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February 1, 2004 1am

After getting home from work at 1am I decided to experiment further with isolating the table using thick pillows of bubble-wrap.  I haven't had much time this last week to work on the table but I have purchased some PVC pipe and experimented with some inner tubes (that unfortunately had to be returned because the L-shaped stems won't work).


After putting bubble-wrap on top of the supports and more on top of the wood at the top I waited for the settling to finish.  After the table had settled for 10 minutes or so I found that 15' away from the table I could walk around with no effect on the fringes (shown below in an mpeg movie).  Remember, this is on the second, wood, floor of a house.

Here's a short movie of the fringes. The smearing at the top was caused by the fringe pattern being partially projected onto the ceiling as well as the wall across the hall from the lab.


February 1, 2004 5pm

We've been working on a display wall for our holograms and finally had the time to mock up the shelving and start mounting the shelves on the wall.

Here's the mockup of the shelving, frames and other display items.

Ok we like the layout, so start making the shelves appear in 3D.

Ok, all the shelves are up...

Let's see what it looks like with the frames and a few other items on the wall.

Here's the mostly-finished wall.

Now we've taken a ladder and the track lighting and we're experimenting with the placement of the light.


After getting that far on the wall it was getting late and it was time to prepare some tubing and inner tubes we'd purchased earlier in the day.

First thing to do is take some replacement tire stems and cut off the rubber at the bottom

So that the end of the stem will fit into the 3/4" tubing.

Now prepare to remove the valve cores from the tube stems.  Use some thin needle nose pliers to loosen (partially unscrew) the core

and then use a paper clip to rapidly unscrew the core

until it can be removed from the stem.

Now mix some epoxy and put some around the end of the valve

Push the valve into the end of the tubing and smear epoxy around the valve and tubing so that the junction is completely sealed.

Here are a couple of valves sealed and curing.

Do the same with the inner tubing.

We now have extensions on each inner tube that will allow us to adjust the air level in each tube independently and without jacking up the table.


February 5, 2004

The new inner tubes are under the table and I've been doing several inflation tests over the last week.  Each day I've been varying the amount of pressure in the tubes (I started with them barely inflated), letting the table settle overnight and then recording the fringes over a 30 minute period in the morning while stomping around the house, opening and closing doors, etc.  We don't normally do those things while making an exposure but we need to know what affect those actions have on the table.  So far I've settled on 4.75" of inflation with the 8" tubes we've got.

I've been projecting the fringes out of the lab onto a wall across the hall.  The object in the upper left is an attic door pull that turned out to be a very convenient gauge for measuring fringe movement.  The object in the lower right is a mount pole that is on the table and was intended for the same purpose. If you look carefully you'll see some interesting (to a geek) diffraction effects around the pole.

February 7, 2004

I finally had a day off from work so I starting making a mess in the garage.  I've had all of the parts I needed to make a test breadboard out of PVC pipe and steel but not had enough time to get things started.  Today that changed.

Started out by cleaning both 1' x 4' sheets with an orbital sander and acetone.

Rigged a simple jig for cutting the 2" sections.  The blade is raised as high as it will go and the stop on the left allows me to just push a new section into place without measuring each time.  The stop is shortened so that the cut piece won't bind against the fence after it's been cut off.

Laying out the pieces

They're all cut. 226 pieces of 1.5" PVC pipe.

Next I used a sander to smooth the ends and mixed up a cup of PC7 epoxy thinned with denatured alcohol.  After spreading the epoxy on the bottom plate I put PVC back down, put the top plate on and weighed it down with two cinder blocks.

I then set up a space heater to keep the whole business warm (it got down to 36deg F last night) and let it cure.


February 8, 2004 10am

Finished up the display wall by wiring the track lighting.  Now we need to fill the frames with holograms (the ones there now were there just to help with the placement of the lights).


February 18, 2004

The new canopy finally went up.

Started off with a backer board on the wall to provide support for the metal pipes.

Holding up the pipes with a long pipe clamp while I fasten the frame to the backer board using U clamps over the tops of the pipe.

Put up a board on the ceiling so that the support strap would be fastened to a joist in the ceiling.

Strap in place and fastened to the frame so that it is now holding it up.

Black plastic along the wall.

And finally, plastic all around.

It's not complete just yet (I still need to install the safe and un-safe lighting inside) but I've discovered one nice side effect of the design and that's the fact that I can get inside the canopy and work at the table without having to move the curtain aside or deal with supports getting in my way.

It's certainly a big change from this:


February 26, 2004

This morning I finished hanging the overhead lighting above the table.  Each socket is individually wired so that we can control both a white light and safe light over the table.

Here's a look at the table as lit by the white spotlight.  We'll use this when laying out components.

I've been working on a second breadboard (the first one turned out badly enough that I decided to scrap it and start over) and got all the PVC sections glued to the first sheet of steel last night.  This morning I decided to see how stable the unfinished platform was.

It actually seems pretty decent.  In the morning I'll do some tests to find out if the apparent stability is due to the breadboard or if it's just because the interferometer legs are so short.


2003: Feb | Mar | Apr | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2004: Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec
2005: Blog
2006: Blog
2007: Blog

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