big tig alum job (for me)

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Got an order from a local fisherman (shell) for an aluminum culling board and "A" frame.I asked a question or two about grades of aulm. earlier.I'll try to get a picture of one on a boat for all of you that never saw one.All is 6061 except the big sheet for the work surface which is 5086.The reason is that the sheet of 3/16" 5086 (true marine grade) was only @$15 more than the sheet of 6061, but the pipe and other profiles were 3 to 4 times more expencive in 5086.I think that 6061 would be fine as all of it is not in tha water...unless it sunk...when there are bigger problemsspecks:2x2x1/4 angle1/4 x 6 for the carrying edges1 1/2" sch 40 pipe cut in half for the ends of the board.a frame:1 1/2" sch 80going to put 3/4" sch 40 on the top edge of the 1/4" x 6" as you rub against it as you lean over to cull the bay scollops.pic time:took some quick ones before i left....so they are messy. this is the board, and some of my sh!tIgnore the 30A it will get another post. I tigged everything that i will post here....although some might look like a spoolgun bead Attached ImagesG
Reply:Some of the beadsinverterarctime 3/32" pointed at @35 deg. (included)8 gas lense20 CFH, argon3/32 filler 4043 and 5356 200A peak 60A background 1.2 seconds per pulse70% EN130 (ish) Hertz7 secs postflowdid most of this with the 4T function and a momentary button as i didnt want to lug the pedal all over the place.had a lot of black speckles on the first few welds (not pictured yet) as the flow was set at 10cfh then when i got that sorted the bottle run out so i got the spots again.20cfh and a new tank fixed all that. Attached ImagesG
Reply:Looks good from here...What's with the coin?...zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:The material is all 1/4"?  Was there any bevel or gap on the first weld?  Im asking because it looks a bit cold from here, second one looks spot on for an inverter.Have we all gone mad?
Reply:A frame, with the old black steel one behind itVery hard to get in the crotch of some of these welds.got so much stickout i hadnt enough gas coverage.....black dots again.i turned this a couple of times, but most was done in vertical and up to 12 o clock. Attached ImagesG
Reply:Originally Posted by zapsterLooks good from here...What's with the coin?...zap!
Reply:Originally Posted by sn0border88The material is all 1/4"?  Was there any bevel or gap on the first weld?  Im asking because it looks a bit cold from here, second one looks spot on for an inverter.
Reply:ok last for nowthe a frame goes on the culling board and then the "donkey" ( in this pic) hangs below.I think i'll bolt the new alum frame for this to the board so it can be removed separately. Attached ImagesG
Reply:Looks good..The end of the weld where the wishbone is there is a hole...kinda..Just fill that in and all is well...Those dimples are where cracks start.....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Originally Posted by zapsterLooks good..The end of the weld where the wishbone is there is a hole...kinda..Just fill that in and all is well...Those dimples are where cracks start.....zap!
Reply:Originally Posted by gordfraserany sugestions how to weld the crotch...i couldnt reach in far enough.
Reply:Originally Posted by zapsterUse a gas lenz and put your tungestion out about 1/4" from the cup and turn the gas up to 15..20..You'll get in there.....zap!
Reply:Originally Posted by gordfraseri had it a lot further than 1/4"to reach i had it @ 1". maybee more. with a no8 lense.i tried it later with a normal no6 collet which got me closer with less stickout (5/8" to 3/4" from a bad memory), but the tung was still deep blue when i stoppedit is tough to know now as there is black dots all over and i cant get in to clean it up so whatever i try will always have contamination.
Reply:Might help if you put a piece of scrap on the opposite side of the joint that your putting the torch in from.  Tap your pedal and let some of the postflow gas collect in there, and then weld.  Its worked for me on a few special occasions I had to use extreme stickout.Have we all gone mad?
Reply:first thing i reached for...the grinder,but it wouldnt reach.i'll find something....as it is anoying me.even if i have to file it outthanksG
Reply:Everything is looking quite cold, I'd ditch the pulse, pre heat, and go with a 1/8" tungsten. Your really need a watercooler and more than 200A, but I understand you gotta work with what you have sometimes.
Reply:Originally Posted by PassengerEverything is looking quite cold, I'd ditch the pulse, pre heat, and go with a 1/8" tungsten. Your really need a watercooler and more than 200A, but I understand you gotta work with what you have sometimes.
Reply:A butt joint will take less heat than a fillet..After awhile you will get the hang of it..You're doing just fine now.....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Yes a fillet will usually take more heat to weld than a butt joint.Post #5, Pic #2 shows an ending crater.  Ending crater = crack initiation place    Fill it in and make sure none of the welds are concave or dipped or sunken.Post #5, Pic #4 shows the weld bead ending on a 'corner'.  Try to warp the starts and stops 'around' a corner to minimize chances of crack initiation.  (Yes I know a fish-mouthed joint isn't -really- going to have a corner, or at least it shouldn't, but the way he cut the pipe and joined it for the A-frame triangulation he sort of has a 'corner' going on.)A T-joint fillet can run with a little less gas flow than an 'open' joint configuration (outside corner, pipe outside weld, etc) because the base material helps keep the blanket of gas in the area a bit better.  The 'open' joints don't have that benefit, so you -may- have to increase the gas flow a bit.  Good tip from snoborder88 about putting something behind/around the pipe to sort of trap the blanket of shielding gas in the area.Also, isn't the rule-of-thumb to use about 1 second of post-flow per ~10 amps of current?  At 200 amps on an air-cooled torch, that would be ~20 seconds post-flow.  Much more post-flow than your 5-7 seconds you said you had!  That could be why your tungsten turned colors.  The best laid schemes ... Gang oft agley ...
Reply:Thanks for the feedback.But..... Originally Posted by MoonRiseAlso, isn't the rule-of-thumb to use about 1 second of post-flow per ~10 amps of current?  At 200 amps on an air-cooled torch, that would be ~20 seconds post-flow.  Much more post-flow than your 5-7 seconds you said you had!  That could be why your tungsten turned colors.
Reply:Gord,Coming along.Your last comment did concern me a bit. (put it up to 8.  Screw the expence(sp))You'll find that dealing with aluminum, it's the "little things" that make all the difference in the world between "just getting it done" and a professional job.Rule of thumb IS 1 sec postflow/10 A welding current.  I agree that you may be able to get by with a "little" less but 8 sec seems awfully short for those amps, particularly with an 1/8" tungsten.  Don't be penny wise and dollar foolish.Anytime you increase your stickout, you need to increase your flow.What kind of flowmeter are you using that measures in tenth's of a cubic foot?  My Smith (good one's I might add) won't come close.  I guess I could guess at the percent of the ball.Good suggestions so far.PS.  Don't know if you checked, but had a couple suggestions on your "spoolgun thread".Overall, this looks like a nice project.Last edited by SundownIII; 07-30-2009 at 01:05 PM.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:Sumdown111 Originally Posted by gordfraserThanks for the feedback.But.....it was 7.4sec when i looked.the tung was not red when the post flow stopped.I set the post flow by the tungsten not by a specific time.i put it up to 8 to be certain...screw the extra expence
Reply:In your post #12 above, you said "but the tung was still deep blue when i stopped".That indicates that the tungsten oxidized somewhere during the welding process.  That means that air/oxygen got near or onto the tungsten while it was hot, ie inadequate shielding gas somehow.  The somehow could be a gas leak letting air into the argon flow (hose or fitting leak doing a venturi and sucking air into the line/flow), or inadequate preflow or postflow, or shielding gas turbulence or other flow disturbance, or excessive stickout.The tungsten doesn't have to be red-hot to oxidize, it just has to be pretty hot (but that could look totally not red-hot).  Red-hot is the other side of 1000F+, the tungsten could still oxidize in the high hundreds of degrees.If the tungsten turned any color other than plain white/silver/grey, then it oxidized.  Oh, and remember that aluminum is not a 1:1 replacement for steel in its strength or material properties.  Depending on how much stress was on the original steel A-frame and its base tabs, you -may- have to up-size the aluminum dimensions to equal the original steel structure's strength.  YMMV.Interesting project.    When will the scallops be ready?     Mmmmmm, pan-seared scallops.  Yum.    The best laid schemes ... Gang oft agley ...
Reply:Out of curiosity wouldn't this thing be safer as stainless steel than aluminum ?I.B.E.W Electrician and Damn Proud of It !!!! .Virtus Junxit Mors Non Separabit http://www.shrinershospitalsforchildren.org/
Reply:pretty cool. I start to learn tig on tuesday.25 years of age.Been welding since Feb 23rd 2009.LU1007 Millwright (A1)I agree with lots of the comments on here...    Especially, the stopping on the corners = potential to crack/tear..I also agree you need more post flow time.. I think it is something like 20-25 post flow recommended..
Reply:Originally Posted by MoonRiseIn your post #12 above, you said "but the tung was still deep blue when i stopped".If the tungsten turned any color other than plain white/silver/grey, then it oxidized.
Reply:this it the 8' long welds on the inside of the board ( it is turned on its side)Was going to spoolgun it, but after welding the back of the framing with it ithought id tig it.it was a 50/50 decision....i just enjoy tig better.can get about 3 to 4 feet before my glove starts smoking222Ano pulse109 Hrtz20% cleaning14 sec postmomentary button on repeat slope.hard to get picks with the flashnot much more to do Attached ImagesG
Reply:thought i was near done, then i remembered the 3/4" sch 40 pipe along the top to soften the edge.more smoke off the glove. Attached ImagesG
Reply:A foot pedal and pulse would be your best friends!
Reply:Originally Posted by smokeshowA foot pedal and pulse would be your best friends!
Reply:sorry, late update.here it is. there should be a small frame below to hold the donkey, but i took it off so it would sit nice.Re did the bad welds in the crotch of the "a" frame. cut the bad stuff out with a jigsaw (all i could find). i re welded it with the same lense and NOT excessive stick out. wasnt as hard as i remember, just cheated the torch angle a bit from both sides.The tung wasnt blue when i was done this time.Customer is happy = me happy Attached ImagesG
Reply:What do you know.the new 18 350A CK watercooled torch showed up, just as this was going out the door.torch is so much lghter than the 26 aircooled.a well i didnt have time to make the cooler yet so its not so bad. Think i have all the parts now apart from the aluminum to make the tank and enclosureDare i order another sheetG