Best Glue for PLA 3D Prints: A Comprehensive Guide to Gluing PLA Parts Together

In 3D printing with PLA, part maintenance and repair work generally requires the use of a glue that can reliably hold things together. It can be constructing a large scale model, repairing a delicate piece, or integrating several pieces to create additional functions—achieving seamless results with PLA requires finding the right glue for PLA. On the contrary, adhesives can’t all be treated the same way, and the unique characteristics of PLA warrant special considerations when preparing the right bonding technique. In this guide, we will identify the best adhesive options for PLA, examine their pros and cons, and offer recommendations to ensure your PLA prints remain securely fastened together under strain. After reading this article, you will have no questions concerning finding the right glue for your 3D printing requirements.

What’s the Best Glue for PLA 3D-Prints?

The selection of the best glue for 3D prints of PLA materials depends on the application and how strong the bond should be. Widely regarded as effective, cyanoacrylate adhesive (widely known as super glue) works particularly well because it dries quickly and strongly adheres to PLA surfaces. Two-part epoxy, on the other hand, works better for more complex and larger joints as it is much stronger and more durable. Also, some bonds, although requiring more delicate handling, can be seamlessly fused with the use of solvent-based adhesives, dichloromethane, or 3D printing-specific glues. Regardless of the type of bond created, all surfaces must be clean and spatially correct to achieve optimal results.

Understanding Different Types of Adhesives for PLA

Comparing Super Glue vs. Epoxy for 3D Printed Parts

Why Choose Specific Brands like Loctite or Weld-On?

Loctite and Weld-On are some of the brands to use because of their reliability and history in the industry, and Weld-On is part of his brand family. Loctite has focus on adhesive technologies which span over industries such as automotive, construction, and household. Their products provide high bond strengths, accurate dispensing, and extreme resistance to temperature, moisture, and vibrations. Their anaerobic adhesives on the other hand provide robust sealing and locking capabilities with leak and loosening resistance.

Like Weld-On, a company well-known for plastic bonding solvent adhesives, specializes in plastic bonding. Weld-On’s adhesives brand thermoplastics like PVC, CPVC, and acrylics, are used for durable seals. Widely used for plumbing, construction, and industrial manufacturing, these adhesives are preferred due to chemical bond strength, gap filling, and high order of compliance with safety and performance standards, reliability in demanding applications.

How to Glue the PLA Parts Together Effectively?

To join PLA components, select the correct adhesive for the job. Super glue is a common example of a PLA suitable adhesive due to its strength and ease of application. Like with any adhesive, surface prep is critical. Clean the surface with isopropyl and let it dry to remove dust, grease, or residue. Grit blasting, sanding, or any abrasion method helps in roughening the surface which increases adhesion. Apply a precise amount of glue to one surface only. Press the two parts together firmly. Once the glue has fully set, the bond is fully healed. For functional or structural components, it is best to use some form of sustainment while the bond cures such as clamps. Good bond prep and alignment ensure a high-quality and low-visibility joint.

Step-by-Step Guide to Applying Glue for PLA

1. Prepare the Surfaces

Start with thorough surfaces cleaning for the PLA parts. Without cleaning the surfaces, the bond becomes weaker. Use a IPA or similar solvent to remove residue so the adhesive used works effectively. Make sure to let them fully dry, otherwise continue with the bonding procedures will be pointless.

2. Sand the Bonding Areas

Sanding the joint areas and using fine sandpaper (grit 120-240) increases adhesion and roughens the glued surface for better mechanical retention. Rewashing of sanded parts should be done as well to remove dust by using air duster.

3. Select an Appropriate Adhesive

Plastic glues, cyanoacrylate or two part epoxies are most suitable for PLA. For structural applications where propper loading is anticipated epoxy adhesives are stronger and more suited to ensure rigid shear strenthing over time differing them from softer epoxies.

4. Apply the Adhesive

Apply glue onto one of the surfaces andspread it evenly. Be careful not to overapply, as this will lead to squeeze out and a bond which is uneven self leveling due to excess adhesive. A precision applicator can help reduce the flow.

5. Join the Parts

Take the PLA parts, press and align them securely to each other. Closed bond gaps are most desirable. Tightly spaced interfaces lead to better strength due to pressure. For PLA parts the first set holding time for cyanoacrylates is longer than 30 seconds and with epoxies it mostly depends on the formulation from 10 seconds to 3 minutes.

6. Reinforce and Allow to Cure

If you are requiring to bond larger, load-bearing parts together, then use clamps, tape, or a vice to hold the parts stationary during the adhesive curing process. Most types of adhesives take hours to completely cure, check instructions left by the manufacturer for exact time periods. Avoid placing stress on the adhesive bond until it is cured fully.

7. Test the Bond

Gently verify the bond’s strength and test the adherence by applying light pressure. If it withstands the stress, then the structure is confirmed to be operational. If not, review your procedure, focusing on surface treatment and the type of adhesive used.

Using Activators with Super Glue for Better Results

Activators (also called accelerators) are a chemical class whose purpose is to augment the efficiency of super glue (cyanoacrylate adhesive). They perform by lowering the cure time significantly, causing the adhesive to set almost instantly after application. This fast action is particularly helpful when fast assembly or quick strength is essential.

For an activator to be as effective as possible, make sure the surfaces to bond are clean and dry. Warm one side lightly with the activator and allow it to evaporate before applying super glue to the other side. Then both surfaces should be pressed together immediately afterward. The activator initiates a reaction that cures the bond rapidly.

This is particularly useful when working with foam and wood as the porous materials are often much more difficult to adhere together, taking much longer to set. In addition, some activators are geared toward aiding in curing glue where there is minimal air exposure, thus effectively filling small gaps. However, too much activator may weaken the bond as too much chemical reaction can ruin the performance of the adhesive. Always maximize results by following instructions for the best results.

Can You Use the Super Glue on PLA 3D Printed Parts?

Indeed, glue can be used on PLA 3D printed parts without any issues. The adhesive works effectively because of the chemical surface of the plastic. To maximize the bond, the parts must be clean with no grease, dust, and the conjunction must be glued evenly. The connection will be strengthened when the parts are kept firmly while the super glue cures. Super glue is suitable for small parts; however, for larger parts that are load-bearing, additional adhesives such as epoxy need to be used for better durability.

Benefits of Using Super Glue Gel Control on PLA

1. Precision Application

Due to precision combinatorics, Super Glue Gel Control’s thick gel form has ensure accuracy. Unlike adhesive liquid forms that can freely move and spread, the gel does not budge which permits pinpoint placement. This comes in handy for complex or detailed PLA parts as no additional adhesive will be out of place.

2. Strong Bonding Properties

Due to its specific formulation, Super Glue Gel Control is compatible with the surface chemistry of PLA polymers. As a result, Super Glue Gel Control can form exceptionally strong bonds with PLA. Tests have shown that the adhesive, when applied properly, can be loaded up to 2000 psi, which is appropriate for most lightweight and moderate-load PLA parts.

3. Fast Setting and Curing Time

Speed of bonding is one of the most important characteristics offered by this adhesive. Under the right conditions, the curing process begins in 10 to 20 seconds, shortening the time needed to add or repair portions of PLA components. After approximately 24 hours, full bond strength is reached.

4. No Drip Formula

The gel form of the adhesive PLA means that it has a firmness which prevents excess dripping or spreading. This makes it easier to work with sloped or vertical surfaces. Thus, this improves productivity when working with PLA assemblies that are non-horizontal or are complex shapes.

Precise control, dependable PLA bond strength, and ease of application make Super Glue Gel Control an efficient adhesive for both professionals and hobbyists, expanding its potential applications.

Risks of Damaging the PLA with Incorrect Adhesives

Using solvent-based adhesives or other polymer-specific adhesives on PLA will lead to Performance failure. Solvent-based adhesives can be too aggressive to PLA and lead to its deformation, warping, or degradation on an even molecular level. PLA is highly susceptible to some solvents and can undergo changes that weaken its molecular bonds and tensile strength. Additionally, these PLA surfaces will remain uncured and mechanically bonded PLA joints will be created, which is a very weak connection that can snap with even the slightest load. Some studies have shown that thermal instability may also result from the use of adhesives that have strong exothermic reactions with PLA parts. Guaranteeing adhesive compatibility is crucial to preserving PLA materials’ structural strength and functionality for engineering or hobbyist purposes.

What Should You Avoid When Gluing PLA Parts?

• Do not use high-temperature PLA adhesives that cure through heat, and especially not those that exhibit exothermic curing behavior, as these will cause PLA deformation and, in some cases, melting.
• Excess adhesive can lead to uneven bonding and weaken the structure.
• Do not use plastic adhesives because they will not adequately bond with PLA.
• Do not skip the surface preparation step. Ensuring sanded and clean surfaces will enhance adhesion will improve bond strength.

Why Avoid Acetone with PLA Adhesives?

Due to the material chemistry involved, PLA doesn’t bond or treat well with acetone. PLA does not soften chemically with acetone like ABS does, and so attempts to use acetone on PLA can produce inconsistent results from whitening the surface to doing nothing at all. Furthermore, long-term exposure to acetone can reduce the rigidity of the PLA structure, resulting in a loss of mechanical strength. Adhesives meant for plastics or specifically tested on plastics like PLA provide better bonds because of their chemical compatibility and dependability.

Understanding the Importance of a Well Ventilated Area

The adhesives and chemicals as well as 3D printing filaments like PLA require specific air circulation during work processes. Working in a closed room, for instance, can lead to the volatile organic compounds (VOC’s), particulates, and other harmful exhalations to accrue. Lack of fresh air /Poor ventilation not only worsens exposure to harmful elements but might also cause sore throat, migraines, and other health ailments from prolonged breathing in.

To minimize exhaust air pollutants, swivel mounted fans, HEPA filter air purifiers, and closed work stations with fans improve airflow. An increase in ventilation will not only eliminate some suspended harmful particles but also lower the chances of flammable vapors accumulating. Studies have shown that the absence of ventilation maintained at a required level aggravates the adherence to occupational hygiene standards by ensuring and positively affecting the health of people working in those spaces.

How Do You Prepare 3D Printed Parts for Gluing?

1. To Increase Adhesive Bond Strength: Scrub the areas that will be bonded using isopropyl alcohol or similar alcohol solutions to remove residual material, dirt and grease.
2. Burnish the Surfaces to be Bonded: Using fine-grade sandpaper, lightly roughen the joining surfaces to ensure a better hold by the adhesive.
3. Test Fit All The Pieces: Make sure all the parts and components are qualitatively and accurately aligned before gluing. This step is essential in achieving correct alignment and minimizing mistakes in the joining steps.
4. Pick The Correct Bond Exponent: Different parts put together possess a different bond exponent which is specific to that arrangement. An example can be super glue for PLA or ABS specialized glues for stronger holds, or Angles Bond in General.
5. Properly Spread Over Bond Foams: Apply, evenly, and only lightly, layers of glue at necessary and useful points of join. Too much of glue may disrupt adhesion and instead spread out making the bond weak.
6. Join Up Those Pieces Now: Confirm that the parts are securely locked in position carefully observing the directions and times for setting given by the supplier.

Following these ways, you will obtain all benefits of a more exact and strong hold of 3D printed parts.

Sanding PLA Surfaces for Better Adhesion

Rough up sanding surfaces of printed parts makes them easier and more effective to bond. Start with removing appears and gloss finishes found in prints of PLA using coarse gritted sandpaper like 120 grit, then proceed to polishing up with finer ones like 220 grit and up for even textures. The gradual resorting polishing approach not only enhances surface bonding but also reduces the chances of surface blemishes weakening the bond’s durability. Making sure that the sanding process is done in a circular motion eliminates directional bias, resulting in even adhesion diffusion and strengthens even adhesion distribution. Post sanding, clean with isopropyl alcohol to remove any leftover dust that may affect the adhesive plaster application. Following these procedures greatly improves the bond strength and durability in PLA bonded assemblies.

Cleaning Your Printed Parts Before Applying Adhesive

As a best practice, especially in PLA, cleaning your printed parts is critical for achieving optimal adhesion. Contaminants such as dirt, grease from handling, or even residues of the printing materials pose a serious threat to the adhesive’s effectiveness. Take a moment to wipe the parts surfaces using a lint-free cloth to remove visible debris. Follow this step with an application of isopropyl alcohol (no less than 70% concentration) in a clean micro-fiber cloth to dissolve any grease or residue. Make sure that the alcohol is dried completely. In recent updates, it has been noted that chemical agents specialized for thermoplastics ought to be used when stronger cleaning is required. Such chemicals help to mitigate abrasives that cause micro-scratches. All these steps ensure that the adhesive achieves maximum contact with the PLA surface for a stronger, more durable bond.

Reference Sources

1. Instructables: Testing the Best Glue for PLA 3D Printed Parts: Weld-On 16 was identified as the strongest adhesive for PLA, effectively melting and bonding the material. Superglue (cyanoacrylate) and contact cement also performed well, with the PLA breaking before the glue bond.

2. Loctite: How to Glue PLA: High-quality superglue, such as Loctite Super Glue Gel Control, is recommended for PLA due to its strength, ease of use, and quick drying time.

3. Bitfab: How to Glue PLA? 5 Ways to Do It: Cyanoacrylate glue is the most versatile and effective for PLA. Epoxy offers stronger bonds and gap-filling capabilities but is more complex to use.

Frequently Asked Questions (FAQs)

Q: What is the best glue to use when I want to glue PLA together?

A: The best glue for gluing PLA together includes superglue, epoxy resin, and model cement. Each of these adhesives works well with PLA and provides strong bonds.

Q: Can I use superglue to glue PLA together?

A: Yes, you can use superglue to glue PLA together. Superglue, particularly brands like Loctite 401, sets quickly and provides a strong bond suitable for PLA plastic.

Q: How do I apply the glue when gluing 3D prints made of PLA?

A: To apply the glue when gluing 3D prints made of PLA, ensure that the surfaces are clean and free of dust. Then, apply a small amount of glue to one surface and press the pieces together, holding them until the glue sets according to the manufacturer’s instructions.

Q: Is epoxy resin a good choice for gluing PLA together?

A: Yes, epoxy resin is a good choice for gluing PLA together. It provides a strong bond and is particularly useful for larger pieces or when additional strength is required.

Q: How can I ensure a strong bond when gluing PLA together?

A: To ensure a strong bond when gluing PLA together, sand the surface of the parts before applying glue. This increases the surface area for the adhesive and promotes a better bond.

Q: What should I do if the glue is still wet while gluing 3D prints?

A: If the glue is still wet while gluing 3D prints, avoid moving the pieces until the glue has cured. If you need to reposition, use a glue that allows for adjustment before it sets.

Q: Can I use glue sticks for gluing PLA together?

A: Glue sticks are generally not recommended for gluing PLA together as they do not form a strong bond. It is better to use adhesives specifically designed for plastics, such as superglue or epoxy.

Q: Should I heat up the glue when gluing materials together?

A: Some adhesives, like certain epoxy resins, may require heating during the curing process to enhance bonding. Always refer to the specific product instructions for guidance.

Q: How much glue should I use when gluing 3D prints together?

A: When gluing 3D prints together, use a small amount of glue to avoid excess that can weaken the bond. A thin layer is typically sufficient for a strong connection.

Q: Can I use Weld-On 16 for gluing PLA together?

A: Weld-On 16 is primarily designed for acrylic and may not be the best choice for gluing PLA together. It’s advisable to stick with adhesives that are known to work well with polylactic acid, such as superglue or epoxy.