[Otto Nobedder]

I finally had the opportunity to do a bit of crappy aluminum...

I've been discussing the need for "surgical clean" for aluminum, and the excessive push for this. Here's a drip-pan... It's been under a semi-trailer for over 3 million miles of gravel, dirt, salt, sand, oil, etc. In both pictures I'm welding new metal to it.

First picture, absolutely NO cleaning of the old metal. New metal dressed only by grinding a bevel on it. Note there's a bit of pepper in the middle of the weld. This dressed out with the wire wheel. I don't recommend this for a critical weld, but wanted to show it.

GEDC1454.JPG (163.35 KiB) Viewed 2168 times

Here's a similar weld, three feet away on the same tray, where the only cleaning was to dress the surface of each piece with a wire wheel. The only flaw in this weld is from bumping the tungsten with the filler tacking the left side, which remained after the weldout as one speck of pepper. JUST a wire wheel to prep this old crappy metal... What good would acetone have done me?

GEDC1455.JPG (163.42 KiB) Viewed 2168 times

My point is, "surgical clean" is overkill for 99.5% of aluminum welds.

Steve S

[admin]

Steve, I am with you brother. Most times good enough really is good enough.
There are always exceptions like clean room welds for semiconductor industry.

But for run of the mill aluminum Tig welding there is a point of diminishing returns where a lot more time and effort may yield only marginally better results.

Thanks for the thought provoking post.

Jody


Sent from my iPhone using Tapatalk

[Otto Nobedder]

Thanks, Jody,

I do sometimes work to "oxygen clean" standards which screws up the equation, but that's another topic,and I'm ready to NOT discuss it at the moment...

Steve S

[Superiorwelding]

I have got in "discussions" here and other places on this topic. I am another that firmly believes there is way to much emphases placed on a extremely cleaned alum. I have always preached that if you are just practicing a wire brush is more than enough, if even that. I wish I could show some pics of the last alum job, I ONLY used a wire brush on half if it. The rest was the cleaning action only.
True story, I was talking to a newbie the other day and he started telling me the importance of all this complicated cleaning. It amazed me how much they push this in schools and other forums. It is no longer learning to tig weld, it's how much cleaning we can do.
With all that said I am fully aware of the fact a aluminum weld sharply decreases in strength per weld imperfection but for practice who cares?
I am not sorry I am rambling, this is a good place to discuss this. I will have to add more later.
-Jonathan

[aeroplain]

Amen!! , as I've said before, I'm self taught on TIG, started on Alum. Short "stick-out", gas to high, amps to low...etc. These issues have been addressed for the most part. I fix boats so things need to be strong and I get nervous when I see my welds. Nothing has come back yet, knock on wood! It's very rare I get to weld on clean material; it's often on the bottom of the hull and I have never seen a boat come in clean. Gas, oil, bilge scuz, mouse pee, corrosion... I keep trying to "stack dimes" and am getting better all the time, but I don't get to weld with much regularity and pepper is an everyday thing for me. Jody's vids have helped immensely! Anyway, some days I clean a lot, others I just brush it quick or Scotch-Brite and go.









All manner of gunk jammed in the crack by the time I see it i.e., silicon sealant...


Glad I bought two.

[TamJeff]

I agree.

[sgtnoah]

I wouldn't disagree with anything said here (I don't have near enough experience to have an opinion on this one!).

That said, as a guy who is new to TIG, I suppose I err on the too clean side simply because I am trying to build my skills and if a weld turns out poor I want it to be due to my technique (not the base metal or filler) - so that I can see that I did something wrong and try to figure it out and fix it. In other words, I can't blame that pepper on the metal - I must have goofed something up. And I have, many times. Torch angle too steep, trying to weld on a saw cut edge, trying to weld with the overhead door open, bad gas lens insulator - pretty sure I'm on a mission to try all of the goof-ups out, one by one!

Anyway, I don't get too crazy with the cleaning. But everything does get an acetone wipe and wire wheel pass between passes.

Once I get better at this and my confidence goes up, or I start doing this for a job and need to get a larger quantity of work done per hour, I'm pretty sure I'll step on the gas and go with what is recommended above.

Just a thought.

-- Pete

[gamble]

I cut my aluminum on the plasma cnc. Hit the edges (front,back,side) with a flap wheel (used on steel and aluminum) and start welding. No acetone, no wire brush.
But that's not what i would recommend, it's just what works for me. As I am a hobbyist and don't work in a clean room.

[Superiorwelding]

Anyway, I don't get too crazy with the cleaning. But everything does get an acetone wipe and wire wheel pass between passes.
-- Pete

Ok, don't take this wrong but this is a good opportunity for us to discuss this in a more open format, but that is way overkill. Yes there are applications out there that might require this or customers that want it but for general use it is a waste of production hours.
Keep in mind, 90%+/- of the work out there NEVER allows or does that kind of prep. The only time I ever spend that kind of time on prep is if the customer wants to pay me for it or if it is a proof of concept and I want it to be extremely nice and clean. Generally customers will go through the roof if you were to break down the time it took for prep or if they were to see you doing it in person. They feel that is a waste and don't want to pay for it.
I would like to hear from someone who does clean like this on a daily basis and hear their side of the story as well, not as a debate but so we all can gather information.
-Jonathan

[MinnesotaDave]

Ok, I'll fess up - I don't clean a whole lot.
If the aluminum has dirt, oil or crud on it, I wipe down with acetone - hand brush after if it's crusty.

I normally cut with blade tools so the edges are clean (including chop saw and table saw).
But I found with plasma edges I had to dress the edge or I get a lot of black specks.

I'm not trying to be lazy, just practical about time needed.

[zank]

Well, I clean like this. It gives me an easier time with the thin wall material. For steel and aluminum, I give everything a good cleaning and then a wipe down with acetone. Generally, the low alloy steel tubes I use come polished from the mill. But if there is any scale or if I'm using regular 4130, the scale gets removed about an inch back on the OD and ID. I also back purge the steel frames. The aluminum gets a good brushing to remove surface oxides, which is a bit worse on the 7005 and 7003 tubes vs nice 6061. There are some additional steps with titanium. It helps me sleep better at night and removes some variables from the equation. But the welding is only a small part of the overall build for me. The additional time is built into the cost of the frame or complete bike. But I realize this is not common practice elsewhere. Everyone must make their own choices.

[Otto Nobedder]

Now, I'll throw in the mix...

I've been paid really good money to clean fanatically for welds that didn't really require it. 6061 aluminum pipe, sch. 10, with backing rings. The spec called for 10% x-ray. We were paid to clean the metal to surgical extremes, and even sanded and solvent-wiped the welding rods.

Was any of this needed? Not really. It WAS for cryogenic service, which is still my everyday job, and, on reflection, I think this requirement was to help protect "less than qualified" welders from screwing up, as we had a few of those, too...

Steve S

[hacadacalopolis]

Dave, I saw those before (corner joints)... Still cant get over how good they look!

Guys, how are these welders getting the polished chrome look I see a lot on AL custom intake piping done for Cold Air performance on autos.
With a piece I had the other day I could not find any noticeable buffing marks on the tubing.

[AKweldshop]

Clean ALWAYS helps!

[Superiorwelding]

Dave, I saw those before (corner joints)... Still cant get over how good they look!

Guys, how are these welders getting the polished chrome look I see a lot on AL custom intake piping done for Cold Air performance on autos.
With a piece I had the other day I could not find any noticeable buffing marks on the tubing.

Are you referring to the intake as a whole? If yes, they buff them. There are several ways it can be done but if you and I were doing it in our garage it would be buffing compound and a buffing wheel.

John,
Yes clean does in fact help, that cant be denied but it is not always necessary.
-Jonathan

[Bill Beauregard]

I saw a big difference in a welder's ability to weld dirty aluminum when I switched to square wave AC. I have 2 very old four foot square drawer boxes in my van. They take a real beating in the truck. cracks develop at stress points, the aluminum is "pickled" at these points, and is pretty cruddy. In some cases layers overlap, I can't clean inside the joint. The Dynasty is amazing in its ability to cathode clean and weld well.
I have an old Linde book that explains that sine wave power must reestablish an arc twice each cycle. The oxide layer, and contamination offer a lot of resistance to the flow of electricity, hampering the establishment of an ionized arc in the workpiece negative half cycle. A square wave power source switches direction of flow so quickly it maintains ionization, return flow need not reestablish giving it much more effective cleaning action than sine wave even at 50/50 balance of most sine wave welders.
Don't mention this to Zapster on Welding Web. He'll tell you it's all nonsense. He gets welds of much greater quality than I from an antique welder. As the saying goes, the proof is in the pudding.

[MinnesotaDave]

Dave, I saw those before (corner joints)... Still cant get over how good they look!

Guys, how are these welders getting the polished chrome look I see a lot on AL custom intake piping done for Cold Air performance on autos.
With a piece I had the other day I could not find any noticeable buffing marks on the tubing.

Thanks

My brother buffs out aluminum stuff he buys or gets welded to a mirror finish - done right there should not be any buffer marks.
...I do not buff however - I'll leave that to my brother takes forever!