguishable from the Unifrax stuff I usually use, both to build with and, as far as I can tell, in terms of durability. If welding is anything like a possibility, I'd urge you to consider the HTZ rather than the HPS, though HPS should be fine if you are simply forging and are not just using a burner tuned for welding (high flame temperature) with the pressure turned down (low heat input). Refractory Ceramic Fiber is well established technology and the
  9. I've not seen a Devil Forge forge up close and have some reservations about them, much as with anything built down to a price. I recently bought one of their DFP burners to play with and have not had the chance to do so yet. It does have a screwed choke adjustment which seems nicely progressive and, assuming it draws enough air fully open for a near-neutral flame, looks to offer good control of atmosphere and flame temperature. I got the standard DFP because the choke adjustment on the more expensive DFPprof does not look as sensitive in the pictures. I usually use burners based on A
  10. The issue is not that 15N20 and 1095 is a dubious mix (it isn't). It's that makers of dubious Damascus in various parts of the World tend to claim that the mix they use is 15N20 and 1095.
  11. It's probably this one?: http://www.bladesmithsforum.com/index.php?showtopic=25573
  12. The idea that there is a sharp transition from Oxidizing to Reducing is one of those oversimplifications that are very useful when trying to explain broad general principles, but which can get you into deep trouble if you take them as gospel. If you try to think in terms of there being a range over which the atmosphere varies between strongly Oxidizing and strongly Reducing, then factor in the position of the workpiece within the flame itself (within the flame, the Oxygen and fuel gas have not yet finished combining, so there will be more free Oxygen available to react with the steel in t
  13. Just a heads-up on the TM902C pyrometers: I'd had about 30 or so that were boringly reliable and as accurate as big-name branded instruments costing more than ten times as much over the full range. I bought another ten last year and put them on the shelf. They were bought on ebay and came from China. Before I use one for the first time, I usually put it on the calibrator to check it is reading sensibly. I did this with several of the new batch and found they were all horribly inaccurate once the temperature got much above 800 degC (1472 degF). Below that temperature, accuracy se
  14. There have been a couple of comments on the jet size that seem to suggest confusion over units. The link to Grant Thompson's video in the OP shows a .6mm tip, which is about .024". Probably about a .030" hole, as the hole is bigger than the nominal wire size it is intended to pass. If anything, it looks like it's too small to me. It's hard to tell what's going on with the choke in the last video, but I get the impression it is going too lean and going out when the choke is opened? If so, and it's a .6mm mig tip, I might try a .8mm mig tip and see if it improves things, but only
  15. The continuous edge for tile cutting does not seem to clear very well on anything but thin tile, so avoid them. Either the segmented ones or the ones with a continuous edge but alternating thick and thin bits when viewed edge-on should work well. The "turbowave" ones from tool station at 3 quid would be my choice.
  16. I'd try chain drilling out the corners with a masonry drill bit used without hammer, or perhaps a tile drill if you can find one long enough, then go at the straight runs with an angle grinder. The diamond disks for angle grinders are cheap and extremely effective. Screwfix or Toolstation are probably the best source over here. Buy the cheap ones. The expensive ones are better for specific tasks, but only really worth it if you need to cut 300 slabs for an awkward-shaped patio. Don't use your best grinder. Work outside. Wear a mask. Expect a huge amount of extremely fine dust.
  17. KBAC 27D looks like a good drive. Lots of guys use it Stateside. As far as I can tell, it has 2 big advantages there. First is that it will take either a 110V or a 220V supply, though the motor is limited to 1 1/2 HP on 110V. This probably does not matter to you in Oz. Second is that it is a sealed drive. This is essential for a grinder. However, there are lots of other manufacturers of sealed drives. Invertec are probably the European go-to sealed VFD manufacturer with their IP65 and IP66-rated drives and there are sealed drives available from most of the big manufacturers. I'm ha
  18. I'm fairly sure John Nicholson at Massey Forging in the UK ("John N" here on the forum) is selling Chinese hammers again.
  19. Looking at the photo of the motor rating plate, it's rated as a 2.2 kW motor at 50 Hz and as a 2.5 kW motor at 60Hz, so you'll want the 3 kW VFD to allow the possibility of running to 60 Hz. You'll need to connect in Delta, but I assume you are already running in Delta on the capacitors. The speed you can actually run to will probably depend on the current draw and you won't know the speed/current relationship until you actually run it. I had some brief hands-on experience of a Chinese hammer on a HuanYang VFD when I helped set the VFD up, It worked, but I don't honestly know how well
  20. IME the best way of running a 3-phase motor on single-phase mains is with a Variable Frequency Drive. Search for "2.2kw VFD" on ebay and you'll find plenty of HuanYang drives. Filter for buy now and sort by price+postage. Best to go advanced and limit location to somewhere that is not going to mean import charges. They are cheap drives but seem to work pretty well.
  21. The apology should be mine: It didn't read the way I intended at all. I tend to be somewhat anal and pedantic about stuff like this, partly because it tends to get picked up and taken out of context when someone has a problem and Googles it months or years down the line. It was with such a future Google-jockey in mind that I posted.
  22. Can you post pics? It's quite difficult to suggest what can most usefully be shown by photos with no prior information. Best approach is to give it a run, take photos of everything you can and post the long shots first. If the guys that know what they are doing ask for specific details after that, you have the photos ready. The most useful shot is usually taken in the dark from a distance off to the side and shows the Dragons Breath from both the front and rear ports. Long shots in bright daylight don't normally show the Dragons Breath at all and are of limited help when it comes to di
  23. Gary, is there any chance of a link to the original source? I'm struggling to find it with Google and I'd like to try to get full the context so that I can understand the bigger picture. In particular, I'm interested in what effect any surface coating might have on things.
  24. "Pressure gauge" in this case is likely to mean a U-tube. Take a transparent tube, fix it in a U shape and half fill it with water. The water in both legs will be at the same level until you apply pressure or suction to one leg. When you do, the height difference between the legs is the pressure. Measuring in inches gives "Water Column. Measuring in cm gives millibar.
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