Clarification on Filler Rod Types (ER70-S*)

[eSCHEn]

Okay so I grabbed some filler rods a while back from my local but when I came to use them I realised they were R45

I've passed them on to a mate who uses them for modelling so no loss.

However I do still need to get some new rods and I've been getting the specifications sorted in my head and would be grateful if SWK could cast their peepers over this and let me know if I've got it right.

My current rods are ER70-S3 as that's what's available by the handful in my local place. However I notice there's actually several varieties of ER70-S* with different coatings etc. Am I correct in what I'm saying here (I've omitted what I saw as the less common ones):

ER70-S2 - "thicker", more viscous pool for doing awkward joints and pipe roots.
ER70-S3 - general purpose, good for whatever you want bar specialized situations.
ER70-S6 - for "dirty" metal, eg mill scale or light rust you can't get rid of for whatever reason.

I understand what the E, R, 70, S and 1..6 means in terms of semantics but wanted a more experienced opinion on my assumptions.

Also, where does the A* classifications fit in? Are they equivalent?

Given I do nothing particularly special, I assume I'll be fine keeping on with the ER70-S3s that I normally use?

Thanks peeps

 

[Brad93]

ER70-S6 wont give you a cleaner puddle with TIG, as it only has one deoxidiser - Silicon, whereas ER70-S2 has three usually. With MIG ER70-S6 will give a cleaner puddle on dirty material. I guess because of the process and active gas. Im sure TechnicAl will advise better.

I alway use S2.

http://www.weldingtipsandtricks.com/er70s2-er70s6.html

 

[eSCHEn]

Yes, not cleaner but wetter so that it'll cope with impurities better is what I meant to say.

 

[Brad93]

If you watch that Welding tips and tricks video you will see that whilst wetter having more silicone doesnt mean it will handle the impurities better.

 

[eSCHEn]

Just saw the damn link, bloody small phone screen! Thanks Brad.

Edit: good video, that guy is pretty good at explaining it. I'm not sure the nicer looking S2 bead would be my choice vs the S6 one though. I imagine the reason it looks nice is because the impurities are hidden under the bead rather than being brought up and out?

 

[Maker]

ER70-S6 is actually made as MIG wire, it has more than enough silicon which would be burnt off when migging but not when tigging. It would probably be a problem for really critical work but it doesn't matter for most if not all hobby use.

 

[TechnicAl]

ER70S-2 is the so called Triple Deodised. Compared to S-6 it also has lower Silicon and Manganese. This is because it is designed to be used under INERT gas which does not change the weld chemistry
The ER70S-6 has higher Silicon and Manganese and is designed to be used under an ACTIVE gas which removes a proportion of both of these elements. The final weld will have similar chemistry to the S2 weld

So S2 is TIG wire and S6 is MIG (actually MAG) wire

S3 is cheap S2 without the deoxidisers........Personally I would avoid it.......Ive never seen any used. Its an old spec that no-one ever used until the Chinese became prevalent.

S6 welded under INERT gas (TIG) will produce a weld that has higher Si and Mn than optimum so will be a bit more brittle (I dont mean it will snap like a carrot)

 

[eSCHEn]

Al, you're a goddamn hero you know that? Thanks very much!

So do the A* classifications correspond to flavours of the S* ones?

Edit: I also need to get my eyes checked - my rods are ER70-S6 not ER70-S3

 

[TechnicAl]

Not sure what you mean by A classifications

 

[eSCHEn]

The A18, A15 etc ones sorry.

I see a whole plethora of options on pages like this: http://www.rapidwelding.com/dynamic/Category.aspx?c=TIGSTEEL&o=0&zl=2&sq=14

*Sigh* and now I also see they do match (so A15 is S2).

 

[TechnicAl]

Loosely A18 is the same as S-6 and A15 is S2

the G3Si1 and G4Si1 split the S6 into 2 specs

the G2Si1 (or W2Si1) is the S2 / A15