These were done on mild steel, about 1/4" and 3/16" thick, with a lincoln spt-100 mig, using .030 wire, and c25 mix. How do they look?

 

Too cold, weld looks contaminated.

 

I did not prep it for welding, the metal was rusted, so that would probably cause the contamination? and in the pics, the welds look convex, they're actually pretty flat

 

Yup they are contaminated cause you didn't clean the surfaces enough.
go on with a wire brush on a buffer, it should do the trick for surface rust on steel like that.

other than that, turn up the heat a bit, maybe you'll need a little more wire once the heat is turned up, but it all depend on speed...

set that machine to the best you can and it should give you some pretty descent weld with the c25.

Hope this help a bit...

Kranked

 

got a new thingy you might like, since your a 110 welder fellow. Just picked it up today, its a newer type of welding wire. You use it with gas, but it has a flux with it too. The normal just flux cored is called innersheild, this stuff is called outersheild. You run it with slightly lower amps, slightly higher speed, pulling motion, and a little extra gas. It welds like you were using a 220 welder. It puts down heavier beads than i have ever seen with a 110 mig welder, really strong and super clean, absolutely beatiful from a 110 machine. comes in .35 diameter.

I really can't wait to try it a little later in the week. I have the Sp-135 and really like it for all the little repair stuff that my dad and i do. Works great and is really functional in almost every situation.

If i get a camera for Xmas i will post some pics of this new wire and hopefully you all can get a better idea of it from that.

 

Outershield is a gas shielded flux core, it welds better than gasless flux core, and in some cases better than regular mig wire. You can also kinda get away with using it outdoors/breezy conditions because it is pretty self-shielding. When I was in welding training program, we used that some, it burns extremely hot, and you really can't weld anything thin with it, but it will definitely lay down some very good beads on thicker stuff. I found it was almost impossible to lay a bad bead with it that didn't have good penetration and strength. The only problem was the intense heat it tended to put into the part, which from what I was told makes it difficult to use on anything very thin. We were using it in spray arc mode though too, so that does tend to put more heat into stuff, I'm not sure how it would perform under short arc. Haven't actually run across it other than in that class. Might have to find some to try.

 

yea, spray arc isn't exactly possible with 110, which is why i am interested to try this out on the thicker material.

 

soo...where can i get this outtershield wire?