philb86 Posted February 12, 2021 Share Posted February 12, 2021 45 minutes ago, Mikey98118 said: Anytime the experts want to say something useful, they are welcome to take my place. There are loads of other things I could be working on. Meantime I won't hold my breath while, waiting, and waiting, and... Hey ummmm, nope, nothing here. Nothing but gratitude for your help getting my burners optimized to the best they could be. Been awhile since I posted, but I did however drop down to the .023 nozzles, and I cannot say how nice the burners work now. I forgot to post the results, since the burners are now in the forge, and most my time has been spent learning to forge things. Thanks again Mikey, I really appreciate the help and patience while working through the issues I had with me. Link to comment Share on other sites More sharing options...
Mikey98118 Posted February 12, 2021 Author Share Posted February 12, 2021 Actually, I was picturing the typical combustion experts employed by industry, who basically have nothing to say to Joe Public. Had hoped your silence meant your task was satisfactorily completed. New you were very close. What is that heavy looking monster in the foreground of the photo? Link to comment Share on other sites More sharing options...
philb86 Posted February 12, 2021 Share Posted February 12, 2021 That is a feed roll for a turning machine that turned 4" diameter titanium. Think the reverse of a lathe, bar was fed into machine with a rotating head that removed the material. Its hardened 4140, 5" thick and 13.5" diameter. The place I worked at before I got laid off due to the pandemic was tossing it due to a crack at the keyway slot. I asked if I could have it and they said yes. It sat on my floor for about a year, and when I couldnt find a decent anvil, I got the bright idea to use it as my anvil. Works quite well, has crazy rebound and doesnt ring. Link to comment Share on other sites More sharing options...
Mikey98118 Posted February 12, 2021 Author Share Posted February 12, 2021 Crazy bounce without ring is a big enough plus to keep it around for years and years Link to comment Share on other sites More sharing options...
Frosty Posted February 12, 2021 Share Posted February 12, 2021 Twigg: Reading your reply I realized I should stop using "induction" to describe NA burners, it is too easily confused with electric induction forges. I'm not crazy about "entrainment" as a descriptive term but it's not confusing. If I slip and use induction again, please yell at me so I'll get the change locked in. Frosty The Lucky. Link to comment Share on other sites More sharing options...
Mikey98118 Posted February 12, 2021 Author Share Posted February 12, 2021 After switching from "entrainment" to "induction" for nearly 100 pages, I think that switching back to" entrainment" will cuase even more confusion. Link to comment Share on other sites More sharing options...
ThomasPowers Posted February 12, 2021 Share Posted February 12, 2021 Perhaps discuss the Mikness of the Frosticity? Link to comment Share on other sites More sharing options...
Alphafarrier Posted February 12, 2021 Share Posted February 12, 2021 Hey guys. Quick question. So I know that the overall length of the accelerator assembly is important, however if the accelerator tube is long enough, does it matter how long or short the mig tip is? I've been looking to move to a 1 1/8th inch mig tip, down from a 1 1/2" (I can buy the shorter ones pre-tapered!) Link to comment Share on other sites More sharing options...
Mikey98118 Posted February 13, 2021 Author Share Posted February 13, 2021 If the gas tube that the MIG contact tip screws into is 1/8" schedule #80 pipe or any other tube with an approximately 3/16" inner diameter, that can be directly threaded into, you can get by with the shorter MIG tip; otherwise not, on most burners; this does not include "T" burners, which do fine with the shorter tip. In other words how good the streamlining is between the gas tube and MIG tip is more important than Tip, or tube lengths. Link to comment Share on other sites More sharing options...
Alphafarrier Posted February 13, 2021 Share Posted February 13, 2021 Thanks Miley. This is for a Mikey style burner, and yes, the id of the accelerator tube is the correct size to be tapped directly into. When you say I can get by with the shorter tips, do you think they will hurt performance vs the longer ones? Link to comment Share on other sites More sharing options...
Mikey98118 Posted February 13, 2021 Author Share Posted February 13, 2021 Nope; performance will be just fine with the shorter MIG tips, so long as your gas tube can be directly threaded for them. Originally, I used 1/8" shedule #40 pipe for my gas tubes. because the schedule #80 pipe was harder to find; a mistake in judgement, as Larry Zoeller showed when he choose schedule #80 pipe and the shorter tips quite successfully Link to comment Share on other sites More sharing options...
Skidpad13 Posted February 13, 2021 Share Posted February 13, 2021 Mikey, following up on this. If using the 1/8" schedule 80 nipple, how critical is it to grind the threads off the end that the MIG contact tip will be threaded into? If the idea is to streamline, I would think that both these threads and the transition to the tip should be as smooth & gently tapered as possible. Thanks for indulging my neuroses Link to comment Share on other sites More sharing options...
Mikey98118 Posted February 13, 2021 Author Share Posted February 13, 2021 I like to taper them at least sixty degrees. Link to comment Share on other sites More sharing options...
Skidpad13 Posted February 13, 2021 Share Posted February 13, 2021 Got it, thanks! Link to comment Share on other sites More sharing options...
Mikey98118 Posted February 13, 2021 Author Share Posted February 13, 2021 Members 4,947 posts LocationSeattle, WA Why use 3D printer nozzles? The gas orifice on most burners works best as a tunnel; not as a hole. In fact, I used to call them "accelerators" to stress the reason why I prefer MIG contact tips to mere holes in end plates. Just as a long rifle barrel while increase bullet speed, a tube can increase the speed of gas molecules. Note: To all things there are limits. Faster gas molecules in a gas jet can induce more air; a generally desirable outcome. BUT, if the gas jet is too fast, some of the fuel molecules will outrace the incoming air, giving incomplete mixing. When I started making burners too small for MIG contact tips to work, capillary tubes were mounted in the tips, to keep the accelerator effect going. Finally, with 0.020" I.D. capillary tube in 3/8" burners, friction losses caused me to turn the gas pressure up so nigh that, you guessed it, there started being funky mixing. The answer was to shorten the capillary tube to just under 5/16" to lessen friction loss. !/4" burners use 0.013" I.D. tube, or much smaller holes in flat plate. Either way, the tars and waxes in propane will create cleaning problems. The tubing needs to be even shorter than it is for 3/8" burners. All of this leads up to 3D printer nozzles a smarter choice than gas tunnel orifices in smaller burners. the nozzles have something in common with torch tips; streamlining for fluid flow; but their cost is negligible. Link to comment Share on other sites More sharing options...
dian Posted February 14, 2021 Share Posted February 14, 2021 interesting, because my understanding was that sonic speed at a pressure ratio of around 2 (?) was max atainable speed and the mass flow would be proportional to the pressure ratio above that. Link to comment Share on other sites More sharing options...
Mikey98118 Posted February 14, 2021 Author Share Posted February 14, 2021 I'm not suggesting anything remotely approaching sonic speed. Link to comment Share on other sites More sharing options...
dian Posted February 14, 2021 Share Posted February 14, 2021 maybe i missunderstand, but it appears that at a pressure ratio of a little over 2 the flow is sonic through an orifice. Link to comment Share on other sites More sharing options...
Mikey98118 Posted February 14, 2021 Author Share Posted February 14, 2021 On 2/12/2021 at 9:34 AM, ThomasPowers said: Perhaps discuss the Mikness of the Frosticity? Good one 12 hours ago, dian said: maybe i missunderstand, but it appears that at a pressure ratio of a little over 2 the flow is sonic through an orifice. The only reference I find on the Net about sonic speed is about breaking the sound barrier. I don't know what you are referring to. Link to comment Share on other sites More sharing options...
Frosty Posted February 14, 2021 Share Posted February 14, 2021 On 2/12/2021 at 8:34 AM, ThomasPowers said: Perhaps discuss the Mikness of the Frosticity? It got me laughing and I couldn't even think of a comeback. That's high on my list of good ones. Frosty The Lucky. Link to comment Share on other sites More sharing options...
Mikey98118 Posted February 14, 2021 Author Share Posted February 14, 2021 I simply couldn't decide which jibe was funniest; kept going back and forth, while my grin grew completely out of control... He will bare watching Link to comment Share on other sites More sharing options...
ThomasPowers Posted February 14, 2021 Share Posted February 14, 2021 You will need a stronger stomach than most to watch me when I'm bare. Been *years* since the last time I went skinny dipping. Link to comment Share on other sites More sharing options...
twigg Posted February 14, 2021 Share Posted February 14, 2021 Lol Thomas Dian, if you're thinking of the equations for compressible flow, remember there's friction and probably turbulence in the nozzles / mig tips (especially the mig tips!). If no energy is lost to heat or eddies, then 2:1 pressure ratio would get you to Mach 1. I suspect the flows are highly compressible, but I wouldn't want to bet either way whether or not they get sonic (especially in the mig tips!). Maybe you can make a burner with a de Laval nozzle for an accelerator, huh? (That doesn't sound very useful, I'm just pulling your leg) Link to comment Share on other sites More sharing options...
Mikey98118 Posted February 15, 2021 Author Share Posted February 15, 2021 Yes, the compressed fuel gas that travels down a MIG tip must transverse narrowed passageways, before (from hose to gas pipe; then from pipe to tip) and during its journey to the tip's exit through the gas orifice. The tip narrows through half of its length. The remaining half is subject to friction losses. Link to comment Share on other sites More sharing options...
Hawkbox Posted February 15, 2021 Share Posted February 15, 2021 Huh, that's fascinating and I really like the design Skidpad did up just to help wrap my head around what was being talked about. If it ever warms up enough outside that my water bucket in the garage thaws out I'll have to go down this rabbit hole again. Regarding 3D printing nozzles, I have to imagine that's not on your bog standard Ender 3 Pro unit? The tolerances seem like they would be far to fine for your average home use printer? Link to comment Share on other sites More sharing options...
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