Acrylic car sun visor project.

Years ago, it was standard for many cars to come with tinted, transparent sun visors. They were intended to be seen through, not around. In recent decades, manufacturers have switched to simply tinting the top portion of the windshield ("windscreen", if you're in Europe), and making the sun visors opaque, usually vinyl-covered foam or something.

You can see an example of the tinted plastic visors of yore in this video form Jay Leno's Garage, where he gives us a tour of his 1937 Tatra T37. He talks about the visors at 18:18, and you can also see them at 16:56.  https://youtu.be/c2XyLgv-UQY?t=1016

BMW equipped the Z3 - and its variants - with sun visors so tiny as to be nearly useless. So a few years ago, I thought I'd try making some transparent ones out of colored acrylic ("plexiglass" if you're casual about copyright law). As acrylic, they could be bigger, since they could be seen through, and by taking advantage of the "Well, they were nearly useless before. How much worse could I do?" rule, I felt free to make them sort of functional, and far groovier than they were before.

That project, I didn't photographically document. I made them from amber / orange acrylic, with a second layer of smoked acrylic in the top half. So, the lower portion would filter some sunlight, and the upper portion would filter out more.

Recently, I realized that the Z3 M Coupe's roof was drilled for grab handles on both sides, with the handle only appearing on the passenger side. You'll recall that the Z3 was produced with distinct budgetary and schedule constraints, so they only made one type of roof, no matter what country the car was sold in. For 'Merica, the driver's side had the factory roof-grab-handle holes filled with plastic plugs, which, conveniently, were in exactly the spot that I'd been wanting a third sun visor, for when the sun burns off side of my head, leaving me embarrassingly half-headed. For this new effort in visormaking, I did take pictures as I went, so the curious can watch along and maybe get a laugh. Some observers have noted that my sun visors "would look great with the 'sun visor delete option'", so I'm aware that not everyone will be a fan of the look. Such persons might be disappointed if I don't cry myself to sleep because they don't like my 70's-style-tinted-amber-car-sunglasses.

Anyway, the photos:

The previously-facricated sun visor whose design will be shared by the new one. BTW, the factory sun visors are all stored safely away, so this is completely reversible, in case I decide I hate them too. These first ones were made using the hinges and brackets from a sacrificial pair of Ebay sun visors. The look of these visors is kind of "prototype factory race car", I guess. You definitely have to like the look of exposed mechanical parts. To make them read a little more as "intentional mechanical honesty", rather than "hideous redneck science project", all the metal parts are polished.

Having carefully Dremeled open the weensy little Z3 sun visor, we find a tough polypropylene (I think) insert, inside the leather textured PVC casing. The black bracket will be needed for the new visor, since the exact sorcery to making spring steel clips, which hold the visor in any position you need, is not something I can pull off in my garage workshop.

This is the part from the factory Z3 visor I need. The rod is welded to the mounting bracket, and the clips on the ends are folded springs that rotate around the rod. Their clamping force provides resistance that keeps the whole mechanism from being a floppy mess. The rotation is very stiff from the factory, but we'll be addressing that issue later on.

Fist , the paint is all removed with a wire wheel. Previous experience has shown that the brackets seem to be made from stainless steel, or at least some kind of steel that doesn't mind being left uncoated, since the last visors I made were stripped and polished, with no signs of grunginess or rust in the three or so years I've had them.

Having test-fitted the angle of the bracket in its grab-handle position in the car, the mounting bracket needs a little more bend in it. Enter my new three-in-one metal shear / brake / slip roller to add some bendiness to the bracket. This is the "brake" part of the machine, which is a fancy way to say "bender up to and including ninety degrees of relatively thin metals".

The bracket will go here, but not wanting to make new holes in the head liner, I'll be making a strap to screw to the existing holes. As a bonus, the strap will also cover the holes. Since the strap will be totally visible, it will need to not look ugly.

Acrylic isn't that resilient. It's prone to cracking if it takes too much structural stress in a small area, and since the acrylic will be taking the force of the springs when I move the visors around, the mounting holes where they screw to these spring clips will be the likeliest place for the acrylic to  break. I want the stiffness of the hinge to be just enough to hold the visors in place without drooping. Right now, they're really strong, so to take some of the fight out of the spring clips, I'll be  removing material from them by cutting slots in their spines. Not having dealt with this exact mechanism before, I didn't know exactly how much to remove. So I moved gradually, shading in the area to be ground away with a sharpie. The grinding was not done with a Sharpie. That would take too long. The shading was done with a Sharpie. The grinding was done with a Dremel and a stone bit and a steel burr bit.

After more grinding and testing the hinge action a few times, this turned out to feel about right.

The strap will screw to the factory holes, and the visor bracket will screw to this. It was cut from ordinary aluminum you can get at a hardware store. It's not especially strong, and the aluminum isn't anything like 6061 or anything, so don't expect to use it for anything high-performance. But it is at least easy to work. This piece is 1/8" thick by 1" wide.

The black plastic cover was part of the Z3 eBay visor, and was meant to go with the hinge bracket. I plan on using it as part of the new one.

If you were around in The Seventies, the "drilled for weight" look might work on you. Elvis' sunglasses were drilled for weight, for example. Elvis himself was definitely not, however. To my eye, drilled is good, and countersunk drill holes are even better.

You're always wondering if the project will look like shit, until your start in on it with the buffing wheel. Then you start to feel like a rock star.

Test fitting all the parts together to make sure I didn't forget anything. All the screws are stainless, pulled from Dad's Old Chest of Many Many Random Components. Cap nuts always look more finished than regular nuts, and they shine up on the buffing wheel really nicely. My dad called them "acorn nuts", but he was from "down south", and the drawer you buy them from at Ace Hardware calls them "cap nuts", and I got tired of getting stared at, so I call them "cap nuts" too, now. The hex bolts were also buffed up. Those holes in the spring clips? They're where the acrylic will be bolted to the hinge. Since the spring clips are spring steel (duh), they're really tough. Drilling those four holes in the spring clips either broke or dulled four drill bits without going all the way through. In the end, a high speed steel burr bit in the Dremel finally got through. I don't mind telling you that sucked.

Everybody uses cardboard to figure out the shape of what they're making, for reasons that probably don't need explaining.

Plastic was sourced from Delvie's Plastics. They're not a sponsor, they're just easy to deal with and they tend to have everything. Surprisingly, you can cut acrylic sheet with a table saw, provided the blade is nice and sharp, and you don't push it through too fast. Acrylic likes to chip, but you should be able to avoid that if you're gentle with it.

The hardest part of this shape is the notch at the top, where the visor gets out of the hinge's way. Internal cuts are harder than external ones, like the four corners, and if I screw up and have to start over with a new piece, it will be here in the notch. Internal radii are best done by drilling the corners first, and then connecting them with a cut. Considering the brittleness of acrylic, I used a forstner bit. A forstner bit is a special kind of drill bit that cuts from the outer edge of the hole first.You get cleaner holes this way. A normal drill bit cuts from the center outward, and when used on acrylic, you always get chips at the edge.

Before connecting the holes and finishing the notch, I checked the spacing against the plastic hinge cover that will need to fit in there. At the top of the photo, you can see a small set of forstner bits, which are definitely recommended for any workshop.

Completing the notch with, first, a bandsaw. This blade is coarse, and meant for wood. I really need to change it to a finer-toothed blade more suitable to metal and plastic, which seems to be what I spend more time working with. Anyway, since acrylic likes to chip and since the blade isn't ideal, push slowly and carefully.

Connecting the corner holes with a Dremel abrasive disc. Since it's handheld, the cut can be crooked in at least two directions, so make the cut a little conservative, and plan to sand/file to size.

Notch is now a notch, but not a nice one.

Sanded, radiused, and finished notch. This piece is the larger of the two, and is amber colored.

The smaller smoked piece of acrylic is shaped in the same way. This is a socket, chosen by eye for the corner radius and cleverly used to mark out the corners, to keep them uniform.

Test fit of amber and smoked pieces. Shaded areas will be removed from the smoked layer.

Corners are easy. Disc sander.

Final test fit before peel and assembly.

The plastic comes with a paper film protecting both sides. It's tempting to take this off as soon as you get it, but if you do, you'll ruin the finish while working on it, and once scratched, it's impossible to polish it back to factory perfection. Wait until you're completely done shaping before peeling it. Plus, you can draw and write on the paper, so, yeah, just leave it till the end. Fun fact: while taking this photo, my phone's camera software decided that this was best shot with "FOOD" mode. Yeah, I guess it had a point.

Smoked acrylic being peeled.

Since these pieces will be sandwiched together (hopefully forever) they need to be really clean where the surfaces meet. Dust or dirt trapped between them will be really annoying to look through. There are special spray cleaners for acrylic, which also have an anti-static ingredient, to keep them from simply sucking up every shaving and crumb of plastic in town as soon as you wipe them off.

Final assembly... which is out of focus.

Still some dust and shavings to clean off.

Well, that seems to have worked, somehow. I have yet to test fit myself in the car with a helmet on, though. I'll find out at this weekend's autocross.

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Thankfully, I did think to make sure they don't collide when they're both up in the folded position. Now that I look at them together, I notice that the the smoked layer on the new one (on the left) is on the inside, rather than the outside. This will bug me until I fix it this afternoon.

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