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I Forge Iron

G-son

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Everything posted by G-son

  1. No, I have not experimented with jet position yet. It is set at about ½" out now.
  2. Well, it's alive! Silver soldered a few more pieces together today to hold the gas tube/tip in the 18mm mixing tube, and cobbled together a nozzle without remembering anything about what length or diameter, so it became about 27mm diameter, started at 1" length but it couldn't take much gas then, increased to about 1½" and got what you see in the pictures and video. As suspected, gas supply from disposable canisters is an issue. Works fine with the flame turned down, but at wide open pressure drops in minutes. Water bath should help a bit at least. In the picture with three flames, the two left ones is with the burner turned down to the smallest stable flame, and the right flame is turned up "high" (as high as it went with little gas left and no water bath, far from the actual max under better conditions). The video goes from low to high and back to low. At around 9 seconds the flame seems to "lift off" from the burner, a very clear and sudden change in the flame right at that setting. Now I'm about to read up on nozzles, as that might be something I should try changing.
  3. I'd probably make a new steel piece to replace the missing area, and braze it in there.
  4. Yes, I am aware the tip goes just before the beginning of the mixing tube. I intend to put the copper tube through some kind of clamp to lock the tip in position, and the clamp attached to the funnel edges probably. I used a long piece of copper tube because I want some distance between the burner and the gas canister, should make it easier to keep the canister in a water bath at the same time as the burner is in a usable location. The copper tube is indeed too soft to take the weight of canister/burner, but adding two or three steel rods is a simple matter once everything is in the appropriate location (and the copper tube has been bent ~45 degrees, unless I change my mind before I get there). If I find the tube is too long it's a simple matter of heating the soldered or brazed end to take it apart and cut to whatever length seems appropriate at the time. I have looked at the proven designs. They require materials I don't have and don't know where to buy around here, so I'm experimenting with what I've got instead.
  5. Well, only one funnel on each size of mixing tube, don't know which one matches the mig tip size best yet. But yes, that's where' it's going. Anything specific that makes you think it won't work, or is everything about it wrong?
  6. I hit a few problems a year ago and put this project on the shelf, I didn't have the materials I wanted and couldn't think of a good method to get the tip centered using what I had available at the time. I've realized if I'm waiting for perfection I'm never getting it done, so I'm at it again, with slightly lower standards - better to get a working prototype done and learn something from that, than having a pile of unfinished parts on the shelf. This is my creation from today. A 0.6mm MIG tip with a tapered down tip and filed down thread (done with a drill and a file) to fit in the end of a 6mm copper brake line. Soldered that to the brake line (easy to heat and remove, if I need to). On the other end there is what used to be a camping stove, that attaches to a disposable gas canister. I removed the burner, drilled a bigger hole through the jet, drilled a recess that the brake line dips into and silver soldered them together. I know the gas in those disposable canisters isn't propane and I'm sure they can't deliver enough gas to feed a burner like this at full throttle for long, probably not even in a water bath, but this is the stuff I have here and now, so I'm using it. I might just learn that it doesn't work, or that it works great with the gas turned down far enough.
  7. Great! So, no air choke now. That makes life easier. I do like that version of gas assembly holder, but I have not been able to find suitable small tubing yet. I'll dig through the scrapheap some more, if I find something good I might go your route, otherwise it'll be the clamp style - or something completely different, if some piece of scrap jumps put at me and gives me another idea. There's bound to be some compromizes when any build is based on materials you have, rather than the materials you want. I have indeed read the Burners 101 from start to finish (a couple of months ago so I might have forgotten some bits) and asked a number of things a few months back. Showed how to make sheet metal cones there back then. How to build and properly aim the gas assembly with what I've got has been on my mind for a while. I don't have a clear picture of it yet, but I'll get there. I did think about putting this build in that thread, but I decided it would be better off in it's own thread. This build may take a while, and in your thread there would be probably 30 other discussions mixed in between it, it's hard to follow something when it gets spread out like that - and that's the downside of that thread, there's huge amounts of great info in there but it has become spread out and mixed with some not so relevant stuff - all important to the people that posted it, but perhaps not to everyone who reads the entire thread. Once this burner is done (successfully, I hope) it might be a good idea to make one post about the build in burners 101, showing the basic steps through the build and with a link here for those who want to read it all in detail, but for now the slow build is probably better off here.
  8. Thankyou! I hope it will be a functional burner too! Thankyou! Longer mixing tube has been suggested for a calmer flame in handheld burners (i.e, burners not used in forges etc.), and since that's the kind of use I'm planning first I thought I'd start with a bit extra length. Once it's completed and tested I can easily shorten it, adding length is a bit more complicated (quite doable, but requires more work than simply cutting the end off). So called ½" pipe is actually 15,75mm, I've gone up to 18 & 20mm to better match the 0,6mm MIG tip. Do you think the MIG tip still is a bit big for that? I'm building a standard linear burner. My current plan for mounting the gas tube etc. is to make a clamp that grips around the mixing tube, and bend a piece of flat bar back around the funnel, there's a crude drawing in the attached picture. This construction would allow me to move the mixing tube/funnel closer or further away from the gas jet, just by loosening the clamp. It would also allow me to change between the 18mm and 20mm tube (or another, if I need to make more to find the right size) on a single gas jet/tube etc. assembly, so i don't have to make two diffrent sets of "gas assembly mounts". To me, this is a prototype build, I'm trying to keep it simple while still being able to easily swap out pieces. I do however like your suggestion of turning vanes in the funnel very much, I have been thinking quite a bit about diffrent ways to help the air rotating down into the funnel and vanes should be both simple and effective. I will certainly try vanes, in one form or another. Also thinking about multi-step cones, i.e. starting with a short shallow angle cone on the mixing tube, then putting a short steeper angle cone on that, and possibly more stages. Aerodynamics 101, avoid large changes of direction as it will result in turbulence. A multi stage cone can go from large starting diameter to a shallow angle mixing tube entry without being very long... but that kind of experiments lies far down the road. I still haven't figured out how I'll make the air choke, but since this burner isn't going into a forge (I don't have one) I don't think the chimney effect would be a problem for now. Ideally, I'd like to end up with a burner that runs a neutral frame w/o restricting the air flow into it - my logic being that any time you have to intentionally restrict flow you're wasting energy, energy that could have been put to use in a better designed burner running wide open. That's part of the reason I'm trying two mixing tube diameters (and can try more), I'd like the basic design to get as close to neutral as possible running wide open, and only adjust by choking as little as possible if I have to. I might run out of patience for redesigns further down the road, but that's the intention right now. Sheet metal has one very big advantage. With a little bit of knowlege and a few basic hand tools, you can make almost anything out of it. Remember, most of the cars from the 1920s and earlier were not stamped like modern day production, they were shaped using hammers, mallets, blocks of wood, and other rather basic tools. If people can create curvy body panels that way, something like a funnel (that only requires the metal to bend one way, not stretch or shrink) should be within anyones grasp if they just want to give it a try.
  9. Spring is here, so now it's time to try a burner build. First out is a linear burner, mostly for handheld use (that's the plan anyway). I intend to build it mostly of stuff I already have, the first picture (if they show up in the correct order this time) shows the lawnmower handles that the tubing is cannibalized from - they're both 22mm/7/8" outside diameter, but the more expensive mower had 2mm thick metal, while the cheaper ones were 1mm (0.080 & 0.040"), making the inside diameter 18 and 20mm. I'm using a 0,6mm MIG jet, and since so called ½" pipe (actually 15,75mm inside diameter, almost 5/8") supposedly is a bit too small for that jet, I'm hoping 18 or 20mm will be correct. I was aiming for 10x id in length, the 20mm tube is exactly that, the 18mm is closer to 9,25x id, I couldn't get a longer straight piece from that scrap. The cone templates were calculated using http://craig-russell.co.uk/demos/cone_calculator/ (remembering taking metal thickness into account when feeding in the numbers) Dimensions used were big end 3x tube diameter, and length 4x. Other sizes can easily be made, and since I've soldered them in place I can just apply heat to remove these, should I want to. Templates were transfered to thin sheet metal, and that was shaped using a rubber mallet and the first steady thing of suitable diameter I could find - the seat post on an old bicycle. Once they were roughly the correct shape I silver soldered the joint, after that I spent some more time getting it round. Final step for today was silver soldering the cones to the tubes. Now we're waiting for another warm day with dry weather, no more progress until then.
  10. This is a box of main jets for small Dellorto carburetors, used on mopeds and other small twostroke engines. They are easily available, often in sets of ten, and the size is (unlike many other jets) graduated in hundreds of a millimeter, i.e. 68 means the jet has a 0,68mm hole. The step between jet sizes is about 0,025mm, so the series usually goes 60, 62, 65, 68, 70, 72, 75 and so on (I'm suspecting that the actual hole sizes may be in even 0,025mm steps all the way, but the stamped numbers are rounded to even numbers). Thread size is M6x0,75 for the ones in the picture, Dellorto also uses M5x0,75. There are many other types of jets around for carburetors, the hard part might be getting a tap for the correct thread or jets that fit a standard thread. These jets are not designet to produce a straight jet of fuel (or gas, or anything else), it is just supposed to be a flow restriction of very precise size. I am not sure if the relatively short hole with a sharp step at the beginning works well as a gas jet for a burner. Coming to think of it, I do have a couple of scrap (a.k.a. spare part) carburetors somewhere, maybe I should take the part that the jet screws into from one of them, and try building a burner around that.
  11. Right, actual diameter of pipe isn't as "advertised". If I found the right pipe chart actual ID of sch40 ½" pipe is 0,62", about 15,75mm. Adding 1/8" (3,2mm) to that we end up just under 19mm. I don't think I have 19mm in the garage, but both 18mm and 20mm should be available. I'll try those first, since I already have them and they're pretty close to your recommendation. When pipe diameter has been used to determine other dimensions (such as mixing tube length 9 times the diameter), is that based on nominal diameter or actual diameter? Since a ½" pipe is actually 0,62", that's a 24% diffrence, quite alot.
  12. Mikey: I'd love to give advice on things like hammer patterns, but I can't say I know enough to help someone with that. I started out cutting out a piece of metal, grabbing a mallet (or hammer, tried those too but they tend to dent the metal instead of bending it), and holding the metal over any rounded metal object in sight trying to figure out how to get that mallet make that metal thickness move the way I'd like it to. It's more a matter of getting a feel for how the material and tools work than an exact science, so the best thing to do is to simply give it a try. Being my first burner build, I am thinking "keep it simple, stupid" is the best foundation to stand on. A vortex burner may be a good project later, but for now I think atmospheric is the best way to go. Crawl first, run later! For size, I'll build it around a "0.6mm" MIG tip, so if I'm not mistaking that'll make the mixing tube ½", or close to that. (I can roll a short tube out of sheet metal too, so it might be easier for me to alter mixing tube size to fit the gas jet, than change gas jet size to fit the rest of the burner - as long as a slightly uneven tube isn't a disaster.) SLAG: You are very welcome! Always nice to know that work gets apprechiated! (That goes to all of you.) Frosty: Did you make nose cones (that finish into a point), or cones with both ends open like this one? The open ended ones are fairly easy to work with (as long as the metal isn't too thick or "springy"), while a cone that goes all the way to a point can be difficult - the closer you get to the tip, the tighter the metal has to bend, and the harder it is to hold something inside as an anvil to hammer it against. But absolutely, it's much easier to make them in paper first so you can see what you're going to get. Making prototypes can save alot of time sometimes!
  13. Allright, here we go, a basic tutorial about making a cone from sheet metal. First, we need to know the dimensions. I have selected to make a small cone, 13mm (just over ½") small end diameter, 39mm large end diameter, and 52mm length. 1:3 small to large diameter, and 1:4 small end diameter to length ratio. (Do keep in mind, it is the inside dimensions you want correct in the end, if you use thicker material you need to compensate by adjusting the diameter you use for calculating. Hade I used 1mm thick sheet metal it would end up 12mm inside diameter and 14mm outside diameter in the small end, for example - i'd have to add 1mm to the diameters to get the right end result.) I simply googled "cone template calculator" and found http://craig-russell.co.uk/demos/cone_calculator/ In the first picture you can see how I have filled in the three measurments, and inside the red circle the calculator shows that the template should have an angle of 87.31 degrees, small radius 26,8mm and large radius 80,4mm. If you're smart you will make a reusable template of paper, stiff cardboard or something like that, and then transfer the outline to metal. In this guide, I'll just scribe the lines straight on the metal. Picture two shows the tools and material I'll use, the metal was cut out of an empty shaving foam can just because I had one available. About 0,15mm thick. Picture three shows the two straight lines scribed at as close to 87,31 degrees angle as I can - or rather, as close to 87 degrees as I can with the junk I've got available here. Picture four shows the two radius lines scribed using calipers. (If you are making a paper template, there are obviously better tools for drawing circles - but I don't know what they're called in english, and if you have them I probably don't need to tell you how to use them anyway.) In picture five the cone has been cut out. If you look closely, I have left about 4mm outside the two straight lines. In picture six I bend the excess into flanges that can be soldered/brazed to each other once the cone is completed. With thicker metal I would not make any flanges, instead I would cut the metal along the lines. Thicker metal can be welded/soldered/brazed edge to edge once the cone is completed, very thin metal can not - at least not with common DIY equipment. In picture seven the cone is carefully bent little by little around a permanent marker. Any sturdy round object with suitable diameter will work - the marker is too thick for the final stages, but worked excellent to begin with. If you use thicker metal you will probably want to use a rubber mallet or something similar to carefully "massage" the metal around a piece of round bar or tubing. Go slow, it is very easy to make sharp bends instead of a continuous round shape. It's better to make 20 passes end to end rolling it a little tighter each time, than to try to get it completely round in the first pass. In the last pictures you see the finished demonstration cone, ready for silver soldering the flanges - that I won't be doing now, burnt paint smells awful indoors. I just folded a small piece of scrap metal to hold the flanges steady together in the pictures. There you go, a very basic tutorial about how to make your own sheet metal cones, I hope it all makes sense. Sorry about the picture quality, but I think the idea is clear enough. There are many diffrent ways to do the metal work, use whatever suits you and your tools best. Once you have the template, the rest is just a matter of cutting and bending metal - and thanks to nerds there are plenty of easy ways to make the template. If you don't want to draw it yourself you can use the software available at https://www.conelayout.com/ to print it ready to use. Sorry, the pictures ended up in the wrong order and I'm not allowed to edit it. The last picture should have been first, and the first two last... Oh well. They're there at least.
  14. Most of my tools and materials are in cold storage over the winter, but I'll see if I can put something that makes sense together with what I've got at home.
  15. "Sorry for the slow reply; it is the flu season in my house. The smaller a burner is below 1/2" size the trickier it is to tune. The smallest Mikey burners I have built are 1/4" size; while I can make them run with perfect flames, they have a very short turn-down range, which means that I can build hotter linear burner because their lower quality flames can be turned up much stronger. Smart is as smart does.." No rush. It's a project for this spring probably, so I've got plenty of time to do research and try to find materials. Allright! I'll probably go for ½" first and hope I can get enough gas to feed it - if I can't get it to work on a handheld burner I can still keep it until I buy a bigger propane tank, and move on to a smaller burner build for the handheld. "I went through a phase were flame nozzles were kept as short as practical; this is a mistake with smaller burners, because axial alignment becomes much more important in every part of them. 2-1/2 times the mixing tube diameters work out best. About 3/32" to 1/8" thick spacer rings in step nozzles generally work out best. " Great info, thanks! The smallest burners certainly seem to abide by a diffrent set of rules. "No; a three to one ratio of air opening to mixing tube inside diameter is what I recommend for Vortex burners, and the minimum ratio I would recommend on for linear burners without superchargers." "If you can easily create your own sheet metal cones, then you have a great advantage, because you can choose to use longer cones; here is a fine place to go with four to one length to diameter." Okay! To be clear, the 4:1 length to diameter of the cone, that's relative to the mixing tube (and cones small end) diameter? Lots of diffrent diameters everywhere, and english is just my second language - easy to get confused... If I got this right... Let's go through the numbers for the cone using a ½" mixing tube. Air opening with the 3:1 ratio would be 1½" diameter. Cone length with 4:1 ratio makes the cone 2" long. It does sound like a fairly steep angle, but perhaps that's the way it's supposed to be. Dimensions doesn't sound completely crazy, so I'm guessing I haven't made a mistake in the calculations. I think most people can make their own cones out of thin sheet metal. The original reason I bought my welder was to make tuned exhausts for twostroke engines, and those are made up mostly of a series of sheet metal cones welded together. There are ways to calculate and draw a template that rolls into a cone of any desired size, but today most of us are lazy and lazy means someone has made a computer program for it. Just put in the desired dimensions, hit print, and you get a template to cut the sheet metal after. Once the metal is cut out, it "only" has to be rolled into a cone - a bit of a challenge if you use too thick metal but a piece of round bar or pipe with appropriate diameter and a mallet usually makes that job resonably easy. Weld or braze the seam (maybe even soft soldering works at the back end of a burner?) and you've got your very own cone, any size you like it.
  16. I don't know about the effect in a forge, or using propane, but... If you use oxygen/acetylene welding for hardfacing (applying a layer of very hard and wear resistant metal, often to protect a cheaper base metal) you use a acetylene rich flame. The excess carbon increases the carbon content in the surface of the steel, lowering the melting point so the thin surface melts enough for the hardfacing to stick - in my handbooks in swedish they say you want the surface to "sweat", but not melt. You want to avoid a normal weld with deeper penetration, as that brings more of the soft base metal into the hardfacing, reducing its properties. O/A welding is not all that common any more due to being slow and expensive, but compared to MMA/MIG/TIG it still puts down the cleanest hardfacing layers thanks to the ability to use a acetylene rich flame to just barely melt the surface - the electric welding methods all cause deeper penetration (at least in this case when you want to avoid penetration).
  17. I just read the entire thread, start to finish. Too bad it's so long I've probably forgotten the first half by the time I finished it... There's a huge amount of info here, alot of it easy to understand, some would benefit from a simple picture or something like that - english is my second language, so every once in a while something just doesn't translate. I have a hand held torch using disposable gas cartriges (same as weed burners use), it works well for what it is but it is simply too small for many occasions. I do have a oxyacetylene welder I can use for those accasions, but it isn't easily portable so the goal is to build a bigger capacity handheld burner, still using the cheap disposable butane/isobutane gas cartriges. I am making the assumption butane/isobutane burns similar enough to propane, so a burner based on the information I've found here (and hopefully understood correctly) would be close enough to be tuneable to a good flame. The torch "to beat" is a handheld Campingaz unit with a 5mm (just over 3/16") mixing tube. It can get small steel items hot enough for hardening, just barely hot enough for bronze brazing two M6 screws together. Alot of what I do is general mechanic jobs, like heating aluminium engine blocks/wheel hubs to release the old bearings and insert new ones. Nothing fancy really. The temperature I can reach today is acceptable, but I want to be able to get bigger items that hot and/or reach that temperature quicker. A logical solution seems to be a bigger capacity burner (and not made of brass) for any general heating use, and once I've got that perhaps a beancan forge or something like that. Would be nice to be able to start forging... but general heating is the main idea. The basic plan is a linear burner, because I have read here they work well in small sizes. I'd like to use a MIG tip for simplicity (assuming the gas canister can give off gas fast enough to feed that, worst case I'll have to put it in a water bath to maintain temperature), if I can get my hands on a more suitable jet in the 0.5-0.6mm range for a good price I'll might go with that instead. Either way, I'm aiming for somewhere around 3/8"-1/2" mixing tube. Mixing tube length rule of thumb says 9 times diameter, although I remember someone mentioning handheld small torches might benefit from longer tubes. I'm thinking 10-11 times diameter to begin with, shortening it is simple. I'm thinking a stepped nozzle. Overhang slightly longer than mix tube ID. Not sure about nozzle ID, but that should be simple to experiment with. For the other end of the burner, I'd like some input. If I understand correctly, linear burners likes to have some sort of "funnel" before the mixing tube, with a starting diameter of ~4x tube ID. I can easily cut and roll a cone of sheet metal, and weld or braze it to the tube, would that be a sensible construction? Aerodynamically, it would seem way better than the pipe reducers others have used successfully... although sometimes you need a "less aerodynamic" design to cause some turbulence or for other reasons, so that might not be a good thing. Also, if such a cone seems like a good design, should I go with a short cone with steep walls (red in the picture), or a shallower, longer cone (green)? I'm guessing the shallower cone would flow more air (perhaps a good thing with a 1/2" tube and slightly too big MIG jet), but again, aerodynamic efficiency isn't always what you need. I'm guessing I'd want some form of air choke. Right now I don't have a clear design for the gas jet/tubing or how it will be held in place, that depends on what I can get my hands on, but something like a washer sliding on the gas pipe should work for choking I think? (Orange on the picture.) Any input is appreciated!
  18. For the correct mixture with air, you need about twice as much methanol as gasolene. The diffrence is not quite as big when using ethanol, but you still need way more than you would need gasolene. Bottom line, if something is designed to mix gasolene and air in the correct proportions to burn, there will be adjustments needed to increase the amount of fuel alot before it can burn alcohol well. Well known from people running engines on various fuels, a carburettor designed for gas might not even have large enough passages where the fuel enters the carburettor to let it keep up with how much fuel the engine needs running on alcohol - and that's before you even get to all the diffrent parts that makes sure the carb adds a specific amount of fuel to the air coming through it.
  19. You may be able to make the rebar into the shape of a knife, but it is unlikely that steel can be heat treated. The result would be too soft to hold an edge, and a knife without a sharp edge is kind of useless - except perhaps as a butter knife. You need steel that can be hardened.
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