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Max's BADASS Display, Part 5
Max Maxfield Max Maxfield
5/2/2014 04:45 PM EDT  
 18 comments

Good grief! Things are positively racing along here in Max's World (where the colors are brighter, the butterflies are bigger, the birds sing sweeter, and the beer is plentiful and cold). In my previous post on the Bodacious Acoustic Diagnostic Astoundingly Superior Spectromatic (BADASS) display, I described how I was starting out by creating a paper and cardboard prototype.

(Click here to see a larger image.)
(Click here to see a larger image.)

Well, I'm happy to report that the front panel is coming along in leaps and bounds. I've routed out the plywood (which will be stained to look like old wood) to accommodate the hardboard display and control panels (which will be painted to look like antique brass). In fact, I've been beavering away doing a whole bunch of things, all of which will be revealed in future columns. For the moment, however, I have a bit of a poser to ponder.

In order to give the whole thing more visual interest, the inner hardboard panels will be attached to the main plywood panel using brass acorn nuts. Also, each of the 256 tri-color NeoPixel LEDs in the main display area are going to have an associated brass surround.

Originally, I'd simply planned to use regular, flat brass washers, but then I started to think that these might be a tad boring and let the rest of the presentation down. Then, much to my surprise, I ran across some gorgeous countersunk brass washers as illustrated below:

Oooh! These look so tasty. I couldn’t resist them. But now I have a problem -- how am I going to attach them to the front panel? In order to understand the issues involved, let's first consider the cross-section shown below:

This is just a quick sketch I threw together in Visio, so it's not to scale. I've shown things as having sharp corners and suchlike. In reality, everything is sumptuously smooth and curvy. However, there are two problems (sad face). First, I have some thin sheets of translucent white plastic -- about the same thickness as a piece of paper -- which were kindly donated by my chum, Rick Curl. The image below shows a piece of white paper at the top overlaid by a sheet of this translucent white plastic film at the bottom.

Although it looks like you can see right through these sheets in the above image, they appear to be opaque when whatever is behind them is dark. My plan is to cut discs out of these sheets and stick them behind the central holes in the washers. The thing is, I don’t want to see any glue from the outside of the assembly as illustrated below:

The next problem will present itself when I attempt to glue the washer-film combo to the hardboard panel. Once again, I don’t want any glue to be visible from the outside of the assembly as illustrated below:

My concern is that -- although the wall of the brass washer is reasonably substantial with regard to its structural strength -- it's really rather thin when it comes to sticking it onto a flat surface. When we are talking about having 256 of these little rascals, we obviously want to have really solid bonds. The last thing I need is for them to be dropping off all of the time.

So, the bottom line is that I need some method for attaching disks of the translucent film to the inside of the washers, and for attaching the washers themselves to the main panel, all without seeing any glue, which would totally ruin the effect.

It probably won’t surprise you to hear that I already have a cunning plan. Indeed, it's a plan of such awe-inspiring cunning that we could pin a tail on it and call it a weasel (as the Black Adder would say in the UK television sitcom). However, it may well be that you have a plan that is even more cunning. If so, now would be an excellent opportunity for you to share it with the rest of us.

Related posts:

— Max Maxfield, Editor of All Things Fun & Interesting Circle me on Google+

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Clive
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Re: Fresnel lens maybe...?
Clive "Max" Maxfield   7/9/2014 9:53:25 AM
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@slomobile: Whichever way you go, you might consider using a 1 1/16" Forstner or anular bit (ideally spun by a cnc mill for accurate grid placement)on the face of the hardboard to positively locate each brass washer.

That's not a bad idea -- I was already moving to using a CNC machine to drill the holes, because having them wander aroudn even a little will ruin the whole look of the thing.

slomobile
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Re: Fresnel lens maybe...?
slomobile   7/8/2014 6:43:43 PM
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Whichever way you go, you might consider using a 1 1/16" Forstner or anular bit (ideally spun by a cnc mill for accurate grid placement)on the face of the hardboard to positively locate each brass washer.  You can fine tune the depth to just barely capture the film/lens between washer and board eliminating the need for glue there.  A small bit of glue in the recess can unobtrusively secure the washer if needed.  The hole depth can also be used to adjust distance from LED to film/dissuser/lens.

Max The Magnificent
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Re: Fresnel lens maybe...?
Max The Magnificent   7/3/2014 4:37:41 PM
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@jb0070: The "filler disk" could asily be glue, or wood putty / paste...

Thanks for the suggestion -- in fact I now know exactly which way I'm going to do this ... keep watching EE Times for my next blog on this topic...

jb0070
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Re: Fresnel lens maybe...?
jb0070   7/3/2014 4:30:28 PM
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The "filler disk" could asily be glue, or wood putty / paste (or something similar --- does not nned to be a washer / metal / "finished product"). Both harden and can be glued easily, and allow for clean up" before assembly. This can also be done to "mount" whatever lens you fit into the hole.

Max The Magnificent
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Re: Make the Film Disk bigger
Max The Magnificent   5/8/2014 9:47:57 AM
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@AnSc.de: Make the film disk as big as possible to fit under the washer...

This is a variation on one of the approaches I was considering -- but I think it's a better idea than mine ... let me look into this...

 

AnSc.de
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Make the Film Disk bigger
AnSc.de   5/8/2014 1:22:29 AM
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Make the film disk as big as possible to fit under the washer.

Then you can glue it to the inside of the outer ring, so the unwanted glue on the inner ring is avoided.

Then you can use the space of the film disk below the washer to glue the washer in place without unwanted glue outside the washer. Or use here a ring of double sided adhesive film.

You still have to be careful with the amount of glue...

 

crude Inkscape sketch:

Washer with Disk and Glue

 

Max The Magnificent
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Re: Fresnel lens maybe...?
Max The Magnificent   5/6/2014 10:21:57 AM
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@jstabler: I suggest you make a filler disk with a center hole the same size as your brass washer...

This sounds like a good plan ... I'll add it into the mix ... I'm still looking at a variety of alternatives ... I'll be posting a follow-up blog when I make my final decision... watch this space :-)

jstabler
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Re: Fresnel lens maybe...?
jstabler   5/5/2014 7:27:02 PM
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I suggest you make a filler disk with a center hole the same size as your brass washer.  It doesn't matter what material you use, could be another very cheap washer.  Glue your translucent disk to the filler disk.  Glue your new assembly to the brass washer.  Glue the final assembly to the surface of your project.  If you select your glue positions carefully, the glue should be hidden when you are done.

Max The Magnificent
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Re: Fresnel lens maybe...?
Max The Magnificent   5/5/2014 2:29:58 PM
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@perl_geek: Two thoughts for the mass-production...

I'm currently exploring a variety of options. I must admit that the Fresnel lenses do look rather tasty -- but it depends on (a) how they fit in the washers and (b) if I can find a really low-cost source.

I have one on order at the moment so we can check point (a) -- depending on the result we can decide what oiur next move shoudl be.

perl_geek
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Freelancer
Re: Fresnel lens maybe...?
perl_geek   5/5/2014 2:25:27 PM
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Two thoughts for the mass-production; 3-D printer to create multiple copies at once, or a CNC machine to mill them. (Out of a large sheet, so lots created per loading.) At least the machine wouldn't get bored.

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