I built a workbench and painted it with some rust-oleum paint that I had on hand. I know I could have sanded the top a little smoother (plywood) than what I did but after painting the top is not a smooth glass like finish like I have on another bench I made and just applied polyurethane(several thick coats) Can I put polyurethane on top of the paint to smooth it out? Will it stick to paint? Thanks for your help.

I am going to be painting my home and replacing some of the T1-11 siding where needed in about a month. (I will be using my two-vacation to do this.) I have decided that I definitely want scaffolding to do this. I'm not real fond of ladders. I've priced scaffolding and it is pretty expensive and doesn't have the adjustability that I want. I basically need a 3-foot scaffold height on two sides of my home, a 4-foot on one side, and mostly 5 on another, with a max of 7-foot at one section. Also, the rental opportunities within reasonable driving range are slim. Long story short, I want to build my own scaffolding. I planned to put in on four hard wheels so I can kind of move it around. I have gone to the hardware store and looked at the various metal things that reinforce where one might join two or more pieces of wood, but I have no idea how strong is strong enough for certain key things. Like will a 2 X 4 be okay for each of the four uprights? (I expect it to be about 3 feet wide and 8 feet long.) And is it safe to have multiple 2 X 4's and a piece of plywood thrown on top for a working platform? Are there any simple sketches on the web anywhere? I've looked but only got complicated engineering websites that I didn't understand. Any guidance would be helpful. I would hate to bolt a bunch of wood together only to realize that it was heavier than I could possibly move or too flimsy. Speaking of bolts, are two 1/4 inch bolts strong enough in each end of a supporting 2 x 4? I expect a loading of only 250 pounds, me and either a sheet of T1-11 or a 5-gallong paint pail. Thanks!