Newbie seeks advice to improve welding

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I have been reading this forum for a few days and am impressed with the depth of knowledge.  I hope one of you is kink enough to help.I bought a small welder last month and am learning to weld.  Only 25% of my welds are good.  I appreciate any advice you could give me on how to improve my welding.My goal is to build some furniture made of thin-wall 1-inch-square tubing.  The welds don't have to be pretty, but they should be strong enough to take some abuse.Here is my current setup:Butt welding 1-inch square tubing, .065-inch wall thickness (16 gauge) mild steel.Use a 90-amp wire feed welder with .030-inch flux core wire.Wire speed is set to slow and power is set to minimum (80 amps).Auto darken helmet set at 10.Here is a picture of my setup:This is how I practice my butt welding:I lay the two pieces of tubing end-to-end with a small gap between them.The gap should be about 1/2 the thickness of the metal.I tack weld the two pieces together.Then I use some .030-inch flux wire to measure the gap.Then I think about how I will do the weld:The puddle is a crater of the molten metal, like water from a garden-hose nozzle digging a crater into the earth.  Puddle diameter should be twice the metal thickness if there is no gap; slightly smaller puddle diameter if there is a gap.Then I weld:I start by holding the arc at one point until a puddle forms, then move the arc along the gap, adjusting  speed so that a constant puddle diameter is maintained.  Slow at first, faster as the pieces heat up.  Holding constant contact tip to work distance (electrical stickout).Then I test the weld:Put the tube in a vice and bend the weld open (only one side was welded so its easy to bend open).If it breaks at the weld, it is a cold weld.If the sheet metal tears along the edge of the weld, its a good weld (pictured below).Holes are bad.  I do not see the hole while welding, but I can hear the tone of the arc change.Here is a break down of my weld performance:60% are cold25% are good25% have holes10% of the welds are part cold and part hole.Seems like there is a very little margin between burn through and a cold weld.Questions:What percentage of welds should be "good" before I start welding furniture?The furniture will be made of the same 1-inch square tubing I am practicing on.The welds don't have to be pretty, but they should be strong enough to take some abuse.When I hear a hole melt open under the arc, is there some immediate action I can take to save the weld?Would .023 inch flux wire make welding 16 gauge easier (I am currently using .030 inch flux wire)?At first my welds where improving with practice, but now I'm not making any progress.What am I missing?Thank you.
Reply:Answers:1.  How much should be "good welds" on furniture?  95% or greater.  Anything less risks injury to the owner of the furniture.  Especially a chair.2.  When you hear a "hole" happen, release the trigger & look for it with the light from the hot metal.  Reset your wire stick out, zap for a short second, release trigger.  Move to one side or the other, zap it again.  Repeat until you've filled the hole.3.  .023 would help, but I don't think they make a flux core wire that small.  If you have gas for your rig, you can use a .023 solid wire & gas on this thin tubing.What I do when welding 16ga tubing & .030 flux core wire, is small "c" shapes from one side of the open area to the other.  Pause at the solid metal, move fast over the opening.   Imagine your joint like this & fill the area with the c motion.  Like this:   -c-c-c-c-c-c-c-c-c-c-c-c-c-c-If it looks or sounds like it's going to burn through (make a hole) release the trigger & pause.  That amount of amps on this thin metal will burn right through.Another thing is, on this thin metal, you really don't need the gap.  Butt it up solid, the flux core wire will penetrate enough to weld this thin stuff solid.  Keep practicing, cut off the bad ends & try it again.MarkI haven't always been a nurse........Craftsman 12"x36" LatheEnco G-30B MillHobart Handler 175Lincoln WeldandPower 225 AC/DC G-7 CV/CCAdd a Foot Pedal to a Harbor Freight Chicago Electric 165A DC TIG PapaLion's Gate Build
Reply:Thanks Mark.  This is exactly the kind of advice I needed.Tomorrow. I'm going to practice "release the trigger & pause" before I turn on the power.Then I will try the ccccc motion without a gap, ready to release the trigger if I burn through.I am psyched!
Reply:I would change the joint  type you're practicing.  In your furniture making, how often are you going to butt weld the tubes together?  Probly not much.  If you want the tube to be longer, you just cut it longer, no need to splice them together. Most likely, you will be welding the tubes at 90* junctures to eachother, so do your practicing on that type of joint.  You will be practicing fillets on 2 sides and grooves on 2 sides.  However, the grooves will only have one side as a tube edge, the other side is the tube corner.  This is alot easier joint to weld than an end to end tube butt joint.  Concentrate the heat more on the tube corner and wash over to the tube edge.   On the fillets, concentrate the heat equally on both sides, using a 45* work angle.You are dragging the torch rather than pushing with your fluxcore wire, right?.030 fluxcore is fine for welding the 16 ga steel.  If you are working indoors, you can go with .023 solid wire and C25 or C15 gas.  Outdoors, stay with the fluxcore.Be sure to change the polarity if you go with solid wire and gas.  Torch on the positive terminal for solid wire.  Torch on the negative terminal for fluxcore wire.Also, your method of attatching the ground cable to the work, although creative, is not that great.  If your clamp is too small to clamp around the 1" tube and too big to fit into the end of the tube, go to the welding supply and buy a little bigger clamp that can open wide enough to clamp around the 1" tube.  Clamps are pretty cheap to buy and easy to install.  Beats fighting with the brick and you won't be able to use that brick when you're actually building the furniture.Last edited by DesertRider33; 10-04-2009 at 12:43 AM.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:Just remember that, once it cools, that flux core is going to give you fits trying to start again over it's own slag. Pulsing is kind of tough with flux core. Plus it's a bad habit to get started, welding over slag.Next you need to get the 'amps/power' thing sorted out. With wire feed the feed speed dictates the amperage. Without seeing the manual on your machine I would imagine what you call power is the voltage setting. It is a matter of finding the right settings. From looking at the spatter balls laying all over the place I would guess you need more of both, wire speed and voltage. You're not going to find any .023 flux core.
Reply:Yeah, having just welded a fence out of 16 gauge square tubing, the part that jumped out to me from your original post was the lowest and slowest power and speed settings.  I know with my Hobart 140, I'm using the 3 out of 4 setting most of the time, with a wire speed around 35.  What welder are you using, and what does the chart inside its door recommend for that wire and 16 gauge?  I'm guessing higher settings and faster speed is going to help.Jack OlsenMy garage website
Reply:DesertRider,I started with butt welds because I thought it would be the simplest. I was planning to learn "T" joints after I get the fundamentals down. I am surprised to hear that a "T" joints are easier than end-to-end butt joints.  I will give it a try.I tried dragging and pushing and didn't notice any advantage either way.  What is the advantage of dragging?  I read the Lincoln weld pack 100 manual at http://content.lincolnelectric.com/p...ture/e7350.pdf.  Page 27 says: On thin gauge sheet metal, use the “push technique”.  But it doesn't explain why.When I clamped ground onto the tube, the weight of the cable rolled the tube, so I used the weight of the brick to hold the tube down.
Reply:Sandy,Yeh, I noticed that welding over slag made for a weak weld.
Reply:Jack,My welder is a Chicago Electric MIG-100 Model 94056 ($80 at Harbor Freight Tools).I bought it for one project that's all 16 gauge.  It has worked well so far.Features include:"MIG" in the nameNo capability for shielding gasLive wire (strike arcs without pressing the trigger)No chart for wire speed or metal thicknessFor $80 I expected a minimal welder.  It would have been nice if a chart for wire speed and metal thickness where provided.  The manual is at http://www.harborfreight.com/manuals...4999/94056.pdf  Specifications are on the front panel:How does more voltage help if I am already burning through?  Its counter intuitive to a beginner like me.Thank you for you help.Last edited by wolfv; 10-04-2009 at 11:57 AM.
Reply:I'm surprised that you get a spark without pulling the trigger on the gun.  I couldn't find it on the manual where it says it's a live wire, but I'll take your word for it.  If it were me, I would experiment a bit more.  Try with the switch set at "low" (80amps) & adjust the wire speed according to how it works on the metal.  Try going at minimum wire speed, and turn it up a little at a time to make your welds more stable.  If that doesn't work, try it on "high" (90amps) with a slower wire speed.  I think the "High/Low" indicates max output for the welder & 90 amps seems a bit high for 16ga metal.  I had to ignore the chart on my Lincoln welder & adjust it to how it welds.To push, use a reverse "c" movement.  Like this:<-)-)-)-)-)-)-)  (arrow indicates travel direction)  Pause at the ends of the ")", travel fast over the center of the ")".  You are basically manipulating the puddle to wash over the edges onto the other side of the joint.  Watch your puddle & move it according to what the metal is telling you.  Pause if it looks like it's going to burn through, let it cool.  Then clean off the slag, start welding again.  A wire brush is handy to clean off a fairly hot weld with flux core.  I use one with a built in scraper to tap the slag off while it's still hot (just not cherry red hot).A "T" joint is much easier to weld.  Basically you form the joint & angle your gun to 45*, pull the trigger & move.  Manipulation of the gun tip to wash the puddle onto both sides of the joint isn't really necessary, but helps sometimes.  The solid base of the "T" will handle a bit more heat than the thin vertical portion of the joint.  More surface area to handle the heat.  Pushing a weld will allow for a bit less penetration, to help control/prevent burn through.Post up some more pics, there are guys on here that are absolute "artist's" in their welding ability.MarkI haven't always been a nurse........Craftsman 12"x36" LatheEnco G-30B MillHobart Handler 175Lincoln WeldandPower 225 AC/DC G-7 CV/CCAdd a Foot Pedal to a Harbor Freight Chicago Electric 165A DC TIG PapaLion's Gate Build
Reply:If my welding pictures are not showing up in my posts, you can view them at welding album
Reply:Originally Posted by MarkBall2Pause if it looks like it's going to burn through.
Reply:What I've noticed is when the puddle is red & flowing good, it tends to have a few little sparkles of yellow at the edges of the puddle.  I usually release the trigger for a few seconds at that point, then continue on while it's still hot & hasn't had much time to form a slag cover.  The weld is still red, but I can see the whole area is red, instead of just the puddle.If you wait too long, slag will form, then you need to wait for it to cool more (about 2 minutes) then clear the slag off before you start welding again.  I can usually see the red color pretty easy as I have a Auto Darkening hood & it lightens up instantly after breaking the arc.MarkI haven't always been a nurse........Craftsman 12"x36" LatheEnco G-30B MillHobart Handler 175Lincoln WeldandPower 225 AC/DC G-7 CV/CCAdd a Foot Pedal to a Harbor Freight Chicago Electric 165A DC TIG PapaLion's Gate Build
Reply:How does more voltage help if I am already burning through? Its counter intuitive to a beginner like me.
Reply:Fluxcore welding a slag process.  Drag the torch when using fluxcore.  Pushing can cause slag entrapment in the weld.   It is fine to use push with solid wire and gas.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:Originally Posted by wolfvFeatures include:"MIG" in the nameNo capability for shielding gasLive wire (strike arcs without pressing the trigger)No chart for wire speed or metal thickness