timgunn1962

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About timgunn1962

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    Lancashire, England
  1. Devil Forge

    I've not used their forges, but I bought one of their burners out of curiosity and found it to be remarkably good. I was not impressed by the need to push the hose over a plain tube. With O-clips it works well enough, but is somewhat inelegant. That was my only gripe. The DF... series burners have a threaded choke adjustment which makes mixture/temperature control a breeze. It's fine enough to hold accurate Heat-Treat temperatures for steels that need a soak when used in a reasonably well-designed HT forge. Their DFProf... series burners seem to have a sliding choke. I have not used one but I'd expect it to be anywhere near as controllable as the DF... With the likes of Wayne Coe able to supply realistic quantities of the better forge building materials in the US, I'd definitely recommend building the forge yourself. If you would rather buy a burner than make one, you could do a lot worse than the DF.
  2. Ribbon burner forge question

    It's your burner, your blower, your gas train and your forge. There will be enough differences between yours and anyone else's that it's not realistic to apply their numbers to yours. There's a trade-off between the distance needed for good mixing and the distance over which the flame can propagate through the mixture. If things go wrong and you get a flashback, the flame will travel, accelerating as it does so, back through the mixture. Effectively, the further back your mixing point is, the bigger the potential explosion. There looks to be plenty of length between the gas injection/mixing point and the burner. The bend before the burner looks to have wrinkles on the inside radius and these seem likely to promote turbulence, and therefore mixing. I don't think you'll have any problem at all due to insufficient mixing as it stands. Unless you do, there is nothing to be gained by moving the gas injection point any further back and there is a (probably fairly small?) safety risk if you do. Butterfly valves are horribly non-linear and the butterfly throttle seems unlikely to give as fine a degree of control as a gate valve with its fine-threaded adjustment. If you are measuring gas pressure, the gauge needs to be downstream of the needle valve. At the low pressures you are likely to be seeing (probably Inches to tens-of-Inches Water Column), a U-tube manometer may be the best type of gauge to use. Cheap and accurate too. Basically it's a transparent hose formed to a U and half-filled with colored water. As Frosty says, it'll become second nature pretty quickly, but having some measurements can help you understand what is going on until then if that's the way your head works. It's worth noting that the CFM rating of blowers is seldom of any real use to us. We tend to operate at the higher-pressure end of the performance curve and the CFM rating is usually the maximum flow at zero pressure. If the blower specs give a static pressure (most don't), this is the more useful value to us. I calculate that to burn 80 CFM air with Propane would use between 24 lb/hr of Propane (burning to CO2) and 35 lb/hr (burning to CO). Most of the forges I have seen have used much less Propane than this: typically 5-10 lb/hr, suggesting around 11-33 CFM air actually used.
  3. huffing at high temp?

    You could try turning it up. Huffing is often a result of the flame speed through the mixture being faster than the mixture speed along the burner tube. Flame speed tends to increase as the temperature increases. Increase pressure and the mixture speed should increase, maybe enough to stop the huffing. It might not work but it’s easy to try.
  4. is my forge hot enough to weld?

    Unless you have some good reason to believe the thermocouple reading is incorrect, it would seem sensible to assume it is giving a true reading. Without details of your reference, my guess would be that you are referring to something from Omega that refers to Mineral Insulated thermocouples (probably touting their Omegaclad XL sheath material) AFTER some extended period of time at high temperature. Type K is very prone to "drift" when used for long periods over about 1000 degC (1832 degF). Has the thermocouple spent a long enough time at a high enough temperature for drift to be an issue? What is the colour showing? Back before IR pyrometers became common, there was a pyrometer system that used an electrically-heated wire. This was viewed with the object being measured in the background. The heating current in the wire was adjusted until the wire became invisible against the background. The temperature of the wire was then read from the display. If the inside of the forge, or at least the workpiece, is uniformly the same colour as the tip of the thermocouple, you can reasonably take it that the thermocouple is reading the temperature of the forge/workpiece. If you cannot locate the tip of the thermocouple anywhere hot enough to match the forge/workpiece, you probably have the wrong thermocouple and/or thermocouple location. With only 4" insertion through the mouth of the forge, this seems quite likely. What are you trying to weld? I have seen all sorts of numbers thrown about with regards to welding temperatures and it seems that more experienced welders tend to be able to weld at lower temperatures. A few years ago, I went to a bladesmithing hammerin where lots of Pattern Welding was being done, by a cross-section of people, using a vertical Propane forge and a small Anyang power hammer. The forge was set up by an experienced smith and successful welds were produced by almost everyone from the complete beginner to the really-rather-good. At the end of the day, I stuck in a Type S thermocouple and measured the forge temperature at 1280-1330 degC throughout the working zone. As a result, I tend to regard 1300 degC, 2372 degF, as a "very good" welding temperature for steels with a Carbon content of about 0.8%. There were a number of failed welds, of course, but all of them clearly a result of some cause other than forge temperature. I can't speak for Iron or steels with lower Carbon contents, which I would "expect" to need higher temperatures than the 0.8%C steels used at the Hammerin. Do you have pictures of your setup, or a link to a thread showing it? One of the things I have seen on a number of occasions is NA burners built with gas jets that are too big to achieve the flame temperature needed for welding. It seems all wrong to anybody who does not understand the chemistry involved, but going to a smaller gas jet quite often raises the forge temperature by increasing the ratio of air to fuel. It usually works if there is significant (excessive?) Dragons Breath, indicating a very fuel-rich mixture.
  5. Quick and dirty burner help.

    A Naturally Aspirated burner uses the speed of the gas emerging from the jet to entrain the combustion air. The gas speed through the jet is dependent on the diameter of the jet, the shape of the jet (they are almost always round holes, but the shape of the lead-in affects the "discharge coefficient"), various technical characteristics of the gas (we can usually ignore these since they remain constant once we've fixed the gas we are going to use) and the pressure difference across the jet (we don't usually vary the downstream pressure significantly, so this is normally the gas pressure supplied to the jet). If I am understanding the OP, the picture of the burner is not the one in use? The description seems to be of a straight nipple without a "flare". I'd be strongly inclined to fit a flame retention cup. http://amalcarb.co.uk/downloadfiles/amal/amal_gas_injectors.pdf The flame retention cup shown in the Amal leaflet works very well with the Amal low-pressure burners and has worked equally well for me on homebuilt burners. The "burner port nozzle with chamfered end" is not usually necessary IME. Without it, the "burner port nozzle diameter" will be the inside diameter of the nipple. The retention cup ID will need to be "about" twice the nipple ID: if you are using a 1" nipple, the retention cup should be 2" pipe, but the diameter ratio is not critical to the point where you need to worry about the pipe schedule. The transition from nipple to cup needs to be a step change. A perfectly-machined transition is not needed but just screwing on a 2" x 1" reducer with a tapered transition does not work nearly as well as the step. It may work well enough for your purposes though: possibly worth a try if you cannot easily make a square-edged cup? The air:fuel ratio (and therefore the flame temperature and Oxidizing/Neutral/Reducing characteristic) is a function of the burner design (effectively a constant once you have stopped fiddling with it), and the jet diameter. To tune the burner, you will need to be able to change the jet diameter. This looks like a fair amount of work with a drilled hole in the gas tube, but it is possible: start too small and open out the hole in very small steps until it works as you want it to. I'd keep going until it is obviously too big, then make a second tube and drill it to the size that worked best. If you have a jet that is "too small" and fit a choke, the burner will run lean with the choke fully open and you can adjust the choke to richen the mixture until it is optimum for the task in hand. This is the way I tend to build high-pressure Propane burners. It may not be so good for a low-pressure burner because using the smaller gas jet will mean less gas and therefore less heat input (heat is not the same as temperature) and you will not have the option of increasing the gas pressure to get the heat input back up. You mention that you don't need more heat, so this may be an easier option than faffing about with drilling all those holes.
  6. suitability of refractories

    1/ There doesn't seem to be anything nasty in there. The big question is really "what is the other 2%?" There doesn't seem to be anything that would fuse the Zirconia together and it might tend to come off easier than you'd like. I gather other products can be prone to this too. 2/ We tend to use refractories in ways that do not correspond to the manufacturers intended scenarios. In particular, we cycle the temperature at rates and frequencies that are simply not seen in their usual industrial applications. Applied over rigidized Kaowool, or its equivalent, many smiths have found 1/2" of Mizzou to work well. The number of variables in forge building and use is vast, so it is unlikely that anyone will be able to say definitively that you'll have no problems. 3/ No. If you need insulating, use Kastolite 30. 4/ Probably not. However, within reason, you can usually dilute it with water and make it go further. You need some depth to the rigidized layer and it is probably better to soak deeply with a diluted mix than to only get shallow penetration at full strength/comcentration. 5/ Not worth the effort for such a small reduction in forge volume. It would be better to reduce the opening(s) with a narrow strip of Kaowool, rigidized and coated, wrapped around the inside. It might be thought of as a way to reduce the chamber length to get the volume down. More importantly, it reduces the open area and therefore reduces the heat loss. The volume-per-burner guidelines are just guidelines, based on "normal" practice. If you build a 3" diameter forge 50" long or a 9.4" diameter forge 5" long, you are unlikely to find they work well, despite meeting the 350 cu in guidelines.
  7. Question about lining.

    Maxwool is a Nutec trademark. Kaowool is a Morgan Thermal Ceramics trademark. Otherwise, you'd really struggle to find a difference between them. The Maxwool will be fine. Going by the Kaowool TDS, the 8 PCF is a better insulator than the 6 PCF. It certainly seems stronger/stiffer in use. For us, it is definitely worth the extra money. I've not seen a full Nutec TDS, but I'd expect the Maxwool to be the same There are 2 useful grades of Maxwool: HPS (2300 degF) and HTZ (2600 degF). The HTZ incorporates some Zirconia to achieve the higher temperature rating. If you are buying a roll and have any plans for welding in the forseeable future, the HTZ in 8 PCF is the stuff to go for. 1" thickness is probably the most useful. If you are only ever going to be shooting for forging temperatures, the HPS will be fine. It's worth noting that the rating temperature is usually based on permanent shrinkage, rather than a melting point or other catastrophic failure temperature, so the 2300 degree-rated blanked will not suddenly become a dribbly mess at 2301 degF. It will still work pretty well in a welding forge, even a hot one. I picked up a roll of the 1", 8 PCF, Nutec HTZ for cheap a few years ago and made several forges with it. None of them was perfect, but the HTZ was certainly not to blame for any of the shortcomings. I've been looking for more since my supplier closed down. As an aside, (Materials) Safety Data Sheets are not often particularly helpful when comparing products. They are usually written, by people who specialize in writing them, to provide only the legally-required safety information without giving away anything that might be commercially sensitive or useful to a competitor. Often they are all the information you have. When dealing with refractories, even the Technical Data Sheets are limited. They will not normally tell you how prone to cracking on fast heat cycling a particular IFB or castable is for example. For that sort of information there is no substitute for real-world experience. If you can get hold of one of the real technical project guys/gals at a major refractory supplier and pick their brains, you can learn a lot very quickly. They get involved in the big-ticket industrial projects and tend to be well protected from penny-ante timewasters who only want one roll of blanket every few years (i.e. me and, probably, you), so getting to speak with them is seldom easy. Otherwise you are stuck with either picking up whatever collective knowledge has been acquired on sites like this one, or doing the donkey work yourself.
  8. Gas Forge Build

    Dry it out as well as you can before applying fire. It's usually no problem firing with the burner to heat-cycle the rigidizer unless the blanket is still pretty wet. In that case, the steam produced will tend to cool and richen the flame. It can even be sufficient to extinguish the burner completely. If it happens to you, don't panic. It's often only a problem because it's the first time the burner has run, it has not been tuned and it is having to cope with abnormally steamy conditions. Get things dry by other means before making any adjustments.
  9. Reil Burner Problems!

    What pressure are you running it at? Burning back down the tube is usually an indication of insufficient flow. The mixture needs to be flowing towards the nozzle faster than the flame moves through the mixture. Normally, I'd say try turning it up. However, without the forge to stabilize the flame, the odds are high that you'll go straight from burning in the tube to flame lift-off as you turn it up. You really need it in the forge.
  10. Reil Burner Problems!

    Copesy, The little DIY minimig welders over here tend to use MB14 MIG tips with a standard M5 x 0.8mm metric coarse thread, so suitable tapping drills (4.2mm) and taps are easy to find. The tips range from 0.6mm to at least 1.0mm wire and the holes will be about 0.15mm bigger than the nominal wire diameter. I have 0.6, 0.8, 0.9 and 1.0mm tips with M5 threads. As well as being small in diameter, the M5 tips are short, so should not have too big an influence on the inlet airflow. If the standard sizes are not ideal, you can always open them out. When I have played with non-standard jet sizes, the starting point has been a MIG tip that is too small, then open it out one drill at a time with a set of 60-80 number drills and a pinvice. The MIG tips are copper and quite grabby, but spinning the pinvice by hand and only going one size at a time has been fine. Do not waste your time trying to tune your burner out of the forge unless you intend to run it out of the forge normally. The forge automatically stabilizes the flame because the forge atmosphere is effectively just a mass of flame. Faffing about with flares and flame retention cups to get a similar effect outside the forge is all well and good, but the big lump on the hot end of the burner just makes mounting the burner more awkward, and prone to burning away or melting.
  11. Forge dosent seem to be getting enough air

    There is a lot of room for improvement, as said above. However, the easiest single thing to do to improve the burners you have is probably to fit smaller gas jets. You clearly feel there is not enough air for the gas. Turning that around, there is too much gas for the air supply. Fitting a smaller jet will reduce the gas supply relative to the air supply and will increase the flame temperature. I would probably aim for a jet diameter around 80% to 85% of that which you are currently running (64% to 72% of the current area), fit the new jets, see what happens and decide where to go from there.
  12. Help! Kaowool Info

    I get the impression from the spec sheets that something quite unusual is going on with ceramic fibre blanket. For some reason, the higher-density varieties seem to have reduced thermal conductivity (i.e. they are better insulators). http://www.unifrax.eu.com/web/Audit.nsf/ByUNID/D0B83D7C069DC6DB85258220006F5398/$File/Fiberfrax Durablanket S EN.pdf This is exactly opposite to the vast majority of insulating materials. I am pretty sure that compressing the blanket will not significantly reduce its insulating ability on a per-inch-installed basis and will most probably increase it.
  13. Reil Burner Problems!

    Copesy, making forge burners can be very rewarding, but it can also be an exercise in frustration. It will not be helped at all by the fact that most of the well-documented designs are based on US pipe fittings and parts. There are some substitutions that can be made without effectively altering the design, but there's something of a Catch-22, in that you won't be able to identify which changes are significant and which are not unless you understand burners well. If you understood burners well, you would not need to build someone else's design. A 0.6mm mig tip is intended for 0.6mm diameter wire. The need for clearance to allow the wire to feed during welding means that the hole is usually about .007" bigger than the nominal wire diameter. In this case, nominal diameter is around .024" and the hole diameter will be around .031", equivalent to a number 68 drill. The biggest factor in burner performance is the Air:Fuel ratio. Using a bigger gas jet than the design calls for will (usually) cause a richer-than-optimum mixture and a reduced flame temperature. In the UK, arguably the best approach is to buy an "Amal atmospheric injector" (now made by "Burlen Fuel Systems") in the correct size for your application. For reasons I will not bore you with, the injectors jetted for Butane tend to work very well in forges: better than those jetted for Propane. Usual disclaimer: I have no affiliation with either Amal or Burlen other than as a very satisfied customer.
  14. Reil Burner Problems!

    1/ Yes. 2/ Yes, but only because you are using Butane (I assume that's 0 degC, 32 degF?) 3/ Probably: it certainly won't help. 4/ Probably: it certainly won't help. Best to wait until you have the correct reducer though. The "this" link in your post seems to return to this thread. Butane regulators are, to the best of my knowledge, 28 mbar fixed-pressure in the UK. Clip-on, rather than screw-in. You NEED a Propane cylinder with a screw-in connection (there are also clip-on cylinders like the Butane ones. Again, these use a fixed-low-pressure regulator, 37 mbar for Propane, and are no use to us) and an adjustable regulator to suit. 0-2 bar is good. 0-4 bar is overkill, but works and may be easier to find. Do not buy a 0.5-4 bar regulator: the lack of control at the bottom end makes it truly horrible to use once lit and unnecessarily exciting to light. Make sure it goes down to zero. You need to build EXACTLY to a "known good" burner design. The majority of the documented designs are for US fittings, making sourcing them in the UK a minor nightmare. ANY deviation from the documented design, however trivial, means that you have redesigned the burner and that you will need to make your new design work: not a problem if you understand burners, but the learning curve is steep and tends to be expensive in either time, money or both. The best advice I can give is to google, and buy, a Long-Venturi "Amal atmospheric injector" (usual disclaimer: I have no affiliation to them other than as a satisfied customer). The range jetted for Butane actually seems to give the best results when running on Propane in forges (without a secondary air supply).
  15. pyrometer

    When testing burners and forges in expectation of things getting properly hot, I use a type S thermocouple, as I have picked one or two up over the years when decommissioning plant. Much too fragile/expensive to install permanently (They are Platinum-based and new replacements would cost around $500 each). They have recrystallized Alumina sheaths 10mm in diameter (about 3/8") and are 500mm, 20" long. The RA sheath is usually considered good to 1600 degC, 2912 degF, but the Type S tables go up to 1768 degC, 3214 degF. For more regular use, I reach for a handheld Mineral-Insulated type K thermocouple, 24" long and 1/4" diameter below the handle. My preferred one is an Omega KHXL-14U-RSC24, which has the proprietary Super Omegaclad XL sheath, but mostly I use 310-stainless-sheathed examples because I can get them cheaply enough to accept their limited life at welding temperatures. It may be worth mentioning that the failure mode I see most with the Mineral Insulated probes in forges is failure of the metallic sheath. When it gets hot, an Oxide layer forms. When it cools, the Oxide layer detaches. It does not take many cycles for the sheath to be lost and holes to appear. Oxygen can then get in, the thermocouple wires Oxidize and the thermocouple fails. Types 304 and 316 stainless steels tend to lose the Oxide layer when cycled through about 850 degC, 1562 degF. Type 310 is a 25% Cr, 20% Ni stainless. The extra Chromium helps it to form a stronger Oxide layer and the extra Nickel brings the thermal expansion coefficient of the metal closer to that of the Oxide. As a result, type 310 tends to hang on to its Oxide layer until it is cycled through around 1100 degC, 2012 degF. The Super Omegaclad is claimed to be good to 1335 degF, 2440 degF. In my limited experience, it certainly seems to last better at high temperatures than 310SS. I find the 310 sheaths seem to last somewhere in the region of 20 cycles to error reading (over-range for the type K, so 2500 degF-plus) before failing. A good bladesmithing welding temperature seems to be around 1300 degC, 2372 degF so it should be enough for most smiths to learn to recognize the correct temperature range. For electric HT ovens, I use type N thermocouples, which are "only" good to 1300 degC, 2372 degF (vs 1372 degC, 2500 degF for the type K), but were developed to be much more stable than type K when used at temperatures above 1000 degC, 1832 degF. Again, I use super Omegaclad when budget allows, 310SS when it doesn't. I tried InfraRed pyrometers in waste-gas burners at work and cannot say I had much success with them. The readings tended to be considerably higher than the Type S thermocouple readings and I felt the thermocouple was more trustworthy.