You’re getting to the end of a roll of filament, and you’re not confident there’s enough left to justify using it for another print. So you throw it in the drawer, next to the other almost-empty spools from the last time this happened.

Here’s what you should be doing instead.

Weigh the filament and print with confidence

Credit: Patrick Campanale / How-To Geek

The main problem with an almost-empty spool is that you don’t know exactly how much filament you have left. You can’t exactly unravel the spool, but there is a trick you can use to weigh it without the mess. Since your slicer knows how much filament is required for a print, you’ll be able to commit to printing an item since you’ll know, more or less, how much is left on the spool.

When you open a new spool of filament, weigh the whole thing. Now subtract 1KG from the weight to get the spool weight. You can now use this as a starting point to estimate how much filament you have left. Weigh the nearly-empty spool and subtract the spool weight you worked out earlier. The number you get should be the amount of filament left on the roll.

There are some caveats here. You should ensure that the new spool of filament is the same type as the old one. It should also come from the same manufacturer, since the spool should be identical. You could also weigh an old empty spool, as long as you account for the cardboard roll on which the filament sits.

Use filament offcuts for test prints

Test prints are occasionally necessary, and I’m not talking about the humble Benchy and other calibration tools. While temperature towers and XY cubes have their place, the most useful test prints save you filament by allowing you to test the fit and finish of larger projects.

This is possible by using the cut tool in a slicer to isolate sections of a model that you want to try first. By not printing the whole model, you’ll save time and money (and you won’t be disappointed when the item doesn’t fit properly). Naturally, this works best for prints that are designed to hold something or fit something specific.

The only thing to remember is to use the same type of filament for testing that you’ll be using for the final print. If you’re going to print an item in PETG, don’t test the fit with PLA since the two may behave differently in the finished product. The same goes for differences in PLA, with basic, silk, matte, and others all behaving slightly differently.

Small prints you might otherwise skip

Credit: Tim Brookes / How-To Geek

There are many items we recommend against printing, mostly because it doesn’t make financial sense to do so. I’m talking about small, mass-produced injection-molded parts like wall plugs, zipties, cable ties, keychains, bookmarks, and other miscellaneous items.

Though these items do not “cost” a lot of filament or time, they’re so cheap to buy (and in such vast quantities) that it usually makes little sense to dedicate a fresh roll of filament to them. But let’s say you’ve weighed out your last few grams of filament using the tip at the start of this article, and you’re itching to get rid of the last meter or so.

In that case, you can fill your build plate with however many of these items you think you’ll realistically use and print away. Delete items and re-slice the model to get an updated estimate of how much filament the print will use to plan accordingly.

Filament hinge pins

Saving a few scraps of filament purely for use as hinge pins makes total sense, especially if you only have a few grams left. Many items have hinges that are designed around the common 1.75mm filament width for final assembly, and it’s nice not to have to unload a spool just for this purpose.

Filament clips

Credit: walter / Thingiverse

It’s important to take care when unloading a spool of filament, not to allow the spool to unwind. Doing so can result in a web of spaghetti that requires a filament respooler to solve. It’s a very unpleasant task, especially if the filament manages to tangle itself.

Most spools have small holes in the housing for poking filament through and safely storing it. This is the same technique used when drying out filament, so it can spin and dry evenly in a filament dryer like the Bambu Lab AMS 2 Pro. But bending the filament in this manner can cause it to snap (especially brittle filaments, like carbon blends).

So why not use your old spools to produce filament clips? These simple, potentially money-saving devices (like this one) keep your filament secure when drying or in storage without bending or breaking it (and it never hurts to have spares). If you use a device or dryer like the AMS 2 Pro, make suire you print a compatible clip (like this one) that doesn’t attach to the outer spool so that the filament can still rotate.

NFC tag holders

Credit: Adam Davidson / How-To Geek

NFC tags feel a bit dated, but they have so much to offer. The only problem is that they’re often just thin paper stickers. The more you tap your phone or other device against them, the more they wear. Even though each NFC tag can only be flashed once, you’ll want to keep them in good condition for years to come.

That’s where NFC tags come in. They’re small prints that make a world of difference if you rely on a tag for any purpose. They come as keychains, display stands, Wi-Fi connector stands (perfect for guest rooms), or as the most basic 2g case.

Wondering where you’re going to use these tags? Try your Home Assistant smart home.

Wondering what else you can do with your not-quite-empty spools? Check out our last round-up of ways to use your last few grams of filament.

And check out what to do with the fully empty spools too.