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1/4 Barrel Prop, How I made it.

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Firstly Mods, Is it possible to get a Forum Topic dedicated to props? building of, lighting, wiring etc...

Warning, kind of a long post, but with pictures :)

I'm just finishing up on a new prop for this year. I call it a 1/4 Barrel prop. I have seen a lot of spheres people have made with dumb RGB's and have not seen one where someone made one with smart RGB. I liked the look but have no need for an actual sphere in my display, hence the 1/4 barrel look. I needed another smart RGB prop on the right side of my display with some size to display across all my smart RGB props. It's size is 5' 3" tall and 5' 5" wide. Essentially it is a matrix with 2 radius's, 1 vertical and 1 horizontal. Having the radius's, gives the illusion of the light fading away from your viewing perspective.


Materials used;
.090 thick aluminum for the bottom and top plates.
.063 thick aluminum for the vertical strips and the belly band strip.
1" X 1" aluminum square tubing for the 3 supports for the top and bottom plates.
Pixie16 with 16 ports of 50 pixels.
Band Aids, should have sanded better. :)

I started this project by drawing the prop out with Google Sketch Up. (free 3D drawing program), I was able to build it to the size I thought I wanted then scale it for equal LED placement. On the Vertical rows, the pixels are evenly spaced at 2 1/2". In the middle Horizontal, they are also 2 1/2 inches but get closer the lower and higher away from center.


I had originally intended to build this prop by hand. (cut all the material by hand) Recently at work I have been using the CNC Router table more and more. The boss being a fan of my light shows, allowed me to cut scrap aluminum on the router table for this project.

The software for the table router is more CAD like than Google Sketch Up. This allowed to very quickly determine angles and spacing of the vertical strips. This picture shows the top and bottom plate already cut, it's drilling holes to give me line up points for the vertical strips.


This picture show the Vertical strip being cut. They are 1 1/4" wide by 65" tall. Since I was to lazy to walk out to my barn and measure the flange on a Pixel 16 light, I cut the LED mounting holes 1/4" and figured I could drill then later. More about this later.


This is the frame welded together. You can see the line up holes on the bottom, this allowed me to center each strip, and keep an even distance for the mounting strips. Since I knew I was using a Pixie 16 with 16 ports of 50 pixel each for a total of 800 pixels. Each strip has 25 holes drilled exactly 2 1/2" apart. There are 32 strips. Hence 32 X 25 = 800 pixels.


Here the vertical strips are being mounted.


After all the vertical strips were mounted I riveted a strip of .063 x 1" in the center horizontally to keep the pixels (in the center) at a spacing of 2 1/2".


A quick poof can paint job.


Installing the LED's. I mentioned before that I had only drilled the pixels mounting holes 1/4" and that I would drill then out later, this came back to haunt me. In other projects with Pixie 16 lights, I have used drilled holes in Corex and pushed the pixels through and the room for error was greater. The strips being only .063 thick (smaller then 1/8") required the holes to be exactly the size of the pixel flange for them to snap in. I used a micrometer and determined the size hole I needed was 15/32" (a 1/16" shy of 1/2") I bought a brand new sharp drill bit and tested on a spare piece of metal, everything worked great when it was laying on the table.

At this point the vertical strips were already mounted so I started drilling them out. I got to the 3rd hole and the drill bit caught and twisted the metal before I could stop the drill motor. I switched drill bits to a step up bit and determined I needed to stop 1 step/shoulder from going all the way through. This proved challenging and I ended up going all the through on some holes, meaning the pixels do not snap in and lock in place, they fall out. You can see zip ties I used to hold them in while the adhesive silicone set up on the back to make the secure. Hindsight tells me I should have drilled the holes on the drill press over wood, before the strips were mounted. Live and learn. :)




Finished with the installing the pixels and a profile view of the finished prop.



A straight on view of the finished prop.


Overall, I really like how the prop turned out. I have the storage room in my barn on a wall so size was not really a factor, other than I wanted a decent resolution (pixel spacing) and a large sized prop. Once i had all the pieces cut, it was assembled and lit over a weekend. I do my lights shows during the summer months, so hopefully I will post some videos of it in action will all my other props in a few weeks.


The video shows a minutes worth of sequencing I used for testing. There is both effects from S5 SE and Superstar.


Edited by default
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FWIW I found a 12mm step reamer (part of a kit) on Amazon (And it, the kit,  was less than a SAE Greenlee found at home stores.

Nothing like having Metric tools for doing exact, metric holes ;)

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Protip that I have used before:  A piece of masking tape on the drill bit at the stop point can help.  You may need to replace the tape if you go too far but it should stop you (or at least give you the time to let go of the button).

If you are going to be doing a lot of drilling for pixels, I would recommend a small cheap bench drill press.

That's a great looking prop!  Nice build :D

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45 minutes ago, DevMike said:

If you are going to be doing a lot of drilling for pixels, I would recommend a small cheap bench drill press.

100% agree with this, but don't do what I did five years ago.  Most drill presses that consumers are going to buy are not designed for continuous operation.  I drilled 50 holes in PVC half pipe for my pixel tree.  As soon as one strip was done, I started the next for a total of 600 holes.  The motor was never given a chance to cool down and failed when I had five holes to go.  Lesson learned - if I do the same process again, I will split one pipe in half, and drill the 100 holes.  Then split the next pipe while the drill press motor cools down.


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  • 9 months later...

Great prop!  I'm going to attempt to build one.   I'm curious how the string of bulbs laid out.  Did you use the cosmic color bulbs?   Then was it one 50 bulb string to every other vertical strip?   Did you use the Superstar editor with a 16 CCR license?

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  • 2 weeks later...

Sorry for the late reply. Missed this message.

Each vertical strip has 25 holes. The first strings starts in the lower left, goes up to pixel 25, then the other 25 pixels on the string go down the next (2nd) vertical strip. This same pattern continues all the way across.

I used the square LOR pixels. I wanted the extra shoulder to snap in againest the strip.

Link to the Pixels used here.

I use both SS and S5 Editor for sequencing this prop. This sequences just like a matrix, (25 x 32). The radius both left and right, and top and bottom, help with the illusion that the lights are traveling around a corner.

Hope this helps.



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