[mcmillinwd]

Has anybody welded a squat rack or weight bench and be willing to share their ideas or plans?

[Alexa]

For brain storming. Go to Google Images and type in: dyi weight bench. There are lots of examples to evaluate.

[TTT]

Difficulty kind of depends whether you want it to be adjustable or not. For the bench I wouldn't bother, I'd just copy the dimensions of one of the red Forza benches on the lowest setting since this pretty much works for people between 5'5 and 6'4, but obviously if you are letting kids or smaller women use it you need it with a lower option. You could search and email Forza for dimensions ("to check it will fit in your gym") or go to a decent powerlifting gym that has one. If you are a novice at weight lifting you need to know that the benches with narrow supports are terrible. The bar needs to be held close to the sleeves. Same with the squat rack but that's more obvious.

For the rack there are about a million possible designs and you need to be more specific as to what you want.

If you make the stuff out of box section then I'm pretty sure 4mm is thick enough, most stuff in most gyms I've been in is thinner.

I haven't made this stuff but I did make a reverse hyper bench out of 3mm box with a stick welder and 6013 rods. I also have a pair of wooden squat stands at my friend's house. Needless to say they are not adjustable, just built to be used by people from about 5'10 to 6'1.