bertie_bassett Posted August 29, 2019 Share Posted August 29, 2019 evening all have found some brass nozzles for 3d printers which i believe could make good replacements for the mig tips everyone seem to be using these days. i know the mig tips are easy to come by but the printer tips seem to have a better range of sizes so should make tweeking/optimisation easier. i picked up a mixed bag starting at 0.1mm up to 1mm for only a few pounds on ebay. They go up in increments of 0.1 mm so have scope for fine tuning. hopefully i have some pics below, its only a simple straight line burner, original plan was to blank off the 15mm pipe and screw the nozzle in but i found a brass hose nipple that was a perfect fit so went with that instead. ( yes it is a little crooked) only had a small chance to play with sizes so far, but had good burn with 0.5mm. originally tried with 0.4 but couldn't get a stable flame, i think the gas velocity was too fast? 1 mm gave a lot of dragon's breath but back pressure was giving some issues with flames coming out the inlet. Oh and 5mm was very interesting! ( some wally forgot to fit a nozzle before testing) Quote Link to comment Share on other sites More sharing options...
Frosty Posted August 29, 2019 Share Posted August 29, 2019 That might be a good option Bertie, depending on availability. It's certainly worth a try. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
G-son Posted August 29, 2019 Share Posted August 29, 2019 I mentioned these in burners 101 when I had the same idea in may, the general opinion seems to be that the short orifices is a problem. But I like that you are trying them and the results will be interesting once you get it tuned, I will too sooner or later assuming I don't get my hands on other better options by then (even if others may not be quite happy with them they may be good enough to do what I need them to do - if I don't try i won't know.) Quote Link to comment Share on other sites More sharing options...
bertie_bassett Posted August 29, 2019 Author Share Posted August 29, 2019 awwww i thought id had an original idea oh well at least it isn't a totally idiotic idea. ill havent had a good look at the internal shape but id think that as long as the final edge of the orifice is clean/sharp then the gas jet will come out smoothly in a straight line. which as i understand things is all that is needed for an injector? my burner seems to like running with the nozzle only just sticking into the pipe so i don't think i needed the hose fitting. perhaps if i get time over the weekend ill try some other variations and see what works and what doesn't. Quote Link to comment Share on other sites More sharing options...
G-son Posted August 29, 2019 Share Posted August 29, 2019 Well, few ideas are so unique so no one has had them before. Turns out other people had thought of it long before me too. You don't have a flame retention nozzle on your burner in the picture, do you run it that way or did you just not include it in the picture? Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted August 29, 2019 Share Posted August 29, 2019 On 8/29/2019 at 3:02 PM, G-son said: I don't get my hands on other better options by then (even if others may not be quite happy with them they may be good enough to do what I need them to do - if I don't try i won't know.) they very well might be good enough, and good enough is good enough I believe that the idea floated on the Burners 101 thread was to use regular gas jets, which weren't an optimal configuration (much like this one isn't). The difference this time is that these nozzles look to come in very small orifices; that makes these worth trying. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted August 29, 2019 Share Posted August 29, 2019 I have noted the idea on Burners 101.Burtie is welcome to post on that permanent thread. Or not; his choice. Quote Link to comment Share on other sites More sharing options...
Frosty Posted August 30, 2019 Share Posted August 30, 2019 It's a good idea no matter who thinks of it first or whether it actually works very well or not. It's not like one of you guys saw it somewhere and thought, "Ah HAH, I can pretend to think of it and garner admiration and rewards!" An honest idea is an honest idea. With as many fuel gas burners in the world I doubt very much anybody has thought of something new in a long while. Good on both of ya! Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
bertie_bassett Posted August 30, 2019 Author Share Posted August 30, 2019 thanks Mikey ill pop over there and comment when i have done more testing. if i can scrounge enough parts ill try some other burner designs. G-son - i have only had it lit when in the forge, havent got round to making any sort of flame retention nozzle/flare as yet. more interested in getting it optimum in the forge. the smaller jets seemed to blow out any flame in the forge but perhaps more air was required. i do also have some proper gas jets from a hob, thought they might be worth a try. Quote Link to comment Share on other sites More sharing options...
G-son Posted August 30, 2019 Share Posted August 30, 2019 I applied some math to the list of suggested jet size list a while back, and they generally said that the jet size should be about 4% of the mixing tube (actual) diameter. So if the mixing tube is 15mm internal diameter I would have started trying with 0.6mm and worked my way from there. Quote Link to comment Share on other sites More sharing options...
bertie_bassett Posted August 31, 2019 Author Share Posted August 31, 2019 well i had another play last night and didnt have any luck at all not sure why but the thing wouldn't run smoothly at all and kept trying to burn in the tube. i think the wind may be affecting it as i am using it outside. oh and i must apologize to Mikey i did not realise the burner was a copy of your design. I simply laid out all the random fittings i had until something looked easily adaptable dn similar to ones i had seen online. Now i know what the origional design was i can check my dimensions and se where i deviate. have also found a 1/2" T along with a smaller swept bend which may make reasonable burners, just need to find the right diameter pipes to go with them Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted August 31, 2019 Share Posted August 31, 2019 12 hours ago, bertie_bassett said: oh and i must apologize to Mikey i did not realize the burner was a copy of your design. Apologize for what? If I hadn't wanted what I'd learned past on, I'd have kept quite about it. Nor do I care how much people mix and match burner designs; just so long as I don't hear something like "I did everything you said to and it didn't work," after they do just exactly whatever they please, instead Quote Link to comment Share on other sites More sharing options...
Mr Moose Posted September 1, 2019 Share Posted September 1, 2019 But thats the New American way. Quote Link to comment Share on other sites More sharing options...
bertie_bassett Posted September 7, 2019 Author Share Posted September 7, 2019 good job im british then :p not really had a chance for any further testing, been too busy and i need to remake the burner as it was only slapped together for a quick trial. i have however had a closer look at the nozzle internals, im no expert of flow dynamics but i think it should give a decent 'jet'. the main bore is basically just a 1.3 x 10mm drilled hole followed by a 0.4 drill (or other nozzles size) final orifice is 0.4x 1mm. pic below is of some filament i managed to remove and should explain things better. Quote Link to comment Share on other sites More sharing options...
bertie_bassett Posted September 29, 2019 Author Share Posted September 29, 2019 well i had a little time to play today and built a better burner for testing, this one is much closer to a Mikey burner ( i think) The tube is 1" external and approximately 3/4 internal, with four air slots cut with my mill. Rather than just cutting straight down into the tube i cut in from the side which has created a sort of tapered leading edge. Not sure if that is going to create an issue or not but it may nudge the airflow into a slight vortex. anyways i found the 0.8mm and 1mm nozzles both seem to run well, the best placement i found was having them only just showing through the air slots. the 0.8mm seems to be stable at a slightly lower pressure but i haven't got a gauge so cant give any numbers. will have to try some more testing in the dark when i can actually see the flame! hopefully the pics will explain a bit better Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted September 29, 2019 Share Posted September 29, 2019 Circumstances always alter cases, when it comes to design But the principles you apply to design don't change. You will be happier with your burner if you move the gas jet forward; why? Because most of its air will be induced at the forward end of the air openings. Bernoulli's Principle can only be applied in direct proportion to how you allow it to be. Quote Link to comment Share on other sites More sharing options...
bertie_bassett Posted September 30, 2019 Author Share Posted September 30, 2019 i thought it should be further forward based on the others i had seen, but the flame seemed stronger and louder with the jet where it is now. also seemed more stable at low pressure as i was getting a lot of pulsing as the gas tried to burn in the tube. it also seems prone to blowing out completely if i crank things up too high? pics below show the flame as best as i could get it last night in a dark workshop, couldn't run for too long as it was raining out so had the doors shut. lowest it will go is on the right. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted October 1, 2019 Share Posted October 1, 2019 You can do a lot better than that flame. I don't know what your problem is, but I would rather see you build a linear burner than settle for such a flame from my design. Quote Link to comment Share on other sites More sharing options...
bertie_bassett Posted October 1, 2019 Author Share Posted October 1, 2019 hmm seems ill have to try harder. I can try moving the nozzle further forward to see what that will do, i wont pretend to understand why that would be better but will follow the voice of experience. Only other thing that is different is the side edges of the air slots which were cut on a tangent, perhaps that is causing more turbulence rather than helping the air in. Have made a quick sketch of what i mean below, wont take long to mill off the offending parts and the tube should still be strong enough. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted October 1, 2019 Share Posted October 1, 2019 That part should be okay; not known. Quote Link to comment Share on other sites More sharing options...
bertie_bassett Posted October 2, 2019 Author Share Posted October 2, 2019 well i had time for a little play but tbh im not sure i am any further forward. tried moving the tip further towards the mixing tube but with a 0.8mm jet, it would either burn in the mixing tube at low pressure or blow out at higher pressures. couldn't find a stable position. so i moved up to a 1mm jet, that initially was very unstable. was about to give up when i noticed the end of the jet was damaged, i must have dropped it at some point and dented the orifice. swapped a new 1mm jet in and it seems to be stable. Pics below show the jet position and the flame achieved. all other settings are the same as i simply slid the jet in and out and took a pic. i then took a file to the damaged jet, seems the 1mm bore isn't very deep and i was soon into the wider opening behind the tip. ended up with something near 2mm which gave an interesting flame. Very lazy with lots of yellow in the end at lower pressures and one huge tongue of blue when cranked as far as i dared inside a wooden workshop. so al in all i have some results but cant interpret them to know good from bad. i also have a suspicion i need to be running these tests longer to prove anything reliably, the flame holder did glow dull red occasionally but Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted October 2, 2019 Share Posted October 2, 2019 I think you will find that the parts you are using for gas orifices will work Jim Dandy for very small burners 3/8" and under, but won't work worth beans for 1/2" burners and up. WHY?!?!? Because friction losses through very small orifices (.020" or smaller) make tube shaped gas orifices, like those formed with MIG contact tips, counter productive; thus the very short orifices found in 3D printing nozzles are good enough for small burners, but just don't cut the mustard with larger burners. Quote Link to comment Share on other sites More sharing options...
bertie_bassett Posted October 3, 2019 Author Share Posted October 3, 2019 oh well i was hoping that the pics would have shown some improvement but perhaps id be better off just giving up as im clearly on the wrong path thanks for the help anyway Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted October 3, 2019 Share Posted October 3, 2019 I don't think you are" on the wrong path," just not using the right part for this burner size. I think that 3D printer nozzles are an important find. But just like everything else about burners, they need to be used the right way at the right time. Quote Link to comment Share on other sites More sharing options...
Another FrankenBurner Posted October 4, 2019 Share Posted October 4, 2019 On 8/29/2019 at 11:49 AM, bertie_bassett said: (yes it is a little crooked) That last photo you posted, it may just be the photo but that orifice/jet looks very out of alignment. If so, that is a problem. Out of alignment, even a little, can cause major problems. If you can disconnect the burner from the fuel line and connect it to a water line, this will tell you immediately. Quote Link to comment Share on other sites More sharing options...
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