What wall thickness lets the light through?

In my case 2 mm was too much: it let very little light through. I dropped to 0.8 mm, which is nicely translucent but a bit fragile on the overhangs, and ended up at 1.6 mm as a middle ground between strength and letting light pass. It depends on the filament: with matte PLA you need to go thinner than with a semi-transparent one.

Can you 3D print a lamp and have it be transparent?

Not fully transparent, but translucent yes. Matte PLA only lets a little light through; if you want more, reduce the wall thickness or use a semi-transparent filament. I tried orange matte PLA and, with a soft light inside, it ended up with a nice lava-lamp effect.

How do I hide the seam on a lamp?

The slicer (Bambu Studio in my case) has a dedicated seam setting. I set it to random: instead of a straight line top to bottom, it scatters the layer change into little dots. It doesn't disappear entirely, but it hides far better than leaving the full line marked.

Why does a lamp take so long to print?

Because they're large, hollow parts with lots of overhangs that force supports. Some of my designs ran 14, 13 and even 23 hours. Shrinking the size, simplifying the shape to avoid supports and reducing wall thickness cut that time a lot.

Projects

I designed and 3D printed a lamp from scratch (secretly, for my girlfriend)

Every light at home is white and too bright, and both my girlfriend and I prefer warm, small lamps. The problem is that the ones I like are as cool as they are expensive. So I set out to design and print one from scratch, in secret, to see if I could get her to like it. This is the whole process, fails included.

Watch the video on YouTube ↗

The constraint that shaped everything: a light that only shines upward

Before I even started sketching I made my first mistake: I went to AliExpress and bought this light that connects over USB-C and has a switch. The problem is it's not a bulb that emits in all directions, but a round, flat light that only shines upward. And that conditions the whole design: the lamp has to be built so the light comes out the top and spreads. The entire shape revolved around that limitation.

The light link is an affiliate link: if you buy through it, I get a small commission at no extra cost to you.

The base dilemma: one piece or two?

My first model had a big flaw. If you print the whole lamp as one piece, bottom to top, there's a point where you'd have to pause the print to insert the LED and route the cable through the neck and out a hole. Hugely complex, and on top of that you could never swap the LED if it died. The alternative was to make it in two pieces: the base separate from the top. At first I said I didn't like that solution… and ended up making it in two pieces anyway, because it was far simpler.

The screw-on cap

I started with the hardest part: how to fix the light to the lamp. I came up with a kind of cap that screws on from below, with a thread at 0.2 mm tolerance. I printed a first prototype to see if it worked. It fit pretty tight —it was actually hard to turn— but I liked it, because I figured it would wear in over time. I also had to open a bigger hole than planned so that not only the cable but the switch (1.5 × 1.5) and the USB connector could pass through.

Wall thickness: from 2 mm to 0.8 to 1.6

Here I got it wrong several times in a row. I started with 2 mm walls, thinking it'd hold up better, but it was too much: it let little light through. I dropped to 0.8 mm, which is far more translucent and still strong, but on the overhangs and toward the top it was a bit marginal. I ended up at 1.6 mm as a middle ground: stronger, better finish up top and still lets light through, at the cost of more filament (that base alone was already 100 g).

The seam set to random

When I printed the first test sphere, the seam —that vertical line where the head jumps between layers— showed a lot. Bambu Studio has a dedicated setting for this, so I set it to random: instead of a straight line top to bottom, it scatters the jump into little dots. It's a half-solution —the dots are noticeable— but much better than leaving the full line marked all over the lamp.

Impossible print times and abandoned designs

The big enemy was time. One version ran 14 h 20 min; another one I was excited about, 23 hours, almost a full day, and with so many supports that they grew out of the lamp itself: straight up unusable. I tried flat-topped sketches to drop keys on, a sort of hourglass, a stool… and dropped them one after another, between parts separating while printing in mid-air, a layer that shifted and even the head rubbing against the printer. I learned the hard way that black lets no light through, so better to test in blue or light colors.

The idea that saved it: add a constraint (and a function)

While listening to a podcast I heard that to be creative you have to set yourself constraints. I'd half-accidentally set one midway through: I didn't want a lamp that was just a lamp, but one with an actual use. I got up from my chair, turned around, and noticed that if my girlfriend has anything, it's a ton of pens and markers. I added a hole so it doubles as a pen/pencil holder. That idea solved two things at once: it gave the lamp a real function and, in passing, saved me most of the supports.

The reaction and the result

The final print took 10 hours and I had a single shot at it. It came out with its flaws: a layer that shifted, the seam dots, a slightly rough top and a hole that didn't fully close. But when I showed it to my girlfriend and switched on the light, she said it looked like a lava lamp and that she loved it. And honestly, it surprised me: on camera it looks great and in person it really draws the eye. For the first lamp I've ever designed and printed, it turned out original though imperfect. With a bit more know-how it would have come out really well… and probably a little smaller.

FAQ

What wall thickness lets the light through?: In my case 2 mm was too much: it let very little light through. I dropped to 0.8 mm, which is nicely translucent but a bit fragile on the overhangs, and ended up at 1.6 mm as a middle ground between strength and letting light pass. It depends on the filament: with matte PLA you need to go thinner than with a semi-transparent one.
Can you 3D print a lamp and have it be transparent?: Not fully transparent, but translucent yes. Matte PLA only lets a little light through; if you want more, reduce the wall thickness or use a semi-transparent filament. I tried orange matte PLA and, with a soft light inside, it ended up with a nice lava-lamp effect.
How do I hide the seam on a lamp?: The slicer (Bambu Studio in my case) has a dedicated seam setting. I set it to random: instead of a straight line top to bottom, it scatters the layer change into little dots. It doesn't disappear entirely, but it hides far better than leaving the full line marked.
Why does a lamp take so long to print?: Because they're large, hollow parts with lots of overhangs that force supports. Some of my designs ran 14, 13 and even 23 hours. Shrinking the size, simplifying the shape to avoid supports and reducing wall thickness cut that time a lot.

Want to replicate it? Here's the lamp model on MakerWorld. I've got more things I've built in Projects, and if you're fighting the seam or overhangs, take a look at my 8 tricks to improve your 3D prints. All my designs are free on my MakerWorld profile.