Hello BearBryant (Roll Tide!) I haven't come across anyone yet with reports of how the Krylon spray product might work. I met one person who planned to use it over a year ago, but when I contacted him for an update, he said his build had been delayed. Since this thread, another HFGH owner posted to the thread linked below. Rtyu said he'd applied the Top Secret TS-100 coating mentoned above, three years ago, and was still very pleased to see no deterioration. You will find his posts close to the end of this thread: HFGH Polycarbonate Panels Failing, Part 2 Between the two products, I'd probably bank more on the Top Secret coating, because it's roller applied, and that will likely allow a thicker and more consistent protective coating than the Krylon spray product. Just a guess on my part, though.

Yes, it has been neglected and has a ton of algae on it and some discoloration from age but that provides some protection in the summer ;)..I haven't had any major issues at all and this has been one of the best birthday presents ever and well worth the cost. Even including the wood foundation that cost as much as the greenhouse it has been a bargain. I'd buy another one in a heartbeat.

Lowla, sorry for not seeing your post sooner. I've had a Harbor Freight 10x12 greenhouse for about ten years. I have a blog about building our HF greenhouse and I try to field questions when I can. I've had folks tell me their GH wasn't fitting together correctly, but so far the problem was always somewhere in the construction process; I've never known anyone who had to drill new holes to make things fit correctly. The HF kits do have their weaknesses (see my blog below) but the parts are, in my experience, drilled correctly for assembly. My advice (and sorry it's so late) would be to take some of the frame apart again and get it to the point where you can move the pieces around to make sure they are square and plumb as you go. (You might have to take the roof off, I'm not sure.) The aluminum frame is quite soft, and it's quite possible to put it together with the pieces "a little bit off" from square. Unfortunately If you start out with the parts a bit out of square, as you go further, each new layer of parts can compound the problem. You may have to disassemble some of the frame to start correcting, but you won't have to start all over. You can remove some pieces and get to a point that will allow you to merely loosen the nuts...not remove them...and ease the pieces back into square. At the early stages of assembly, there is flex and "wiggle room" in the frame as you're starting. Use a level as you go. Make sure each vertical post is truly plumb and square before you tighten down any braces. Then your panels will fit into the openings as intended. I hope you can fix the problem! My blog for my own 10x12, if it helps: Building our Harbor Freight Greenhouse

I believe what you refer to as "Glazing bars" are sold in greenhouse supply catalogs as "Double H Extrusions" to join 2 polycarbonate sheets. You can bolt shelves to those but most larger greenhouse owners just use tech screws to fasten almost everything. When going through the polycarbonate side the neoprene washers are necessary. They are usually $6.85 for a bag of 100.