Help with HF spot welder setup...

[Crash]

Some friends talked me into helping them build up a few rifles from flats but in the past I've never had good luck with the spot welder. I have the 110V HF spot welder with a new modified lower tong that AK-Builder currently sells. I find that I can get a good spot weld holding the trigger on for 3 seconds but the overall look of the welds is not like the factories. I don't get the indent or depression of the weld and the weld is not always smooth. I can post pics later if needed.
What does everyone else do? Do you adjust the tongs to just touch each other prior to putting them in the receiver? Do you leave a small gap to accomidate the flat and rails so there isn't a lot of inward pressure? Any advice would be appreciated...

Crash

[Tx Dogblaster]

Adjust the tongs so that they're touching. This way when the receiver is pit between the contacts you'll be able to squeeze them pretty tight. I don't think you'll ever get the welds to look the same as the factory welds. The 110v HF welder isn't capable except maybe on very thin sheetmetal. I've made some nice spot welds with our Lenco machine at work but it's $10k vs $150. I would suspect that the 220v machine would make much nicer welds but it would take more practice with to keep from blowing through the metal.