The resin printing workflow, start to finish

What actually happens during each stage of a resin print?

Resin printing is a five-stage cycle: preparing the vat and slicing the model with supports, running the print itself, washing the still-tacky part in isopropyl alcohol to remove uncured resin, curing the washed part under UV light to reach full hardness, and finally disposing of the used IPA and waste resin correctly. Skipping or rushing any one stage produces a part that looks finished but is not actually safe to handle or structurally sound.

Unlike FDM printing, where a finished print is done the moment it comes off the plate, a resin print is not actually finished until it has been washed and cured. A part straight off the build plate is still coated in and saturated with uncured resin.

How much resin do supports actually cost me on an angled print?

Supports typically add 30 to 60 percent of model volume on angled resin prints, which means the resin bill for a support-heavy print can be nearly double the part itself. Orienting a model to minimize overhangs, or accepting a slightly rougher surface on a low-visibility face in exchange for fewer supports, meaningfully cuts resin cost on repeated prints.

Because resin is sold by weight and volume differently across vendors, this support overhead is worth accounting for before you commit to a print orientation, not after the vat is already full.

Why is a millilitre of resin not the same as a gram?

Resin density is about 1.1 g/cm3, so 100 mL of resin weighs roughly 110 g, not 100 g. Some vendors price resin by the litre and others by the kilogram, and comparing prices directly without converting both to the same unit, such as price per kilogram, will make one option look cheaper than it actually is.

This matters most when a slicer reports the model and supports in milliliters but the bottle on your shelf is priced by weight; convert one to the other before assuming you know the real cost per print.

What should I actually do before I even open the resin bottle?

Put on nitrile gloves before opening the bottle, not after resin has already touched your skin. Uncured resin is a skin sensitiser, meaning the reaction it causes builds up with repeated exposure over months, and once a person becomes sensitized the reaction can persist permanently and end their ability to work with resin at all. The goal is to keep resin off skin in the first place, not to wash it off quickly after contact.

Make sure the room has real ventilation, since resin off-gasses while curing, and have a lint-free cover or a lid ready for the vat when the printer is not actively running, which limits both fume exposure and unwanted curing from ambient light.

What happens after the print finishes, before it ever touches wash fluid?

Let the part drain over the vat for a few minutes before moving it, since resin still clinging to the part will otherwise drip onto your work surface and gloves. Remove the build plate with gloved hands only, and use a scraper rather than fingers to release the part.

From here the part moves directly into the wash stage; do not set an uncured part down on a bare surface or touch it barehanded, since it is still fully coated in uncured, sensitizing resin at this point.

What is the right way to deal with the resin-contaminated IPA once I am done washing?

Used isopropyl alcohol from washing resin prints is not a drain matter. Pouring it down a drain sends dissolved uncured resin into the wastewater system, where it does not belong. Instead, leave the used IPA in a clear, sealed container under sunlight or a UV light source until the dissolved resin cures and separates out as solid material.

Once cured, filter out the solid resin, let it fully harden, and dispose of it as solid waste. The now-cleaner IPA can typically be reused for another wash cycle or two before it needs replacing.

Safety