How to Glue 3D Printed Parts: Picking the Right Adhesive for the Job

Solvent welds, glue layers and fasteners

Before you grab a tube, it helps to know what the adhesive actually does to the plastic. According to the Polymaker wiki, the 3D Gloop line of solvent-based glues partially dissolves the surface of the print, so the two faces fuse into what is essentially a seamless weld at the molecular level. Super glue and epoxy work differently. They add a layer of material between the parts, and the joint is only as good as that layer's grip on the plastic. That is why surface prep matters so much with them.

There is also a third option people forget about: skip the glue entirely. For some filaments, and for anything you will need to take apart later, a screw, a clip or a threaded insert beats any adhesive. So start with three questions. What material is it? How much force will the joint see? Can you clamp it while it cures? If the part needs to come apart someday, design in heat-set threaded inserts or screws instead of a permanent bond, since Polymaker notes that steel-reinforced epoxy joints often take grinding to undo.

PLA, ABS, ASA and PETG: start with a solvent weld

For the rigid filaments most of you print every day, the Polymaker wiki puts 3D Gloop at the top of the list. It comes in material-specific versions, PLA Gloop, ABS/ASA Gloop and PET Gloop, each matched to the chemistry of a particular plastic. In other words, you do not reach for the same bottle on a PLA enclosure and an ASA bracket. The wiki reports that PLA Gloop performs reliably and that PET Gloop is especially effective on PET and PETG, which have a reputation for being hard to bond.

What you get is a clean joint with no added thickness, easy to sand and paint over. The catch is practical: per the same source, the bottle design makes it awkward to reach into tight spots. On a complex assembly, wet both faces first and then press them together instead of trying to work glue into the seam afterward. Polymaker also points out a side use: applied sparingly, these glues can improve bed adhesion or smooth a surface. If you try that, test it on a small area of a coated build plate before going further.

Quick fixes: gel super glue

A broken tab, a tiny clip, a decorative piece you cannot fit in a clamp: that is where super glue earns its spot on the bench. The Polymaker wiki names Loctite Super Glue Gel and Gorilla Glue Super Glue Gel as popular picks for rigid plastics like PLA and ABS. The gel formula lets you place a precise bead and resists running and accidental spills. According to the wiki, it also dries clear in under a minute, which is exactly what you want for a fast repair.

It is the classic quick repair, not a structural fix. Polymaker spells out two limits: it is not suitable for nylon, and the bond may fail under prolonged stress. Keep it for small parts, display pieces and repairs that will not be working hard. One practical annoyance the wiki mentions: some glue tends to stay trapped inside the rigid outer casing of the bottle, so you may have to dig it out to use the whole thing. For a PLA or PETG part that really has to hold, step up to a solvent weld or an epoxy.

Parts under load: clamp a two-part epoxy

When the joint has to take real force, the Polymaker wiki recommends a two-part epoxy such as Devcon Plastic Welder. According to the wiki, it forms a bond stronger than the layer adhesion of many printed materials. That means if the part ever breaks, it will often break beside the joint rather than through it. It does not make the assembly fit for safety-critical use, though. The print itself is still the weak link, so treat the glue as one factor, not a guarantee.

Epoxy rewards a bit of discipline. Mix both parts thoroughly, assemble, and clamp. The wiki lists an initial hold at 10 minutes and full strength after 24 hours, so leave the part alone until then. It also mentions that the two components occasionally flow unevenly, possibly because of age or storage conditions, so make sure your mix looks uniform before you apply it. For a big model printed in sections, pair the epoxy with pins or keyed joints; the guide to splitting oversized parts and adding connectors covers the design side.

Plastic to metal, and why nylon is different

Mounting a print on a steel rod, an aluminum plate or a metal bracket changes the problem. A solvent cannot dissolve metal, and super glue struggles to grip two such different surfaces. For these hybrid joints, the Polymaker wiki points to J-B Weld, a steel-reinforced epoxy. The wiki describes the result as a near-permanent bond that often takes destructive methods, like grinding or melting, to separate. Full cure takes 12 to 24 hours, so plan your project around that wait.

Since you cannot undo it, dry-fit everything and mark your alignment before you mix. Nylon is the outlier in all of this. Polymaker advises against using adhesives on it at all because the bonds perform poorly, and recommends mechanical fasteners like screws and clips instead. If you print in nylon, build the assembly into the CAD model from the start with screw bosses, snap fits or clip features rather than flat faces meant for glue. The same thinking applies to any part you will need to open, adjust or replace later.

Surface prep and cleaning up the seam

The Polymaker wiki is blunt about it: surface preparation, meaning sanding and cleaning, is critical for every adhesive. Scuff the mating faces to break the glaze of the layers and give the glue something to bite into, then wipe off dust and finger oils. Polymaker's sanding page suggests starting at 220 grit for most materials such as PLA, and 240 to 320 grit for ABS, which sands more easily. Go easy with power sanders on PLA, since heat buildup can soften and distort it.

After the glue sets, you may still see a gap along the seam. For functional parts, Polymaker mentions Bondo automotive body filler, which is strong but realistically needs a power sander or rotary tool to shape. For display pieces, lightweight spackle spreads by hand and sands easily at 800 grit and up, with model putty sitting in between. Always try your glue and filler on a scrap print first, then move on to painting your 3D print. Work in a well-ventilated room and follow the label on each product.

Sources and limits

• Polymaker Wiki — Glueing
• Polymaker Wiki — Sanding

We organize manufacturer and community documentation; we have not measured these products ourselves. The manual for your exact model takes precedence over general guidance.