Welding Options

Okay, so rebuilding deck under wife's orchid shade house for the third time...previous wood and bamboo rotted out again.damp and termites.

So the deck is on a slope lower end about 800mil. Top flat section will be concrete.

So want to use combination c and box section steel for the frame over the slope. Not sure what decking to use at this stage , maybe wood or maybe sheet over with a couple of layers of cement sheet add mesh re-bar then concrete.

Thought at first I would bolt all the steel together Mechano style but..

Have absolutely no experience of welding and thought it might be a fun experience to try it and would certainly be handy around the farm for so many jobs.

Found an excellent website that gives a detailed welding 101, lots of others show video etc too but difficult to view with GPRS.

Anyways question is : What is is better for all purpose welding, gas or arc?

Seems many types and makes/price of arc welders available in LOS.

Need recommendations for a particular type/wattage or even model of arc and/or any other info on gas welding.

thanks to all you pipe fitters, oil and gas industry types, plumbers and bakers.........