I once tried something a lot of years ago that worked for me.
I had a friend that had aquired several satellite dishes in a local auction from a company going out of business. I got a couple of small six foot dishes from him that were made from a very thin fiberglass and aluminum frame to support the parabolic dish.
I had remembered seeing an old school movie about the nasa experiments using dishes for solar heaters. So i decided to experiment with one of these. I took an old paint roller, a can of 3m spray contact adhesive, and a couple of rolls of aluminum foil to this dish. I sprayed the strips of foil heavily with the adhesive spray, and rolled them into place with the old small paint roller. It was hard work, to follow the curvature of the dish, but eventually I got-r-done. I put the original feed support back onto the dish, and took off the feed horn, and placed a small steel mesh piece over the hole, draped a few pieces of bacon on the mesh, propped up the dish, and aimed at the sun, and WHAMMO!! french fried bacon in 10 seconds flat!
I had originally meant to carry my experiments further, such as a collector to boil water in the focal point, and a light-dark sensor on each side to track the sun via a polar mount, but money and time back then would not let me. But I now have a renewed interest after finding this site, so, who knows what I will try next. Maybe build a Stirling engine from old weedeater parts, and install it up there??