# So, who can explain this then?



## Ian Bee (Apr 27, 2014)

So, after watching Lazze, spot welding some Aluminium sheet together using a spot welder, and some mild steel stock separating the copper electrodes from the Aluminium, https://www.youtube.com/watch?v=gcgC3V3mkcw I thought I'd give it a try as well!


I welded two pieces of 1.6 mm. 5005 Aluminium together, whilst using 2 pieces of 0.55 316 Stainless Steel to keep the separation.  Worked a treat!


I tried differing pressures, as well as spot timing, and was quite impressed, but NOT as impressed as I was when I tried to separate the Aluminium coupons, tore the Aluminium right off the welds, these welds are keepers!


My question is, WHY does Aluminium behave differently under the spot welder when I use the Stainless Steel strips?  Can I simply turn up some Stainless Steel electrodes, and place those in my welder instead?


Anyone...?


----------



## JimDawson (Apr 27, 2014)

I'm going to go out on a limb here and say that the stainless would present too much resistance over the length of the electrode.  It would be likely that the electrodes would just get hot and the weld quality would suffer.  Making some thin stainless ends for your copper electrodes should work.

I suspect the reason that the aluminum welds better with the stainless buffer is the the stainless is actually getting hot and that is what is actually doing the welding.  The aluminum does not present much resistance to the circuit, just slightly more than the copper.


----------



## Ian Bee (Apr 27, 2014)

Jim, thank you!

I had posted this question on another forum, and the same kind of answer came back.


----------



## NodakGary (Apr 28, 2014)

I am thinking the steel or stainless steel gets so hot in a small spot from the spot welder and that this heat is what is fusing the aluminum together. The electrodes are the source of the heat of course, but, it is heat from whatever source that fuses (welds) the aluminum. I saw that video also and that is the assumption I came away with.
NodakGary


----------



## TOOLMASTER (Apr 28, 2014)

http://www.hobby-machinist.com/showthread.php?t=19505&highlight=spot+weld+aluminum


----------

