The breadboard I made is 8"x18", a 16 GA steel top and bottom, 20 aluminum can in between glued side to side and top and bottom with epoxy.
The interferometer is composed of a diode laser, beamsplitter and two mirrors each mounted on a machinist magnetic base with a short stud. The beam is about 3" above the top surface. A simple lens spreads the pattern to a screen.
The tests have gone very well. I tried it with and without an innertube for isolation at different places all over my house including the front porch (solid concrete), wood floor, on a coffee table, on my holography table and on a counter top.
The vibration sources I used were dropping objects on floor, stomping on floor, walking, furnace running, washing machine, highway traffic and trains on the nearby tracks.
I haven't had the time to work on it much the last few days and it looks like my weekend will be shot doing something else. Before I get too excited about the results I need do some further tests:
1) Test that it was indeed the aluminum cans doing the magic and not just the sheet metal itself over the short dimensions of the interferometer. This can be tested by simply setting the interferometer up on a sheet of metal the same size as the top without the cans.
2) Test that the stability is not due to the robust nature of the machinist bases with short studs. This can be tested by replacing the short studs with longer posts.
3) Squeeze more hours into each day.
I'm itching to build a bigger breadboard and try out a 2 beam transmission setup on it.
Oh well, John beat me
Tonight I intend to clean off the steel from my first attempt and use PVC cement to bond the sections together prior to adhering the whole mess to the bottom plate (I won't necessarily do both tonight). For those that don't know, my last attempt failed because I over-thinned the epoxy. This time I'll just heat it so that it's good and syrupy while I'm spreading it.
The reason I'm building a breadboard is to test the idea of making a honeycomb using aluminum cans. I made two so far; one was a 4' straight line of cans between 1/8" steel strips to measure the deflection, the second measures 8"x18" with 20 cans between 16 GA steel sheets to check with an interferometer. I'm now working on a 2'x2' breadboard to do further interferometer tests and set up some 2 beam holograms. If these tests pan out, I'll consider scaling up to a larger table.
I got this idea some time ago and got more interested in actually trying it after reading the posting of John Laux's brillant work making a honeycomb using ABS plastic sections.
For me, the breadboard is a step along the path to a more stable table. I just spent some time expanding my table and I'm now working through some PVC tests and trying to get hold of some hexcel. If I can do the latter, I'll make my table top out of that. If I can't, I'll do a full top using PVC (similar to John Laux's design).
I never would have guessed that it would take this much time to glue these cans. I'm doing it can by can, row by row. If I ever build a larger table I'll ask John Laux for pointers on how he did his pipe sections. There must be an easier way. It is getting closer to being done, I have 7 of the 10 rows done.
Sorry I haven't posted in awhile, I have been soooo busy with work, and maching new parts for the lab I just haven't had time for anything else.
I am very glad to hear that your experiments with aluminum cans is going so well, and I also apologize for not doing the wood floor tests with my breadboard in the past like I said that I was going to do.
One of the reasons that I opted for the PVC design is that I didn't have to work with epoxy to put them together...only the steel top and bottom to the final core.
With PVC they make a great cement that comes in a can and has a cotton ball at the end for the application.
The best thing about it is that it dries almost on contact.
Here is what I did...see if you can apply it to your setup...I clamped down a 4ft+ piece of wood 1"x1" to the future bottom of the table. Make this as long as your row is going to be and mark it with a sharpie so you don't have to remember when to stop (it's all about repetition)you don't want to be bothered with counting 800 pieces in my case. Also clamp a smaller piece of the same size wood to one end to make an "L", square these two pieces up and start making your rows.
Once the glue has set up move the row off to the side and build the next one. Keep going until you are finished....
Once you have all of your rows done put one row back on the wood "L", take another row glue the sides that will make contact and place against the first now here's the trick...I went to Home Depot and bought 2 - 3' to 4' "Quick Release Clamps" the kind with the squeezable triggers. After you glue the first 2 rows together slap the quick clamp on each end this will hold them in place. Now glue the third, release the clamps put the rows together and clamp again.
I had to do 4 sections of 2'x 4'. To glue those pieces together I just moved them close together applied glue to both sides and then put a ratcheting nylon band clamp around the 2 sections and ratcheted away until the sections were forced to come true. You can buy these in 4 qty. at Home Depot for $10.00.
You could probably get away with using the band clamps when gluing the rows together, I had the luxury of having help from a friend so we would each handle the Quick Clamps and it only took us 2 days to do all 800+ pieces.
In fact I would use the Band Clamps on aluminum cans because they don't have the strength of the PVC pipes. They would probably buckle under the pressure if you used the Quick Clamps. The band would also force the center of the row to stay in contact with the other row and not bow out.
You probably already had ideas similar to this in the past, I haven't found the "Magic Bullet" to speed this process up any faster...except more hands in the pile.
Good Luck and let me know how it turns out...cause I might need to make yet another table and I am seriously considering a "double deck aluminum can table" ~ steel - aluminum can core - steel - aluminum can core - steel sandwich to be more precise!
A place to forge new ideas into hologaphy! http://holoforge.org
I just glued my last can in place a few minutes ago. I'm using a 1/4" plate of glass to hold the bottom 16 GA sheet steel flat with clamps along the perimeter. Each time I glued a row I put a 2" wide strip of 1/4" glass on top of it with bricks on it to press the tops of the cans even.
Now that the last can is in place, all 85 cans are setting there with 10 strips of glass and 30 bricks on top.
I'll let the epoxy set till tomorrow or Friday night before I try to epoxy the top 16 GA steel in place using another 1/4" glass plate and a bunch of bricks to press it flat.
If any cans are too high, I'm thinking of gently using a hammer.