What Is Water-Washable Resin? A Comprehensive Explanation

Traditional resin 3D printing requires a series of cumbersome cleaning processes. For instance, you need to wear gloves, a respirator, and use harsh chemical solvents such as isopropyl alcohol (IPA). This is annoying, but what if there is a better way? Washable resin is undoubtedly an innovative solution, providing you with a simpler post-treatment workflow. In this article, we, HeyGears, will provide a comprehensive introduction to what washable resin is, its unique advantages and limitations, its comparison with traditional resins, and, most importantly, the basic safety and handling methods you need to know.

What Makes Water-Washable Resin Unique?

Water-washed resin is a type of UV-curable resin. Its core advantage is that it can use clean water instead of chemical solvents like IPA (isopropyl alcohol) to clean uncured resin. The principle behind this is that it adds special components to enable the uncured resin to dissolve in water. In this way, the post-processing becomes much simpler. We don't have to constantly come into contact with those highly irritating chemical substances, and the cleaning process is also smoother. It is so friendly for 3D printing enthusiasts at home or ordinary players.

Moreover, its smell is much less than that of traditional resin, and it is more comfortable to print. Although the initial price of a single bottle might be slightly higher, in the long run, since you don't have to always buy the expensive and hard-to-find IPA, you can save a lot of money. There's also cleaning, which is extremely convenient. Just rinse the printed object in water, and the uncured resin will fall off. It's much more convenient than traditional resin cleaning, which requires multiple steps and chemical agents. Both time and energy can be saved.

However, when cleaning, it should be noted that if the printed matter is soaked in water for too long, it will absorb too much water, the surface details will be damaged, and it may even crack later. In addition, like most common 3D printing resins, it does not have biocompatibility certification. This means that it cannot be used in scenarios where it comes into contact with food, in an aquarium, or in prolonged skin contact.

Water-Washable Resin vs. Normal Resin: The Ultimate Comparison

A thorough understanding of the key differences between water-washed resins and ordinary (standard) resins will help you determine which material is most suitable for your 3D printing needs.

Post-treatment: Water washing vs. IPA cleaning

This is the significant advantage of water-washed resin, which greatly simplifies the cleaning process after printing.

The post-treatment process of Water-washed resin is straightforward. Just rinse the printed part in a container filled with clean water. To better remove the residual uncured resin from the surface and crevices, a soft brush can be used. For batch cleaning, professional cleaning workstations or ultrasonic cleaning machines can be used. Generally, it is recommended to control the cleaning time to around 45 to 60 seconds. It is important to avoid soaking the model in water for a long time, as excessive water exposure may weaken its surface details. This method significantly enhances convenience and safety by reducing exposure to harmful chemicals and avoiding handling flammable liquids, making it particularly attractive to home users and small studios.

For ordinary resins, a more complex and stricter post-treatment process is required. You must use isopropyl alcohol (IPA) or other similar solvents for cleaning. This means you need a dedicated cleaning area, personal protective equipment such as protective gloves, and a well-ventilated space. IPA is not only flammable but also usually has a strong odour and requires careful handling and proper disposal. This cleaning process is not only messy and time-consuming, but also may become expensive over time, as IPA can be contaminated by uncured resin and requires frequent replacement.

Print quality and detailed presentation

Both of these resin types can provide high-quality printed parts and exhibit complex details and excellent surface finish.

Although some resin 3D printing experts believe that ordinary resin may have a slight edge in printing accuracy, especially for components that require very fine tolerances or extremely complex details.

But for the majority of daily users, this difference can be ignored to the naked eye. Water-washed resin is also fully capable of producing aesthetically pleasing and detailed printed parts. However, it should be noted that when water-washed resin printed parts are subjected to stress or frequent processing, their details and overall performance may not be as stable as those of ordinary resin.

Durability and strength

This is the most significant difference between the two and also one of the most crucial considerations when choosing resin.

Common resin: It is usually superior in terms of toughness and flexibility. It is less likely to crack or break when subjected to force, making it the preferred choice for functional components, engineering assemblies, or practical items that are frequently used and subject to mechanical force or frequent operations. Common resins also offer a wide range of formulations (for example, flexible, tough, and high detail), which can be adjusted according to specific needs, thus having greater versatility. Although post-processing may be more troublesome, the long-term durability it brings is often worth the extra effort.

Water-Washable Tough Resin: Water-washable tough resin is usually more brittle. To address the brittleness issue of standard water-washed resins, the toughness of the resin, which combines the convenience of water-washed resins with enhanced durability, is twice that of standard water-washed resins. It can serve higher-intensity projects, such as large models or frequently operated miniature models and figurines. It can also provide a certain degree of flexibility, making it easier to remove the print from the build board and reducing the risk of accidental damage. After cleaning, if you want to achieve a cleaner and clearer effect, it is recommended to perform a final rinse with ethanol.

Cost considerations of different resins

The cost of using a 3D printer not only includes the price of the resin itself, but also the related consumables.

Common resin: The initial price of a single bottle is usually cheaper. However, it requires continuous investment in purchasing IPA or other cleaning solvents, which can be contaminated by uncured resins and need to be replaced frequently. Therefore, this continuous expense may make ordinary resin more expensive in long-term use.

Washed resin: The initial cost per bottle may be higher than that of ordinary resin. However, in the long run, since there is no need to purchase isopropyl alcohol or other cleaning solvents, it has the potential to reduce your ongoing consumable costs, depending on your local water and resin prices.

Key environmental impacts of resins and Disposal considerations

Regardless of the type, all liquid photopolymer resins are chemical irritants and potential sensitizers, posing risks to health and the environment if handled improperly. The label "washed with water" is highly misleading in terms of disposal and by no means implies that it can be discharged at will.

• Resin toxicity: Washing resin with water is not a more environmentally friendly solution. In liquid form, it can cause skin and respiratory irritation. Repeated skin contact may lead to allergic reactions (sensitization). If not handled properly, it is toxic to the environment. Accidental ingestion of photosensitive polymer resin is extremely dangerous and requires immediate medical attention. In addition, most of the standard resins are currently on the market. It does not have biocompatibility certification and is uncertified for food contact, medical use, or use in aquariums. It should not be used for items like drinkware, pet toys, or any application involving prolonged skin contact or ingestion.

• "No Dumping": This is a crucial safety and environmental warning. Under no circumstances should cleaning wastewater containing resin be directly poured into the sewer. These waters contain uncured resin particles, which are highly hazardous to water treatment facilities and may contaminate drinking water sources. The issue is not about your pipeline, but about "what lies at the end of your pipeline".

• Lack of education: Regrettably, there is a widespread problem of users lacking education, as no one actually reads the Material Safety Data Sheet (MSDS) of the resin. In order to compete on price, companies often fail to fully educate users about the dangers of resins and the correct handling methods. This kind of "suicidal price-cutting competition" has led to the neglect of necessary safety precautions.

• Correct waste disposal methods (for polluted water): To responsibly handle wastewater containing resin, it must first be safely treated:

1. Sunlight curing: Place the wastewater containing resin under direct sunlight for several days until all the resin particles are completely cured and separated from the water.

2. Filtration and solid waste: Once solidified, the solid resin particles are filtered out and treated as general waste.

3. Water recycling or evaporation: The filtered water can be reused to clean the next batch of water-washed resin or continue to be exposed to sunlight until it is completely evaporated.

4. Comply with local regulations: Always ensure that you follow the local guidelines regarding the handling of potentially hazardous substances.

When handling liquid resin or uncured printed materials, always wear gloves to avoid direct skin contact. In case of contact, rinse immediately with plenty of water. Ensure that the printing area has good ventilation; Consider using VOC air purifiers like HeyGears GreenPrint Purification Unit or discharging the gas outdoors through pipes. 3D Musketeers will even turn on the whole-house VOC filter one hour before resin printing and keep it on for six or seven hours after printing to ensure that the air is adequately filtered. At the same time, avoid operating the resin near the sink to prevent accidental contamination.

Here’s a little intro for the table:

To help you pick the right resin for your 3D printing needs, check out this table comparing water-washable resin, normal resin, and water-washable tough resin across key aspects like cleaning, durability, and cost.

Feature	Water-Washable Resin	Normal (Standard) Resin	Water-Washable Tough Resin
Cleaning Agent	Water (tap water)	Isopropyl Alcohol (IPA) or other solvents	Water (with optional ethanol final rinse for best results)
Cleanup Effort	Straightforward, quick rinsing	Messy, tedious, requires a dedicated station	Straightforward, quick rinsing
Odor Level	Less noticeable odour	Stronger fumes require ventilation	Less noticeable odour
Durability	Generally more brittle, prone to cracking	Superior toughness and flexibility	Enhanced durability, twice as tough as standard water-washable
Ideal Use	Display models, miniatures, figurines (low stress)	Functional parts, engineering components, prototypes	Larger models, functional parts, frequently handled miniatures (medium stress)
Upfront Cost	Can be higher per bottle	Often cheaper per bottle	Can be higher per bottle
Ongoing Cost	Low (no solvent repurchase)	High (regular IPA repurchase)	Low (no solvent repurchase)
Wastewater Disposal	CRITICAL: Must be cured in sunlight, filtered, then disposed of as solid waste. NEVER down the drain. Toxic in liquid form.	Solvents (IPA) must be carefully handled and disposed of according to local hazardous waste regulations. Toxic.	CRITICAL: Must be cured in sunlight, filtered, then disposed of as solid waste. NEVER down the drain. Toxic in liquid form.
Biocompatibility	Generally not biocompatible	Generally not biocompatible	Generally not biocompatible

Table: A Comparative Analysis of Three 3D Printing Resins

The Innovation of Water-Washable Tough Resin

Introducing Water-Washable Tough Resin

To address the brittleness issue, manufacturers have developed innovative formulations like "Water-Washable Tough Resin." This new class of resin aims to offer the "best of both worlds"—the durability of normal resin with the easy cleanup of water-washable resin. Products like UltraPrint Modelling PAWW10 Water-Washable Modelling Resin are formulated to be significantly tougher than their standard counterparts.

Benefits and Applications of Water-Washable Tough Resin

Stronger Parts: It allows for printing parts that can withstand more handling and stress without easily breaking.
Versatile Use: This makes it suitable for a wider range of applications, including larger models and frequently handled miniatures or figurines.
Easier Print Removal: The added flexibility makes removing prints from the build plate safer, reducing the risk of accidental breakage.

Essential Safety and Responsible Disposal for Water-Washable Resin

Understanding Water-Washable Resin Toxicity

It is crucial to remember that all photopolymer resins, including water-washable variants, are toxic in their liquid form. They can cause skin irritation, allergic reactions, and are harmful if ingested.

Mandatory Personal Protective Equipment and Ventilation

Gloves: Always wear nitrile gloves when handling liquid resin or uncured prints.
Ventilation: Work in a well-ventilated area, such as a garage or a room with open windows.
Respirators: Consider a respirator with organic vapour cartridges for extended work sessions.

The Critical "Drain Ban"

This cannot be overstated: the water used to wash your prints is contaminated with toxic resin particles. Pouring it down the drain is irresponsible, highly damaging to the environment and water systems, and is likely prohibited by local environmental regulations.

Step-by-Step Responsible Disposal of Contaminated Water

Sunlight Curing: Place the container of contaminated water in direct sunlight for several days. The UV rays will cure the resin particles, causing them to clump and separate from the water.
Filtering and Solid Waste: Once the resin has hardened, filter the water to collect the solid, cured resin. This solid waste can then be safely disposed of with your regular rubbish.
Water Reuse/Evaporation: The filtered water can be reused for future cleanups or simply allowed to evaporate. Always follow local guidelines for the disposal of hazardous materials.

Practical Tips for Optimal Water-Washable Resin Printing

Post-Processing Best Practices

Thorough Cleaning: Use a soft brush to ensure all uncured resin is removed from intricate areas.
Avoid Prolonged Soaking: Do not soak models for more than a minute to prevent them from becoming waterlogged.
Drying is Key: Ensure your models are completely dry before UV post-curing. Any trapped water can cause cracks.

Enhancing Print Success with Water-Washable Resin

Flex Plates: A magnetic flex plate makes removing prints from the build platform significantly easier and safer.
Combating Bubbles: In your slicer, increase the "light-off delay" to give the resin time to settle, preventing bubbles from forming in critical layers.
Utilize Slicer Tools: Use tools like UV Tools to identify and fix potential printing issues before you start.
Strategic Orientation: Orienting your models to minimize the need for support material can improve overall print quality and reduce post-processing.

Conclusion

Ultimately, water-washed resin really offers a great upgrade to traditional resin! It makes the post-3D printing processing much simpler, eliminating the need to deal with those highly irritating chemical agents. For those of us who enjoy tinkering with handicrafts and creating, it's simply too friendly. It can make the workbench much cleaner and is also very convenient to use. More importantly, we must keep in mind our responsibilities in terms of safety and environmental protection. As long as we operate in a good way and have a good understanding of its characteristics, we can use water-washed resin to make 3D printed works more outstanding, and at the same time protect our own health and our Earth.