Washing and Curing Resin Prints: Why It Is Not Optional, and How to Size a Station
By Print Farm editorial · Published · Updated
Washing and curing are part of the print, not an accessory to it. A model lifted off the build plate is coated in uncured liquid resin, which is the sensitising, aquatic-toxic form of the material, and its surface polymer chains are not fully cross-linked, so it is softer and dimensionally unsettled until it is post-cured under 405 nm UV. Skipping either step gives you a tacky, weak, hazardous object. Size the station by the wash basket and cure chamber dimensions, not by the printer it is marketed alongside: in this catalog the wash windows run from 131 x 90 x 220 mm up to 230 x 135 x 260 mm, and the largest printer here builds bigger than any of them.
What each step is actually doing
Washing removes the film of uncured resin the part carries out of the vat. In alcohol this is a solvent action; with water-washable resin the carrier is water. Either way the used liquid becomes resin-laden waste, and it has to be treated as such.
Curing finishes the polymerisation the printer started. The LCD exposed each layer only long enough to solidify it and bond it to the layer below, which is why manufacturers publish short per-layer numbers, for example 8 seconds normal exposure on Elegoo Standard Resin. A post-cure under 405 nm light drives the reaction to completion, which is what makes the part hard, stable and non-tacky. A washed but uncured print is still an exposure hazard.
The V2.0 and V3.0 are 2-in-1 units: one machine that washes, then converts to cure. The X and XS bundles are two separate machines, which means you can wash one batch while another cures, and the XS adds a handheld UV lamp for interiors and undercuts. All four have 0 to 30 minute timers; the V3.0 holds 7.5 litres and the X/XS wash unit 7000 ml.
Match the station to the print, not to the printer's name
Run the numbers before you buy the bundle. A Mars 5 builds 143.43 x 89.6 x 150 mm, which is already wider than the Mercury Plus V2.0's 124 mm with-plate wash window and wider than its 140 mm cure turntable diameter; full-footprint Mars prints come off the plate, go in the basket (131 x 90 x 220 mm) and get cured lying down or in pieces.
A Saturn 4 builds 218.88 x 122.88 x 220 mm. The V3.0's with-plate window is 214 x 135 x 180 mm, so a full-height Saturn print must be removed from the plate and washed in the basket, which handles 230 x 135 x 260 mm. The Jupiter 2 builds 302.4 x 161.98 x 300 mm, larger than every wash basket and every cure chamber listed above, so Jupiter owners wash large parts manually or in sections. None of this is a defect; it is just the arithmetic that the bundle pages do not do for you.
Isopropyl alcohol cleans standard, ABS-like, tough and rapid resins, evaporates cleanly and leaves crisp detail. The costs are fire risk (flash point 11.7 degrees C, vapour 2.1 times heavier than air) and the fact that you are storing and eventually disposing of resin-saturated solvent. Elegoo's Rapid Standard Resin listing names isopropyl alcohol or ethanol as the cleaning agents.
Water-washable resin, 18 listings in this catalog, removes the solvent entirely. It does not remove the hazard: that formulation's SDS classifies it Aquatic Chronic 2, H411, toxic to aquatic life with long lasting effects, so the rinse water is contaminated waste and cannot go down a drain. The practical routine is to cure the settled solids out of the water in daylight and dispose of them solid. Choose water-washable for convenience and fire safety, not to skip waste handling.
Cure technique, and the case for the two-machine bundles
Even 360-degree turntables leave shadows. The Mercury Plus V3.0 answers this with 24 UV LEDs at 405 nm arranged around a rotating platform; the Mercury XS answers it with two L-shaped light bars of 14 LEDs each plus 4 beads under the turntable and a handheld 405 nm lamp for cavities. If your models are hollow, deeply undercut or have interior detail, the handheld lamp is the feature to pay for.
Start with short cure cycles and add time. The timers on all of these stations go to 30 minutes, which is far longer than most small parts need, and the useful test is tactile: a fully cured surface is hard and not tacky. Cure with the part rotating and reposition anything with a large flat face that sat against the platform. The V3.0's cover blocks 99.9% of UV and has a micro switch that stops curing the moment it is lifted, so do not defeat it to peek.
Wash liquid does not last forever; it saturates with dissolved resin and stops cleaning. Elegoo sells replacement washing buckets separately, at $28.99 for the Mercury Plus V2.0, $36.99 for the V3.0 and $39.99 for the Mercury X/XS, and a second bucket is the cheap way to keep a clean rinse and a dirty first wash going in parallel. A stainless funnel at $8.99 filters vat resin back into the bottle so cured crumbs never reach your release film, and a $14.99 pair of silicone mats gives everything wet somewhere to stand.
Can I just leave prints in the sun instead of buying a cure station?
Sunlight does cure resin; the manufacturer's own spill procedure relies on it. It is unreliable for finished models because the intensity, angle and duration vary, so parts cure unevenly and one side is done long before the other. It is fine for curing waste before disposal, which is what the SDS describes.
How long should I wash a print?
Long enough that the surface is not glossy or slick when it comes out, then a short second rinse in cleaner liquid. The stations here have 0 to 30 minute timers; small parts rarely need the top end. Over-washing in alcohol is mostly a risk for very thin features, which can soften and warp.
Do I need the separate wash and cure bundle or is the 2-in-1 fine?
The 2-in-1 V2.0 and V3.0 are fine for one batch at a time, and the V3.0 has the largest cure chamber here at 250 mm diameter by 290 mm. The Mercury X and XS bundles are two machines, so washing and curing run in parallel, and the XS adds a handheld UV lamp for interiors. If you print in batches, the bundle saves real time.
Can I reuse the alcohol?
Yes, until it stops cleaning. Let the used alcohol stand in a sealed container so the dissolved resin settles, decant the clear liquid to reuse, and cure the sludge solid in daylight before disposal. Never pour either the alcohol or the sludge down a drain.
Editorial conclusions are drawn from the Elegoo catalog data and the manufacturer documentation listed above; we do not claim to have used every product shown. Updated 2026-08-25. Corrections: contact us.
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