i always use a football needle. The ones with a straight hole out the end and a side hole. I bend it slightly curved making sure not to pinch it shut. I the take a peice of argon hose about 5 feet long, one end i put on a oxygen hose fitting. The opposite end i put one of the adapters for the football needle for use of a compressor, that way changing needles is easy. I then remove a valve from an old argon Y set-up. That way u can leave the purge flowmeter set at whatever u want control flow with the valve. I use the same basice set-up for basic purging just with an old gas lens replacing the needle.