Welding Tips and Tricks

Hello I’m new to this forum and have a question about tig welding copper, what I will be welding is a 1/8” copper buttweld about 17” long for a whistle housing that goes on a bouy. I have my choise using either my Miller 250dx or a lincon 200 tig would the Miller 250dx be able to run a bead with straight argon or should I get a bottle of helium because of the amount of heat that I need to apply.thanks any input would be appreciated .

You could preheat the material

Your going to need around 200 to 225 amps with pure argon, 3/32 electrode should be ok on dcen.