That's an awesome spot welder. Aluminum is tricky stuff to spot weld. Your gonna have to clean the weld areas on both pieces with a stainless steel brush to get the oxidation off. Steel is much more forgiving. I don't have any specific reccomendations for you on time and amps. I have a cheap Harbor Freight 220v spot welder. Let me see if there are any reccommended time,-amps settings. If you dig around online, you might be able to find that info. That kind of info is non machine specific.
If i were you i would start experimenting on some pieces of steel first, to get a feel for the machine. I think aluminum is gonna be more of a challenge, and "flying blind" with aluminum is gonna present more variables into the mix that just don't exist with mild steel. When i spot weld steel on my cheapie, there's no timer involved. It's set to full blast i squeeze the 2 pieces together between the electrodes and flip on the power. Then the steel gives off a tell-tale spark once the pieces have fused together and it is done. The spark is your clue to a good weld. Forego the timer for now, you can time your sparks manually and start writing things down like amps and time it takes to spark. With this info , you should be able to get started.
