7.2 Gluing models

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Gluing models is a proven technique that is quick and easy to carry out. Parts can be permanently bonded together. It is therefore often possible to print complex models as individual parts and then glue them together.

For a durable bond it is important that the two surfaces to be glued are as flat as possible. Of course, the surface to be glued should also be large enough to ensure a permanent bond. The manufacturer’s specifications regarding curing time and contact pressure must also be observed.

If the surfaces to be glued are rough and uneven, fine sandpaper should be used to make them sufficiently smooth. Clean the surface thoroughly with alcohol and allow to dry. Both surfaces should be completely free of dirt, loose particles and grease.

Gluing PLA

Gluing models made of PLA works very well with the appropriate adhesives.

After extensive testing, we can recommend the following adhesives for PLA:


Superglue works very well with an activator spray. It is colourless and transparent but can leave a white residue on some materials. Superglue hardens quickly (20-40 seconds), but it requires a largely gap-free bond.

Superglue bonds particularly quickly and well if one side of the joint to be bonded has been sprayed with activator (this side must still be wet when bonding). The adhesive then takes effect in a few seconds and cures perfectly.


A positive feature of epoxy is that you can use it as both an adhesive and a filler. If your 3D printed object has a gap, you can fill it with epoxy. If you compare epoxy to other methods of bonding 3D printed objects, it requires more work to the same quality of bond. It is usually supplied in two separate containers, the contents of which must be mixed together before bonding. In one container is epoxy resin, in the other container is a hardener. These components must be mixed in a certain ratio. Once you have done this, the mixture is applied to the surfaces to be bonded. Then you join the individual parts together. Depending on the mixing ratio and the type of epoxy, curing can take anywhere from a few minutes to several hours. Once the epoxy has cured, you can sand or even paint it.

If you are using epoxy to bond 3D printed parts, the surfaces do not have to be completely flat. The epoxy can also be applied in a relatively thick layer.

UHU Hart Kunststoff

According to UHU, this adhesive can be used for all common hard plastics, has a temperature resistance from -30 °C to +90 °C and is resistant to water, oil and diluted acids and alkalis.

UHU Hart has another advantage: it can also be used as a filler or to stiffen sagging overhangs.

UHU Allplast

The properties are similar to UHU HART KUNSTSTOFF, but UHU Allplast is also said to be able to bond materials such as wood, paper, cardboard, leather, metal, glass and ceramics.

UHU Plast Special

UHU Plast Special worked very well with parts that are subject to heavier loads.

Gluing PETG

PETG can be bonded in a similar way to PLA. Superglue and UHU Hart Kunststoff are often the best choice here as well.