I don't have any sheet metal - steel or aluminum - and I checked prices on a sheet big enough and it was too expensive. I had the PVC pipe sitting around for ages so that material was free. In the end solid 1/4" PVC is as good (possibly better) than sheet metal or sheet aluminum. It's easy to work with. It's lighter. It won't rust. It's more than strong enough for its intended purpose. I'm not hung up on everything has to be metal.