timgunn1962

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About timgunn1962

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  • Birthday 03/15/1962

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    Lancashire, England
  1. Which bricks have you got, Mikey? Closest to the rating and density that I can find find specs for online are the K26, which I thought had been around a good while (since 2001-ish?). They look good for insulation value, but I've not seen anything on their tolerance of temperature cycling and they are a little pricy over here to just pick up a few to play with. I gather there's also a new JM23-400 ultra-lightweight IFB from Morgan that was announced in 2015, but I'm struggling to find any specs on it, so it may be that I've just not found the specs on the newer stuff. A possible source of powdered Bentonite clay in the small amounts needed to mix at 5% with a few pounds of Zirconium Silicate might be a home brewing supplier: Bentonite is often used as finings to clear wine.
  2. My guess is that the analysis was done using an XRF gun, which will not (usually) detect Carbon. XRF is very quick and easy to use, so gets used a lot for identifying alloys in the scrap industry. There the value of the scrap is largely dependent on the alloying elements and tramp elements present. The analysis allows control of the inputs of the alloying and tramp elements to the remelt. The Carbon content is adjusted during the production process anyway, so there is little value in measuring the Carbon content of the input material and it is not cost-effective to add Carbon measurement capability to the instrument. Analysis of the heavier alloying elements will usually be enough to narrow down the range of alloys into which a particular sample might fall. In many applications outside the scrap industry, this is enough to be useful.
  3. It's probably a type K, but maybe a type J. It is quite likely to have it marked somewhere on the gauge. The thickness of the "legs" on the thermocouple itself strongly suggests it's a base-metal type, not a Platinum-based type (R,S or B), but it's worth checking: in the (unlikely) event it is Pt-based, the scrap value of the thermocouple would certainly build (and perhaps even buy) you a new forge with temperature measurement. I don't recognize the colour coding on the wiring. There have been lots of different standards in different places though and I'm only familiar with one or two (I am also colourblind to the point where I sometimes need to ask someone else what colour things are when wiring up instrumentation at work). https://www.omega.co.uk/techref/colorcodes.html If you really need accuracy, I'd be a bit wary of using it as-is, unless you have some way to check the calibration. Ice/water is the usual check for zero degC, but it's not much use with a scale that starts at 20 degC. Human body temperature at 37 degC would give a readily available fixed point for checking at low temperature and boiling water at sea level provides a fixed point at 100 degC. It gets a bit more difficult finding usable fixed points at higher temperatures though, and it's less easy than it sounds to get reliable ice/water and boiling point fixed points. If your forge temperature is sufficiently adjustable, decalescence/recalescence might provide a reasonable check temperature. Using the forge as an oven for tempering does not sound easy. The thermocouple and readout would certainly work at Austenitizing temperatures (usually somewhere in the region of 800 degC), but getting a forge to run down in the 150-450 degC range which covers most tempering operations is definitely pushing the boundaries. I certainly cannot manage it with a forge that will reach forging temperature. I can get stable temperatures from about 750 degC to about 1500 degC from a forge, using a burner based on a commercial Venturi mixer. Going much below about 750 degC (1382 degF) is difficult with my setup. I am pretty confident I could build a purpose-designed gas oven that would do the job, but that's a whole different animal: certainly not a forge.
  4. Matt, are the problems occurring with the burner in the forge or are you still trying to run it with the burner in open air? Frosty, I was under the impression the T-burner was only really intended for use in a forge. I don't see any real application for one as a torch, but I could easily be missing something obvious. Have you done any development work with them outside a forge?
  5. Unless you are intending to use it outside a forge, try it in a forge. The flame in the forge will be drawn into the mixture stream and stabilise the burn on the burner, much as keeping the torch there does outside a forge.
  6. Look up "normalising steel" on the smithing and bladesmithing forums. The grain will have grown at forging temperature and it sounds like you did nothing to get the grain size down before quenching it. Normalising involves heating to JUST above critical (look for decalescence), then air cooling to black. It starts new grain formation but doesn't allow the time at temperature for the new grains to grow big, thereby setting things up for the Austenitization and quenching with nice fine grain.
  7. As others have said, more information is really needed. If it is running outside a forge, it's pretty much normal behaviour for a burner. The gas/air mixture emerging from the burner causes a low-pressure zone which draws additional air towards the burner. If the flame starts to lift, there is nothing to stop it and it may continue lifting until it goes out. In a forge though, rather than drawing fresh air, the low-pressure zone draws the forge atmosphere instead. As the forge atmosphere is basically a big flame, it tends to stabilize the burn on the end of the burner. If you hold a torch to the edge of the burner when running outside a forge, it will do the same thing In a cold forge, it can also happen. It's not usually a problem in a forge built well from well-insulating materials: the forge temperature rises quickly and the forge atmosphere reaches the temperature needed to stabilize the flame, but it can be an issue when trying to dry out a lining for example. In this case, the undried lining is a big heatsink and the evaporating water will also tend to cool the forge atmosphere. The result is that the stuff being drawn toward the burner is too cold to stabilize the flame. In a hot forge, it seems quite rare to have a problem with flame stability in still conditions, though it can still happen when the wind is sufficient to blow the flame away. In my (limited) experience, breezy conditions seem to affect NA burners with less highly-engineered mixing sections more than those with textbook or near-textbook Venturis. Blown burners seem to be even less affected and may be a better choice if your forging conditions are likely to be windy. If the intention is to run a burner outside a forge, or inside a forge that needs to run at an unusually low temperature (for Heat-Treating or similar), a flame retention cup can often be used to provide a "miniature forge" in which a toroidal (donut-shaped) ring of flame is established on the "shelf" of the retention cup and this will often stabilize the flame sufficiently. I tend to do this when building forges specifically for HT, but do not find is necessary for forges intended for forging or welding.
  8. Realistically, probably not. It's a pipe-or ribbon-burner and works very well for things like heating fish kettles, barbecues, boilers etc where the hot zone being heated is not particularly hot and the tube does not get hot enough to become an ignition source. The narrow slots (or often small holes instead) are narrow enough that the flame-front is robbed of its heat as it tries to pass through the slot/hole and the flame therefore stays above the burner. Put it into a forge at HT temperature and the heat soaking into the tube is very likely to raise the temperature to the point at which the inside of the tube becomes hot enough to ignite the gas/air mixture in the tube. If Wikipedia is to be believed, the autoignition point of Propane is 455 degC, 851 degF. That is well below Austenitizing temperatures. A pipe burner might be ok for a tempering setup though. Ribbon burners as used in forges tend to use a big lump of insulating ceramic ("about" the size of a brick) with holes cast or drilled through it to stop the heat soaking back into the plenum, which is usually steel and outside the forge for cooling, to overcome this problem.
  9. If you are sizing your gas jets to get the mixture you want, either by altering the hole diameter or by altering the length of the jet, you'll need consistency. In theory, if you have a leak that is repeatable so that every time you take the jet out to modify it and put it back in, the leak remains the same, there is no problem. As soon as the leak becomes a variable that affects the mixture ratio, it will play merry games with your burner tuning. In practice, ensuring your leak is consistent would be both onerous and pointless. Sensible folk just avoid creating leaks. The tape vs goop argument will go on forever. I made the move to anaerobic sealants about 30 years ago because I found it just did what I needed it to do with no fuss and, very importantly, no leaks. Something I've not seen mentioned much is that using tape needs care and some skill. Whilst it's a long way from brain surgery and can be covered in a 10-minute show-and-do, I'm guessing most of the guys asking the tape or dope? question are doing so because they genuinely have no idea. They won't have had the 10-minutes of one-to-one instruction from someone who knows and are therefore probably best advised to use an anaerobic sealant, just because there is less chance of getting it wrong.
  10. The baffle reference was from post#2, made by John McPherson, so it doesn't seem to be a case of British and American English terms being different. It seemed like a perfectly adequate functional description of an adjustable choke so, when the discussion seemed to be going off in a different direction, it seemed reasonable to offer the accepted term (which is the same over here). It was intended to make it easier for the OP to follow John's advice: Diamondback offer chokes as an option. I tend to be quite impressed by the guys who have the brains to work out first-hand what is actually going on, and the decency to pass on that knowledge, without necessarily knowing the accepted terminology. Full marks to John. I guess I've spent far too much of my working life around the sort of lower-management pillocks who use jargon unnecessarily, solely in order to feel superior to those who don't.
  11. I am surmising that your concern is over the Superwool's ability to handle the temperature it might see at the interface with the Kast-O-Lite, given its classification temperature of "only" 1200 degC/2192 degF and continuous use temperature of 1000 degC/1832 degF? It is entirely possible to calculate the theoretical interface temperature and make the Kast-O-Lite layer thick enough to bring the interface temperature down to whatever you decide is appropriate. I did something similar a long time ago for a waste gas burner we built at work and found it a PITA, involving some pretty daunting math, a lot of iterative calculation and many, many hours reading textbooks. The main reason I'd not do it for a forge though is that it needs real numbers that few of us have: I'd be pretty surprised to find that more than 10% of smiths could tell you their forge temperature within about 20 degrees, for example. Most of us basically just copy what others have done until we build up enough experience and understanding to work out how to improve things ourselves and, if we do a good enough copying job on a good enough initial design, improvement is not always needed. The Superwool does not melt at 1201 degC, or even close to it, so exceeding the classification temperature, even by some considerable margin, is not going to leave you with a dribbly mess and no working forge. In your shoes, I'd have no qualms at all about using an inch of Kast-O-Lite 30 over rigidized Superwool. In reality, I'm inclined to suspect that the biggest issue you'll have to contend with in respect of longevity is getting the forge properly dried out before first firing. Incomplete drying causes the water trapped in the refractory to flash off to steam causing cavities which greatly weaken the structure.These cavities seem to join up with temperature cycling. "Build it Saturday, use it Sunday" seems to be a recipe for a short-lived forge. "Build it June, use it August" seems rather closer to the mark, though climate is obviously a big factor. In some locations, it may even be necessary to take steps to slow the drying (though Astoria, OR probably isn't one of them). I'd build it, use it for six months, see what needs changing and build the next one as soon as possible so it can be dried fully before needing to use it. It's worth pointing out that the single biggest non-human factor in determining how well or badly a given forge works is the burner. Be prepared to spend at least as much time researching burners as you do researching the structural parts of the forge and do not make the mistake of costing the burner separately from the forge: A burner made from pipe fittings might look like a huge saving against the cost of a commercial item. However, once you factor in things like taps and tapping drills, the construction materials for the forge, any coating used, the regulator, hose and first fill of gas, the overall percentage saving tends to look at lot less impressive. If the pipe-fittings burner will do what you need it to do, great, that's the way to go. Mention of an HT oven and the size of forge given in the OP is suggestive of bladesmithing to me and I'd expect a burner with air:fuel ratio adjustment to be advantageous in that application.
  12. "Intake baffles to tune the fuel/air mix to prevent scaling" sounds like adjustable chokes to me.
  13. It looks to me like it's 1200 degC rated. http://store.armilcfs.com/high-temperature-insulations-refractories/boards.html http://store.armilcfs.com/pdf/Ceramic_Fiber_Board.pdf There are Low-Density boards rated for both 1200 and 1400 degC. I've not seen one rated for 3000 degF (1649 degC). http://www.unifrax.eu.com/web/Audit.nsf/ByUNID/D600A55D633ECF7685258128001AEAC0/$File/Fiberfrax Duraboard 120 EN.pdf http://www.unifrax.eu.com/web/Audit.nsf/ByUNID/0BDEDE9E3537A2F285258128001B037D/$File/Fiberfrax Duraboard 140 EN.pdf
  14. When you take a look inside the burners, pay careful attention to the jet arrangement. It's worth having calipers and a thread gauge handy so you can measure the threads if the jets screw in. A set of number drills would also be useful to use as go/no-go gauges to measure the orifice size in the jets. Cheap import ones are fine and 50-80 should cover the range you are likely to want. They can be used by hand with a pin chuck to open out jets made from brass or Copper (MIG tips are copper. Most commercial gas jets are brass). Pretty much any Naturally Aspirated burner can be made to work if you are able to tune it by changing the jet size.
  15. I am in the UK so can't answer for the "standard BBQ Propane tank" question, but I strongly suspect the answer is yes. Over here, most BBQs run on fixed low pressure (35 mbar, 14" WC) regulators and the cylinder fitting for these is different to that for the high-pressure regulator needed for most gas forges. The pics are not very clear: what is the discoloration on the pipe half-way between the open end and the nearest burner? It could be that the pipe has a welded blank in there. Easy way to check is to poke something down the end and see if it stops there. If it's not blanked already, it needs to be. I'd be inclined try to arrange some sort of support for the pipe or the burner feed lines to take the strain off the spiders in the burners. If there's any movement that shifts the gas jets out of alignment with the center of the intake bells, even slightly, it will change the air:fuel ratio and make tuning trickier than it needs to be.