Gluing resin 3d prints
Best Glues for Your Resin 3D Prints – How to Fix Them Properly – 3D Printerly
When you realize resin 3D prints are weaker than filament, you wonder how to best glue them together if they break. I’ve had a few resin 3D prints break on me, so I went out to find the best solution on how to fix this.
The best way to glue your resin 3D prints together is to use an epoxy glue combination. Mixing the epoxy solutions together and applying it to a resin print can create a very strong bond that will make prints durable. You can also use superglue, but it doesn’t have as strong of a bond.
There are a few options that you’ll want to learn about, as well as the techniques, so keep on reading to find out.
What is the Best Method to Glue UV Resin Parts?
The best method to glue 3D resin prints is using the resin itself. You may need the help of a strong UV flashlight or UV light chamber to set and cure the parts properly.
Once the resin is dry, sand the joined part enough to remove any bumps to get a smooth and efficient finish.
The other most common methods for such purposes include superglue, silicone glues, epoxy resin, and a hot glue gun.
There can be many reasons that lead to you needing to glue resin 3D prints. In some cases, your resin print fell and a piece broke off, or you may have just been handling the piece a little rough, and it broke.
It can be pretty frustrating to spend all that time on a 3D print and see it break, though we can definitely work towards fixing it and making it look good again.
Another reason for why people glue their UV resin parts is when they are printing a large model which needs to printed in separate parts. Afterwards, people will use adhesive substances to glue these parts together for the final assembled model.
The process of gluing resin 3D print can be a difficult job if you don’t pick the right glue for the purpose.
There are a variety of options available in the market, some are so good that they will almost look invisible after applying while some may result in bumps, scars, etc.
Each glue comes with its advantages and disadvantages, so you have to pick one that is much suitable for your print and its condition.
The parts to be fixed should be cleaned thoroughly before the gluing process, you may need to sand the print as well to get a smooth finish.
Safety should always be your first priority. The resin itself is toxic and needs to be handled properly but the glues you are using could be harmful as well.
Wearing nitrile gloves, safety goggles, and other accessories are essential whenever you are working with resin and other substances.
Best Glues/Adhesives That Works for Resin 3D Prints
As mentioned above there is a wide range of glues that can be used to fix the resin 3D prints while some are better than others.
Below is the list and a brief explanation of the glues and methods that are the best suitable and can help you with all types of resin 3D prints in almost all types of situations.
- Epoxy Resin
- UV Resin Welding
- Silicone Glues
- Hot Glue Gun
Superglue is a versatile material that can be used to glue almost any type of print, except flexible 3D prints, because it forms a hard layer around the print which can be broken if the print flexes around.
Before and after applying the superglue, if the surface is uneven or bumpy use some sandpaper to get a flat and smooth surface.
Wash and clean the surface with alcohol to ensure that the surface is totally free of any type of dirt particles or grease. After applying the superglue, let the print dry for some time.
A very popular one that should work great for your resin prints is the Gorilla Glue Clear Superglue from Amazon.
Its high strength and fast drying time make superglue an ideal adhesive for fixing resin prints and a variety of home projects. Its bond is reliable, long-lasting, and can completely dry within 10 to 45 seconds.
- Unique rubber offers great impact resistance.
- Tough properties bring everlasting bond and strength.
- Comes with an Anti-Clog Cap that allows the glue to stay fresh for months.
- Crystal clear color that can be used for a resin print of all colors.
- It can also be useful in projects with other materials such as wood, rubber, metal, ceramic, paper, leather, and many more.
- No need for clamping as it can dry in just 10 to 45 seconds.
- Best suitable for DIY projects that require instant repairing.
Now, although superglue works really well for gluing pieces together, epoxy resin is in another category. When you need something extremely strong to hold certain pieces together like thin long-projected parts, this works very well.
Using superglue is known to still result in a piece being broken off with a certain amount of force behind it.
One user who has years of experience in assembling D&D miniatures stumbled across epoxy, and said it really changed the level at which his minis performed.
He went with one of the most popular options out there.
Check out the J-B Weld KwikWeld Quick Setting Steel Reinforced Epoxy on Amazon today for fixing your resin 3D prints efficiently. The best thing about this is how it sets a lot quicker than other epoxy combinations out there.
It takes around 6 minutes to set, then 4-6 hours to cure. After this point, your resin 3D prints should function almost as if it was done in one piece from the start.
- Has a tensile strength of 3,127 PSI
- Suitable for resin prints, thermoplastics, coated metals, wood, ceramic, concrete, aluminum, fiberglass, etc.
- Re-sealable cap that prevents resin from drying and leakage.
- It comes with an Epoxy syringe, stir stick, and a tray to mix two-part formula.
- Great for plastic-to-metal and plastic-to-plastic bonding.
- Best for repairing bumps, cracks, scars, and filling dents, voids, holes, etc.
The process could be a bit difficult as this solution comes with two separate containers, one contains the resin while the other has the hardener. You need to mix them on a certain ratio to get the job done.
Epoxy resin can be applied to any type of surface even if it is uneven or bumpy. You can even apply thin layers on the print as they will form a better and beautiful finish.
Epoxy resin can be used as a filler as well, if there are any holes or voids in the broken print.
UV Resin Welding
This technique uses the resin that you 3D printed with to create a bond between the two parts. UV light needs to be able to penetrate through and actually cure the resin though, so a strong UV light is recommended.
The video below goes through the process, but remember to be wearing gloves when handling resin of course!
In order to resin weld properly, you should apply a thin layer of the UV printing resin on both broken parts of the 3D print.
Press and hold the parts together for some time so that they can create a perfect and strong bond.
Make sure that you press the parts immediately after applying the resin because a delay can cause the resin to cure and become hard.
Using UV printing resin for gluing purposes is considered a feasible method because of different factors. First, as you have printed your 3D models with this material, this solution will be available to you without spending extra money.
If you can resin weld the 3D part well enough, you can get pretty good adhesion that doesn’t look bad either.
It is recommended to look for another gluing method if a 3D model is printed using a fully opaque resin because the bond may not get strong enough if the resin is hard on the edges but soft between the two parts.
Silicone Glues & Polyurethane
Polyurethane and Silicone can form a very strong bond and an easy-to-use solution. The only drawback of using this method is that it requires a thick layer of about 2mm to get a strong bond and good adhesion.
It becomes difficult to completely hide the bonding layer because of its thickness. There are different types of silicon glues depending on their chemical properties and characteristics.
Make sure that the prints are pressed effectively because the silicon glue can take a bit longer to cure efficiently. Some types of silicon can also get cured in a matter of seconds.
Check out the Dap All-Purpose 100% Silicone Adhesive Sealant from on Amazon today for fixing your resin 3D prints properly.
- Composed of 100% silicone rubber that can help to fix 3D resin prints efficiently.
- It is waterproof and considered best suitable where strong bonding is required such as for building aquariums.
- Flexible enough that it doesn’t crack or shrink after bonding.
- Clear color even after drying.
- Harmless and non-toxic to water and other materials but should be used following the safety measures while gluing resin 3D prints.
Another suitable option and alternative to gluing your resin 3D prints together is the classic hot glue. It is an easy-to-use method and creates a perfect bond with high strength.
The best thing that comes with hot glue is that it cools down in a few seconds without a need for clamping. While choosing this method, do keep this fact in mind that hot glue will be applied to the thickness of about 2 to 3mm.
The hot glue applied to the model will be visible and this is the only drawback of this method. It’s not the most ideal for miniatures or other small 3D prints.
Before applying the glue, it is recommended to clean all parts of the resin print to remove any dirt or loose particles. Using a hot glue gun for gluing 3D resin prints allows you to apply glue on the surface easily and efficiently.
Make sure you take care of your safety and don’t come in contact with the glue as it can burn your skin.
I’d recommend going with the Gorilla Dual Temp Mini Hot Glue Gun Kit with 30 Hot Glue Sticks from Amazon.
- It has a precision nozzle that makes operation a lot easier
- An easy-squeeze trigger
- Weather-resistant hot glue sticks so you can use it in or outdoors
- 45-second working time and withstands strong impacts
- Has an insulated nozzle that prevents burns
- It also has an integrated stand to keep the nozzle off other surfaces
post processing - What glues for bonding printed PLA to injection-molded plastic?
PLA is a nice one, and gluing has been a topic on some of our most favorite maker's channels. For example Stefan from CNC kitchen (this video) and Joel the 3DPrinting Nerd (this video). Also, in 2022, Tom's 3D ran a test on glues for PLA, PETG and resin prints. Here some information from them together with my own experiences. Most of these glues are not exactly PLA specific by the way and work for many other materials too. Be careful with PLA containing infil though, as that can seriously alter the properties.
Step 0: Safety First!
Some of these methods are working with chemicals that can irritate the skin (resin, cyanoacrylate), have irritating fumes (acetone), or are flammable (acetone). Others (Cyanoacrylate) are not heat-stable and break down into their components under heat.
Use proper protection when working with glue! Eye protection and respiratory protection, as well as gloves, are to be used when necessary. Read the manual of the products you are working with!
For most glues, it is advisable to prepare the surface: sand it to increase the surface area, remove grease from fingerprints etc. Follow the manual!
- Cyanoacrylate - yep, the "one kind for all" is a solution for PLA too: Superglue. However, look out for what type you get! Some are clearly better than others, and using an accelerator can change the properties of the glue spot.
- Together with talcum powder, CA glue ("superglue") can fill gaps easily. However, a gap-bridging bond isn't the strongest, and working can be finicky. Yet if the parts do sit flush, a CA glue bond can be a almost as strong as any 2-component glue bond tested, according to Tom.
- CA is not stable under heating and when heated too much it breaks apart into a rather noxious fume! This can be handy to break metal-CA-metal bonds in machining of small parts but keep this in mind if you want to use inserts or plastic-soler pieces on the same areas! Don't tack with CA in those cases.
- Epoxy resin - Epoxy is a favorite for very tough gluing, a few droplets can stick a car to the roof. .. and it warms up in curing. If you take a slow curing resin, you can safely use it to glue PLA without the part deforming.
- Uncured Resin and their hardeners are strong skin irritants.
- 2-Component Acrylic resin is just as good as epoxy often, as Tom noticed. It's very comparable to Epoxy in performance.
- Urethanes - 2 Component Urethanes offer strong but flexible bonds and work great according to Joel. Their curing process is also exothermic, so take care to not 'cook' your piece.
- 2-phase Putty - in a similar vein come 2-phase putties like Green Stuff or Miliputt, which harden after mixing. Their heat generation isn't too big and they allow to fill gaps easily. My favorite stuff though is not the expensive modeling putty but the stuff from the home depot: stuff like Pattex Repairsorry, no English site for this or UHU Repair All Powerkitt harden within an hour, are surprisingly cheap and get a smooth surface.
- Acetone - We all know that you can smooth and glue ABS with Acetone or an acetone-ABS slurry. Tom (Thomas Sanladerer) made a few experiments with it. He discovered that it works for at least some types of PLA in the following fashion: apply some acetone to a spot and press the second piece (that also was prepared this way) to it and they might melt themselves together after some time.
- Effectivity of this depends very highly on the exact PLA you got.
- Acetone is highly flammable.
- There's a type of glues commonly called "Kraftkleber" or "Alleskleber" in Germany, for example, UHU Hart or Pattex KraftkleberGerman. While they often stick to PLA, I personally don't like their gluing power and find them often quite messy to work with. Also, they very much fail in loadbearing joints.
- Wood Glue - Yes, Wood Glue. PVA Wood glue as well as its non-water-soluble cousin ("Express") have proven themselves to me as a rather nice surface coating to smooth over print lines as well as a good solution to affix paper and wood to prints. It is less of a solution for plastic-plastic bonds but works OK-ish.
Glue? Why glue?!
What better way is there to combine parts than welding or soldering?! Often none. My personal all-time-favorite PLA glue is PLA itself, by using it as PLA solder. This method also works for most other filament types, but is not advisable for ABS and other plastics that emit fumes without wearing respiratory protection! In any case, you need to work with an exhaust, as you heat your plastic in a not always fully controllable way. If you can, use a soldering station where you can set the temperature of the iron.
- Take the pieces and make sure on both sides is a cavity that can be filled.
- Take a soldering iron and set it to around 200°C.
- Take a length of PLA filament.
- Melt the filament with the soldering iron and use it as solder when combining the two pieces. Make sure that at least some filament gets into the cavities and sticks there - it can help to stick the soldering iron into the goop in there to force it to merge with the infill/walls and press together to hot PLA goop filled pieces against the iron before pulling it away, pressing the pieces together.
- As the PLA cools and hardens, the joint is usually tougher than the actual layer boundaries.
Instead of using a soldering iron, one might also use a 3D printing penOne that eats filament, not one for PCL or some gel!, but I don't like those personally.
On a different note, a soldering iron is also a very good solution to make inserts into PLA - heat up the metal insert (like a nut) and press it into an undersized hole, and it will mold the plastic around itself into a perfect fit without any glue.
An alternative to using direct heat from a soldering iron is friction welding. For this, take a rotary power tool and some filament. Insert the filament into the tool, tighten and cut so that about an inch is reaching out of the claw. Turn it on at medium speed, about 800 to 1200 RPM. Now, once you press the tip of the spinning filament against other PLA it gets hot and melts, creating a welding seam. Joel has a good explanation.
Bonding a 3D printed model
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This guide will help you properly glue the separately printed parts of a 3D printed product using 3D printing and made of a white, strong and flexible material known as nylon 12 or polyamide 12. We will look at the elements that were made by 3D printer EOS based on selective laser sintering (SLS) technology . For EOS, PA 2200 is used.
Note that these recommendations only apply to nylon 12 or polyamide 12. Other materials have completely different properties that require special consideration.
First of all, I would like to advise users to glue the model only in exceptional cases: if it breaks or you need a product that exceeds the maximum printing capabilities of selective laser sintering technology (20x25x33 cm). As a good example for our guide, we will take the model of a stress ball (you can see it in the photo above).
How often and easily elements of a model printed on 3D printer break depends on its design and the material from which it is made. For example, the thin tail of a monkey figurine can easily break if you press hard on it with your finger. However, if the model has as few protruding parts as possible (the same limbs), then it will be possible to break it only with a hammer. Selective laser sintering makes nylon extremely durable and resistant to various influences. Therefore, when the product breaks, cracks form on it, first of all. Thanks to the diamond-shaped structure, the ball turned out to be quite impact-resistant. Yes, and the model broke only after someone stepped on it through negligence.
Let's look at how we can glue our 3D product.
The real name of superglue is cyanoacrylate. This variety also includes substances such as ethyl-2-cyanoacrylate, n-butyl-cyanoacrylate and 2-octyl-cyanoacrylate. The most common superglue is ethyl 2-cyanoacrylate. The other two varieties are mainly used in medicine, so you are unlikely to find them in a regular store. However, all of these adhesives can be used to repair or join parts made from nylon 12.
Araldit (epoxy resin)
An alternative to superglue is ordinary epoxy resin. However, we decided to still use superglue for our small repair, because it is somewhat more convenient to use.
Be sure to read the instructions on the packaging carefully and follow them. For example, you need to use the adhesive in a well-ventilated area and store the substance out of the reach of children. Moreover, do not let the glue get into your eyes, otherwise the consequences will be terrible.
The adhesive should be applied sparingly, removing residue with a paper clip. After drying, the color of the glue is slightly different from the material of the model, so its excess does not look very aesthetically pleasing. The glue connects the parts of the product so firmly that it does not even need to be sanded. If the surfaces to be glued are cleaned in advance, this will only enhance the effect. Having studied the next photo of the ball, you can make sure that the repair was successful. At the same time, the gluing line is almost imperceptible.
Glue doesn't always work
However, glue doesn't always work. Basically, problems arise due to the fact that the properties of the adhesive and the material from which is made 3D model are different. Nylon 12 (polyamide 12) is not as flexible as glue. As a result, although our ball was completely repaired, its properties were not completely restored. After half an hour of continuous bouncing, the ball disintegrated again, because. the glue could not withstand the pressure of external forces on the sphere of the model. Thus, superglue only returns the appearance of the product, but the functionality is different. Therefore, it is not recommended to restore products such as springs or hinges with glue.
Painting the glued part
If you paint a model that has been glued in some places, the join lines, like the glue itself, may become more visible. In other cases, as can be seen in the photo of our ball, painting, on the contrary, only hid the defects. We used regular paint like Tamiya Spray.
When gluing before painting, it is very important to carefully apply the adhesive, making sure that it does not spread and remove residues in time. Otherwise, the paint will stick to the glue and it will become more visible. In addition, using a regular paper clip, carefully remove the remaining paint in the holes.
We recommend using adhesive only in exceptional cases, such as when you need to restore the product to its original appearance. At the same time, apply the glue carefully - this is very important, especially if you plan to paint your model in the future. Also, be aware that bonding does not fully restore the functionality of products printed with 3D printing technologies .
SLSWhite durable plastic
How safe are 3D printing resins?
Filament Deposition Modeling (FDM) material extrusion is the most popular polymer 3D printing method, but resins are becoming more and more important to consumers. Resin technologies such as stereolithography (SLA) were previously only used in dental laboratories, engineering departments and manufacturing plants due to the high cost of the equipment. Now that machines have become more affordable, more and more ordinary users are using SLA technology, which calls into question their safety.
Unlike FDM devices, resin printers use photosensitive liquids to print, curing materials with ultraviolet light. Liquid polymers pose a greater potential health risk than raw materials in fiber form. The toxicity of the resource may put off some users, but printing with resin can be safe if the right algorithm is followed.
What are the potential risks of resins
The word "toxicity" is troubling, but according to the definitions developed by occupational safety and health professionals, any substance that, under certain conditions, can cause harm to health or disease, is "toxic". According to this formulation, many substances around us are potentially dangerous, including perfumes and mattress filling. But are there any particular risks when using liquid resins for 3D printing?
The main concern with photopolymer resins is that they can cause skin irritation on contact. In some cases, contact of the substance with unprotected skin results in burns and blisters, which may require medical attention. If the materials come into contact with the eyes, they will cause irreparable damage.
Many resins are sensitizers, which means that prolonged exposure sometimes causes a mild allergic reaction. The chemicals that make up most resins are irritants that provoke the appearance of dermatitis - inflammation of the skin due to rejection of foreign elements. The skin quickly absorbs such chemicals, so prolonged contact with the composition or exposure to a large dose can lead to more serious consequences.
Another problem with resin 3D printing is air pollution. The material releases fumes, potentially reducing indoor air quality (IQA). Poor IQA scores can lead to headaches, fatigue, or more serious reactions such as breathing problems. These effects are due to volatile organic compounds (VOCs) and other small particles that cause an inflammatory response in the airways, leading to swelling or tenderness.
Long-term effects from working with liquid polymer are rare but significant:
• If the vapors are inhaled for a long time, chronic diseases of the respiratory system may appear.
• Some of the VOCs emitted by resins are suspected to be carcinogens, so they are likely to cause cancer after prolonged exposure.
• Constant physical contact can lead to severe allergies.
Standards and manufacturer's instructions
On the other hand, most resins on the market do not pose a significant hazard. Companies that produce such materials must comply with government standards and additional recommendations ISO 9001. Regulations ensure that chemicals produced by businesses are minimally harmful. However, some hazardous elements, such as asphalt fumes and synthetic mineral fibers used in fiberglass, are still widely used and over half a million workers are exposed to them.
Manufacturers usually provide Material Safety Data Sheets (MSDS) that list any possible health concerns. For example, corneal burns from overexposure to the eyes, or nausea and vomiting if swallowed. All these documents are provided in order to provide users with maximum safety when using consumables.
Some compounds may be more dangerous than others for certain people. If a person does not know if they are allergic to any materials, they should act as if they are and handle the product with care.
Several government agencies have conducted research on the safety of epoxy 3D printing. They all showed that long-term emissions from printing are mostly negligible, although risks exist if proper precautions are not taken. Since studies have found traces of hazardous substances when working with resin formulations, safety regulations must be observed.
3D printing resins are not as scary as they seem, but they still need to be handled with care. First of all, direct contact of the mass liquid with any part of the body must be avoided. Safety goggles and nitrile or latex gloves should always be worn to prevent toxins from getting into the eyes or onto the skin.
Also make sure that the work area is well ventilated. Ventilation is critical for any 3D printer, but especially for resin printing equipment. It is best to work under an exhaust hood, but if this is not possible, it is advisable to print near an open window with a fan.
Read the safety data sheet from the manufacturer before opening the photopolymer container. If there are any special instructions regarding the use of the material, then they are reflected in the document.