I currently have a Lowe 1600 and want to extend the deck about 2.5 to 3 feet. Working on a frame now with angle iron and rivets. Just curious how thick the aluminum deck should be so it is strong. any suggestions?

you will need aluminum angle welded under it to strengthen it, I would use 1/8".

better option would be 5/8" cdx plywood with at least 3 coats of resin on it, cut the first two with acetone 50/50 and paint on then one or two more of just resin.

this is my extension in my 82 champion 184 notice the divider in the middle for support. there is no flex at all in mine and it is about 4'x32 wide. and I used thin wall aluminum angle with stainless screws.

Thanks for the advice. I will have to find someone to weld the aluminum for me. I love how yours looks!