#resin #saturn-4-ultra #hoopat #vat #fep #upgrades # Overview The **Hoopat Quick Release Resin Vat** is a third-party replacement vat from Chitu Systems (CBD Tech, the CHITUBOX people). It swaps the stock screw-down film frame for a **screw-free clamp system** — pre-cut release film drops in and locks with clips instead of ~20 screws and a torque-balancing ritual. $99.99 USD, free shipping, full metal construction. For the **Saturn 4 Ultra 16K the correct model is X4H**, not X4. ==X4H is the only variant with the pogo pin for the 16K's vat heater — buying X4 by mistake loses heating.== # The Benefit - **Film changes in ~30 seconds** instead of 15–20 minutes of unscrewing, tensioning, and re-torquing - **Even tension by design** — the clamp applies balanced pressure, which removes the usual causes of uneven film stretch: print defects, poor layer bonding, premature film wear - **Metal body** — corrosion resistant, won't warp like the stock aluminum frame over time - **Upgraded version adds a silicone seal ring** on top of the film to prevent the resin weeping that plagued v1 Real value is behavioral: when a film change is trivial, you actually change the film instead of nursing a scratched one and risking an LCD. # What I'd Need | Item | Choice for my printer | Price | |---|---|---| | Vat | Hoopat **Upgraded Version / X4H** | $99.99 | | Bundled film | "Vat + 1 Free PFA Film" or "+3 Extra PFA/ACF Films" | included | | Refill films | PFA/ACF Films, **X4H / Upgraded Version (With 5 Seal Rings)**, 5 pcs | $37.99 | Notes: - Refill films **must** be the "Upgraded Version (with seal rings)" variant to match the upgraded vat. Old no-ring film is explicitly **not** recommended on the new vat. (The reverse works — new ringed film fits old vats.) - Third-party film works but you punch the alignment holes yourself. - ~$7.60/film at the 5-pack price — more than bulk Elegoo PFA, but pre-cut and ready. # PFA vs. ACF Both are the "release film" the resin cures against. Same job, different chemistry. | | **PFA** (often sold as nFEP) | **ACF** | |---|---|---| | Material | Melt-processable PTFE variant — single-layer fluoropolymer | Fluoropolymer laminate w/ controlled-release adhesive layer | | Look | Crystal clear, ~93%+ transmission | Hazy/matte on one side, thicker (~300µm) | | Peel force | Baseline | **~40% lower** | | Best at | Fine detail, crisp features, general use | Large flat cross-sections, dense parts, thick/viscous resins, fast-curing resin | | Trade-off | Higher suction on big flat layers | Slight detail softening; thickness can shift exposure | | Lifespan | 2–3× standard FEP | Long — gentle release reduces wear | **For the Saturn 4 Ultra 16K, PFA is the sane default.** Elegoo deliberately moved the Saturn 4 Ultra line *back* from ACF to clear PFA because the tilt-peel mechanism already kills most of the peel force — so the reason to run ACF largely evaporates, and you keep the better clarity and detail. Reach for ACF only if printing big flat-bottomed or high-surface-area parts, or a heavy/viscous resin where suction failures show up. ==Switching between film types = re-run exposure calibration. Different thickness and transmission.== # Gotchas Collected from Chitu's own FAQ — these are the documented failure modes: - **Remove both protective layers** from the PFA sheet (one per side). Leaving one on breaks the seal and causes leaks. - **Clip with both hands simultaneously.** One clip at a time creates uneven tension and gaps. - **Don't repeatedly clip/unclip the same film** — it stretches the alignment holes permanently and it will never seal again. - **ACF installs matte side DOWN**, toward the LCD. Upside down dramatically increases peel force → failed print + deformed film. - **Re-level the build plate** after installing the vat, and bump bottom exposure slightly on the first print. - **X4H only:** the bottom probe must align with the heating element on the right side of the LCD, or the printer throws an error. # TODO - ==Decide PFA vs. ACF for first order — leaning PFA (stock behavior, better detail, tilt-peel already handles suction).== - ==Check whether Hoopat X4H vat volume/geometry changes the resin fill line vs. stock.== - ==Verify Chitu's Facebook group 5% coupon is still live before ordering.== - Re-run [[Resin Printing Notes|calibration]] after install — exposure will shift. # References - [Hoopat Quick Release Resin Vat — Chitu Systems](https://www.chitusystems.com/products/hoopat-resin-tank) - [PFA/ACF Films for Hoopat Resin Vat](https://www.chitusystems.com/products/pfa-acf-films-for-hoopat-resin-tank) - [Chitu Hoopat installation instructions](https://support.chitusystems.com/en-US/docs/hoopat/latest/instructions) - [r/ElegooSaturn — Update on Hoopat vat from Chitu Systems](https://www.reddit.com/r/ElegooSaturn/comments/1vv4mid/update_on_hoopat_vat_from_chitu_systems/) - [Siraya Tech — ACF vs FEP vs nFEP](https://siraya.tech/blogs/news/acf-vs-fep-vs-nfep-2-0-finding-the-best-resin-3d-printing-film) - [Siraya Tech — Deep dive into ACF vs nFEP peeling force](https://siraya.tech/blogs/news/a-deep-dive-into-acf-vs-nfep-films-peeling-force) - [Phrozen — Differences between FEP, PFA (nFEP), and ACF](https://helpcenter.phrozen3d.com/hc/en-us/articles/6399641736857-What-are-the-Differences-Between-FEP-PFA-nFEP-and-ACF) - [Maker Hacks — Saturn 4 Ultra review (notes the ACF → PFA switch)](https://www.makerhacks.com/elegoo-saturn-4-ultra-12k-review/) - [[Resin Printing Notes]] - [[Saturn 4 Ultra 16K Build Plate Leveling]] # Hoopat Model Compatibility | Model | Printers | |---|---| | X2M | Anycubic Photon Mono X / X6K / M3 Plus / X2 | | X3 | Elegoo Saturn 2 / 3 / 3 Ultra | | X4 | Elegoo Saturn 4 / 4 Ultra | | **X4H** | **Elegoo Saturn 4 Ultra 16K** | | X5 | Anycubic Photon M5 / M5s / M5s Pro |