Cleaning Up Seams
TL;DR: Let the squeeze-out harden... one hour minimum. Then lay a sharp blade flat against the surface and shear the seam off with a light sawing motion. You may still see a seam or some scar artifacts, but trust us: it's way easier to hide than sanding.
Rule #1: Let it dry. We mean it.
Fresh squeeze-out is dissolved plastic soup... a plastic/Gloop! amalgam. Touch it now and you'll smear it into the surface. It's a classic rookie move that turns "crisp seam" into "crime scene." Give it at least an hour to fully harden. And there's no rush on the other end: the cut works just as well hours, days, weeks, or months later. (Cured Gloop! is patient. Be like cured Gloop!.)
🖼 ARTWORK — Side-by-side seam comparison, same two-cube joint. Left: seam smeared while wet — cloudy smudged patch, sad face tag "WIPED WET". Right: crisp hardened bead of squeeze-out, relaxed face tag "LEFT ALONE ✔". This exact comparison is demonstrated in the video and it's the single most convincing image in the series.
Rule #2: Blade flat, slice light
Any sharp knife or fresh razor blade will do the job. The Bureaucrats strongly recommend a handled or guarded blade. The Scientists just get it done with a disposable razor blade at an angle... do as we say, not as we do on camera.
Technique:
Find a flat plane next to the seam.
Press the blade flat against the surface; the surface is your guide rail.
Use a light sawing/scraping action to shear the hardened seam off flush.
Come at it from a couple of different angles to catch everything.
If your parts weren't perfectly aligned, the blade may take a tiny nibble out of the lower part. That's geometry's fault, not yours.
🖼 ARTWORK — Close-up of a guarded/handled razor tool held flat against a cube face, small back-and-forth sawing arrows, a curl of hardened purple seam peeling away. Inset: blade angled INTO the surface with a red X ("don't dig — glide").
Rule #3: Perfection is optional
Up close you may see faint scarring where the seam was. That's just the nature of glue. Science Sauce it may be, but it's science, not magic... and it has its limitations. From about a foot away, it disappears entirely. If your project demands invisible, a light sanding pass finishes the job; if it just needs to hold (which it will, it's literally welded), you're already done.
Verdict from the lab: letting it dry and cutting it off beats smearing it wet, every single time. Ten seconds of blade work > an afternoon of regret sanding.
Rule #4: Skip the cleanup entirely (helpful tips for planners)
If you don't want to worry about cleaning up squeeze-out at all, there are a couple of other options available to you.
Design in a trough. If you have full control over your design, we recommend placing a trough around the perimeter of the mating surface. Ideally it's 1–2mm wide and about 1mm deep, set back 2–3mm from the perimeter. When you Gloop! the surface, the trough acts as an expansion area, capturing what would be the ooze/squeeze-out and preventing it from showing on the surface.
Mask the perimeter. If you can't design in your own ooze prevention, another option is masking off the perimeter of your print with masking tape or plumber's putty/pliable wax. This protects the surface from any runs or drips. After the Gloop! hardens for a bit, remove the putty or wax and clean up with a fabric cloth. This method really requires you to push the putty/wax down onto the surface; if you don't, the Gloop! will seep through, making it a pointless endeavor. When you remove the putty/wax, you will undoubtedly leave behind residue that needs to be wiped away. You may still need to cut away some Gloop!, but this gives you the absolute best finish.
🖼 ARTWORK — Two-panel inset. Panel 1 "THE TROUGH": cross-section of a mating surface with a small moat 2–3mm inside the edge, purple squeeze-out flowing into it instead of out the seam. Panel 2 "THE MASK": top-down part with masking tape/putty ring around the joint line, a drip landing harmlessly on the tape.
Bonus tip for the finishers: planning to sand or paint over the joint? Cured Gloop! sands and paints just fine... details in the FAQ.
Next: ready to scale up? Big Prints & Multi-Part Builds →