Harris Welco aluminum 26 3/32 Covered Electodes Question

Date 01-15-2010 18:19

My first question is, what are you using this on? My second question is, why are you using this stuff?

IMO, stick welding aluminum is a dangerous practice, and should only be done when all other methods fail. The inherent inclusion of contaminants from the oxidation of the flux coating, the generally (in my experience) poor arc characteristics, and the large amount of heat input all lend to a weld that will not be nearly as effective as one laid down via GMAW or GTAW. I have used these aluminum covered electrodes throughout my career in the Navy, and it is right next to impossible to attain any kind of decent profile uniformity, and the defect rate is always high.

That said, if you must use these electrodes, I have found it useful to plan the welds to be short, no more than 2-3" in length. Not only will the rod melt completely, but the part as well. I would not preheat to anywhere near 500 deg. F...the base metal melts at about 1100, and depending upon the size and shape of the part you're heating, you can easily reach that inadvertently with the torch. You may want to bake your electrodes first, just hot enough to get the moisture out of the cover. That box may say all position on it, but I would not try anything other than flat. Wear some very good protective clothing. That coating contains magnesium, and man does that stuff hurt when it hits your skin. By that same token, you might want to up your shade one in the hood, because it burns fairly bright.

Hope that helps a bit. Good luck! :)

By ronnie taylor (**)

Date 01-15-2010 18:48 Edited 01-15-2010 18:55

Thanks, bozaktwo1 for your reply It is not my first choice to use these rods but it is my only option since I dont have a tig or spool gun. The weld will only be about 4'' long on a stepdeck trailer where the stepdeck joins the flatbed. The box does say all position and I truely believe your right about welding in the flat as oposed to any other position as my test run showed in the flat position I found the rod to be very fluid here is a picture to show what is to be welded we just bought this trailer and whoever welded it before did not do such a good job. As always I appreciate the advice Thanks Ronnie

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By jwright650 (*****)

Date 01-15-2010 19:00

After looking at the picture....I would venture to guess that this crack will show up again and again, each time it might move over the width of the bead.

By ronnie taylor (**)

Date 01-15-2010 19:25 Edited 01-15-2010 19:32

Mr.Wright,Thanks even know thats not what i wanted to hear:) any ideas what i could do to stop it? I was hoping that heating after i welded it would relieve the stress.

By bozaktwo1 (***)

Date 01-15-2010 19:40

You might try a doubler plate. Grind the whole mess flat and slap a good 1/4" piece of 5052 on top, weld all around.

By bozaktwo1 (***)

Date 01-15-2010 19:43

Or do a complete excavation and fill it up. But there you have to be really clean.

By ronnie taylor (**)

Date 01-15-2010 19:47

Thank you sir.

By jwright650 (*****)

Date 01-15-2010 19:43

Aluminum is not a material that I have alot of experience with, however I offer this suggestion.
I wouldn't heat it after welding...I would run the welder as cold as possible and travel as quickly as I could. Aluminum doesn't like all of that heat and welding too hot or too slow creates a large Heat affected zone(HAZ) which is where it looks like the previous welds cracked.

I'm hoping the others that frequent the forum who are experinced in aluminum will chime in and either confirm or correct me.

By ronnie taylor (**)

Date 01-15-2010 19:48

Thank you Mr.Wright

By bozaktwo1 (***)

Date 01-15-2010 19:49

When is the crack occurring? Immediately after welding? During welding? Or after cool-down?

By ronnie taylor (**)

Date 01-15-2010 20:28

I dont know i didn't weld it. We just bought the trailor.

By jwright650 (*****)

Date 01-15-2010 20:14

Read through this thread and see if any of this might help....

http://www.aws.org/cgi-bin/mwf/topic_show.pl?pid=70944;hl=welding%20aluminum%20cracking

By bozaktwo1 (***)

Date 01-15-2010 20:44

That thread is awesome. Thanks, John.

I was under the impression that the picture I was seeing was the results of your weld, Ronnie. Well, in any case I wouldn't try to weld right over it...no telling how much gunk is in that crack. There are other methods for stopping cracks, but I feel the same way as Jon about that one. It will likely recur. Which part of the trailer is this in? Does it bear a load?

By ronnie taylor (**)

Date 01-15-2010 21:11

Here is a little better picture of what I am dealing with. We have the trailer upside down because I also have to replace the 5th wheel pin, plate and support beams but you can see where the weld is and it is going to be more or less tork when being loaded and unloaded than load bearing To Mr. Wright the thread was very informative and helps alot Thank you all Ronnie

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By Lawrence (*****)

Date 01-16-2010 05:25

Ronnie

If I'm looking correctly at the pics, that joint of yours is pretty important.

I would recommend using SMAW for aluminum only for ornimental and emergency welds..

Anything else needs a proper process... (GMAW/GTAW)..

Rent equipment or hire out the joint if this is an important structural componant.. In my opinion SMAW will not do the job.

By bozaktwo1 (***)

Date 01-15-2010 19:48

John, one of the problems with the covered aluminum electrodes is that they don't like to run cold at all. Zero arc control.

By jwright650 (*****)

Date 01-15-2010 19:56

Then he will have to travel as quickly as he can and still put some material down, lots of small quick stringers vs a big, slow heavy pass.

By joe pirie (***)

Date 01-15-2010 20:11

Had a salesmen bring in these aluminum stick rods several years ago to a compressor shop.
we were tig welding up ring grooves in pistons to be remachined. Tried burning a couple of rods
on a plate as per mfg peramaters. Thru the rest in the trash can absolutely worthless for a quality weld

By Blaster (***)

Date 01-15-2010 20:35

I tried a free sample of aluminum stick rod from Rockmount (a "Boutique" electrode supplier) that actually welded pretty good.... for aluminum stick rod.

The problem with aluminum stick rod is you need more current when you start, less once underway, and little at the end of joint.... just like when TIG welding aluminum. So any fixed current setting is a compromise that will likely result in problems somewhere in the weld.

If you have a power source that will accept a remote you could try using a foot amperage control if you have one. If not, you could try using a dial type remote amperage control and either adjust it with your left hand while you weld, or have a savy welder watch as you weld and turn the dial as necessary during the weld to give you the right current level.

In any case I would much rather use TIG or MIG on any aluminum project and would have to be pretty hard up to resort to stick on anything that mattered much.