4043 Al Filler Rod, Won't Come Clean?

By Lawrence (*****)

Date 10-14-2007 20:57

If the welding rod is shiney I don't think it is the problem... If it is grey or has white chalky redidue than you prolly ought to just get fresh rod.

Adding aluminum to a weld pool takes a slightly different technique than adding steel. You will usually get a better metal transfer if you almost jab the wire just inside of the leading edge of the puddle as opposed of adding it in front or at the leading edge as often is the case with steel.

Keep the filler rod as close to flat as possible and keep the electrode as close to perpendicular to the base metal as possible.. If the electrode is pointed forward (toward the filler) the heat radiating off the electrode will ball the filler wire up before you can add it every time.

Also unlike steel. Aluminum needs a nice big puddle because of its high rate of thermal conductivity.. If you have just a tiney little molten pool, the addition of filler can rob heat and freeze the pool, causing the filler to stick or ball up.

So make a nice large puddle and then add your filler (almost jabbing it) into the front third of the puddle, keeping the feed angle low as possible. The puddle should not shrink or freeze, it it does you need more amperage.

Try the technique changes and let us know what happens.

By 803056

Date 10-14-2007 21:03

You nailed it with your last sentence.

You will have to abrade the rod to remove the heavy oxides and hydrates. Wiping it isn't aggressive enough.

Go to a marina and get some stainless steel wool. You can find it in the grocery store on occasion. Do not use scotch brite or emery paper; both typically use aluminum oxide as the abrasive.

Once you abrade the surface, wipe it with an isopropyl alcohol or acetone soaked cloth as you are currently doing. A synthetic material be less likely to leave "lint" on the rods. The lint is a good source of cellulose and can cause a porosity problem.

Good luck.

Al

By DaveBoyer (*****)

Date 10-15-2007 04:34

In addition to all the above, be sure to keep the hot end of the rod within the shielding gas covered area when You are not adding metal.

By TaylorTolliver (*)

Date 10-18-2007 02:32

for the TIG i have welded. i like to use 2% thoriated tungstens also... thought Id like to share. haha

By 803056

Date 10-18-2007 13:16

I hope you are not typing to use EWTh-2 with AC on aluminum.

Al

By DaveBoyer (*****)

Date 10-19-2007 03:46

Al, since You happened to mention it, WHY are We not supposed to use the red ones on aluminum, and what are the benifits & uses of all the other "newer" electrodes? I probably have used 2% thoriated on aluminum, and have probably made about every other mistake as well. " I used wax to mend My wings, I've done all the dumb things"

By Lawrence (*****)

Date 10-19-2007 11:25 Edited 10-19-2007 11:27

Dave

I can pitch in a little on this one.

Thorium electrodes tend to grow little nodules at their ends when they are overheated in service. These nodules tend to cause the arc to wander..... The worst part of this is that when the nodules are growing on the end of the electrode, tungsten is also transferring across the arc into the molten pool (tungsten spitting) and will be cause for RT rejections. Thorium electrodes also tend to produce longitudinal splits when used with high current AC.

Zirconium (Brown) and Cerium (orange) when they begin to overheat and melt will tend to form a ball at the end and not transfer across the arc. Both of these are a best choice for AC aluminum with a transformer rectifier power supply. Pure (green) tungsten has such a low melting point (comparitively) and is such a poor emitter that its way better to just spend a couple extra bucks and buy a doped electrode for AC aluminum.

Others choose lanthanum (black & gold), especially those running inverters... Also a better choice than thorium or pure.

Having said all of that. People use thoriated electrodes to make RT quality welds on aluminum every day... They are just darned sure not to overheat their electrodes.

By 803056

Date 10-19-2007 20:55

When welding with GTAW, you have to make a couple of choices; weld with direct current, either straight polarity (EN), or reverse polarity (EP), if not direct current, then alternating current.

Direct current, electrode positive (straight polarity) can be used to weld most metals and EWTh-X, EWCe, or EWLa are the electrode types most often selected. Good arc efficiency is achieved with about 70% of the energy transferred into the weld.

Alternating current typically utilizes EWP or EWZr. Both pure tungsten and zirconiated tungsten will form a hemispherical end or a balled end if the electrode diameter is matched with the proper amperage range. The energy transfer is only about 50% into the weld, however you have the benefit of cathodic cleaning of the base metal with AC.

As stated by Lawrence, EWTh-X will form little nodules at the business end when welding with AC. The arc is unstable and the tungsten spits, sputters, and in general give a rather unpleasant welding experience.

Pure tungsten tends to contaminate easily and it doesn't carry the amperage the EWZr will. So the tungsten with the brown paint strip is usually preferred by all but the company "bean counters" when welding with AC.

Your choice of AC or DC is highly dependent on the metals being welded. Aluminum usually is welded with AC, argon shielding gas for thickness up to about 1/2 inch, argon helium mixes for thicker sections, and EWZr electrodes (with a balled end) for better current capacity and resistance to contamination. That's not to say you can't use DCEN, but the shielding gas of choice is usually helium, the electrode is usually EWTh-2 (with a tapered end), and there is no cathodic cleaning as is the case with alternating current. Thus, it is very important to clean the material just before assembly and welding if you elect to weld aluminum with DCEN.

Other threads have addressed the pros and cons of EWTh-X, versus EWLa and EWCe-X.

I hope Lawrence and I have answered your question.

Best regards - Al

By XPERTFAB (**)

Date 10-19-2007 23:15

If when I get to the pearly gates and St Peter is trying to decide if I get to go inside. I sure hope Lawrence is there to explain why I am a perfect candidate for admission. His replies are so spot on and thorough. In a world where being thorough iat anything has become passe' (just ask a teenager!) Lawrence is a role model for how to communicate as such! Thanks for a great reply!
XPERTFAB

By DaveBoyer (*****)

Date 10-20-2007 03:33

Lawrence & Al: I recall the nodules [I guess] or at least the arc wandering, but I probably dipped the electrode and contaminated it too. I have a box of 1/16" Zr as well as the usual red & green, I will try them the next time they are appropriate. I only recently made the leap into the 1980's with the purchase of a Syncrowave 300 to replace My old 360 A/BP, I don't see an inverter in My future. Thanks for the explanations.

By Lawrence (*****)

Date 10-20-2007 04:04 Edited 10-20-2007 04:11

Hey Expertfab

When you get to those pearly gates... Don't worry about making a case for yourself..

Ephesians 1:4
According as he hath chosen us in him before the foundation of the world,
that we should be holy and without blame before him in love.

The "perfect candidate" has already done what is necesary :)

The theme continues:

Timothy 1:9
"Who hath saved us, and called us with an holy calling,
not according to our works, but according to his own purpose and grace,
which was given us in Christ Jesus before the world began"

By Tommyjoking (****)

Date 10-20-2007 11:32

HAIL the lawrence!!!!!!!!!!!!!!

I have been making XRAY quality welds with 2% for YEARSSSSSSSSSSSSSS yep I agree its not the best but you kno what..... it will shoot fine even on a $175,000 turbine. Lawrence I REALLY LIKE YOUR quotes.....I will see your there my friend and you can show me all I did not know.

Best Regards
Tommy