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Nice color, but not shiny weld bead on stainless sheet

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Nice color, but not shiny weld bead on stainless sheet

Postby mrapala1 » Mon Feb 05, 2018 8:39 pm

Hello. My name is Mariusz.

I have a question.... why my bead is not shiny? :)
The colors are good - goldish, pale blue, purplish but they are not shiny. They are not gray or overheated. They look like frozen/matt/flat.

I am welding 1mm (18ga, 0.039) thickness stainless steel sheet (butt weld) on some scrap parts.
I use pink ceramic #12 cup with gas lens and 1,6mm (1/16) 2% lanth tungsten sharpend like a needle (brand new, grinded on a wheel used only for tungsten)
I keep my torch at almost 90 degree, very close to the puddle.
I use 1mm (18ga, 0.039) filler rod mainly 308lsi but I've tried 316 (I don't know exactly what is the base material made of other than it's stainless) Without adding filler problem still exists..
I use pulse but average output is at 15 to 23 amps

I used diffrent gas flow setups. From 10cfh (5lpm) to 30cfh (15lpm).
For the tests I didn't use backpurge, but welded thin SS sheet on thicker aluminium sheet to act as heatsink.

And now is something that I don't understand. On the welding side beads are matt/flat/frosted but nice colors. HOWEVER!! On the other side they look amazing chrome/gold/straw//blue and purple VERY shiny. AND this is WHITOUT using backpurge.

I spreayed soapy water on gas lines and got very small bubbles on flowmeter, connection and cup isolator. The bubble are so small I dont think it's the problem. I am pretty sure there always be some small bubbles in the gas line somewhere... Or am I wrong?

The fan on my welder is doing it's job so I put some ply wood screens around my welding area.

I bought Argon about 2-3 years ago. Maybe some moisture inside?

Any other Ideas?

The weldinge machine is DIGITIG 205P AC/DC

Any help is priceless...

Thank You!
Last edited by mrapala1 on Tue Feb 06, 2018 4:29 pm, edited 1 time in total.
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Re: Nice color but, not shiny weld bead on stainless sheet

Postby cj737 » Tue Feb 06, 2018 9:27 am

Is the material you are welding clean, clean, clean? If you are using an known grade fo stainless to weld, then it is quite possible the surface is full of contamination. The heat from welding pulls it into the bead. Scrub it and clean it. Then try it again. If you wipe the area with a clean towel and some acetone, does the towel show grime?

With a #12 cup, I would run 20-25CFH, not 1 CFH lower.
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Re: Nice color but, not shiny weld bead on stainless sheet

Postby mrapala1 » Tue Feb 06, 2018 4:29 pm

Thanks for answer!

The meterial is clean. It might be leak inside the welder which I didn't checked.
I ran out of argon, so I'll be buing fresh bottle.. we'll see.

Any one had leak in gas line? What was the symptoms?

Thank You!
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Re: Nice color, but not shiny weld bead on stainless sheet

Postby cj737 » Tue Feb 06, 2018 4:41 pm

Introducing oxygen into argon will create a very poor weld, just like a badly shielded weld (or backside). Because your flip side had good color and shine without a purge, I personally would suspect something different. Even a small amount of air leak would not, in my opinion, cause the discoloration only on one side. I would think it would adversely effect both sides unless the leak were substantial?
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Re: Nice color, but not shiny weld bead on stainless sheet

Postby mrapala1 » Tue Feb 06, 2018 6:45 pm

Today I swapped my gas lens and cup to no. 7, the flip side was sugaring. The front bead was the same - matt.

Maybe the grinding wheel is bad? I only use it for tungsten though. It is quite coarse-grained. Could this be a problem? Maybe I should use finer grinding wheel? I have seen on YT someone has polished his tungsten to a mirror like finish...

Maybe there is some sort of contaminated layer on my SS? I only brushed it with SS brush and wipe it with acetone. I will grind some of it and see what's happen.

I will also check out gas line inside the welder.

Thank You for Your time, Sir.
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Re: Nice color, but not shiny weld bead on stainless sheet

Postby tungstendipper » Tue Feb 06, 2018 7:26 pm

Too much heat.
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