Made a spring fuller from used car coil spring. It has been annealed. I can now cut it with a hack-saw.

 

I'd very much like to mig weld a hardie shank to the bottom of this spring fuller. Is there a process to use in order to perform this? I don't have a stick welder w/fancy welding rods. 

 

The other thing; I'm thinking I **may** need to harden this fuller and temper it. If so should I harden the entire spring fuller and temper or only a portion of it? If tempering isn't required, possibly harden it just a slight amount like slowly cooling it in hot oil or air cooling? 

 

I can quench this spring steel in water and afterward it is glass hard and shaters when struck w/a hammer. When it was in it's ORIGINAL spring state.....I could cut it with a hacksaw, easily. 

 

I have found that automotive springs, when they are springs, are quite soft. Same is true for heavy/over the road truck flat spring.I can drill them with a drill press and cut them w/a hacksaw.

 

Thusly, my fear is destroying this fuller, by stricking it with a hammer, if not hardened in some form. 

preheat, weld, then go directly to heating in the forge and normalizing it.

 

I have a swing arm fuller that uses a piece of coil spring as an arm and I use it normalized.  I do replace the arm every 5-8 years depending on how heavy of use it gets.  Maintenance is not a bad thing.

I agree with Thomas. Preheat (look up proper temps but likely between 300-500 degrees F), weld, post heat or as Thomas suggests go straight to the forge and normalize. All of my struck tools are left normalized (which is technically heat treating).

I'd preheat to greasy stick temperature, (if you search the forums for greasy stick you'll find more info on this).  As otherwise suggested normalise immediately after welding before it has a chance to cool down.