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Technical Welding cast aluminum intakes- setting up the machine

Discussion in 'The Hokey Ass Message Board' started by Roothawg, Jul 9, 2020.

  1. Roothawg
    Joined: Mar 14, 2001
    Posts: 20,236

    Roothawg
    Member

    So, the Caddy intake has a couple of spots that need to be welded up. I have n't done a lot of aluminum welding on the TIG machine.

    Basically, there are small holes where the alignment dowels have rubbed through the top. Maybe the size of a pencil eraser. My thoughts were weld it up, buy a new intake gasket to use for a guide to re-drill the alignment hole.

    I would like to practice on some other things first. What are some of the tricks that make welding cast aluminum easier?

    So, how would you set up the machine? Don't assume I know. I have an assortment of Tungsten and cup sizes.
    • I have no TIG gas lens. Do I need one?
    • Should I Preheat the casting with my Oxyacetylene setup?
    • Should I bead blast the area first?
    • When setting up the machine, how do you determine how much amperage for something that large?
    • What size tungsten should I start with?
    I am about half tempted to hire this out, which is something I never do.
    Should I tackle it? I can TIG weld mild steel, but aluminum is a black magic art to me.
     
  2. squirrel
    Joined: Sep 23, 2004
    Posts: 46,889

    squirrel
    Member

    find some other old cast aluminum to learn on! not your good intake

    If the dowel holes won't make a vacuum leak, I'd leave it alone.
     
  3. Jmountainjr
    Joined: Dec 29, 2006
    Posts: 1,222

    Jmountainjr
    ALLIANCE MEMBER

    My first question would be how big is your TIG machine? Aluminum takes a lot of heat to weld in order to prevent post weld cracking when welding most things bigger than sheetmetal. Aluminum castings are porous and it takes a lot of work to get soaked in oil out of the pores. Not much voodoo to it, but more details than steel.
     
    Last edited: Jul 9, 2020
  4. Roothawg
    Joined: Mar 14, 2001
    Posts: 20,236

    Roothawg
    Member

    It's a Miller 250 Synchrowave.

    I have seen them drilled all the way through on some intakes. I just think it looks dorky and I am putting a show polish on this one.
     

  5. Jmountainjr
    Joined: Dec 29, 2006
    Posts: 1,222

    Jmountainjr
    ALLIANCE MEMBER

    That should work. It's about the minimum, but you can do it with that if you decide to tackle the project. And Squirrel is right, as about always, to practice on a junk cast aluminum something. Most of my cast aluminum welding failures were due to not being able to get all of the contaminants out of the casting. I try to get it clean and then soak in vinegar. Before welding I heat it and if you still have oil seeping out it's back to more cleaning. Should you use a brake clean product insure that it's non chlorinated!
     
    Last edited: Jul 9, 2020
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  6. ekimneirbo
    Joined: Apr 29, 2017
    Posts: 1,459

    ekimneirbo
    Member
    from Brooks Ky

    What type of torch do you have.....air or water cooled? When you turn up the amps to practice aluminum welding, an air cooled torch tends to get pretty warm in your hand. Just welding holes should be fine, but the pre weld practice could be a little warm. Then you have to get the new holes in the right place. Would it be easier to just use slightly larger dowels?
     
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  7. alchemy
    Joined: Sep 27, 2002
    Posts: 15,870

    alchemy
    Member

    I think lacquer thinner works well to clean the oil out, and heating it up when welding won't give off toxic fumes.

    I usually blast the part clean, then use a stainless brush that I only use on aluminum to scrub the surface even cleaner. Don't contaminate with anything that's been used on steel.

    Then I give it to my little brother to weld, as he's much better at it than I am.
     
  8. Marty Strode
    Joined: Apr 28, 2011
    Posts: 5,157

    Marty Strode
    Member

    You don't need a gas lens, some pre-heat will help. I try not to glass bead aluminum before welding, as it contaminates the area, with imbedded glass. It helps to pass a propane torch over the area to be welded. If it leaches some black residue to the surface, hit it with a clean wire brush. Repeat the process until the area is clean. 3/32 tungsten, flush with the cup, to avoid dipping the tungsten. I would start in the upper-mid range of the machine, you can always turn it up. I would use 3/32 or larger 4043 rod. You want a ball on the end of the tungsten. With the machine with argon on and ready to weld, switch to DC reverse polarity, extend the tungsten about 3/16 out of the cup, and strike an arc on a steel surface, and gently step on the pedal, until the tungsten starts to melt, and stop. You will have a uniform ball on the end, switch back to AC HF. You should practice on some scrap, before hand.
     
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  9. Moriarity
    Joined: Apr 11, 2001
    Posts: 19,241

    Moriarity
    SUPER MODERATOR
    Staff Member

    one thing to note also, is the weld will polish a different "color" than the welded area because of the filler rod....
     
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  10. woodiewagon46
    Joined: Mar 14, 2013
    Posts: 1,713

    woodiewagon46
    Member
    from New York

    Marty beat me to it, everything he recommends is spot on. I'm glad he brought up the glass beading contamination. We had an issue welding up aluminum pipe and it drove us nuts. Turns out all the joints were glass beaded. The only thing I would do different is to use a piece of scrap copper to form the ball.
     
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  11. Marty Strode
    Joined: Apr 28, 2011
    Posts: 5,157

    Marty Strode
    Member

    Woodie, do you remember all the colors that lit up, once you struck the arc ? Alchemy's recommendation of the stainless brush is a good one, after blasting.
     
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  12. blowby
    Joined: Dec 27, 2012
    Posts: 6,877

    blowby
    Member
    from Nicasio Ca

    How much gas? Argon mix ok?
     
  13. woodiewagon46
    Joined: Mar 14, 2013
    Posts: 1,713

    woodiewagon46
    Member
    from New York

    Oh, one other thing, I prefer pure tungsten (green tip) or 2% seriated (orange tip) for aluminum. The pure tungsten will hold the ball longer, provided you don't "dip it". If you do touch the ball to your aluminum, stop and reball it. Sometimes if your running very hot it can ball itself, but don't try to get away with it. It will just contaminate your work.
     
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  14. SEAAIRE354
    Joined: Sep 7, 2015
    Posts: 191

    SEAAIRE354
    Member

    I also agree with everything Marty said. And straight argon no mix unless it’s helium. I use 75 argon 25 helium with my Millermatic 250 on heavy stuff as it produces a little more heat but there should be no problems on that intake as far as output from that machine. Also the brake clean with NO chlorine is great advice but personally I gave up on using any of it along time ago. Not worth the risk. I got a good hit of it once and luckily had no lung damage. Stainless brush only for aluminum for me. And by all means squirrel said it best. Practice first on some sacrificial casting first


    Sent from my iPad using The H.A.M.B. mobile app
     
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  15. SEAAIRE354
    Joined: Sep 7, 2015
    Posts: 191

    SEAAIRE354
    Member

    Just realized I wrote Millermatic 250. I meant syncrowave 250. Didn’t mean to confuse anyone.


    Sent from my iPad using The H.A.M.B. mobile app
     
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  16. Lots of excellent tips in the above postings. The only thing I was going to add, is you can find cast aluminum at the scrap yard and the auto wrecker. I always practice on sacrificial stuff before attempting the real repair.
    Among the many excellent youtube sites on welding, the one I go to most often, is called called weldingtips and tricks. He has a lot of excellent tips for aluminum welding.
    I am using a Syncrowave 250, and I love it for TIG welding.
    Bob
     
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  17. 1-SHOT
    Joined: Sep 23, 2014
    Posts: 1,919

    1-SHOT
    ALLIANCE MEMBER

    Marty I have been using a newer aluminum alloy 4943 it seems to wet out better than 4043 . It produces a really nice weld and flows good.
    Jody on welding tips and tricks Has good advice and talks in terms you can understand and has really good Arc Shots. Thats where I picked on 4943 filler. Frank
     
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  18. ottoman
    Joined: May 4, 2008
    Posts: 288

    ottoman
    Member
    from Wisconsin

    Just read up on 4943 and ordered a pound to try out... sounds promising
     
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  19. flatheadgary
    Joined: Jul 17, 2007
    Posts: 818

    flatheadgary
    Member
    from boron,ca

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  20. Budget36
    Joined: Nov 29, 2014
    Posts: 4,284

    Budget36
    Member

    I've done similar, but here's how I did it.
    I bored the hole to a standard size, not worry about being centered, etc. Then knocked in an Al rod. I would watch the other side of the hole and stop the rod before it went all the way through.

    Then cut off the rod flush with the top.

    Then with a punch tap the rod down so I would have a "crater" to weld and fill on both sides.

    Weld and fill it in.

    Is anyone still with me?

    Okay, then not having real machine shop equipment I'd use the flap disc and lots of WD 40 to get it close, then my belt sander to "plane it".

    I'm backwoods I guess.
     
  21. Marty Strode
    Joined: Apr 28, 2011
    Posts: 5,157

    Marty Strode
    Member

    Frank, I have been tig welding aluminum for 51 years ! But an old dog can learn new tricks. Thank You.
     
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  22. Torana68
    Joined: Jan 28, 2008
    Posts: 1,189

    Torana68
    ALLIANCE MEMBER
    from Australia

    Nice round holes?turn up some aluminium so it is a tight fit , taper the top of the rod, weld around the taper. Much less heat, hopefully no distortion. Stainless wire brush everything first.
     
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  23. Rex_A_Lott
    Joined: Feb 5, 2007
    Posts: 1,018

    Rex_A_Lott
    ALLIANCE MEMBER

    You've gotten some good advice. The old man said get it clean enough to eat off of,the clean it some more. He always used isopropyl alcohol, an I've followed suit. Always worked for us.
    When you start to weld, if it turns black, stop. Clean it some more. If you dip the tungsten, stop. Clean it up. Grind out all the contamination with a carbide burr in a die grinder. Before you start back, break about 1/4 of the tungsten off and redo the ball.
    I'm no expert, but I have made about every rookie mistake there is at one time or another.
    Good luck.
     
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  24. Amazing thread
     
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  25. Phil1934
    Joined: Jun 24, 2001
    Posts: 2,715

    Phil1934
    Member

    I've done some aluminum welding where I would get a white corrosion after (due to different alloys?)so consider just tapping for aluminum pipe plug and grinding it flush. Also option if you try welding and it doesn't work right.
     
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  26. ronzmtrwrx
    Joined: Sep 9, 2008
    Posts: 497

    ronzmtrwrx
    Member

    Straight Argon only. No mixed gas for aluminum. I use the purple, lanthanated tungsten.
     
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  27. dirt t
    Joined: Mar 20, 2007
    Posts: 4,672

    dirt t
    ALLIANCE MEMBER
    from Kingman,AZ
    1. HAMB Old Farts' Club

    Also as a rule of thumb, 1 amp per thousand of thickness.
     
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  28. indyjps
    Joined: Feb 21, 2007
    Posts: 3,935

    indyjps
    Member

    Can you bore out the area and press fit an aluminum plug? If anything 2 tacks locks it in.

    Pretty sure thats what Budget 36 is also describing.

    If you practice on a spare cast aluminum piece, no guarantee the manifold will be the same alloy or react the same way under the torch. Its dicey.
     
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  29. Roothawg
    Joined: Mar 14, 2001
    Posts: 20,236

    Roothawg
    Member

    You guys rule. Seriously.
     
  30. SEAAIRE354
    Joined: Sep 7, 2015
    Posts: 191

    SEAAIRE354
    Member

    Roothawg I almost forgot,on your syncrowave as well as most tig machines you have the AC balance controls which will control the penetration or cleaning affect of the arc and can be beneficial.


    Sent from my iPhone using H.A.M.B.
     
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