Aluminium hot pipe welding issue

[duffman1278]

So I'm trying to weld the BOV flange on my hot pipe and for some reason it is just not cooperating.

I've sanded the parts thoroughly, SS wirebrush, and acetone and still I'm just getting issues.

Any help or suggestions with what I could be doing wrong?

I'm using 1/16" 4043 Filler, 3/32 Red tungsten electrode. Syncrowave 180SD.

If I don't go to max cleaning I get black pepper like stuff, but the ball really doesn't let me get a stable arc.

[welder_one]

with aluminum, you cant stress cleanliness enough..... when i would come across aluminum that's bein a pain, i would use a brand new file and clean the parts (sand paper, sanding discs, flap wheels will leave behind residue) after shaping and cleaning, then use either a brand new SS brush or one that has ONLY ever seen aluminum. if that SS brush has been set out for a bit, you might have alot of dust build up there as well, clean the brush with rubbing alcohol, clean the metal to be welded with acetone, then clean it again with rubbing alcohol... dont wipe the alcohol off, just let it dry.

you might switch to a smaller tungsten, and on the more dirty stuff, i like the green band tungstens... they seem to clean a little better to me.

you might turn you pure argon flow up a bit more and turn the fans off thats keeping you cool in your shop..

[duffman1278]

Thanks for the quick reply. I'll just go and buy myself a new SS brush then since they're a dime a dozen.

This really is being such a pain.

Do you think I can reduce the amount of cleaning on the machine if I clean it more? Because it is really becoming stubborn with the puddle and making it huge like the one shown.

[welder_one]

yes... now understand that all my al tig experience is with a transformer machine like the synchrowaves. again, use a file to rough clean the parts... that flange looked like it was pretty heavy on the oxide... the pipe... is it coated with anything? if its even clear anodized, you gonna have problems.... get a file and make sure that you get down to bare metal, then use a new SS wire brush... all of the welds that have already been attempted will have to be ground off as they are already contaminated

[duffman1278]

What a pain in the butt that's going to be but I'll definitely take the parts apart and clean them much more this time.

[DVR/WLDR]

I believe that the red tungsten is most commonly used for ferrous metals and should be pointed. The green or pure tungsten was the industry standard for aluminum forever with a balled end but they now are using more of the gold or ceriated as a all around tungsten and can be used either balled or pointed. mbb

[FusionKing]

From your pics, it looks fairly obvious that even tho you have the wrong tungsten IMO to begin with, it is definitely contaminated (the tungsten)....that is where the black comes from. I used gold untill recently and have now been using rare earth. Even Brown would be good if you want a ball.
It is more than likely because you are using too small of filler and it is easily melted before it fuses to the base metal. 3/32 would be a good choice here. As would pre-heat...your machine is a bit small in the heat department.
I would suggest you practice welding on scrap before that is what this project turns into. You can only clean something like this so much before it becomes something that looks pretty shoddy.
When doing flange joints such as that on aluminum, the condition of the tungsten is super important. Every time you ignore this, your work will show it. As soon as you strike the arc you should have a pure shiney puddle. If not stop right then and fix the problem. Continuing to weld over the bad work only makes it much harder to rework it after you fixed the problem.
I find sandpaper is fine on stuff like this as long as you have cleaned all the surface off before welding. It doesn't look like you did much sanding in the first place from the pics, which BTW are very good and showed great detail. I use a great deal of sandpaper type products in my work everyday. There are many things that I make that there is simply no other thing else that will do the job. You just gotta know what you are doing. Take for instance that pipe....there isn't much else that is gonna restore that finish after grinding etc. except using sandpaper in progressive grits such as 80 then 180 and so on. You just need to know what works and that comes from trial and error. You need to remove the dust from sanding with alchohol or acetone.
Many times I use acid for cleaning projects before welding. It takes more time but the results show in the work.
Good luck on fixing this, I hope you have the answers you need

[SundownIII]

duffman,

Already responded on WW.

Not going to type the same thing twice.

[nocheepgas]

Most sandpapers are made from aluminum oxide, the very thing you are trying to get rid of when you sand it. I think that's counter productive. Try some 3M Surfave Conditioning Discs. for your cleaning, then laquer thinner or acetone.

[Jigantor]

I use lanthanated tungstens now with a point. After a while the point will round I then stop and diamond grind the point back on.
Cleaning is the key but practice with aluminium is the tools.

This is not an awesome weld just some practice I did before a little project.
The base plate is 3mm or 1/8" thick and the tube is 10mm or 3/8" diameter with a 1mm or 0.04" wall thickness.

Practice for a while on some scrap, you have it in no time.

Ji