Dream a little dream

by Phunguss  

 

Summer 2012.  I was working as tech support on a temp contract.  One morning on the way to the job site, I see a maintenance crew dismembering a 12 foot mesh dish.  I casually ask them what their intent for the dish was.  They jokingly told me they would sell it to me.  After I got serious, they said they couldn't sell it and had to move it to storage.

I was bitten.  Ever since version one point zero, I thought about going larger.  I collected random parts from equipment destined for recycling.  I had discussions with colleagues about getting my hands on a large, no longer needed satellite dish.  I finally broke down and started looking on craigslist.  BANG! Within two days, I had a hit and was on my way to starting this new, much larger project.

Craigslist 12 foot

Oh, she was a beauty:

Big doggy

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Danger, Will Robinson!

by Phunguss  

Be warned:  This project has the capability to create severe damage to life, limb, and anything else at the focal  point.  If it feels unsafe, don't do it.

Zowie!

I borrowed and modified this from the Interwebs. 

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Parts is parts

by Phunguss  

Wow.  Disassembly of the large dish was rather quick.  It all broke down into ribs and mesh with a large center hub (about 18 inches).  It was all lightweight aluminum.  Everything fit nicely into the back of a jeep liberty.

Parts of a dish

The tough job was removing the giant steel pipe that was six feet into the ground encased in concrete.  The final attempt was just cutting it off in place and leaving it there. 

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Too hefty

by Phunguss  

The existing control assembly was made of steel and was really heavy duty.  It had to be.  It was a twelve foot sail that had to be stable enough to keep aligned.  This was only one axis, and I needed to control two.  The mental gears started turning, and this piece was donated to another tinkerer.

Heavy lifting

I love the manliness of this setup, but I was leaning towards a more portable device, so weight was an issue. 

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I like ribs

by Phunguss  

Version one point zero taught me to use flexible adhesive.  I had some old tub caulk laying around, so I started with that.  I adhered platters to the ribs.  This was the wrong move as I later realized it was easier to install the mesh before attaching anything to the ribs.

No BBQ sauce here

You can see five ribs covered in platters.  All that is missing is the mesh.

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Divide and conquer

by Phunguss  

The best solution I could manifest was to slice the central hub into three sections.  This would maintain a maximum single dimension of ten feet.  I figured if everything was under ten feet long, two people could easily setup and install the entire device.

Plasma cut central hub

I don't own every tool in the shed, so I had to take this to another shop to cut it.  Thankfully the proprietor will do work in exchange for beverages. 

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A Few Clouds

by Phunguss  

So after completing almost six mesh surfaces, it was a nice sunny day.  There were a few clouds, but I wanted to test what was completed so far.  A curious neighbor saw that I was up to something and came over to investigate.  He helped me with my step ladder and we managed to get it aimed relatively close.  I placed an old dog food can where the LNB would normally go.

Ready to focus

Insert water.  Wait. 

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We have ignition

by Phunguss  

Just as we positioned the test section, a few clouds passed by.  These clouds were sporadic, but seemed to linger in just the right position to detract us from the test.  It was about ten minutes on and off of clouds before we got a good boil.

boiling

This was a nice rolling boil. 

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Safety first

by Phunguss  

A successful test of the first third.  Things got hot, and standing, let alone malingering past the wrong area could leave you with permanent physical damage.  So lets talk about some potential risks and mitigation.

Risk 1. High winds.  This is a 12 foot sail.  A large gust of wind hitting a 12 foot circle can make for some instabilities.  This could flail superheated material in any direction causing severe burns.

Mitigation Theory 1.  The natural design (if you can call it that) of the platters leaves us with some wasted surface area.  This also means it is not a complete solid surface, but more like a wiffle ball.  You often see flaps cut in canvas banners to allow wind to pass through.

R2. Walking through the focal area could potentially blind or burn a person.

MT2. The cradle design of the mount and aiming system will place the focal point approximately seven feet above the ground and five feet from the center of the reflecting surface (see the can on the LNB post).  This will eliminate any chance of a person walking into it.

R3. Too much power.

MT3. Since we only tested a third, we have to have some way to 'blink' or turn off the system if something goes wrong.  This will be accomplished with a simple curtain to cover the reflective surface.  The curtain is still in development, but will be deployed before the final dish is tested.

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Mesh it up

by Phunguss  

Adding the mesh was a little difficult at this point.  I had to use a utility knife to cut off the excess caulk, as it had seeped down into the cracks where the mesh was supposed to be.  After the mesh was in place, I used rubber bands attached to paper clips to help me align the platters in nice rows.

off to a good start

This is section one of three.  Each section has seven mesh surfaces to cover. 

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