Welding Tips and Tricks

While cleaning up shop here I came across some old filler rod. It appears to aluminum, It was in a cardboard tube with Union Carbide markings (might be unrelated), and the rod is stamped '35S'. It's 1/8" diameter.

I'm curious about it, anyone recognize the stamp number? Nothing compelling came up in a Google search. It has to be at least 30 years old, maybe as much as 50.

Pete

Might be magnesium fill too. Dip some in distilled vinegar and see if it reacts.

-Sandow

One way to tell Al filler wires apart is drop the wire onto a hard surface and listen to the ring it has when it bounces.
4043 has a "dead" ring to it, 5356 has a "clear" tone that rings out even in a noisy-ish shop...
Its hard to describe but give it a try with fillers that you *know* are the right alloys and you will hear the difference.
No idea what other alloys do, the only other alloy I have access to is 1100 and some Mg rod, ill try them Tuesday (Woooo time off! )
Other though, 35S *might* be 356? 356 is one of the major casting grades of Al.
Various companies make fillers meant for welding 356 castings that are meant to be heat treated to have full strength welds, maybe that filler is one of them?

PlasmaBrain wrote:One way to tell Al filler wires apart is drop the wire onto a hard surface and listen to the ring it has when it bounces.
4043 has a "dead" ring to it, 5356 has a "clear" tone that rings out even in a noisy-ish shop...
Its hard to describe but give it a try with fillers that you *know* are the right alloys and you will hear the difference.
No idea what other alloys do, the only other alloy I have access to is 1100 and some Mg rod, ill try them Tuesday (Woooo time off! )
Other though, 35S *might* be 356? 356 is one of the major casting grades of Al.
Various companies make fillers meant for welding 356 castings that are meant to be heat treated to have full strength welds, maybe that filler is one of them?

Yes I thought of 356 as well, but looked at the stamp under a good magnifier, and it sure seems to be an S and not a 6. I will try the 'bounce' test.

Does Mg filler spark against a grinding wheel? (this rod doesn't)

Pete

Mg should spark out with a nice blinding white spark.

PlasmaBrain wrote:Mg should spark out with a nice blinding white spark.

Followed by an unextinguishable flame

A full stick of Mg shouldn't light on fire until you chop it into little bits and throw it in a bonfire... Drill chips and shavings however...
Another thing I remembered was something about etching Al with oven cleaner (sodium hydroxide) and the colors it would turn can land you in the ball park of what alloy you are dealing with...
The test could tell most of the major alloys apart... Si alloys would turn one color, Li alloys another, Cu/Mg alloys yet a third, ect ect ect...
The magazine I had the article in is at work... so tuesday I snag it...

PlasmaBrain wrote:A full stick of Mg shouldn't light on fire until you chop it into little bits and throw it in a bonfire... Drill chips and shavings however...
Another thing I remembered was something about etching Al with oven cleaner (sodium hydroxide) and the colors it would turn can land you in the ball park of what alloy you are dealing with...
The test could tell most of the major alloys apart... Si alloys would turn one color, Li alloys another, Cu/Mg alloys yet a third, ect ect ect...
The magazine I had the article in is at work... so tuesday I snag it...

Please do! I (and others, I'm sure) will be very interested in using a chemical analysis to help identify or approximate alloys. I'm thinking the real value is identifying parent metal more than welding rods...

Steve S

Hi everyone,
The lye test will tell you about the elements in the Al alloy, not a definitive test but it will land you in the ball park.
It works by etching the surface and the resulting colors are due to reactions with alloying elements; so it will tell you that an element is present but not how much.
Remove any coatings and grease with appropriate solvents and a clean SS wire brush (manual vs powered to avoid embedding junk into the surface).
Goggles, kitchen gloves, and baking soda are recommended.

Gold = Copper, 2xxx series alloys.
Black/Grey silicon alloys, 4xxx
Whiteish is Magnesium, 5xxx alloys
Blueish Mg/Si alloys, 6xxx.

Not a close as one of the XRF guns or a lab test, but it can at least tell you Something...

Basic guidance beats a wild guess...

Thanks!

Steve S