I have a different brand of aluminum frame greenhouse, but the design is similar to the HF GH. Mine came with flat aluminum struts that were about 3/4" wide about 6' long, and they are screwed to the inside of the frame to provide additional bracing. There are two in each corner and each pair runs diagonally from the upper corner to the base (they basically each span one corner window panel diagonally on the two walls that form the corner). There are also 4 of these struts that run diagonally to brace the roof. Because they are installed diagonally they provide incredible stiffening. My greenhouse just survived a 70mph freak storm with no problem. Below is a link that diagrams how these reinforcements are placed. I would think it would be relatively easy to get some aluminum stock and cut your own reinforcing struts. It could be relatively light gauge because it is not supporting a load, but simply providing tension to the structure. This might even be easier than trying to build a bulky wood frame to reinforce your HF GH, and this approach doesn't take up any room. Here is a link that might be useful:

I must admit that you guys seem like a happy group for people that admit that they bought a less than quality product but decided to make the best of it AND MAKE IT BETTER. That is why AMERICA will always win. We never quit. I personally grew up on an Island, connected to the mainland by a bridge, granted, but the nearest town of any size was 42 miles away and it wasn't all that big either. My father could make ANYTHING FIT or WORK and I can recall time and time again when he did just that. I am very pleased to acknowledge that I have those genes running in my veins. The Oreintials (read China) might be able to make it cheaper, but WE make it BETTER. I absolutely LOVE to read how y'll have improved and strengthen those little flimsy, twisty pieces of left over beer cans and made them into things of beauty and STRENGTH. Long live Reynolds Wrap and Alcoa as well. Give me another beer would you. In a bottle if you please 1eyedJack and the Dawg Stay tuned for the upcoming saga of "The Greenhouse from Hell"

Good point about the warranties! Hmmm, my GH roof is almost always covered with an endless supply of desert dust. I can hose it off, but it will be covered again in no time (in spring, anyway.) I have had a lurking concern that IF there is a panel deterioration problem, it may be heat related. I read a post on another forum last year from a Tucson GH owner who'd purchased two 6x8 kits to use the poly panels in his own homebuilt wood-framed GH. He posted that after a few years the roof panels were brittle and breaking. I know he doesn't use his GH in the summer at all, and I figured his roof panels must have been subjected to extreme temps (if it's 110° outside, imagine what it may be inside an uncooled GH in Tucson, especially the air right under the roof panels...140°? 150°?) I hoped my plan to use the GH year round might help me to escape the same fate (I'm hoping I can keep the temps in mine under 100°, although most of my plants will tolerate that.) Still, I note that the three mentions of this problem so far (the Tucson person, yours, and Jamesy40's) have all happened in southern states. If heat is a problem, mine will likely fail sooner than some...so I'm keeping an eye on this trend! I guess it could be an opportunity to upgrade the roof to 6mm at least, eh? :-) Sheri

Harbor Freight did not suggest this. Lets just say that Harbor Freights Tech support was, um Harbor Freight... I have to admit it was nice, they Cross shipped me new ones, which performed the same as the old ones. I found an overseas manufacturer of similar "budget vents", I think they were called Thermofor, who was very helpfull, and gave me a suggestion. I unscrewed the endcap that has the adjustment screw, and press the plunger till the seal almost comes out, then the oil will start to leak if you press softly on the plunger (If I pressed hard the seal comes all the way out, and you get a big mess ;) then close the whole thing and test. THrough trial and error, I now have all five of my HF openers opening between 65 and 75 degrees. Gato, I am not sure why mine did not work, and yours did, I am only 1300 feet higher than you, but I had a Total of ten from HF (The first five and the second five). Even at 38 degrees they were open five inches under load before I modified them ;) I would not recomend that anyone else try this, because I am sure it voids the warranty. (I tried it on just one first, then got bolder and tried the rest. I did spill all the oil out of one, and I replaced the oil with Cooking oil, even this one is now working ;) so I guess I will have to wait and see if opening them is gonna cause any long term ill effects.