frustrated by cast aluminum - MIG.
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  1. #1
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    frustrated by cast aluminum - MIG.

    First off, I'm an amateur. About as amateur as you can get. I'm a "gearhead" and I weld in my garage for personal projects on cars (and toys) I work on. I'm passable on steel and bar stock aluminum, but I'm trying to weld a cast intake manifold that is giving me fits. I'm new to trying to MIG cast aluminum.

    My setup is:

    a. Lincoln 180 mig - quick specs-

    Input Power 208/230/1/60, Rated Output 208: 130A/17V/30% 230: 130A/20V/30%, Input Current 20A, Output Range 30-180 Amps DC, Solid Wire Size Range .025 - .035 in. (0.6 - 0.9 mm), Cored Wire Size Range .030 - .045 in. (0.8 - 1.2 mm), Wire Feed Speed Range 50-500 ipm WFS(1.3-12.7 m/min)

    b. Spool gun

    c. 100% Argon.

    The "victim": 1994 Chevy LT1 intake manifold. Looks to be sand cast aluminum:

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    I'm altering it to bolt on to a standard SBC. It's been done many times before so I'm not re-inventing the wheel here.

    I've tried varying power settings, feed rates, stick out, travel speeds, gas flow rates and preheating the cast piece. The same result every time:makes blobs on the surface and cracks right off with a firm tap. Nothing ever resembles what would be called a bead. Just little turd balls all over the weld area. When it does look to have maybe stuck, I grind it down and the area looks like the surface of a golf ball (little pits or depressions):

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    So I assume that (somehow) I've still got contamination in the cast causing porosity or gas blowing it's way up through the weld.

    I've tried 5356 and 4043 (both .9 mm). I've baked the intake for 4 hours at 450F. I've cleaned it multiple times with bothwith lacquer thinner and acetone. I've hit it with the flap wheel and stainless wire brushes over and over.

    Every time, same result: balled up on the surface and no penetration to speak of. Tap it with a hammer and it cracks right off. Nothing even looks like a bead. 4043 will "somewhat" stick but still balls up and knocks off easily. 5356 just "sparkles" and rolls off when welding, it just blows right off the surface leaving black burn marks and a "mottled" finish where it blows off. Kind of like it melted and then gas from behind had blown it's way up and through the weld puddle and parent material. Well, if it would even form a weld puddle that is. It looks like no puddle forms in the base material at all.

    Ground clamp is always within a few inches of the work area and on shiny aluminum.

    No matter what I try, I just cannot get it to weld. I'm stumped on what I'm doing wrong here.

    I'm about to try the "vinegar trick"to check for magnesium, but I highly doubt it's anything besides cast aluminum (or an alloy) as it's an old intake from a Chevrolet LT1 engine. I can't see GM going more "exotic" than aluminum on the materials and it looks every inch to be a sand casting.

    I don't have access to a TIG, just my MIG.

    One thing I do notice is that the gun tip and shield get a heavy white coating on them when I try to weld. I know it's not corrosion, I hit it with the flap wheel or SS brush seconds before I hit it with the Lincoln. Cold this indicate something in the alloy that is not "weldable" like a tin, zinc or something else to make the casting "cheaper" for GM to produce? I've actually seen these manifold welded/altered before, so it must be weldable somehow......

    Any ideas on what's going on here?

    Last edited by gr8twhite; 09-16-2019 at 04:44 PM.

  2. #2
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    Re: frustrated by cast aluminum - MIG.

    i'm far from a pro at aluminum, but i have heard that the flap wheel will push contaminants into the metal making it almost impossible to get a clean weld. cast also likes to be dirty pretty much permanently. if you got a stick welder though its just a manifold. it could be done with stick id imagine. i welded a cast housing i found for scrap with a stick welder. it wasn't as bad as some people claim it to be.

  3. #3
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    Re: frustrated by cast aluminum - MIG.

    Would dropping it in an ultrasonic cleaner be of any help? I don't have one big enough to get the whole manifold into it, but I can submerge the part that needs welding.

    I've already hit it with the pressure washer a couple times.....
    Last edited by gr8twhite; 09-16-2019 at 04:58 PM.

  4. #4
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    Re: frustrated by cast aluminum - MIG.

    Did you set up your machine on some clean aluminum to make sure it was running good before you started on the cast?
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  5. #5
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    Re: frustrated by cast aluminum - MIG.

    Is the polarity correct?
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  6. #6
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    Re: frustrated by cast aluminum - MIG.

    Quote Originally Posted by CAVEMANN View Post
    Is the polarity correct?
    Not only that, does the machine have the balls to actually get the transfer mode into pure spray? If it's not in pure spray with the spoolgun, it won't ever melt the base metal. It's too massive, IMO, for just 180A.
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  7. #7
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    Re: frustrated by cast aluminum - MIG.

    Sorry to say but as Oscar said and I will add to that. You are not going to have good results with that machine as you have just found out. Find someone with a TIG machine capable of at least 250amps.
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  8. #8
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    Re: frustrated by cast aluminum - MIG.

    Quote Originally Posted by CrookedRoads View Post
    Did you set up your machine on some clean aluminum to make sure it was running good before you started on the cast?
    Yep

    Quote Originally Posted by CAVEMANN View Post
    Is the polarity correct?
    Yep

    Quote Originally Posted by Oscar View Post
    Not only that, does the machine have the balls to actually get the transfer mode into pure spray? If it's not in pure spray with the spoolgun, it won't ever melt the base metal. It's too massive, IMO, for just 180A.
    Quote Originally Posted by TJS View Post
    Sorry to say but as Oscar said and I will add to that. You are not going to have good results with that machine as you have just found out. Find someone with a TIG machine capable of at least 250amps.
    This is what I was thinking: not enough juice...

  9. #9
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    Re: frustrated by cast aluminum - MIG.

    Are you certain that's straight argon? Looks like you have gas issues to me. I would use a carbide Burr for cleaning and an oxy fuel torch to boil out some of the crap. The preheat will definitely help as well.
    Miller xmt304, Miller S22 p12, Miier Maxstar SD, Miller 252 w 30A, Miller super32p12, Lincoln Ranger 9, Thermal Arc 181I with spoolgun, Hypertherm 10000 ,Smith torches. Esab 161lts miniarc.

  10. #10
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    Re: frustrated by cast aluminum - MIG.

    Quote Originally Posted by M J D View Post
    Are you certain that's straight argon? Looks like you have gas issues to me. I would use a carbide Burr for cleaning and an oxy fuel torch to boil out some of the crap. The preheat will definitely help as well.
    Yep. Pure Ar. I have a bottle just for Al.

    Chipped it all off (almost 0 penetration) and dropped it all in the ultrasonic for now.

    Tomorrow I’ll try to burn it off again and give it another go with some pre-heat. If that doesn’t work, I’ll have to find a local shop that can tig I guess....

  11. #11
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    Re: frustrated by cast aluminum - MIG.

    Are you in spray mode? As I recall my 180c would spray at low wire speed and max voltage and relatively long ..1 inch stick out. Are you pushing the gun?

    Very nice when it sprayed.

    It ran really nice "looking" beads in 1/4 inch laps.
    https://weldingweb.com/showthread.ph...g100-spool-gun
    Last edited by tapwelder; 09-17-2019 at 04:59 AM.

  12. #12
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    Re: frustrated by cast aluminum - MIG.

    You said about baking it at 450F, but is it at this temperature when you're welding? It definitely will work better with a good pre-heat.

  13. #13
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    Re: frustrated by cast aluminum - MIG.

    Quote Originally Posted by Munkul View Post
    You said about baking it at 450F, but is it at this temperature when you're welding? It definitely will work better with a good pre-heat.
    Probably closer to 200F or so once out of the oven and bolted intk the jig. Jig is too long to fit in oven.

  14. #14
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    Re: frustrated by cast aluminum - MIG.

    Quote Originally Posted by tapwelder View Post
    Are you in spray mode? As I recall my 180c would spray at low wire speed and max voltage and relatively long ..1 inch stick out. Are you pushing the gun?

    Very nice when it sprayed.

    It ran really nice "looking" beads in 1/4 inch laps.
    https://weldingweb.com/showthread.ph...g100-spool-gun
    Yep, push only.

    Thing is, I can get nice welds on 1/8 to 1/4 6061 but the cast in this manifold just won’t puddle.

    Getting it to spray transfer is a skill I definitely need more work on. I can never seem to get to the “hum”, it’s mostly the “ripping paper” sound of short/arc or nothing at all....

  15. #15
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    Re: frustrated by cast aluminum - MIG.

    Quote Originally Posted by gr8twhite View Post
    Probably closer to 200F or so once out of the oven and bolted intk the jig. Jig is too long to fit in oven.
    stick the whole thing into your BBQ......and weld it in place in the BBQ....
    like you im just a hobbiest welder, the few times I tried to tig weld cast aluminum I had mixed results from ok to NFG...impurities kept coming to the surface and gave the result you have, some cast stuff is so full of junk its almost unweldable... plus that is a huge heat sink and aluminum loves to soak up heat..
    Last edited by Hobbytime; 09-17-2019 at 09:50 AM.

  16. #16
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    Re: frustrated by cast aluminum - MIG.

    Quote Originally Posted by gr8twhite View Post
    Thing is, I can get nice welds on 1/8 to 1/4 6061 but the cast in this manifold just won’t puddle.

    Getting it to spray transfer is a skill I definitely need more work on. I can never seem to get to the “hum”, it’s mostly the “ripping paper” sound of short/arc or nothing at all....
    If it doesn't hum with aluminium, then you don't have enough voltage. You'll need around 22v to spray 0.9mm alum wire, which from the spec of your machine, it simply cannot deliver at a decent amperage. I.e. if to get an welding arc voltage of 22v, the the wire speed will be have to be lowered - delivering around 100 amps of arc current. It's the physics of smaller power mig welders.

    You could make it spray by turning the WFS way low, and running a longer stickout, this allows a pre-heat of the wire which helps lower the spray transition voltage. But this doesn't equal amps, and AMPS are what you need for this job.

    In fact, looking at your machine spec, I'd be surprised if you're even able to deliver 100 amps of current to the workpiece at max voltage - way too little to make a puddle, and zero fusion. It explains perfectly why it's not working.

    A 250 amp machine, and a GOOD one at that, will be able to do it. Say a millermatic 252 or similar. A 252 is actually equivalent to many "300 amp" rated machines, because it's actually designed to WORK at 250 amps, with a top end of 300 amps. A lot of newer, cheaper machines, like your Lincoln 180, the 180 amps are in fact only the top end, and designed to WORK at wayy less.

    So, being able to spray transfer has nothing to do with welder skill, and everything to do with having a machine man enough for the job.
    Last edited by Munkul; 09-17-2019 at 10:48 AM.

  17. #17
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    Re: frustrated by cast aluminum - MIG.

    Alright. I'm going to admit defeat here.

    After trying multiple settings for WS, V and travel speed as well as cleaning, preheating, etc, it sees I can get it to transition back and forth between globular and spray. When it goes into spray, it gets lots of penetration to the point it will blow right through 1/4" thickness if I'm not careful.

    When it goes globular (or sometimes sounds like short circuit kicking in and out) it just lays ropey turds on the surface.

    Not to mention, I can't seem to end an arc without wasting a tip or having a big blob of molten Al bond to the tip end or the shield. It's either get it in spray/glob and roast a tip, or no penetration and no wasted tips.

    So, I admit defeat. I'm going to bolt it into the Jig and use the MIG to tack some other pieces in place and drop it off somewhere to have it tig-ed.

    It still does Aluminum, but it only seems to work for me on billet or bar stock.

    This piece of cast is just above the ability of both the welder and the weldor....
    Last edited by gr8twhite; 09-17-2019 at 04:01 PM.

  18. #18
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    Re: frustrated by cast aluminum - MIG.

    You will not accomplish what you need without TIG.

    Period.


    ...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.

  19. #19
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    Re: frustrated by cast aluminum - MIG.

    Zap is no diplomat, but he is right.
    An optimist is usually wrong, and when the unexpected happens is unprepared. A pessimist is usually right, when wrong, is delighted, and well prepared.

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