Stick Welding Aluminum - My Experience

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This Thread describes my experience Stick Welding Aluminum.Why stick weld aluminum?If you are like me, there are times when it would be useful to be able repair aluminum with your arc welder – I’m talking simple things such as a holder for a garden hose, etc.  All for about $10!On the other hand, if you have the $$$ and the volume of work, go ahead and do the MIG-argon/spool thing or the AC-TIG thing... maybe even the oxygen/acetylene flux approach.Why this post?The posts that I could find on this subject seemed very weak on pictures of actual results.  There was little information on welding parameters, problems and solutions.  I deal with much of what was missing.Does it work?Yes – both terribly and rather well... details and pictures below.Cost?A pack of ten Hobart 1/8 inch aluminum 4043 stick electrodes was $12, on sale for $8.40 at the Tractor Supply Company store.  It seemed like a good time to try stick-welding aluminum!ResultsThe photo below shows the 8 fillet T welds I made using the Hobart aluminum 4043 electrodes.  Note the recommended amperage for the electrodes was 70 – 120 amps DC+ (Electrode positive). All the test pieces are 1/8 inch thick and formed from plates 6 inches long by 1.5 inches wide.The photo below shows the two different welders that I used to make the fillet welds.The photo below shows my first fillet welds (1 and 2) made using the inverter welder, DC+ at 80 amps.  I didn’t pre-clean the test pieces and they were welded at room temperature – no preheat.Pretty Crappy eh?  Each weld used up a full 13 inch long electrode.  By the way, the pebble-like texture of the welds came from multiple impacts from a small vibrating engraving tool that I was forced to use to get the hard, white slag off the welds.  Nothing else would touch it – although you can see several larger previous impacts from a slag hammer.  Even the engraving tool couldn’t get into some of the tight areas – and you can see the white slag lines.OK, the next step was to see if pre-cleaning (sand-paper scouring) and pre-heat to 300F would help me make better welds... as suggested in previous threads/posts.  Here are the photos as welded.Note the white, glassy or sometimes powdery slag.  Pre-heating to 300 degrees F caused the slag and the weld to widen considerably.Continued in next post...Rick V 1 Airco Heliwelder 3A/DDR3 CTC 70/90 amp Stick/Tig Inverters in Parallel1 Lincoln MIG PAK 151 Oxy-Acet
Reply:Here is the result with the slag removed – again multiple impacts from the vibrating engraving tool.Weld 3 (pre-cleaned) was much better than welds 1 and 2 that had no pre-cleaning.Weld 4, entire T preheated to 300 F, showed a much flatter/broader weld bead – but way too broad!  Yikes!  Pre-heat helped with weld fusion to the base metal but made the weld rather uncontrollable. Note: Again, each weld used up almost a full 13 inch long electrode.  (This is important later.)I should mention that the above welding required quite a short arc – almost maintaining contact with the plate.  I had to keep pushing the rod (gently) into the plate – else the arc would go out.  (Don’t push too hard... or you will stick the rod.)  If the arc does go out, you have to jam it in right away to re-ignite ... else you’ll have to stop and clean off the flux that melted over the tip of the rod.  (This process is worse than removing the 7018 sleeve.)   Also, it’s a real challenge to properly start the rod without sticking it or immediately after lighting... having the arc go out.What was next?It was time for a bigger welder with more amps and a higher open circuit voltage (OCR) to help maintain the arc.  Once again, I pre-cleaned the plates, using sand-paper to scour off the oxide layer in the weld area.  The photos below show the as-welded results of welding DC+ at 110 amps.I went too slow in weld 6 and blew a couple major holes!  Note: Slow here means real fast for steel!Important Tip:  I discovered how to rather easily remove that tenacious slag.  Instead of trying to remove it dry, I put the test pieces under hot running water and scrubbed at them with a tooth brush... the slag dissolved/scrubbed off – leaving a no-hammer/no pebble surface.   Amazing!Here are the photos with the slag removed.Welding with the bigger transformer welder was much easier than with smaller inverter welder; the arc was easier to maintain.Weld 5 was pretty good – my technique was the limitation here.  Once the arc gets going, you have to get going.  I travelled quite fast and discovered that I had burnt only1/2 a rod.  Remember I burnt an entire rod going slow at 80 amps on welds 1 through 4.I thought that I should be burning more than just 1/2 a rod.  In weld 6, I slowed down my travel speed.  I ended up using 2/3rds of a rod but... Yikes!  Look at the heat input!  It’s ‘Molten Metal City’.The bottoms just dropped out – twice! Not pleasant here on 1/8 inch material but... that kind of heat input hold great promise for welding thick aluminum.Learning... maybe it was time to turn down the amps somewhat.  By this time I was getting lazy too, so I decided no more pre-cleaning, go with 100 amps and watch your travel speed.Here are the photos of welds 7 and 8 – as welded (good views of that icky-looking slag.)Continued in next post...Rick V 1 Airco Heliwelder 3A/DDR3 CTC 70/90 amp Stick/Tig Inverters in Parallel1 Lincoln MIG PAK 151 Oxy-Acet
Reply:Here are welds 7 and 8 with the slag removed (hot-water- washed/scrubbed off).Weld 7 was made with two left-over pieces of previous 4043 electrodes and I travelled fast.  You can see where I changed rods and then missed the root of the weld, laying the bead on the horizontal plate.Weld 8 was made using one fresh electrode but I had some issues with consistency of arc length and speed of travel.ConclusionI think arc welding aluminum can be done quite handily.  For the electrode and 1/8th thick material used here, I obtained good results at ~100 to 110 amps and fast travel speed.  The arc is more forceful at 110 amps and that made maintaining the arc quite a bit easier – you just have to compensate for the added heat input by travelling rather quickly.Note too that I have a consistency problem that repeated practice will resolve.  I’m sure a few more test pieces will produce some pretty consistent results.Still, if I can do this – make solid arc welds in aluminum, chances are real good that you can too!Just add $10 worth of aluminum rods to your DC arc welder, follow the guidance here and aluminum may come into the scope of your capability.Thanks for reading...Rick V 1 Airco Heliwelder 3A/DDR3 CTC 70/90 amp Stick/Tig Inverters in Parallel1 Lincoln MIG PAK 151 Oxy-Acet
Reply:I wish you would....now you know....ah, nevermind.My name's not Jim....
Reply:That was a great read, thanks for taking the time to post all the details!Hobart LX235Victor 250 Oxy-Acetylene Rig (welding and cutting)Bobcat 773F-350, 1999, 4x4, 16' 10K# trailerOutdoor Wood Burner - 10 cords/year
Reply:Thanks for posting.I use the rods for a  maintenance contract I have..  It is much easier than dragging a spool gun and gas tank, especially for small non cosmetic repairs.  I also, posted some results a while back.  I found it lays a decent bead if you maintain contact between flux and base metal.  You can feel the contact, it helps with rate of travel, too.  I don't usually pre heat on 1/8",  Al heat itself and maintains heat well after you strike an arc. I have tried it on various machines.  Maxstar 150 wouldn't run it well and thermal arc 80 ran it but inconsitently. Zena wouldn't run it at all won't maintain an arc.  Esab 150 runs the rod quite well.
Reply:Yeah, aluminum is usually a 'hot-n-fast' weld no matter what process you use.I thank you for doing the experiment and putting yourself 'out there' for all to see.Keeping in mind the previous sentence, your welds there do look kind of, well, no other way to say this except ...bad.Although a little bit of weld #7 looks kind of passable.Next, you definately don't want to use an impact device on aluminum.  All those pits/dimples generally look likecrap and also weaken the material to high heaven.  Hot water and the bristle brush is the way to go there for removing the slag.Next, 300F is waaaay to hot to preheat aluminum.  The usual temp limits are 200F MAX preheat temp if required at all and a MAX 250F inter-pass temp limit as well.Next, regarding cleaning.  Usually you do NOT want to use sandpaper to clean aluminum before welding.  A common abrasive for sandpaper is aluminum oxide, and aluminum oxide is what you are usually trying to remove from the workpiece(s) before you weld them!  Granted stick welding is usually a little bit more tolerant of 'crud' than say GTAW , but still you -always- get better welding results when you clean the metal properly before welding.  A common/decent way to clean aluminum is using a DEDICATED stainless steel wire brush or carbide die grinder burr or such AFTER cleaning the metal first with an appropriate solvent to remove grease/oil/etc.  Acetone is a 'standard' solvent to use for such purpose.Safety Note : Solvents may (usually are) be flammable, may have other health hazards, and may have other safety hazards.  Check the label/MSDS first and -KNOW- what you are doing!!!!!!  Be Safe!!!!A 'standard' cleaning method would be to clean/degrease first, then grind or wire-brush, and then clean/degrease again.  Then you weld after that.YMMV, etc, etc.Again, thanks for the experiment and examples.  The best laid schemes ... Gang oft agley ...
Reply:Originally Posted by tapwelderI found it lays a decent bead if you maintain contact between flux and base metal.  You can feel the contact, it helps with rate of travel, too.
Reply:Moving Up in Thickness – From 1/8 inch to 1/4 inchThe first test pieces (9 and 10) were 6 inches long x 1.5 inch wide x 1/ 4 inch thick.  All test pieces were pre-cleaned using 800 grit wet paper.  All welds were made with my larger transformer welder.Clearly, Weld 9 didn’t have enough heat input: a bad combination of marginal amps (110) and too fast a speed of travel – used only 1/2 a 13 inch rod over 5 inches of weld bead.Weld 10 was run at higher amps (120) and a slower rate of travel (only 2/3rds a 13 inch rod over 5 inches)... it was better but still looked a mite cold.I tried again... with some changes in travel speed and amperage.Weld 11 used the higher amps (120) and I slowed my travel speed to use up the entire 13 rod over 5 inches of weld bead.  I obtained a broader bead but still an ugly weld.For Weld 12, I raised the amperage to 140 amps and my travel speed used the entire rod across the weld.  The weld is looking better – but still nothing to be really happy about.The problems were:I had no consistency because everything happens so fast (5 to 10 times as fast as welding steel) ,I felt I was welding ‘cold’ but if I opened a short arc gap, I risked the arc going out,I had inadequate melting/penetration because I have to drag the rod else loose the arc.I wanted to get a smoother bead with more controlled heat input.  In an earlier posting, I had related problems welding steel with 6013; there I changed from welding in the conventional T-configuration to a Y-configuration and tilting the weld uphill at about 45 degrees.  I got more heat input and better control.   I tried the ‘trick’ here... as shown below.It worked!  The weld was easier to control and I felt I had way more time (50+% more) to work with the weld before the rod was all gone.  Here are the results welding with a tilted Y-configuration.Weld 13 looked pretty fair over most of its length... certainly in the ball park of getting a good weld.Weld 14 was pre-heated from 60 to 180 degrees F before welding and obviously using 120 amps was way too much heat input!  I noted so fluid a weld puddle that I was losing control when welding this.It’s amazing the effect that preheating has on aluminum.  180 F is not that hot, still well below the temperature of boiling water (212 F).  Note: This effect comes in real handy later on 1/2 inch thick aluminum.To be continued in the next post...Rick V 1 Airco Heliwelder 3A/DDR3 CTC 70/90 amp Stick/Tig Inverters in Parallel1 Lincoln MIG PAK 151 Oxy-Acet
Reply:Moving Up in Thickness Again – From 1/4 inch to 1/2 inchFor the challenge of 1/2 inch thick aluminum, I was going to need to ‘pull out all the stops’ to get enough heat into the test piece (5 inches long x 3 inches wide x 1/2 inch thick).At the same time, I didn’t want to raise the amps past 120 because:that’s the maximum suggested rating for the rod from the manufacturer, andmany folks use a AC/DC buzz-box limited to ~125 amps.  e.g. Lincoln tombstoneHere was the setup I used – tilted Y-configuration.Here are the results, without (15) and with (16) preheating to 180 degrees F.Weld 15 looked cold – as expected but take a look at weld 16!  MAGNIFICIENT!So where does this bring us?Stick welding aluminum is viable and good results can be obtained BUT you must tune into the key parameters of weld setup/configuration, amps, travel speed and preheat.That’s all she wrote... hope you enjoyed it.Rick V 1 Airco Heliwelder 3A/DDR3 CTC 70/90 amp Stick/Tig Inverters in Parallel1 Lincoln MIG PAK 151 Oxy-Acet
Reply:Thanks for showing us your experiment.I'll keep using ac tig, spool gun or push-pull for my aluminum jobs.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:16 is still looking way cold to me.QamuIs Heg qaq law' lorvIs yInqaq puS
Reply:Have you thought  of using smaller diameter electrodes on the 1/8" base metal?
Reply:Hi Rick,I tried the stuff a long time ago, watched the flux run off the rod everywhere... That was enough for me.There's been an awful lot of dock plates welded with the stuff through the years though.Matt
Reply:Originally Posted by 7A749Did you do any stress tests on that last one?  Just wondered on the kind of penetration you got with it.
Reply:Rick,Post #16, the side view pics of the fillet welds on 1/2 inch plate (weld 16, profile view).  It looks like -NO- penetration into the plate!I fully understand and applaud you for trying these experiments and posting the results (good or bad) for all to see.But unless you were blasting something like 300-500 amps through a BIG rod, 1/2 inch plate pretty much calls for at least -some- bevel prep on the edges to enable the arc and the deposited filler to fuse into the joint and to make multiple passes to fill everything in.  And that is on steel!Yes, I know and understand that welding aluminum is usually more difficult than welding on steel.  Because of the heat conductivity of aluminum being so high, you need some pretty high power/amps to get the welding heat into the metal.  Because the melting point of aluminum is less than half the melting point of steel, you then have the complication of the aluminum melting easily once you -do- get the heat into it.  So those sort of competing factors lead to aluminum welding being hot (to get the heat into the metal as it conducts the heat away quickly) and fast (so you don't have all that arc or flame heat melt right through your workpiece).  No all that easy of a dance.    The best laid schemes ... Gang oft agley ...
Reply:I had another go at duplicating Weld 16.  Here is Weld 21 made with the same parameters: precleaned, preheated to 180 degrees F, 120 amps using vertical up in the tilted-Y configuration.To me, they looked pretty much the same.... (what did I know ) Originally Posted by MoonRiseRick, ... 1/2 inch plate pretty much calls for at least -some- bevel prep on the edges to enable the arc and the deposited filler to fuse into the joint and to make multiple passes to fill everything in.  And that is on steel!
Reply:Have you tried welding DC Negative yet?  Maybe that might change something for the better...or the worse?Either way, this is a good thread.
Reply:Originally Posted by confabHave you tried welding DC Negative yet?  Maybe that might change something for the better...or the worse?  Either way, this is a good thread.
Reply:Rick,OK, it looks like you got at least -some- penetration with the sectioned welds.  Unfortunately, you also got a lot of porosity.    And also the penetration just -barely- went into the corner of the fillet.ps, try polishing the sections a bit before etching them.  Doing so makes the view a little 'cleaner' as the saw lines don't obscure things as much that way.Hey, this has all been done on your time and your dime, so for all that I say thanks.  Aluminum ain't all that easy, eh?    The best laid schemes ... Gang oft agley ...
Reply:DC Negative? Originally Posted by confabHave you tried welding DC Negative yet?  Maybe that might change something for the better...or the worse?
Reply:Hey Rick V, thanks for taking the time and patients for showing all of us just how tricky and hard for somebody to just try stickin Aluminum.  Thanks for all who chimed in with all their comments as well, maybe I'll go use my Aluminum rods I bought a year ago and still in the box....LOL!!!
Reply:I had no idea that AC would make that much of a mess! Thanks for your time on a subject that isn't discussed often enough.
Reply:Hey, thanks for taking the time to try DCEN!
Reply:I had another look at the last photo showing penetration on the 1/4 inch thick aluminum - Weld 22.  I had ground it down on a belt sander and while you can see the weld/parent metal transition, it's not really clear.  I decided to do an acid etch of Weld 22 (DC+) and Weld 23 (DC-), both welded at 80 amps with 180 degree F preheat.Prior to EtchingI cut the weld section with a hand-powered hacksaw.  Then I sanded the face of the weld on a belt sander. Next I used wet-paper of fine 1000 grid to smooth the scratched surface.  Finally, I polished the weld face using a Dremel rotary tool with a buffer disk smeared with a waxy polishing compound.Note:  I'm not happy with how long it takes to polish the weld, so if you have a better idea, I listening.e.g. I've seen fellows who work with granite counter tops use quick change velco disks that slapped onto the face of a rubber-buffer disk mounted on a 4.5 inch angle grinder.  In just a few minutes, changing through say 3 disks, they would have that hard granite shinning so you could see you face in it.Acid EtchingI found I had to use a degreaser to remove the waxy residue left by the polishing compound... else the acid would pool in spots instead of spreading evenly over the metal.  For etching, muriatic acid (about 30% hydrocholic acid) is ok, though it should not be kept near your tools... unless you like rust.  This acid is too slow on steel (needs to be heated [nitric acid is way better] and I found it too fast on aluminum (needs to be diluted).I poured a little acid into the outer channel of plastic top from an aerosol spray can.  I poured a little water into the center cup.  For aluminum, I dipped the brush in the center-cup water and spread it over the weld area, then dipped the brush in the outer-channel acid and spread it over the weld.  I keep repeating this process with more of less acid depending on how the etching proceeds.  Etching starts slow then seems to go pretty fast... and you don't know if you went too far (everything looking dark grey and full of small holes)... until it is too late!  So, I take pictures as the etch proceeds, that way I can choose the best picture for posting.A word on the artist brush!  When I first did etching, I used a cheap 1$ set of paint brushes kids use for water-coloring.    The acid doesn't like the brush plastic-like fibers and glued them into a mush!  Go to the dollar store and pay say $2 for a set of cheap artist brushes that are made of more natural fibers... they don't glue up in the acid.Here's  the Before and After acid etching results for Weld 22 (DC+) and Weld 23 (DC-).Have a Great Day!Rick V 1 Airco Heliwelder 3A/DDR3 CTC 70/90 amp Stick/Tig Inverters in Parallel1 Lincoln MIG PAK 151 Oxy-AcetReturn to SteelAfter stick welding aluminum for about a week, yesterday I returned to stick welding steel... and there was quite a noticeable difference.With aluminum, the rod burned very fast and I really couldn`t see what was happening because a heavy white flux covered the weld area.  Because of these two factors, time and vision, the best that I could do was to focus on trying to maintain a constant short arc length and a consistent travel speed.  It was sort of like welding blind with little feedback.Yesterday, I made a few steel weld beads using 6011, 6013 and 7018.It was like welding in slow motion; it seemed that I had loads of time to adjust arc length, bead width, angle of stick, direction of travel and my speed of travel.  It seemed so easy, it made me wonder why I had trouble doing this just a few weeks earlier.Hey, I could see what I was doing!  6011 in particular showed a clear weld puddle while 6013 and 7018 were not too far behind.  I could push the weld puddle and the slag pool around... awesome.  Yikes, with aluminum, I could never see the weld puddle; it was just buried under white runny flux.Dealing with the challenges of stick welding aluminum has apparently improved my ability to stick weld steel... who`d of thought? Rick V 1 Airco Heliwelder 3A/DDR3 CTC 70/90 amp Stick/Tig Inverters in Parallel1 Lincoln MIG PAK 151 Oxy-Acet
Reply:Is the aluminum rod a whip rod? Did you try welding it without a whip motion?I'm a newbie welder, but this was the first question that came to mind that I don't think has been asked yet. This thread was very interesting to read, thanks for taking the time to make it.
Reply:Hi Taiden,Let me try to answer your questions.Is the aluminum rod a whip rod?The aluminum rod comes with no instructions on how to use it (whip or not) or how best to remove the residual flux/slag.(To remove the flux/slag, I found it best to use hot water and scrubbing with a fiber-bristle brush.)Did you try welding it without a whip motion?Yes, most all these welds were made 'without a whip motion'.As far as the whip motion goes, no whip appeared to work best... just keep moving steadily and don't look back.Frankly, you just don't have time to attempt anything fancy (whip) with the rod burning down so fast.Any whip I did was related to initially starting the arc or re-starting the arc if it had gone out.Example:  Once the arc starts, I may go back momentarily to fill in the arc stike - but that's it... as lingering even a tad too long just piles up a metal lump.Once I attained a stable/steady arc, I found it best to move out at a steady pace - totally focussed on maintaining a constant arc gap, keeping the arc centered between the sides of the T weld and preserving an unvarying travel speed.Rick V 1 Airco Heliwelder 3A/DDR3 CTC 70/90 amp Stick/Tig Inverters in Parallel1 Lincoln MIG PAK 151 Oxy-Acet
Reply:Cool. I was going to hazard a guess that no whip would be best in this situation, and I'm glad that's been confirmed.
Reply:Originally Posted by Rick VIt was like welding in slow motion; it seemed that I had loads of time to adjust arc length, bead width, angle of stick, direction of travel and my speed of travel.  It seemed so easy, it made me wonder why I had trouble doing this just a few weeks earlier.Hey, I could see what I was doing!  6011 in particular showed a clear weld puddle while 6013 and 7018 were not too far behind.  I could push the weld puddle and the slag pool around... awesome.  Yikes, with aluminum, I could never see the weld puddle; it was just buried under white runny flux.Dealing with the challenges of stick welding aluminum has apparently improved my ability to stick weld steel... who`d of thought?