Universal Epoxy Putty GomaGom 29 28g | Cures Underwater

GomaGom Universal Epoxy Putty 29 is a two-part epoxy putty in a 28 g stick format, packaged in a sealed airtight container. Two features make it particularly useful for 3D printing workshops and household repairs: it cures underwater and offers a 12–15 minute working time after kneading — enough margin to position the putty correctly before it begins to set. Once cured, it dries white, and can be sanded, painted, and varnished. It bonds to 3D-printed parts (PLA, PETG, ABS, UV resin), stone, metal, wood, ceramic, porcelain, glass, and most plastics (except polyethylene, polypropylene, and PTFE).

Cures Underwater: The Key Differentiator

This is GomaGom 29's standout property and the main reason it makes sense alongside the GomaGom 31. The 29 cures properly even when the surface is wet or submerged — opening up use cases that a standard adhesive simply can't handle:

Repairing 3D-printed parts that will be in contact with water. Vases, plant pots, bathroom accessories, filter components, and aquarium hardware. If a part needs a seal that holds up to permanent moisture exposure, the 29 is the right choice.

Sealing leaks in pipes and radiators. The manufacturer's own packaging highlights these as typical use cases. Small leaks, weeping joints, mildly corroded elbows — the 29 seals even when the surface is damp at the time of application.

Repairing porcelain and ceramic kitchenware and bathroom fixtures. Teapot and cup handles, vases, chipped sinks. Its water resistance after curing and white finish make repairs nearly invisible on light-colored pieces.

Comfortable Working Time: 12–15 Minutes

This is the other differentiator compared to the GomaGom 31. While the 31 sets in around 10 minutes (ideal for quick repairs), the 29 gives you 12–15 minutes of open working time after kneading before hardening begins — and another 15–20 minutes until it's fully rigid.

This isn't the "hours of open time" you'd get from professional sculpting putties like Green Stuff or Milliput; it's still a fast-setting repair putty. But the extra margin makes a real difference when:

- You need to position the putty precisely in a hard-to-reach area (inside a joint, a crack near fine surface details).

- The repair involves several steps in sequence (filling, smoothing, shaping, correcting).

- You're applying putty to multiple points on a large part without wanting to knead batch after batch.

For repairs where speed is all that matters (closing a crack and moving on), the 31 remains more efficient. For repairs where you need room to work carefully, go with the 29.

Use Cases in 3D Printing

Repairing 3D-printed parts that will be exposed to moisture. Printed vases, bathroom accessories, planter brackets, filter housings, and irrigation system components. Here the 29 is clearly preferable to the 31, thanks to its underwater curing property, which ensures a more reliable seal in damp environments.

Filling gaps and seams on large multi-part prints. When a sectioned printed part has multiple joints to fill, the 12–15 minute open time lets you apply putty across several points before it starts to set.

Repairing UV resin prints with print defects. Delaminated layers, porous zones, edges softened by underexposure. The white finish sands flush and covers cleanly with primer and paint.

Reinforcing critical joints on functional printed parts. Handles, axles, and hinges that will take regular handling. The underwater cure and moisture resistance make these parts suitable for pieces that will be washed or used in wet environments.

Compatible with PLA, PETG, ABS, and cured UV resin. For bonds that only need adhesive without gap-filling, cyanoacrylate is faster and cleaner — we carry the GomaGom 9 Super Adhesive with brush applicator in our catalog.

Gomagom 29 vs Gomagom 31 – Which One to Choose

We carry two epoxy putties from the Gomagom family, each formulated for slightly different use cases:

• Gomagom 31 (30 g, sets in ~10 min, light finish): express repairs. Fix the part and get straight back to work. Typical uses: closing a crack, bonding a break, workshop emergencies.
• Gomagom 29 (this one, 28 g, 12–15 min open time, hardens underwater, white finish): all-purpose repair with working time to spare. Extra time to position the putty correctly, plus it's the only product in our catalogue that cures underwater. Typical uses: parts exposed to moisture, leaks, repairs requiring multiple application points.

When the choice isn't clear-cut, we recommend the 29 for its greater versatility — the extra 5 minutes of working time covers more scenarios without any significant loss of speed.

How to Use It

The process follows the standard two-part epoxy putty workflow, with one small detail to keep in mind:

1. Cut the required amount from the stick. The stick is stored inside the screw-top container, wrapped in clear film.

2. Remove the clear film before kneading. The film prevents the stick from sticking to the container and stops the two components from reacting prematurely.

3. Knead until the putty turns uniformly white. This is the key indicator of a complete mix. If you still see streaks or different shades, it isn't ready — a solid white colour confirms both components are fully combined.

4. Apply within the next 12–15 minutes. Work onto clean, dry, degreased surfaces. Apply light pressure so the putty conforms to the geometry of the area being repaired.

5. Sets rigid in 15–20 minutes. Full strength is reached after 24 hours — for load-bearing joints or parts that will be submerged, it's worth waiting until the following day.

Important safety information. Causes skin irritation and may trigger an allergic reaction. Wear gloves when kneading. Causes serious eye irritation; if contact occurs, rinse with water for several minutes. Keep out of reach of children.

Packaging and Storage

Gomagom 29 comes in a clear plastic screw-top container, not in a blister pack like other products in the range. This has a practical advantage: the airtight lid keeps the stick protected from ambient moisture between uses. The manufacturer's stated shelf life is 24 months when stored in a cool, dry place. For hobbyists who use it occasionally, that means one container can last months without losing its properties — as long as you close the lid properly after each use.

Technical Specifications

• Type: two-part epoxy putty, stick format in airtight lidded container
• Composition: Bisphenol-A-epichlorohydrin + epoxy resins (MW ≤700)
• Net content: 28 g (legally declared with ℮ symbol)
• Working time after kneading: 12–15 minutes
• Setting time: 15–20 minutes
• Full cure strength: 24 hours
• Cured colour: white (grey-white during kneading)
• Finish: sandable, paintable and varnishable
• Sets underwater: yes
• 3D printing compatibility: PLA, PETG, ABS, cured UV resin
• Other materials: stone, metal, wood, ceramic, porcelain, glass
• NOT compatible with: polyethylene, polypropylene, PTFE/Teflon
• Shelf life: 24 months in a cool, dry place
• Safety: skin and eye irritant — wear gloves and avoid eye contact
• Manufacturer: DUNSA (GomaGom brand, Spain)
• References: SKU 16080 / EAN 8414213160802

Why Buy It from Mr Resin

This is the epoxy putty you need if you work with 3D printed parts that will be exposed to moisture — a surprisingly common scenario: vases, plant pots, bathroom accessories, functional components. It's also the most versatile option if you only want ONE epoxy putty in your drawer. If you're already ordering resin, filament or paint, adding the Gomagom 29 fits in the same shipment at no extra cost. Orders over 79 € ship free to mainland Spain.

Mr Resin has been serving more than 5,000 makers across Spain, Portugal and France for years. Our catalogue is built around what the community asks for: printers and materials at the core, plus the workshop consumables that become part of everyday use.

Frequently Asked Questions

What does "sets underwater" mean, and how is that useful for 3D printing?
It means the putty can cure properly even when applied to a wet surface — or one that is fully submerged. In 3D printing this opens up two very specific use cases: repairing printed parts that will be in contact with water (vases, plant pots, bathroom fittings, filter components) with a reliable seal; and applying the putty to parts that cannot be fully dried before repair. This is something the Gomagom 31 does not explicitly guarantee.

How does it differ from the Gomagom 31?
Three practical differences: (1) the 29 gives you 12–15 minutes of open working time after kneading; the 31 sets in around 10 minutes, leaving less time to work. (2) the 29 sets underwater; the 31 does not. (3) the 29 cures white; the 31 cures clear/transparent. For quick fixes, go with the 31. For repairs that need more time, involve mixed materials, or will be exposed to moisture, the 29 is the better choice.

Can it be used to repair UV resin printed parts?
Yes. It bonds to cured UV resin just as well as to PLA, PETG and ABS. We recommend making sure parts are properly washed and cured before applying the putty, and lightly sanding the contact area to improve mechanical adhesion. The white cured surface sands flush and takes primer and paint without any issues.

Why does it cure white?
It's a property of the formulation. The manufacturer's label states it clearly: "turns white once dry." During kneading it passes through a grey-white stage, then cures to a more defined white. For repairs that will remain visible, bear in mind you'll need to sand and prime before painting if you want a coloured finish. On white or light-coloured parts, the cured putty can be barely noticeable even without painting.

Can I use it for miniature conversion sculpting like green stuff?
It's not the ideal option for this. For fine sculpting and detailed miniature conversions, modelers typically use putties with open working times of several hours (green stuff, milliput, magic sculpt). GomaGom 29 gives you 12–15 minutes — enough for precise repairs and quick detailing of simple features, but not for long sculpting sessions. If your main use is complex conversions, look for a dedicated modeling putty instead.

How long does a pot last once opened?
The manufacturer's stated shelf life is 24 months when stored in a cool, dry place. The airtight-lid pot format helps keep the bar protected from ambient moisture between uses, so with occasional workshop use the pot can last a long time. Always close the lid tightly after each use.