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Hello all!Ok, so I went and bought a Lincoln Handy Mig as per the advice of many who write to stay away from Harbor Freight 110V boxes... so here I am.Let's just say that, for the sake of the argument, I know I could weld thinner gauge steel with a gas Mig set-up (or I think I could - see the limitations of my power settings below), but due to constraints I am stuck with flux core at the moment.Let's also say that the welder only has four power settings via high/low switches, and is currently burning through 20-guage tubing when doing a continuous weld with .035 flux core.Now I've read a bunch of times that it's better to use thinner flux core - I'm not arguing that, so I have some .023 on order (will be here next week). The question I have is...Is power output mainly a function of the settings at the box (because my box only goes so low apparently), or will the .023 wire with the same settings (Low and Low on both power output switches, and anywhere from 3 to 5 on the wire-feed speed) transmit less power through, enabling me to run somewhat continuous beads?Thanks!(the last question that hopefully won't need to be answered would be of limiting the power output of my box via some modifications - I've read some posts, here, from very knowledgeable posters who show how to mod other boxes, but I've never read one of limiting power, lol)Last edited by Mambo Dave; 12-16-2011 at 10:34 AM.
Reply:I am not aware of any 0.023" flux core at all. 0.030" is the smallest I have heard of for a home/hobby machine.That being said, your hi/low switch changes voltage and the wire feed control controls the amperage (heat) as well as the feed speed.20 guage is very light to be practicing on but is might be doable after some practice. You might try and move faster to avoid burn through or you can experiment with trigger pulse where you let go of the trigger before you burn through and pull it again before the bead cools so much that the colour disappears.Gordie -- "I believe you understand what you think I said, but I'm not sure you realize that what you heard is not what I meant."
Reply:Thank you. I am hoping the guy at the welding supply store was right and that he could find thinner than .030 flux core, but we'll see next week.At the moment I am just doing a little bit at a time, not quite starting again when the color is still hot. It's making not-so-great looking welds, but the tubes are holding together.I tried faster weld movement, and while I can sort of do it, the accuracy isn't there, and it just won't look like a stack of dimes (at the small scale) as the bead is just a straight-pass. Not great, but it's do-able for the current project.What's your take on thinner wire working any better with what will be pretty much the same low, but not super-low, settings?Last edited by Mambo Dave; 12-16-2011 at 11:26 AM.
Reply:Try backing your work with some copper. That might help you out on the thinner metal.Get some scrap for practice & get your settings figured out.AEAD 200LE, Lincoln precision tig 185, Millermatic 251, Spectrum 625 extreme, Victor torch , Smithy 1220LTD. and Do all C-4 band saw , Always adding.
Reply:That would require copper tubing of exactly the inside diameter of the tubing I am working with, would it not? Sounds like quite a task to find - I am working with 5/8" OD tubing, 20-gauge... ID seems to be 9/16".A Google search brought up this: http://answers.yahoo.com/question/in...8111902AANJGXQ on 9/16" copper tubing being a non-standard size. I like the idea, but I imagine whatever I use for backing is going to have to fit tight, and it's going to stay in there (or get stuck in there) so it has to be cheap and disposable.
Reply:Fluxcored wires are a metal tube or sheath that is filled with alloying ingredients and 'flux'; a witch's brew of organic and inorganic chemicals. The alloying ingredients control the mechanical properties of the finished weld. The flux prevents oxygen, nitrogen, and hydrogen from forming porosity in the weld bead. The flux also introduces chemical into the welding arc that stabilize the arc and make for easier welding and better finished bead appearance. Lastly some fluxes also asist with out of position welding, by forming a shell that holds the molten metal in place long enough to freeze solid.The flux carries very little of the electrical current that passes through the wire while welding. Most of the current flow is through the metal sheath. Smaller diameter wires have thinner sheaths. The thickness and diameter of the sheath determines how much current can flow through the wire. Electrical conductivity or resistivity also affect this, but most flux cored wires for mild or low alloy steels have low carbon steel sheaths. So the electrical conductivity of the sheath is the same regardless of what diameter or even type of filler metal(for mild or low alloy steel)So, the sheath diameter and thickness sets the upper limit for current flow. Just like a water hose flowing water, an electrical conductor can only pass so much current. The more current you force through the wire, the more resistive heating that wire sees. Make the wire hotter and the electrical resistivity increases (or conductivity decreases, take your pick.) The lower limit is determined by how much resistive heating the wire sees from the current flow. If there's not enough current flowing, then the wire tip doesn't melt, the flux inside the wire doesn't melt. If there's no melting occuring the the arc isn't stable and there's no molten droplets of metal to transfer to the weld joint/bead. The wire stubs out on the base metal surface.This is why fluxcore wire diameter affects the heat delivered to the weldment. It's why you can't use thin wire to weld thick material. A very small wire simply can't carry enough current to create enough heat to cause the base metal to metal and fuse with the weld metal deposited.Along the same lines, this is why you can't use large OD wire to weld thin material. It takes a minimum amount of current to melt the sheath and flux in a large OD wire. That amount of current just vaporizes the base metal in and around the weld.The behavior of a tapped power supply like your machine will vary based on the wire diameter. The setting on the machine that work with 0.030" fluxcore on 16 gage steel sheet will not work with 0.045" fluxcore on the same joint and base metal. The wire feed speed and the amperage delivered need to be different with these two wires. The voltage required to establish the arc is different also.Switching to a smaller filler metal wire will aid you in welding thin sheet metal. So will practicing on thicker material to improve your skills. As someone else mentioned, you may have trouble finding smaller diameter fluxcored wire. This may in turn force you to switch to 0.023" solid wire with gas shielding. The smaller diameter solid wire will be substantially easier to weld with on thin gage sheet metal.Hope this helps.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:A_DAB, it was the answer I was looking for (and hoped / believed to be true to a degree).Thanks all!If an argon/CO2 mix will then truly let me weld well at the small scale (I want to be relaxed, not fighting a possible burn-through (only had one) with it like I'm doing), the Handy Mig came with an argon-tank regulator (no gauge on it though), so I might have to go for it and .023 regular wire - problem is that this is outside welding, exposed to some really nice Atlantic breezes - and the wind has been strong for weeks now. Between that environment, and having to constantly move a tank around if I got one - plus the truck being out of commission to pick a tank up with (wheel bearing or brake caliper locking up front wheel), I was, and still am, trying to do flux core. The end goal, for right now, is a motorcycle luggage rack (for saddlebag spacing, too) that will be painted black. It doesn't have to have the most beautiful welds (would love to have them, though, and am taking a welding class at the moment, but am practicing oxy-acetalene welding there), but it does have to hold together for some miles. I don't mind grinding the slop (... actually, it does suck - with only one angle grinder and no bench grinder I am changing between three different discs like a madman on the practice welded tubing) for now.Last edited by Mambo Dave; 12-16-2011 at 01:20 PM.
Reply:Originally Posted by Mambo DaveI tried faster weld movement, and while I can sort of do it, the accuracy isn't there, and it just won't look like a stack of dimes (at the small scale) as the bead is just a straight-pass.
Reply:The smaller the wire, the thinner it will weld as a rule..030 solid wire uses one amp for 2 inches per minute of wire feed speed.I don't know the factor for .023 but I think its about 5 inches peer minute for one amp..045 is one amp for one inch per minute. One hundred inches per minute = 100 amps.IF my numbers are right, .023 at 100 ipm would be 20 amps..030 at 100 ipm would be 50 amps.They all poop out some where over 350 inches per minute.Good luck welding 20 gauge with flux core. Its not a good place to start. Maybe practice on some 11 gauge or 1/8" so you get to know your welder better first.Borrow a mig (with gas) to try.DavidLast edited by David R; 12-16-2011 at 06:40 PM.Real world weldin. When I grow up I want to be a tig weldor.
Reply:Hey Mambo Dave, Thought I might chime in on this topic. If already anwsered then good. In your first post you mentioned burn through with .035 Flux Core wire. You should be using .030 Flux Core as you mentioned working outside. .030 flux core is the same or SMALLER size wire as .023 solid if you compare them in terms of mass. Flux Core wire as you've already learned is hollow. When melted its mass size is small and this is why it works so well on thin materials ( with PRACTICE). I use to use a wire the Twenty Gauge made, but Lincoln bought the company and gone now ( another story for another day). Yeah it was confussing, most folks thought it was .020 but we learned later. Anyway it was a great quality wire for thin metals. Again, if your actually using .035 flux core, stop and try the .030 flux core from a GOOD company like Hobart or Lincoln, NOT Harbor Freight
Reply:Thanks guys,I did try .030, but it was that Italian-made HF stuff. It did work marginally better, but in the end I chanced buying a shielding gas despite me welding outside. (So now I have two opened 2 lb. spools of flux-core that I'll probably never want to use, lol)I try to block the gusts via a large piece of cardboard on one side, and an open shed-door on the other (so I try to let it channel past me). This sorta works, so while it isn't stable air and shielding gas, for the 20-guage it works well enough. Surprisingly, and I'm not sure why, but the 20-gauge tubing I am using seems to allow burn-through faster than 20-guage plate. It's a delicate, stop-and-go process. I'd love to see a real welder "Mig like Tig" on the 20-gauge tubing just to see his settings (which my machine may not be capable of if it requires being turned down farther) and his hand-movements / technique. I'm going to keep playing with the stuff I have (cutting coupons, I guess the small pieces are called, and trying to weld better and better looking welds). I don't know why, but the smaller, thinner stuff and welding appeals to me - specifically trying to do that thin stuff in a common-man way with Mig. I write that because I got to lay some beads of Tig two days ago and, when I got it right, it was apparent that tiny thin welds were do-able with Tig... but Tig is not what I own, nor what is common to find amongst hobbyists.Likewise, I understand brazing would work, too, but as the company I work for just lost its contract, any more investment in tools will have to wait.Lincoln Handy Mig
Reply:20ga for somebody not doing a lot of it (body man) is tough, period.For me to even get anything close to good I have to space a bunch of tacks really close together.Matt
Reply:Originally Posted by Mambo DaveThat would require copper tubing of exactly the inside diameter of the tubing I am working with, would it not? Sounds like quite a task to find - I am working with 5/8" OD tubing, 20-gauge... ID seems to be 9/16".. |
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发表于 2021-9-1 00:02:07