How To Make Parabolic Mirrors From Space Blankets - NightHawkInLight

hello everyone in this video I'll be showing the process I used to make this 28 inch parabolic mirror these can be used for lots of solar applications like heating and cooking and I was also curious to try out a mirror like this to build a DIY telescope optically my design isn't quite up to telescope standards yet but I may get there the process to make these mirrors involves using compressed air to form a sheet of aluminized Mylar commonly sold as space blankets into a parabola this is accomplished by first securing the mylar to a flat airtight surface where it is then pressurized from below like a giant cell of bubble wrap with a prototype in my mind the first part of this project I start work on is the surface I'll use to inflate the mylar I decided to try this 1/2 inch PVC sheet as my material air won't pass through it and it's perfectly flat so it should work well as a base plate to form my mirrors on for this project to work I need an air injection port in the center of my square plate the first step for that is to mount a bicycle tire valve into a small scrap left over from what I trimmed off I then drill quite a large hole into the centre of my base plate with some PVC cement the scrap that I mounted the tire valve in is attached with the valve stem facing outward once I flip over the plate you can see why I've done things this way the valve is sunk below the surface and I won't have to worry about it getting in the way I only need to complete one more step here and that is to sketch out a circle of the same diameter as the mirror I'd like to create with some sandpaper I'll also rough up the surface along the outside border as I'll later be applying glue using the circle as a guide that's it for the forming plate it's now time to take a look at the mylar sheets like I said before aluminized Mylar is sold as space blankets and they come folded up into a tiny package before this material can be used to make a mirror it first needs to have as many of the wrinkles taken out of it as possible a simple wood frame in the shape of a square and just larger in diameter than my PVC plate should work nicely to stretch out the mylar the easiest way I've found to temporarily bond the plastic sheet with the wood was with a coat of spray adhesive I worked on one side at a time attaching the mylar to the top side of the frame then flipping it over I pulled it tight to take out the wrinkles running parallel with the ground by repeating the process on the left and right side I was able to also pull out the wrinkles that ran vertical I could get this tighter but this result should be adequate the baseboard is prepared and now so is the mylar so it's time to see if my method will work from some test cited earlier I found that epoxy is the best adhesive for adhering mylar to PVC so I'll carefully spread a layer around the outline of the circle the mylar is then lowered on top and pressed into the adhesive to get a good seal to provide air pressure all it takes is a bicycle pump though I tried this small one first I later switched to a larger one that I could use without being under the table as soon as the epoxy has been given sufficient time to cure I can begin inflating the mirror I'm not sure how far I can push this mylar before it pops but fortunately it forms a parabolic shape almost immediately what I haven't talked about yet is how I plan to hold the mirror in this shape after it's been removed from the base plate my first test was to cover the mylar in spray foam when it hardened I was hoping it would have stuck to the mylar holding the curve in place this resulted in about the saddest excuse for a parabolic mirror that has ever existed fortunately it only takes a few minutes to scrape off the base plate and try again after inflating this second sheet of Mylar for another attempt I decided to try molding the mirror with fiberglass watching the resin flow over such a smooth curve was pretty cool to see once it was spread evenly I lowered the first sheet of fiberglass on top I noticed at this point I had a small leak so until the fiberglass cures I'll have to occasionally add more air in the meantime I added 2 more layers and to accelerate the cure time I heated the mirror with a hairdryer the mirror I made for my first attempt using the spray foam was damaged when I simply tore it off the plate so for this one I'll cut the mirror off using an angle grinder finally I get to see the result once cleaned up the reflectiveness is actually very good the fiberglass is just a little too flexible and wants to curl up like a taco shell if it's pressed against a flat surface it still holds the parabolic shape I just need something to keep it there I found this plastic landscaping trim that seemed like it would work well for this purpose I quickly shaped it into a ring and held it together with nuts and bolts the ring was then placed on top of my mirror with a weight holding it firmly against my workbench some secures the ring in place and I'll just need to wait for it to dry to see how well it works and here is the final result not too bad for being made from a one dollar space blanket I think an even smoother surface should be attainable if I inflated the mirror a little more before laying on fiberglass my sponsor for this video is Reitan solar a solar panel manufacturing and development company working to create higher efficiency panels at lower cost thanks to new manufacturing technologies the cornerstone of their process is the use of a particle accelerator to cut the silicon substrates that solar panels are built upon this cutting technique virtually eliminates waste which means the best quality of silicon can be used without increasing the cost over lower quality panels better silicon translates into better power conversion and a more efficient solar panel as a whole if you'd like to learn more about rate on solar they're currently running a crowdfunding campaign that you can check out through a link in the video description below take a look I have high expectations for what they'll accomplish I hope you enjoyed this video and if you did you can find more on my youtube channel Nighthawk and light thank you for watching you

Channel: NightHawkInLight

Views: 4,216,143

Keywords: NightHawkInLight, Solar, Panels, Parabola, Space Blankets, Sun, Ray, Free, Energy, Fresnel, Mirror, Lens, Overunity, How to make

Id: 8CLRTa_ocmo

Length: 6min 59sec (419 seconds)

Published: Wed Jul 13 2016