Welding Aluminum any Pro's on here?

Discussion in 'Workshop Tips and Secrets / Tools' started by Armilite, Feb 9, 2019.

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  1. Feb 9, 2019 #1

    Armilite

    Armilite

    Armilite

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    Never Welded Aluminum before, got my New Combo Mig/Tig/Stick Welder a while back, still have to get the Spool Gun for doing Aluminum, but should be getting it soon. I want to add Material to the PTO Case for some Bosses for a Gear or Belt Drive like the 277 Case. I do plan to practic on a junk case before using a good one.

    1. I was thinking of making a Dam around the Area using some Clay, or would I be better just Welding in some chunks of Aluminum to fill in the area.

    2. Is it best to Heat part first in an Oven before Welding on it? What Temp if so?
     

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  2. Feb 9, 2019 #2

    MadRocketScientist

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  3. Feb 9, 2019 #3

    TFF

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    Not an expert but Years and years ago I worked at a machine shop that did weld repairs on aluminum cylinder heads. We pre heated with a bbq grill, shut it off, and welded on the grill. Depending on what the repair was, we would switch between stick and TIG. I'm pretty sure that would have been stick; don't remember what number Rod. Long time ago. Big thing is warping. Have to see on that. Reverse polarity puts a lot of heat in the part.
     
  4. Feb 9, 2019 #4

    lr27

    lr27

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    Wondering if that part is heat treated?
     
  5. Feb 9, 2019 #5

    wanttobuild

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    Boy that is a tuff nut to crack.
    I assume you want the red lines to be stiffened.
    It may sound crazy but I would fabricate new ones out of 7075.
    My next attempt would be JB weld.
    If you have to weld, cut out reinforcement pieces out of your favorite weldable alloy, route a bevel on the edges where it rests against the case and weld.
    I would lean toward fabbing a new one.
    Durafix rods are hard to beat, expensive, and will trap slag in a new York minute.
    Mig on a casting will pinhole.
    Torch (tungsten), will be hard to get in the holes.
    Get a sheet of 7075 and route it out. If you drink some Jack first it will steady your hand.
     
  6. Feb 9, 2019 #6

    Armilite

    Armilite

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    ================================================

    Thanks. Yes, that's a good idea to try. I wish that guy in your Video had turned the Part over to see the Inside. Harbor Freight sells a similar Type Rod that melts at a lower Temp than Aluminum, I think around 750F. I bought some of it a while back to try and fill in some Stripped Bolt Holes and Doctored 670 Case's, but stuck it on the shelf to try at a later date account I didn't have any of the Yellow Map Gas Cylinders it recomended using, and never got around to trying the stuff.

    This is another good video on using the Durafix Welding Rods. I like how they made a dam out of some Copper flat stock. I was thinking Clay would work to make a Small Dam or one of them Copper Welding Spoons.
    https://www.youtube.com/watch?v=2rH681CYDgw

    Only 1992-93-94 670 Cases can be converted to Ducati Dual Ignition. The 1995-99 670 Case's don't have Dual Pickup Slots and Crank Mag End is Shorter so Ducati Flywheel hits back of Case. The Nippon Denso CDI is better than Ducati, but only Single ignition. Skidoo/Rotax Doctored some 670 Case's by oblonging the Top (4) Pro8 Holes, to sometimes cutting off the bottom left Boss, sometimes they did both. It's one of the Cheapest 92hp@6350rpm, or 96hp@6500rpm Engines you can put on a Plane. The Standard 670's use 11.5cr. A 670HO use's 12.5cr and better ported Cylinders only made 1998-99 is about 15hp more, but I don't know of anyone who has converted one for Plane use.

    These Old Skidoo Singles went up to the largest was the 340 Blizzard, Stock (78.5mm x 70mm) 338.9cc and made 36hp. Some of the other Brands of Single Engines went up to around 400cc.
     

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  7. Feb 9, 2019 #7

    Armilite

    Armilite

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    ================================================

    I new they pre-heated cast iron to Weld it years ago, wasn't sure about Aluminium. I only have a Char Coal Grill, but I do have an Electric Stove in the Shop I was going to use for the Engine Coatings that goes to 550F. I was thinking the Tig or Spool Gun would maybe be better than those Welding Rods mentioned above, but there Video's do show some good results.
     
  8. Feb 9, 2019 #8

    Armilite

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    I doubt it. Just a Casting that was machined.
     
  9. Feb 9, 2019 #9

    Armilite

    Armilite

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    ==========================================================

    The Red Area is approximately where I want to Build up a Boss around those Ribs so I can Drill & Tap the Holes, I may even use those EZ Loc Steel Inserts. My Printer is having issues right now, but I have a Drawing I want to Print Out on Clear Transparency Paper and lay over the Case to show exactly where the Holes need to be. The (4) Bolt Holes are 8mm. So If I can just make a Boss say 20mm around that Area it should be Strong enough. The Casting is fairly Thick in that Area. There is actually (2) Types of Case's that can be used. I like the Case that use's the Front Bearing Plate the Best. The other option is to maybe Machine the Area and Weld in some chunks of Aluminum and then Machine it.
     

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  10. Feb 9, 2019 #10

    lathropdad

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    My first bit of advise is to find an expert who does repairs on parts like what you have.

    Second, I would not attempt to weld that part with out a 250 to 300 amp welder. To do this job properly you will need a top level welding machine.

    Next is getting the proper filler rod for the aluminum alloy you are welding.

    If you are not prepared to do a bit of machine work after welding, then don't weld it. The part will warp in the area where you weld. As you weld you are heating and expanding the base metal. You then add filler rod and that fills the gap, crack, what ever. Now when things cool down, you have more metal in the spot you welded. So things in that area will be distorted.

    Sorry to be such a downer.
     
  11. Feb 9, 2019 #11

    blane.c

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  12. Feb 9, 2019 #12

    TFF

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    The durafix rods will do nothing for you. They will pop out with any force. They are light load or cosmetic. Welding is a casting process. Durafix is braising; it does not melt in. To put as much metal as you want on there, it will take a lifetime with a small TIG. A spool gun I have never used, but it might be overkill unless you are building a 50 ft aluminum trailer.
     
  13. Feb 9, 2019 #13

    TFF

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  14. Feb 9, 2019 #14

    wanttobuild

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    LOL
    Don't go to the Bar at Buzzard Rock Marina. The base plates, and the band joist attach fittings on the 6in aluminum columns that support the rafters are all welded by me and I used $400 worth of Hobart Durafix rods.
    Or, just watch a video on utube and walla, you are an EXPERT!
     
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  15. Feb 9, 2019 #15

    TFF

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    Promise
     
  16. Feb 9, 2019 #16

    lr27

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    Is all this really less trouble than just casting a new piece? We used to do that in shop class in high school, though I don't know if the quality was good enough.
     
  17. Feb 9, 2019 #17

    MadRocketScientist

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    There are lots of other videos on youtube of the same process, to get a better idea of its advantages and limitations.
     
  18. Feb 10, 2019 #18

    proppastie

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  19. Feb 10, 2019 #19

    pictsidhe

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    Nobody has mentioned the sheer joy of trying to weld oil impregnated aluminium. Or of repeatedly trying to get the oil out before you try again.
    I've actually just bought some 4043 stick rods. I'll try them out when I get some new aluminium to play with.

    If that were my part, I'd look at alternative ways to mount the whatever to what is already there. Some angle tabs could likely be affixed to the outside with multiple fasteners.
     
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  20. Feb 10, 2019 #20

    akwrencher

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    I weld repaired a lower unit on a Honda 90 outboard several years ago, I think I used 4043 wire. Worked ok, fixed the broken skeg and filled in some really bad corrosion pitting, after grinding them out to clean metal. Then spent half the night re shimming the gears so they ran smooth. Aluminum warps if it even sees you turning on the welder.....
     
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