'Tough' on a resin label means the part resists cracking and shattering, not that it wins every strength test. Formlabs positions Tough 2000 Resin V2 as having strength and stiffness comparable to ABS, for jigs, fixtures and robust enclosures. It positions Grey Resin V5 as a general-purpose resin for form-and-fit prototypes, presentation models with fine features, and jigs and fixtures.
Both resins are from Formlabs and were printed on a Form 4 at 100 µm for their data sheets, so the numbers share test methods. The cure states differ: Grey V5's post-cured values are after 15 minutes at 60 °C, and Tough 2000 V2's after 12 minutes at 70 °C in Form Cure V2. Formlabs also publishes green values, washed but not post-cured, for both.
General-purpose photopolymer resin and Tough resin side by side
| Property | General-purpose photopolymer resin | Tough resin |
|---|---|---|
| Ultimate tensile strength | 62 MPa (green: 46 MPa) | 40.4 MPa (green: 26.1 MPa) |
| Tensile modulus | 2675 MPa (green: 2200 MPa) | 1800 MPa (green: 1235 MPa) |
| Elongation at break | 13% (green: 22%) | 79% (green: 149%) |
| Flexural strength / modulus | 103 / 2750 MPa | 67 / 1701 MPa |
| Izod impact | 32 J/m, listed as notched Izod with method ASTM D4812 | Notched 25 J/m (ASTM D256); unnotched 325 J/m (ASTM D4812) |
| Fracture toughness (ASTM D5045) | Not stated | Kmax 1.65 MPa·m½; work of fracture 305 J/m² |
| Heat deflection, ASTM D648 (1.8 / 0.45 MPa) | 59 °C / 71 °C (green: 54 °C / 62 °C) | 57 °C / 70 °C (green: 45 °C / 53 °C) |
| Shore D hardness | Not stated | 76D (green: 61D) |
| Creep | Not stated | 1.3% strain under 4 MPa after two weeks (Formlabs) |
| Wash in IPA (Form Wash) | 5 min | 15 min, then air dry at least 10 min before handling or curing |
| Post-cure (Form Cure V2) | Default 1 min without heat; full cure 5 min at 60 °C | Default 12 min at 70 °C; low-warp option 12 min at 40 °C |
| 24 h weight gain: acetone / IPA / water | 4.9% / 0.3% / 0.8% | 22.92% / 4.21% / 0.19% |
Values come from Formlabs' Grey Resin V5 (Rev. 01, March 2024) and Tough 2000 Resin V2 (Rev. 01, October 2025) technical data sheets: ASTM methods, Form 4 at 100 µm. Grey V5 post-cured 15 min at 60 °C; Tough 2000 V2 post-cured 12 min at 70 °C in Form Cure V2. Creep data come from Formlabs' Tough 2000 product page; wash and cure settings from Formlabs support articles.
What 'tough' buys you
Tough 2000 Resin V2's advantage is how it fails. It stretches 79% before breaking after post-cure, against 13% for Grey Resin V5, and Formlabs reports fracture properties for it, a stress intensity factor of 1.65 MPa·m½ and work of fracture of 305 J/m², that the Grey data sheet does not include. Formlabs says Tough 2000 V2 has three times the fracture toughness of the previous version.
The cure trades some of that away. Green Tough 2000 parts stretch 149% and survive 11,900 cycles in Formlabs' internal flex fatigue test, against 79% and 3,560 cycles after post-curing, while post-curing raises strength, stiffness and heat deflection. Formlabs' default Form Cure V2 setting for this resin is a heated cure, so the post-cured column is the realistic baseline.
Strength and stiffness
Grey Resin V5 is the stronger and stiffer material: 62 MPa tensile strength against 40.4 MPa, a tensile modulus of 2,675 MPa against 1,800 MPa, and 103 MPa flexural strength against 67 MPa. For a rigid, lightly loaded part, a standard resin is not a compromise.
The impact numbers need care. Grey's data sheet lists 32 J/m as notched Izod but names ASTM D4812, the method Tough 2000's sheet uses for unnotched Izod (325 J/m). Tough 2000's notched value under ASTM D256 is 25 J/m. Because the methods listed differ, the two impact figures should not be compared directly.
Heat and chemicals
Post-cured, the two have almost the same heat deflection: 59 °C and 71 °C at 1.8 and 0.45 MPa for Grey V5, against 57 °C and 70 °C for Tough 2000 V2. Neither is a high-temperature resin. Formlabs also reports 1.3% creep strain under 4 MPa after two weeks for Tough 2000, and no creep figure for Grey.
Solvent resistance differs a lot. In Formlabs' 24-hour immersion test, a post-cured Tough 2000 V2 cube gained 22.92% weight in acetone, 27.69% in xylene and 21.24% in isooctane (gasoline), against 4.9%, below 0.1% and below 0.1% for Grey V5. If a tough part will meet fuels or solvents, check the full table on its data sheet.
Washing and curing
Grey V5 has the shorter workflow. Formlabs lists a 5-minute IPA wash and, in Form Cure V2, a 1-minute unheated default cure with 5 minutes at 60 °C as a full cure. Its finishing guide treats post-curing as optional for standard resins, though Grey's data sheet shows higher strength and heat deflection after a heated cure.
Tough 2000 V2 needs a 15-minute IPA wash and at least 10 minutes of air drying before handling or curing, then 12 minutes at 70 °C by default, or 12 minutes at 40 °C where warping is a concern. Skipping the cure costs a lot: green parts have 26.1 MPa tensile strength and 45 °C heat deflection at 1.8 MPa, against 40.4 MPa and 57 °C after curing. Handling precautions are the same for both resins: gloves, eye protection and good ventilation, as Formlabs and NIOSH describe.
Which should you choose?
Choose General-purpose photopolymer resin if…
- The part is a model, form-and-fit prototype or presentation piece.
- Stiffness and strength matter more than stretch: 2,675 MPa modulus against 1,800 MPa.
- You want a short workflow: a 5-minute wash and a short or optional post-cure.
- The part may meet acetone, fuels or similar solvents, where Grey V5 gains far less weight in Formlabs' test.
Choose Tough resin if…
- The part must flex or take a knock without shattering, such as a snap-fit or clip.
- Your design review uses fracture data, which Formlabs publishes for Tough 2000 V2.
- The part carries a steady load, where Formlabs reports 1.3% creep strain under 4 MPa after two weeks.
- You want a resin Formlabs positions as comparable to ABS for jigs, fixtures and enclosures.
Common questions
Is tough resin stronger than standard resin?
Not in tension or bending. Formlabs lists 62 MPa tensile strength for Grey Resin V5 and 40.4 MPa for Tough 2000 Resin V2. Tough 2000 stretches far further before breaking (79% against 13%), which is what makes it resist cracking.
Does tough resin need post-curing?
Formlabs' default for Tough 2000 V2 is 12 minutes at 70 °C in Form Cure V2. Its data show why: uncured parts have 26.1 MPa tensile strength and 45 °C heat deflection at 1.8 MPa, against 40.4 MPa and 57 °C after curing.
Why does Grey Resin show a higher Izod value than Tough 2000?
The two data sheets list different Izod methods: ASTM D4812 for Grey's 32 J/m figure and ASTM D256 for Tough 2000's 25 J/m notched value. The numbers are not directly comparable. Tough 2000's advantage shows in its elongation and fracture data.
Sources
- Grey Resin V5 product page Formlabs · Checked 2026-11-02
- Grey Resin V5 technical data sheet Formlabs · Checked 2026-11-02
- Tough 2000 Resin V2 technical data sheet Formlabs · Checked 2026-11-02
- Form Wash/Form Wash L time settings Formlabs · Checked 2026-11-02
- Form Cure V2 time and temperature settings Formlabs · Checked 2026-11-02
- SLA basic finishing steps Formlabs · Checked 2026-10-15
- Tough 2000 Resin V2 (Form 4) Formlabs · Checked 2026-10-15
- Safety with Formlabs SLA products Formlabs · Checked 2026-10-15
- Safe Desktop Vat Photopolymerization 3-D Printing CDC / NIOSH · Checked 2026-10-15
This comparison summarizes the cited documentation; it is not a lab test. Properties vary by brand, grade, print settings and orientation, so check the data sheet for the exact product you buy.