Printing custom window latches: what worked for me

I get where you’re coming from with PETG not holding up in the sun, but I’ve had a bit more luck than most folks seem to. I printed some latches last summer, and while they did get a little brittle after a few months, they didn’t totally fail—maybe our porch doesn’t get as much direct light. I did try doubling up the infill and adding a tiny lip on the edge for strength, which seemed to help with sagging. Not saying it’s a long-term fix, but if you’re in a pinch or don’t want to mess with ABS/ASA fumes, it’s worth a shot. Sometimes it’s just about what you can live with for a season or two...

I get the “good enough for a season or two” logic, but honestly, I’m still not sold on PETG for anything that needs real durability in sunlight.

“...they did get a little brittle after a few months, they didn’t totally fail...”

I’ve tried PETG on my south-facing windows, and even with extra infill, it just didn’t last. Maybe I’m picky, but I’d rather deal with the hassle of ABS or ASA fumes once than have to keep reprinting parts. There’s also the energy aspect—reprinting stuff every year just feels wasteful, both in time and electricity.

Not saying PETG is useless, but for stuff that gets hammered by the sun, I’d rather overbuild once and forget about it. Maybe I’m just lazier than most, but the fewer maintenance projects, the better...

That makes a lot of sense to me. I’ve had PETG parts go brittle on my deck after one summer, even with thicker walls and higher infill. Honestly, I’m with you—if I’m going to the trouble of designing and installing something, I’d rather just deal with ABS or ASA once and not worry about it again for years. The fumes are annoying, but it’s a one-time hassle. And yeah, having to reprint every spring feels like a waste of time and energy. Sometimes overbuilding is just the smarter move.

I get where you’re coming from, but I’ve actually had better luck with PETG than ABS for certain outdoor latches, especially in spots that don’t get full sun all day. ABS and ASA are definitely tougher, but the warping during printing is a pain—even with an enclosure. Plus, if you’re not careful with ventilation, the fumes can linger way longer than you’d expect. For me, PETG with a UV-resistant clear coat has held up surprisingly well on north-facing windows. Maybe it’s just our milder summers, but I haven’t had to reprint yet… just my two cents.

- Totally hear you on the ABS fumes... my garage smelled like a chemistry set for days once.
- PETG’s been decent for me too, but I did have one latch go brittle after a winter freeze. Maybe my batch was off?
- Haven’t tried the UV clear coat yet—might give that a shot, since repainting is getting old.
- North-facing windows definitely seem to help. South side? Toasted plastic city.

Can’t say I’ve had PETG get brittle in the cold—mine’s held up through some nasty Minnesota winters, but I always print at a higher temp and let ‘em anneal a bit. Might be worth a try before switching materials. As for the UV clear coat, honestly, I found it more hassle than it was worth. Ended up just printing in black ASA and calling it good. South-facing windows are brutal, though... nothing lasts forever there.

I’ve had similar luck with PETG—seems pretty tough, even in the cold, but I have noticed that layer adhesion gets a little dodgy if I don’t bump up the temp or slow down the cooling. My shop’s not exactly climate-controlled, so in winter I’ll sometimes pre-warm the enclosure with a space heater for a bit. PETG handles it, but you’re right about those south-facing windows. Sun just eats through plastics, no matter what you do.

Tried the UV clear coat route last year on a batch of latches for our back porch windows. Looked great at first, but after one summer, I started seeing flaking and yellowing. Maybe I got impatient with surface prep, or maybe it’s just not worth the hassle unless you’re going for aesthetics over longevity. Black ASA has been my go-to lately too—prints a little stinkier, but it shrugs off UV a lot better. Only thing is, ASA warps like crazy on my old Prusa unless I use a brim and keep the enclosure tight.

Funny thing—I had an old PLA latch last about six months before it turned into something resembling stale bread. Swore off PLA for anything outdoors after that.

One trick that helped: when I do stick with PETG, I toss finished parts into the oven at 80C for an hour or two (just keep an eye on ‘em). Seems to relieve stress and toughen them up a bit. Still, for high-sun spots, ASA or even polycarbonate if you can stand the printing headaches.

Wouldn’t mind hearing if anyone’s had luck with PC blends, though. Haven’t tried those yet—price tag always makes me hesitate.

- I’ve actually had PETG last longer than expected outdoors, even on the south side, as long as I kept the infill high and walls thick (like 4 perimeters). Maybe I just got lucky with my filament brand?
- Tried ASA a couple times but the warping drove me nuts. Even with a brim, corners still lifted unless I dropped the bed temp way down after the first few layers. Not sure if it’s my enclosure or just a drafty basement.
- UV clear coat didn’t do much for me either. The prep is a pain, and it always seemed to peel off in sheets after a few months.
- Haven’t braved PC blends yet either—price puts me off, and I’m not sure my Ender can handle it without major upgrades.
- Anyone else find that color makes a difference? My white PETG parts always get brittle first, while black seems to hold up better. Maybe just coincidence...

That’s interesting about the color difference—

My white PETG parts always get brittle first, while black seems to hold up better.

I’ve actually had some clear PETG latches out on my back porch window for about a year. They held up better than the white ones I tried before, but eventually they started yellowing and got a little brittle, especially where the sun hits hardest. Not as bad as the white, though—those cracked in a couple months. Black seems to last longer, but it gets hot in direct sun, which isn’t always great for moving parts.

For ASA, I did mess with turning off part cooling after the first couple layers. It helped a bit with warping, especially on bigger prints. I usually keep the fan at like 10% just so the overhangs don’t get too ugly, but honestly, ASA is still a bit of a diva in my shop. Enclosure helps more than anything, in my experience. If you can rig up a cardboard box or something around your printer, it makes a world of difference.

Funny enough, most of my window latches are now PETG in a dark gray. Seems like a happy medium—doesn’t show dirt, doesn’t get too hot, and so far they’re holding up.