can you id this tig rod for me

[SQ is the SQUAD]

i am pretty new to tig welding and my boss had some unknown tig rods he got out of a junk truk. he gave me a few to pratice with but i want to know what they are used foor. the seem toi have some copper color coating on the and are stamped er70s-2

[zapster]

70-S2 is filler for mild steel..
it can also be used with chrom-moly tubing..
the copper color is just that...there's no copper coating..

...zap!

[SQ is the SQUAD]

so if i am welding ss to mild steal could i use this rod and have a copper color weld insted of my 309 rod?

[zapster]

stay with the 309..
70-S2 is not recomended for dissimilar metals..:nono:

...zap!

[SQ is the SQUAD]

thanks for the advice.

one last quick question.
being that this is my first wedling experience, iam still trying to get a feel for the type and sized of rods. i seen one thread on another board that someone was using some mig wite to tig a very small root pass. is that a bad thing, and if not what size/type wire should i use for the realy tight spaces

[zapster]

for the stuff you have if its a real tight fit..fusing(no filler) is the way to go..
you dont loose any strength..and its pretty easy...

but if you need filler
get some .045 (i think) 308 for the job..
at least in my world 1/16 for that application is a little too big..
but thats just me..

ask for the smallest 308 filler wire at the weld shop..

...zap!

[SQ is the SQUAD]

ill keep that in mind the next time i go buy my welding supply