View Full Version : Welding wire - copper coated? Why?

07-26-2010, 09:03 PM
I just ran out if a 10# spool welding yet more patches on my 1980 FJ40. This wire is Hobart brand, copper coated ER70S-6 in .030". The non-copper coated is something like $27 a spool and the much-harder-to-find copper coated wire (like what I had) is $76 a spool. I'm doing all this research online, but will probably go to Airgas tomorrow and buy a spool.

What purpose does the copper coating serve? Can I just get the non-copper?
This is on a 220v Miller wire feed with CO2/Argon (Silvershield) gas.



07-26-2010, 09:49 PM
Damn - I thought I had an extra spool of ER70-6 in .030 I could hook you up with, but now I can't seem to find it. 70-6 vs 70-3 is more expensive because it can better alloy with dirty metal, and all the steel we have in our TLC's is recycled crap, so it does help.

I do have ER70-6 in .045 if that helps.

07-26-2010, 10:22 PM
ive never knew there was a diffrence.. i just tell them i need either .23 or .30 and im using a miller 180 and they always get me the right stuff.. the .023 wire 10# spool at airgas was $23.00 so your .030 is possible pushing $30.00ish

07-27-2010, 08:38 AM
I always thought that it was just to keep it from rusting and to lubricate it as it slides through the cable. Maybe Beater can chime in.

The copper coated TIG rods I have at home are not rusty.. the non coated ones are. I don't use the rusty ones, they contaminate the weld.

Bruce Miller
07-27-2010, 08:43 AM
Welding wire is copper coated to help keep welding fumes down, but, more importantly, to improve the machine's ability to feed the wire dependably. For someone new to welding, good and consistent wire feeding is one less critical factor to be concerned with as you try to put down a good weld. Buy copper coated if you can.

07-27-2010, 09:01 AM
there are soooo many benies to using copper coated. here is a link of composition, and the copper is minimal, but important.

I like er70s-2 vs er70s-6 for clean stuff, better puddle control on tig if clean. 6 is specifically made to go through mill scale, but it will contaminate still on tig.


07-27-2010, 09:25 AM
Thanks all - I can count on the Rising Sun club for great, relevant answers. I suppose I could just take regular steel wire and apply a thin coat of 'Birfield Goop' to prevent rusting, right? In fact, that should also completely eliminate upper trunion bearing wear in my Miller welder. The benefits just never end!

I will seek out copper covered wire, since I'm doing a lot of fine bodywork welding on this 1980 FJ, and have been extremely impressed with this welder and wire so far.

07-27-2010, 09:32 AM
if you are doing thin sheet, you may want to use a different wire. What machine is this? Most 220v machines can't go down low enough with enough control for thin sheet, at least home level machines.

esab makes some very good wire -

07-27-2010, 10:39 AM
I just found the unopened box of 70S-6 in .030. You can have it for what I paid if you want it, I'll have to look it up but it was much cheaper than local retail. I'm just north of the Springs, PM me if you want it.

07-27-2010, 01:10 PM
OK - according to the guy at General Air, the copper coating is merely for rust protection, and that the wire also has copper as part of its makeup. Perhaps what I saw online that was silver (raw steel colored) was not really the type I needed. The only wire he had that was $70-something a spool was flux-core, not solid core, as I needed. This ER70S-6 was $29/10#.