The M3DUSA EcoSoy Grey Resin is a plant-based photopolymer resin derived from soybean oil, formulated for LCD/MSLA printers. It offers mechanical properties comparable to ABS — hardness, strength and dimensional stability — without the strong odours or VOCs typical of conventional resins. A solid option if you need professional performance with a reduced environmental impact.
Technical specifications
| Parameter |
Value |
| Colour |
Grey |
| Type |
Eco-Resin (soybean oil base) |
| Mechanical behaviour |
ABS-like |
| Exposure time per layer |
1 – 8 seconds (depending on printer and layer thickness) |
| Odour |
Virtually odourless |
| VOCs |
VOC-free |
| Irritation |
Non-irritating |
| Compatibility |
LCD/MSLA printers (405 nm) |
| Format |
1 kg bottle |
What it is used for
The EcoSoy Grey is designed for users who need functional or prototyping parts with good mechanical resistance and want to reduce exposure to irritating compounds in poorly ventilated workspaces. Its neutral grey tone makes it easy to spot details before final finishing.
- Functional prototyping and assembly testing
- Miniatures and figures with a high level of detail
- Lightweight mechanical parts requiring ABS-like rigidity
- Jewellery and accessories that need post-processing and painting
- Architectural models and scale modelling
- Education and workshops where user safety is a priority
- Printing in semi-open spaces or with limited ventilation
How to use it
- Gently shake the bottle for 30–60 seconds before pouring to homogenise the resin.
- Pour the required amount into the FEP vat of your LCD/MSLA printer. Do not overfill.
- Set the exposure time for normal layers between 1 and 8 seconds depending on your layer thickness and machine power. Dial in with an exposure tower if it is your first time.
- Set the bottom layers with a longer time, typically 4–6 times the normal layer time, to ensure adhesion to the build plate.
- Start printing and monitor the first few layers to confirm correct adhesion.
- When done, remove the part with a spatula while wearing nitrile gloves.
- Wash the part in 99.9% isopropyl alcohol for 2–3 minutes (two-bath wash for best results) and allow the IPA to evaporate completely.
- Cure the part under UV light (curing station or direct sunlight) until the surface is no longer tacky.
- Return any leftover resin to the original bottle by filtering it through a fine-mesh strainer to remove any cured particles.
Usage tips
Working temperature
The viscosity of photopolymer resins increases in cold conditions. If the ambient temperature is below 20 °C, the EcoSoy Grey may be harder to release from the FEP and the risk of print failures increases. Ideally work between 20 and 28 °C; in winter, leave the bottle somewhere warm for a few minutes before use, or use a vat heater if your printer supports one.
Exposure calibration
The 1–8 second range is a guideline. High-power monochrome screen printers typically need the lower end of the range; older RGB screens need higher values. Always print an exposure tower or calibration chart when starting with a new resin — it saves resin, time and frustration. Overexposure penalises fine detail and can damage cheap FEP films.
Washing and curing
Although the EcoSoy Grey is less aggressive than conventional resins, uncured liquid resin is still a potential irritant. Always wear nitrile gloves during handling and washing. For washing, use 99.9% isopropyl alcohol: lower percentages contain water that can cause surface whitening on the part. Do not cure the part while it still has wet IPA on it, as this can create surface stresses.
Frequently asked questions
What is the difference between an eco resin and a standard resin?
Eco resins like the M3DUSA EcoSoy Grey replace part of the petrochemical monomers with plant-derived compounds (in this case, soybean oil). The practical result is a resin with less odour, no significant VOCs and generally non-irritating, without sacrificing mechanical properties. For workshop users, the most noticeable difference is that you can work in spaces with less ventilation without discomfort.
Is it compatible with any resin printer?
The M3DUSA EcoSoy Grey is formulated for LCD/MSLA printers operating at a wavelength of 405 nm, which is the standard in the consumer and semi-professional market. It is not suitable for DLP printers with different wavelengths without prior verification. If your printer uses 385 nm, check with Feroca before purchasing.
Do I need special ventilation to work with this resin?
The EcoSoy Grey is formulated to be virtually odourless and VOC-free, making it more comfortable to use in semi-open spaces. Even so, basic ventilation and nitrile gloves are recommended during handling, as uncured photopolymer resin can be a sensitiser with repeated skin contact.
What should I use to clean parts and the vat?
The recommended solvent is 99.9% isopropyl alcohol. Use two successive baths for a clean wash: the first removes most of the resin, the second leaves the part ready for curing. For the vat, remove the leftover resin, clean with IPA and dry with lint-free paper before storing.
Can I mix this resin with other grey resins to adjust the shade?
Mixing resins with different formulations is generally not recommended, as photoinitiators and monomers may be incompatible and cause curing issues or unpredictable mechanical properties. If you need a range of grey tones, consider using the EcoSoy Grey and adjusting the finish with acrylic paint after curing. Grey alternatives in the Feroca catalogue include the Resina 3D Phrozen ABS-Like Matte Gray and the Phrozen Aqua-Gray 4K.
How long does the resin keep unopened and once opened?
Unopened and stored correctly (cool, dark place between 15–25 °C), the photopolymer resin has a shelf life of approximately 12 months. Once opened, always store it in its original bottle, tightly sealed and away from light. Exposure to ambient UV light (even indirect) can trigger partial curing. If you notice lumps or strings when pouring, filter the resin before use.
Can printed parts be sanded and painted?
Yes. Once fully cured, EcoSoy Grey parts can be sanded, primed and painted with acrylic or enamel paint. The grey tone of the material makes it easy to spot surface imperfections before applying the finishing coat. For best results, apply a grey primer coat before painting.
What do I do with leftover resin and IPA?
Never pour liquid resin down the drain. Uncured resin is a pollutant. IPA used with resin should not be poured down the sink either: expose the container to sunlight to cure any suspended solid particles, then filter and discard the cured solids as solid waste, and dispose of the remaining IPA as solvent waste in accordance with local regulations.
