[PSUBS-MAILIST] Aluminum Welding Technique Question

Sat Apr 26 00:10:50 EDT 2014

James,

There are several things that can make a good welder look bad when doing aluminum if they fail to do some basic things but once you have it, it’s real easy. As far as the ball on the end of the electrode, You can do it the way it shows on the video or I just slightly round the end on a bench grinder and it will work fine.  It will ball on pretty much anything. I was told you couldn’t use a sharp electrode like you would use for  welding stainless steel but that will work too and it will round it’s self out relatively quickly but it’s better to start out with a blunt one. Less chance of transferring any tungsten to the parent metal if it is a super critical weld.
When welding dissimilar thicknesses, if you can, put the thick one above the thin one, favor your heat on the thick one and let gravity do the work for you. If it is super thin you can put your heat on the filler rod and let it fuse in but that is a little tricky. It is also important to try and use the proper sized electrode. I usually use 1/8” but also have two smaller sizes for the thinner stuff. There are trimixes for your shielding gas that they claim will give you better penetration but they are pretty spendy and I have all ways used straight argon with great results.
Aluminum is a lot pickier than steel when it comes to contaminants. For good results, It is imperative that  you clean the aluminum before welding it. Even when I am building something with new aluminum from the mill, I all ways clean the edges where I am going to weld. Aluminum is porous and it may not look contaminated but it doesn’t take much. They make special grinding discs specifically for aluminum as well as stainless steel wire wheels and brushes and do not use them on steel or you will contaminate them. I’ve herd people say they have used some sort of solvent but I don’t feel that it gets as deep into the pours as actually grinding the top layer off. 
I get people all the time that bring me stuff that has been out on the ocean and contaminated with salt air/water and it just won’t take a good weld unless you can physically remove the top layer to get to clean metal. If you were to leave a new piece of aluminum out doors for a while and then put a piece of aluminum next to it that has been cleaned with a grinding wheel and run a bead on both, you will not only see the difference when welding it but you will hear the difference as well. Should have a nice smooth hiss rather than a crackle. There are even things like wave signs that help with the cleaning action and penetration but I don’t think you can vary that on the cheaper machines and I believe they are factory set.  Hope this helps

Rick P.

From: Daniel Lance via Personal_Submersibles 
Sent: Thursday, April 24, 2014 2:24 PM
To: Personal Submersibles General Discussion 
Subject: Re: [PSUBS-MAILIST] Aluminum Welding Technique Question

James , 
I have spent thousands of hours welding aluminum and I agree with your conclusions . The ability to fine tune the frequency and balance control makes all the difference in the world . A big ball at the end of the tungsten just doesn't conduct weld current very efficiently . Inverter type welding machines designed for use on aluminum are terrific. I wouldn't go back to an old transformer type with the add on hi frequency box for all the money in the world. (  the stone age of aluminum welding ) .
Dan Lance

On Thu, Apr 24, 2014 at 3:13 PM, James Frankland via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

  Did anyone get my response and attachment to this post about aluminium welding?  I was braced for a firestorm of criticism but nobody said anything.  Either everyone agrees, doesnt care or didnt get it....which is it?  :)

  Kind Regards
  James F 

  On 23 April 2014 15:32, James Frankland <jamesf at guernseysubmarine.com> wrote:

    Hi All,
    I was going to write my 2 pence worth (UK version) in reply to this, but im just going to attach a sheet i wrote which covers all i was going to say.  I know there are a lot of expert welders on the forum, so this is just my personal take on it.  I can get good results most times. Personally, i dislike the "balled electrode" thinking.  It will ball to a certain extent of course, but I dont like it to become bigger than the diameter of the electrode.  With correct frequency and as little cleaning as you can get away with, i can keep the ball small and arc tight.  The only thing not on this sheet is that torch angle is important.  As near to straight up and down as possible, this prevents the rod turning into a sausage before you get it into the pool.

    Just my 2p.  
    Kind Regards
    James F

    On 23 April 2014 01:01, Steve McQueen via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

      Thanks Dan.  I did use 100% argon gas but my tungsten has a red band (2% thoriated).  I am also getting to know my machine settings so I'm sure they where off. Lots to learn!

      Steve

      On Tue, Apr 22, 2014 at 7:28 PM, Daniel Lance via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

        Steve, 
        Are you using pure tungsten ( green band on one end ) and argon shielding gas ? . With the torch set on DC+ you will usually experience a tungsten melt down. Just set the machine on AC and run a pass on some scrap aluminum . You will get a balled end . Not to complicate things but a balled end is not exactly the most preferred condition in the world. But unless you have an inverter type machine with lots of parameter adjustments you really don't have much choice.  Alec is correct the amperage setting depends on the thickness of the material you are working with . If you are trying to join a thin piece to a thick piece its ok to preheat the thick piece first , just don't exceed 250 degrees F. Old oxidized aluminum is very difficult to weld unless the crusty white scale is removed . It should be nice and "shiny" before you start . And of course a little preheat never hurt anybody . Aluminum is a near perfect material for marine use , it is easy to cut , form , shape and weld . It can be painted , anodized or just left in its original mill finish. 
        As far getting welding advice from Youtube , the only source I would recommend is "Welding Tips and Tricks" . This guy is really, really good .
        Hope this helps,
        Dan Lance

        On Tue, Apr 22, 2014 at 11:49 AM, Steve McQueen via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

          I attempted some Aluminum welding this weekend.  I needed to tack 2 together pieces of a trolling motor mount I modified for my stern thruster.

          I watched a video that said it is important to first first strike an arc on DC+ for a few seconds to create a "ball" on the tungsten tip prior to going back to the AC mode.

          It was unclear in the video if the arc was being struck on an Aluminum piece or the Steel welding table surface.  Does it matter?

          Also they said the amp range should be set to 55-75.  Seem OK?

          Thanks,

          Steve

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