Interest Check: Color Wheels for Vectrex 3D Imager

[jasonbar]

CAD models for the reproduction color wheels have been uploaded to a rapid prototype site, & I'm having 2 made in each of 5 different materials & finishes to find out which materials works & looks best. I should have these back in a week or so.

In talks w/ another shop to laser cut the clear Acrylic disks & print the decal to stick to the disk. I wanted to avoid a decal/sticker, because I fear that it may pull up over time & then rub in the narrow cavity in which it lives inside the goggles. However, I haven't yet had luck finding a place to print directly onto acrylic--they need to be able to print both opaque (black) & transparent (red/green/blue). Still looking.

Thanks,
-Jason

[TrekMD]

Thanks for the update!

[VectorX]

That's cool, hope it works out. There might be other kinks that won't be discovered until they're put to use as well (hopefully not though).

[gliptitude]

Perhaps the decal could be sandwiched between two thinner pieces of plastic, to protect it.

[jasonbar]

Jun 13, 2013 14:51:18 GMT -5 gliptitude said:

Perhaps the decal could be sandwiched between two thinner pieces of plastic, to protect it.

That's a good idea that I already considered and dismissed for two reasons. One, because the disk part of the stock color wheel is a mere .020" thick, so each outer layer of plastic would have to be about .008" thick, which is rather flimsy. Two, because I would need to bond across the entire disk (and the adhesive would likely mess up the printed art) to keep the sandwich together tight--if I use one disk with one sticker, then I need to bond just the inner portion of the disk to the hub--better yet, if I can print directly onto the plastic, there is no chance of sticker peel-up either!

Thanks,
Jason

[gliptitude]

Jun 15, 2013 11:02:36 GMT -5 jasonbar said:

Jun 13, 2013 14:51:18 GMT -5 gliptitude said:

Perhaps the decal could be sandwiched between two thinner pieces of plastic, to protect it.

That's a good idea that I already considered and dismissed for two reasons. One, because the disk part of the stock color wheel is a mere .020" thick, so each outer layer of plastic would have to be about .008" thick, which is rather flimsy. Two, because I would need to bond across the entire disk (and the adhesive would likely mess up the printed art) to keep the sandwich together tight--if I use one disk with one sticker, then I need to bond just the inner portion of the disk to the hub--better yet, if I can print directly onto the plastic, there is no chance of sticker peel-up either!

Thanks,
Jason

Wow. I didn't realize the color wheels were that thin. (Have never seen one in person). I have also never seen a 3D imager in my hands before. Is it necessary that they be that thin, or is there possibly room for a thicker wheel?

Perhaps if there is room for a thicker wheel, the two sandwiched layers could be bonded mechanically, rather than the adhesive?

... I guess as far as the printing process goes though it would definitely be optimal to have the colors screen printed directly on the material, for the least distorted transparency. Is this how the originals were made? ... I just see that there is a big difference in clarity between laser printed overlays and the screen printed originals. It's a challenge to make something that doesn't cause the vectors to look foggy.

Probably you already have some reference of the thickness as it compares to the overlays, but maybe others will find it interesting or useful:

Approximately 460 microns thickness = .46mm = .018"

.5 mm (= .01969") is still an acceptable thickness for a screen overlay, and I believe some of Vectrexmad's Pole Position overlays were that thick. ... So the color wheels are approximately the thickness of the original overlays??? Do they have the same amount of rigidness? ... I had imagined they were MORE rigid.

[gamezone]

My thoughts were or are shared by earlier posts. It would be nice to have an actual 3D Imager. Since your idea is for reproductions, it seems to hold little value by themselves for me at least.

Demand seems to be growing for retro consoles in the other parts of the world, so a market could be out there waiting to be tapped.

[jasonbar]

Making an imager is way beyond my skills & time & budget! =O

Having said that, I have progress on the wheel reproductions:

1 - 3D plastic printed hubs are in the mail, on the way. 2 each of 5 different materials.
2 - I picked up 2 pairs of color wheel disks from 1 shop. They look fabulous.
3 - In a week or two, I'm picking up some color wheel disks from another shop, made with a different process (and a different price & a different predicted level of durability...)

Thanks,
-Jason

[jasonbar]

I've been a bit busy, but I've still been dabbling a bit with the reproduction color wheels. I was delayed for a while by not having NOS color wheels in hand for reference against my reproductions. I got 3 Vectrex color wheels & a second imager last week, so I've resumed my reproduction wheel efforts.


Progress since the last post:

1 - I got my 2nd rev of 3D printed plastic hubs from Shapeways. They fit into the 3D Imager's clamp mechanism much better than my first rev. The hub design needs 1 more slight rev because the square drive cavity on the hub is a smidge too large, resulting in a rattle/knock as the wheel spins, but, apart from the noise, the wheel does spin & operate fine, mechanically (not optically--see below). Regarding the hub 3rd rev, I'm going to put that effort on hold until I achieve a successful transparent wheel coloring process.

Out of the 3 Vectrex wheels & 2 3D Imagers in my possession, I get different "smoothness" results. Some wheels run quieter than others, some tend to scrape when spinning. By studying the geometry of the clamping geometry that holds the wheel in the Imager, I've found that the wheel can tilt quite a bit when installed, & it doesn't take much tilting for the perimeter of the wheel to rub against an inner face in the Imager. As such, I don't want to make the disk portion of the wheel be thicker than the .020" thick stock wheels, because that will make the wheels more likely to rub if they tilt just a little bit off of nominal.

2 - I have good laser-cut clear plastic wheel blanks, cut from .020" thick PETG. They're a good fit, solid, stiff enough, etc.

3 - I tried applying to the clear disks transparent adhesive-back film from 2 different vendors. Neither was nearly transparent enough to see through.

4 - I made a quick stencil & tried transparent Testors spray paint: Transparent Candy Red (SKU# 1605), Transparent Candy Green (SKU# 1601T), & Transparent Blue (SKU# 1257T). I first laid down opaque black spray paint over half of the disk. That was easy. I then shot blue on the appropriate pie piece area. I tend to apply too much paint per pass when painting in general, so I went very light on this application. Half an hour later, the paint was pretty dry & I could look through the disk & see very clearly through it. Unfortunately, the blue tint was very mild--it wasn't even close to being blue enough to match the original wheel's blue. I laid down 1 more light pass of blue paint. After that dried, I was left with a slightly darker blue, but the part was no longer transparent--I could barely see anything through the blue portion. Because of my failure with blue, I never tried out the red or green. So, this process could possibly result in successful creation of wheels that have only a very minor tint, but this process is labor-intensive, tedious, slow, & who wants a barely tinted wheel anyway? Note that I could certainly make "black & white" wheels this way, where the viewer sees proper 3D, but all vectors will be white.

5 - I contacted many silk screen & sticker shops. The few that responded either weren't interested enough to invest in the process, considering the quantity that I'd want, or they knew that they couldn't achieve the transparency requirements with their process.

6 - My current thrust is to instead laser cut 4 different pie pieces & bond them all to the hub. There's plenty of surface area on each wedge to achieve a good solid bond, & I will also attempt to bond the thin radial edges where neighboring wedges butt against each other. I've contacted tons of plastic manufacturers and, I've generally found that rigid transparent colored plastic generally comes in .125" or thicker. Way too thick.

I did (hopefully) hit paydirt yesterday, though. One supplier told me of Lexan 8020, which comes in .020" thick & can be customized to any color. However, nobody seems to carry this in stock (I did find another flavor of Lexan in transparent red, but they didn't carry green or blue), & the minimum quantities to have the factory fabricate per my Pantone color & transparency specs are astronomical. The salesperson did say that she can get me what I seek in vinyl film, however. She assured me that it's rigid enough for my application--I'd previously been discounting vinyl as too floppy. I have samples on the way & should have them in hand in a couple of weeks. I'll check their transparency, print some 1:1 templates to cut out the 4 pieces, see how well the vinyl bonds to my plastic printed hub, & go from there. (Note that, if the vinyl is a bit floppy, I can probably increase the OD of the hub a little to reduce the radial overhang of the vinyl, which will stiffen up the assembly a bit.)

Thanks,
-Jason

[jasonbar]

Because I bet nobody read my long text, here's some eye candy. SolidWorks screen grabs for your amusements.

-Jason

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[TrekMD]

Sounds like you've had quite the adventure trying to get these made. The images look great! Curious to see how the vinyl worked in practice!

[VectorX]

Sept 11, 2013 15:38:15 GMT -5 jasonbar said:

Because I bet nobody read my long text,

I read most of it Speaking of, I figured that vinyl would work, as I thought it would be rigid enough.

[50tbrd]

Very nice. Lots of food for though. Can't wait to see the product.

[jasonbar]

Received vinyl samples in the mail: 5x 8x10x.020 transparent red, 4x 8x10x.020 transparent green, & 4x, 8x8x.020 transparent blue. Alas, the requested opaque black was not sent. I called to inquire but got bumped to voicemail & didn't receive a call back.


My first thoughts:

1 - The vinyl doesn't come with a peel-off backing pattern. It's sandwiched between pieces of tissue paper. Super static cling like a dryer sheetless dryer run in the midst of winter. I worry about it being inadequately scratch resistant, given its soften compared to rigid plastics.

2 - A few sample measurements showed the thickness to be a hair under .020., & the rectangles were cut to an admirably consistent 8x10.

3 - The vinyl is relatively firm. Not hard & brittle like acrylic or ABS or even polycarbonate. The cantilevered length of the wedges hanging over hub to which they are bonded it is only about 1", which isn't too bad, except for that one darn skinny minny red wedge on the MS wheel, which I fear will flap up & down like a cartoon tongue when in action. After cutting & bonding a test wheel, I'll see how rigid the wedges are & see if I need to try to edge-bond the wedges or even create a very very thin annulus around the perimeter to secure the wedges at their extremities--either a thin piece of sheet metal bonded or, hopefully perfectly clear tape laser-cut into an annulus.

4 - The color! My grief thus far in this project has been attaining transparent colored material. This vinyl looks fabulous! I took may pictures with my cheap point 'n' shoot digital to try to consistently & fairly compare the candidates by holding the sample directly against the camera lens & viewing the same static Test Cart screen, on the same Vectrex, with the same ambient lighting, etc. I think that my new vinyl is a close match for the stock colors, & it's better than the Madtronix imager wheels, whose blues & greens are too similar to each other.

Next post starts a picture fest.

Thanks,
-Jason

[jasonbar]

1a stock NE/CC wheel red
1b stock NE/CC wheel green
1c stock NE/CC wheel blue

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