How to Build a <strike>heliostat</strike> Parabolic Reflector




About: Working my dream job in the Telecom industry, so chances are, i'll never have time to respond to comments or messages, nothing personal.

Turn a flat sheet of anything flexible into a parabolic reflector.

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Step 1: Prove It to Yourself

Download this template and print it on cardstock, add something shiny cut it out and tape the edges together, don't cut all the way to the center. The template is Deltacad 6 format

Step 2: Now What?

Wel, you're done, you can print that template out any size and go to town, the plywood dish at the beginning was made that way. However if you like, in the next step i'll give you the math.

Step 3: So Here's the Math

Sort of, for the educated its based on the difference between the arclength integral and x, you can take it from there, for those not fond of thinking read the attached file.

Step 4: Now to Build One

You could just cut one out with a jigsaw like the one at the beginning, but for better accuracy I printed out a section and made a router template

Step 5: Next I Acquired the Materials

I want to say I acquired all these signs LEGALLY, with permission, from the dumpster of a polling place, and I'd really like to see more instructables based on this resource, i know i'm sickened that signs are printed on a material designed to last a million years and are up an average of 2 days.

Nothing like dumpster diving in the rain

Once again these were collected legally.

Step 6: Now Cut Them Out

quick work with a router, lots of plastic curls eveywhere, once they're cut out apply shiney aluminum tape from the hardware store.

Step 7: Now Find a Cool Spot to Work

And tape the peices together, or use cable ties, it came out a little peaked so I added a ridgid disk in the center to flatten the curve, I should have done that first.

Step 8: Finally Flip It Over and Tada a Parabolic Reflector, Now to Turn It Into a Solar Oven

eventually I hope to turn it into a tracking solar oven with drill head motors. a word on the coroplast plastic in these signs, to glue it u can flash it with a blow torch and use super glue, and hot glue works well to glue it together, the "rigid disk is just two pieces with the corrugations orthogonal glued with hot glue. Sorry no pix in operation, it's dark out.



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    99 Discussions


    1 year ago

    Can this be used as an acoustic mirror?


    12 years ago on Introduction

    Animal, can you please post a jpeg or pdf of the template? I plan on making a solar-powered laser (& accompanying instructable) and I need a good template for the experimental dish. I don't have an autocad programs, and the computer from which I'll be printing a large copy of the template DEFINATELY doesn't have one ;-] Thanks-

    4 replies

    Reply 2 years ago

    Just download LibreCAD and be done with it. You can draw, print and design without permission from A desk.


    11 years ago on Step 1

    How come I can't open this file? I have an IMac and the parab16 wont open. also the "dxf" file shows up as a bunch of letters and numbers and lines. Please help a newbie out as I'm not good with this stuff. maybe a PDF file or something like that

    6 replies

    Reply 2 years ago

    If the .DXF file is showing up as a bunch of letters and numbers like a text file looks like, you don't have the correct CAD program installed and your OS is mistakenly opening it with the wrong text editor program. Go download the free LibreCAD program to open the .DXF file correctly.


    Reply 9 years ago on Step 1

    hi well i use Windows XP but i convert the DXF file to EPS and CorelDraw just click on donwload RAR file on this link


    7 years ago on Introduction

    For pete sake people someone talk english here... we are not all science buffs.. just put the math on here so we know what the heck to do. It would some much easier then giving us this sight and that sight.. just tell us what the piece measures that way we all can make on and go about life. I can't open it either and I have the program for it.. SO TELL US PLEASE :o(

    2 replies

    Reply 2 years ago

    He gave us the .DXF file. It has all the dimensions and measurements you need. Apparently you don't have the right program to open the file. Go get a free CAD program to open the file. Something like LibreCAD will work just fine.


    3 years ago

    Hi , I cannot seem to be able to download the parabola math.doc . It says forbidden. Is there any other way to access it?


    4 years ago on Introduction

    Just find an unused satellite dish and convert it....easy


    6 years ago on Introduction

    Get a large smooth beach ball the larger the better because the outer edges of the dish we'll make have to be cut away since they'r perpendicular to (i.e. not reflective the incoming signal. Use polyester laminating resin (fiberglass resin) and 1 or 2 layers of fiberglass cloth to cover half of it (keep it this for light weight). The focal point of the deep dishes is closer to the center than the shallow satellite dishes. This makes it less cumbersome and not as top heavy. Get some tacky adhesive (try 3M or similar) and roll strips of aluminum foil inside with a small smooth ball or 4 inch paint roller covered with a plastic bag. Focal point will be:,or.r_qf.&bvm=bv.48340889,d.cGE&fp=baea18be682a6c13&biw=1024&bih=679 Use the metal rod out of a lamp or other. Make a pivot out of cardboad and polyester laminating resin. Take the rod that bolts to dish and put in the center of a square of cardboard. Place pieces of cardboard to either side of it. The cardboard pieces must not be higher than it's diameter. Remove the rod and fiberglass the pieces keeping them in same position as when rod was present. Do the same for the vertical rod which will be the floor mount. Get a piece of auto inner tube or similar rubber to go between the fiberglassed cardboard. Put the two pieces together (one hole will be vertical the other horizontal). Drill a hole put a bolt with a flat washer through it, another flat washer on opposite side, then a lock nut and a wing nut to tighten it. Cut a large circular piece of plywood for the base. Glue a piece of 2" x 4" wood (or similar) to it in the center. Drill a hole in it's center the same diameter as the vertical rod which will support dish. Place weights (perhaps liquid soap bottles filled with water until you find more aesthetic) on it to prevent tipping. Use an Alfa AWUS035H wifi adapter mounted with cardboard pieces in the shape of an "L" bracket. Punch holes in the cardboard and put 2 rubber bands through to hold the adapter in place (this makes it adjustable). Tape the cardboard mount to the dish and then glue cardboard tabs to the backside to prevent it's moving. Sorry folks this is as simply as I can put it without photos. Ask your friends if they understand. Hav fun . . . digit while U can. Kiss kiss ttfn, bye now


    6 years ago on Introduction

    An easy way to get the diagram needed to build a paraboloid from a flat sheet with different distances from the vertex to the focus