Go out and search online to find a couple reliable sources for intensity of solar radiation for your region and use that data to determine if this project is going to be feasible or useful to you.

Draw up some plans for what you want the shape of your frame to look like. My Choice was based upon the bed frames I found for free. At this point you also want to look at the size you want the focal area to be because it will determine the size of mirror you will use and the spacing needed between the mirrors on the frame. DO NOT make the same mistake I made; keep in mind the width of the material you are using. A small CAD model is great for getting your idea fully formed.  

If you chose bed frames like I did you need to cut/grind away the rivets holding the pieces together. I used an angle grinder with metal cutting wheels(NOT GRINDING). Use a punch and hammer to knock-out the rivets once the heads are gone or just hit the piece on the cement. Cut all the pieces down to their predetermined length. I chose to use coped joints on the corners because it provides more surface area for stronger joints.  I used lap joints on cross beams by simply cutting out a section on the end of the angle iron.

I suggest using an arc welder and then you don't need to brush away thepowder coat paint that is already on the bed frames. It will burn right through it, no problem! Grind off the excess and clean up the frames.

At this point you will want to spray an outdoor paint coat all over the frame to prevent rust.

If you used more metal instead just continue drilling the holes. Cut the composite deck balusters to length using a miter saw. Lay them into position and drill the hole through one side where you already drilled a hole through the frame. Place a washer on the back side and push a bolt through and cap it with a nylock nut. Then drill the other side and mount that bolt as well. Repeat until all balusters are attached to the frame. Draw out the positions of the mirrors on the balusters and drill the those holes as well.

Insert all the bolts, washers, and nuts in their proper positions all around the frame and snug them down.

Place a regular 1/4" 20 nut on all bolts sticking out of the frame and then add a lock washer above the nut. I spun the nut down as far as it would go with my fingers. Screw on all the Ball head mounts on top of the bolts. They will vary slightly in their height but it doesn't really make that much of a difference over all. now if the Ball head mount bottomed out before itreached the lock washer go a head and tighten the nut up against the underside of the Ball head mount. Congrats You Are HALF WAY!!

Find or buy a good quality glass cutting pliers. This tool has a glass cutting wheel on one side and a pliers/breaker on the other.

When dealing with large mirrors make sure your cutting surface is always FLAT and CLEAN. Put some double stick carpet tape on the bottom of your straight edge. The first step is to cut the large sheet into 6" stripes. Measure out 6", lay the straightedge along the line on the glass and use the glass cutting wheel to etch the line all the way across. Do not retrace the line, press hard the first time and keep the cutting tool pressed slightly toward the straight edge or IT WILL WANDER. Place the score line on the edge of your table and put a piece of wood on top of the piece you are going to break off. Gently applied force until the glass fractures. If you did everything correctly it should break perfectly along the score line.

Repeat until all the strips are cut and then start on cutting the 6"x6" pieces. Instead of using the table method to break the 6"x6" pieces off the strip, use the pliers on the tool to apply pressure on the score line and you will get a really nice yield from your mirrors! Make sure to keep your work area clean and also clean the mirrors off before you stack them or the small piece of glass will scratch your mirrors when you move around the stacks.