[Cricket]

Sorry for my welding porno but I would like to find a better way to weld this sh!t.
Perforated aluminum is 0.0325" thick. Supposedly type 3003. Fit was "OK". That means the side seam was straight and the only problem was in some pieces the cut went through the holes... Not much meat to weld. The bottom was obviously cut as close as possible but those damn holes...

Welded at 65A, 30% balance, 4043 filler-1/16", 1/16" 2% lanthanated electrode. Copper backing.
The whole thing is 6" long and 3" in diameter.

I tried to clean the mesh as much as I could, Did not have enough acetone to dip the whole thing in it. But this aluminum is FILTHY! Welding was a Royal PITA. Not much soot but A LOT of sputtering. The arc was super unstable on the perforation. The only way I found to be working more-or-less was to build the bead to the bead itself and "wash" it a little so it will wet the sides. I tried to keep cleaning in the same spot hoping that eventually I will burn all crap out. Got it going till punched a hole and it still sputtered. And the surface does not produce a puddle per say. It stays rough all the time.
I do not know what kind of lube they use for manufacturing but this stiff is not easy to get rid of and it looks like it saturated the aluminum.

I show the best side bead that I managed to make. The bottom is the same porno on all 6 pieces. This project is finished. I'll clean it up with a flap disk and let it be.
The main question is HOW TO WELD IT PROPERLY????
The holes make it almost impossible to get any kind of rhythm. Especially on the bottom.

[dirtmidget33]

The way I would have tackled this probably is, If material feels oily wipe it down with liberal amount of acetone so it gets in perforations. Then heat it up with propane torch along areas to be welded to try and burn oil out of perforations. Take flap disc to edges and flap disk 1/4 to 3/8 inch of way in to top and bottom of areas where weld will be. Wipe down with liberal amounts of acetone again. When welding use a lay wire technique will prolly make it easier to fill in holes. They look pretty small by picture don't think they would be to big a deal to fill in. A copper backer bar would prolly help on long seam to help trap the gas from going threw holes. Maybe use aluminum foil dam to help trap gas on round section. The backer bar and dams all would depend on how they where welding for me, If I was having trouble would try it.

[TRACKRANGER]

Cricket, I think you got a pretty good result considering all, the challenges

I wouldn't be a fan of propane for cleaning this. I would use an Oxy Acetylene flame. Propane can leave a film residue on the surface that might make this job tougher again.

[AndersK]

Run the material thru an alkalene (spelling ?) washer (regular dish washer)

The lubricants and cooling fluids I assume have been used have a tendency to stick on ali.

[dirtmidget33]

I wouldn't be a fan of propane for cleaning this. I would use an Oxy Acetylene flame. Propane can leave a film residue on the surface that might make this job tougher again.

I have reasons on why I didn't suggest Oxy Actylene for this job.

The reason for heating in first place is to boil hydrocarbons and impurities out of perforations and pores in metal. This is gonna leave a residue of burnt hydrocarbons and other things on metal. So any residue the torch leaves is minor. The next wipe down with acetone will remove this. Another thing to remember is this is very thin aluminum, O/A runs hotter then propane and it is easy to start melting the material with O/A. We don't won't the material that hot, propane better suited for just heating to burn out impurities since flame isn't as hot. Less chance of messing up the work piece. Another thing is not everyone has access to O/A where as small propane torch is pretty cheap to buy.

[Cricket]

Thanks for the suggestions. So it boils down to "clean, clean and clean some more"

I was asking around and was told that this lube might be silicone based. That might explain why my acetone wipe did not work and arc did not burn it quickly. Silicone is too damn stable and heat resistant. And it does not burn per say; it breaks down to silica and some other nasty stuff.
Another opinion was that this aluminum was lubricated with fluorocarbon based grease.
Anyway, it is second day and after all handling\cleaning/welding those pieces are still slick-oily... I will have 6 more pieces to weld. Will try to follow your suggestions and report here of the result.
Thanks again!

[Otto Nobedder]

Cricket,

That looks suspiciously like a pump inlet strainer (or fill/withdrawal line strainer) for cryogenic service, meaning the finished product should be oxygen-clean.

I'd suggest making it "oxygen clean" before welding, which means a hot-soak in BlueGold solution. If you have access to an ultrasonic cleaning bath, that's a plus.

That said, There's not anything functionally wrong with your result. Considering where I expect it will be used, you may be stressing too much on the "form".

Steve S

[GreinTime]

BlueGold might be the best cleaner I've ever used.

[Cricket]

Ultrasonic X 2 times with TSP and fine mesh glass beads. After that acetone. It worked!

I do not know if you can see the difference but I certainly do. The bead looks almost the same on the picture but it is MUCH flatter now. The distance between the holes is 1/8"; the bead is about the same wide and maybe twice as thick as the aluminum sheet (0.032"\20 GA).
Tomorrow I plan to weld the bottoms.

Thanks for the advise!

[Cricket]

Steve,
it's more like a diffuser. It supposed to make a somewhat laminar flow.

[Otto Nobedder]

Steve,
it's more like a diffuser. It supposed to make a somewhat laminar flow.

Ah! Thanks.

If I can find the pics, I've something similar that's used as the inlet filter for a liquid oxygen pump. That's what made me think of O2 standards and ultrasonic for the cleaning.

I'm glad it worked for you!

Steve S