Sun-uv-a.....

When you develop your ideas in front of the world you have the chance to look a little silly.  So it is with my last post on the diamond flow chambers.  I spent a good deal of time thinking about how to make those things but apparently not a whole lot of time actually thinking about how stupid they were from a mechanical perspective.  The upside is that I built them exactly how I thought I could, they came out exactly how I thought they would, and I got to use my vacuum cleaner and kitchen oven to shape acrylic, which was actually pretty fun.

Let me just say that the most significant problem with this design, which a few readers caught onto and emailed me about, is that the surface area inside is too large.  Basic physics tells us that pressure times area is equal to force. (To think I majored in physics and still did this).  Lets say the pressure is 1 pound per square inch, and the panel was 12'' X 12''.  I psi may not sound like a whole lot. Heck, household water pressure is perhaps 60 psi.  So, if the pressure is 1psi and the inside surface is 144 square inches, then we have 144 pounds of force pushing on the inside of the panel.  This is a ridiculously huge strain to put on the side joints of the panel.  And guess what happened when I built the prototype and hooked it up to the water hose?  It expanded like a balloon and popped open.  Duh!

To create the panels I built a little vacume former.  The idea is that the edges of the panel were held flat while the vacuum sucked the inside portion of the panel about 1/4''.  I then took the molded panel and solvent-welded it to the a flat panel.  The result was a diamond flow chamber just like I envisioned.  Since this was a fantastically bad idea, I'll just post pictures of the vacuum chamber I used to make it, which worked wonderfully!

Oh, just a note to interested readers and myself:  Setting the oven at 300F and baking the panels for 5 minutes worked well.  320F was too hot...bubbles formed.


 

 The vacuum chamber conneccted to my vacuum cleaner.  The top plate is hinged to the bottom plate, as can be seen in the next phone. (Hey, it works...)

 A better shot of the "vacuum press".  The top plat has a hole in it where it connects to the vacuum cleaner.  The air is then sucked out from the inner portion while the outer portion holds the edge of the panel.

To operate this high-tech device, take the floppy panel out of the oven, place it on the former, close it and stand on it while you turn on the vacuum cleaner.  Allow 30 seconds and presto!

A side view of the panel I created. Its hard to see, but one panel is flat and the other is formed.  When glued together, you end up with a hollow chamber.

A top portion of the panel.  This was after it exploded out the side, so most of the particle escaped. 

I drilled a hole and then used solvent to melt the acrylic into the wire mesh. 

Well, there you have it.  Lets try to forget I ever did this... ;)