If you want to know how to use eco resin, this is the guide I wish had existed before my first pour. The steps are not complicated, but the failure modes are specific, and most bad first casts come from the same three mistakes, all of which I will get to before the end.
I'm Anirudh, founder of Artriso. We make CALSO ONE, a single-component water-based eco resin produced in Hyderabad. This guide is written for CALSO ONE specifically, but the technique transfers to any single-component eco resin.
If you want the full picture on what eco resin is before you start mixing, the complete eco resin guide is the right first read.
What you need before your first pour
You do not need much. The standard kit for a first session:
A digital kitchen scale accurate to 1 gram. This is the single non-optional item. You cannot eyeball the ratio. A scale that costs ₹300 at any kitchen supplies store is sufficient.
A silicone mixing cup or a small plastic bowl with straight sides. Flexible silicone makes cleanup easier, but any clean container works.
A silicone spatula or a low-speed drill with a paint mixer attachment for larger batches. Avoid metal tools, which scratch silicone moulds.
Silicone moulds in the shape you are casting. Coaster moulds and tray moulds are the easiest starting point. The mould should sit flat on a level surface.
CALSO ONE Off White powder, the 1 kg trial pack. This is the right starting size for a first bench test. Do not buy a 6 kg studio pack until you have done at least two pours and understand how the product behaves in your specific space.
Water, measured by weight, not by volume.
Optional: water-based acrylic pigment paste, mica powder, or oxide pigment if you want colour.
The 3:1 rule, and why it matters more than anything else
The CALSO ONE mixing ratio is 3 parts powder to 1 part water, measured by weight.
300 grams of powder needs exactly 100 grams of water. 600 grams of powder needs exactly 200 grams of water. The ratio does not change based on pigment additions, temperature, or pour size. It is always 3:1 by weight.
Why this matters: the water activates the acrylic binder in the powder. Too little water and the slurry will be stiff, will trap air, and may cure with a chalky or crumbly surface. Too much water and the slurry becomes runny, the mineral filler settles unevenly, and the cured piece may be soft or powdery. Both failures are ratio failures, not product failures.
Use the scale every single time. Experienced studio makers who have poured thousands of units still weigh every batch.
Step-by-step: how to use eco resin
Step 1: Weigh the powder. Place your mixing bowl on the scale, tare it to zero, and weigh your powder. A 300 gram batch pours roughly four standard coaster moulds at 5 mm fill depth. That is a good test batch.
Step 2: Weigh the water. Tare the scale to zero with the bowl still on it. Add your water directly to the powder. 100 grams of water for 300 grams of powder. Do not mix yet.
Step 3: Mix. Begin mixing immediately after water contact. Use long, smooth folding strokes with the spatula. Mix continuously for 60 to 90 seconds. The target texture is thick smooth paint or pancake batter without lumps. Avoid whipping motions that pull air into the slurry.
Step 4: Add pigment if using. If you are colouring this batch, add pigment now, immediately after mixing. Fold it in with 10 to 15 strokes. Do not over-stir at this stage, the batch is already moving toward set.
Step 5: Pour. Pour steadily into the mould starting at one end and letting the slurry flow to fill the cavity. For trays, a slow pour from a height of about 5 cm lets you watch the slurry settle. Tap the mould on the work surface two or three times to release trapped air pockets near the bottom.
Step 6: Wait. Pot life from first water contact is 12 to 15 minutes at typical Indian indoor temperatures of 24 to 30 degrees Celsius. Once you have poured, do not touch or move the mould. Leave it flat and undisturbed.
Step 7: Demould. Thin coasters are ready to demould in 45 to 60 minutes. Mid-size trays in 60 to 90 minutes. Thick or sculptural pieces in 2 to 3 hours. The piece should feel firm and not depress under light finger pressure. If it springs back like rubber, it needs more time. Peel the silicone mould back slowly and evenly rather than pulling from one corner.
Step 8: Cure and seal. Full cure is 24 hours. After 24 hours, apply a clear sealer appropriate for your end use. Stone wax for a satin matte finish, GlazeSeal for a higher sheen. Sealing is especially important for coasters and anything that will contact liquids.
The three first-pour mistakes that explain most bad casts
These three mistakes account for roughly 80 percent of the failed first pours we hear about. Learn them before you pour, not after.
Mistake 1: eyeballing the ratio. "Close enough" is not close enough. The 3:1 rule is non-negotiable. A ratio of 2.5:1 produces a stiff, bubbly, undercured cast. A ratio of 3.5:1 produces a runny, soft, uneven cast. Measure every time.
Mistake 2: adding powder to water instead of water to powder. This sounds like a small thing but it produces lump pockets that are almost impossible to break down once formed. Always weigh the powder first, then add the water on top.
Mistake 3: demoulding before the piece is ready. The piece may feel firm on the surface at 30 to 35 minutes and still be soft in the core. Pulling a piece early tears the surface and leaves a white powdery mark where the mould separated too soon. Wait the full time. Your first pour is not the time to test the lower edge of the window.
What to make on your first pour
Start with a flat mould with no undercuts. A simple circular coaster mould at 5 mm fill depth is the ideal first cast. It uses a small amount of powder, demoulds cleanly in under an hour, and gives you direct feedback on the finish before you try anything more complex.
Once you have two or three clean coaster pours behind you, the same technique scales directly to trays, planters, and sculptural work. The variables do not change, the volume does.
The full range of shapes is available across the CALSO ONE collection page.
Where to go from here
If you want to understand the full chemistry of what you are working with, including how eco resin compares to epoxy and why the single-component format changes the learning curve, the complete eco resin guide covers all of it.
Questions about a specific pour problem? Write to contact@artriso.com. I read every email from first-time buyers and reply within two working days.
Frequently asked questions
What is the correct mixing ratio for eco resin?
For CALSO ONE and most single-component eco resins, the ratio is 3 parts powder to 1 part water, measured by weight on a digital scale. This is not by volume. A 300 gram batch needs exactly 100 grams of water. Do not adjust this ratio based on temperature, altitude, or pigment additions.
How long does eco resin take to set?
CALSO ONE has a pot life of 12 to 15 minutes from first water contact, meaning you have that window to pour. Demould time is 45 to 60 minutes for thin coasters, 60 to 90 minutes for mid-size trays, and 2 to 3 hours for thick or sculptural pieces. Full cure is 24 hours.
Can I use eco resin indoors without ventilation?
Yes. Eco resin is a water-based acrylic compound with no solvent and minimal VOC emission. Basic ventilation, meaning an open window or a fan moving air through the room, is sufficient. No respirator is needed for normal studio use. This is one of the primary advantages over epoxy resin, which requires strong ventilation and a proper respirator.
What happens if I get the mixing ratio wrong?
Too little water (ratio tighter than 3:1) produces a stiff slurry that traps air and may cure with a chalky or undercured surface. Too much water (ratio looser than 3:1) produces a runny slurry where the mineral filler settles unevenly, resulting in a soft or powdery piece. Both are ratio failures. The fix is simple: use a scale every time and measure to the gram.
Anirudh Rapole is the founder of Artriso, the Hyderabad studio behind CALSO ONE. First pour questions? Email contact@artriso.com.
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