I Want to Make 500 Mould Candles for Diwali — How Many Silicone Moulds Do I Need to Meet the Deadline?

The one formula that sizes a mould order

Every mould order for a festival deadline comes down to the same division. You have a number of candles to pour, a number of days to pour them in, and a number of times each mould cavity can be filled, set, emptied and reset in a day. Multiply the last two, divide the first by the result, and round up. That is the number of cavities you need.

Written out: cavities needed = pours ÷ (cycles per day × pouring days). If your mould has one cavity, cavities equal moulds. If it has fifteen, divide again by fifteen. The arithmetic is simple. The inputs are where makers go wrong, usually by guessing the cycle time or forgetting that not every pour becomes a sellable candle.

Getting the three inputs right

Pours, not orders

You promised 500 candles, but you will not get 500 perfect ones from 500 pours. Air pockets, chipped edges, wicks off centre and surface marks all take a share. Plan an allowance; 8% is a reasonable starting point for a first festive run, which turns 500 into 500 × 1.08 = 540 pours. Track your real reject rate on the first day and adjust the remaining days.

Pouring days, counted backwards

Start from the day the candles must leave you and count backwards. Subtract packing time, which is your own estimate. Subtract cure time: CSI's product pages state 48 to 72 hours for soy as the minimum before burn testing, and the last pour still needs to set and be checked. Whatever is left is your pouring window. In this example, the reader has 9 pouring days.

Cycles per day, measured

This is the figure you cannot look up. One cycle is the time from pouring a cavity to having it empty, clean, re-wicked and ready again. Most of that is waiting for the wax to set enough to release cleanly, and it depends on your wax, the candle's thickness, the mould and how warm your room is during the festive season. CSI publishes no demould times. Pour one test candle this week, note the time, and check every half hour until it releases without marks. That is your demould time.

Suppose your measured demould time is about 4.5 hours, and resetting the mould takes another half hour, so one cycle is 5 hours. In a 10-hour working day that is 10 ÷ 5 = 2 cycles. Never round cycles up: a third cycle that finishes after you have gone home is not a cycle.

The worked example: 500 candles, 9 days

Now the division. 540 pours ÷ (2 cycles × 9 days) = 540 ÷ 18 = 30 cavities. If the design is a single-cavity pillar, that is 30 moulds. The table shows how strongly the answer depends on the cycle time you measure.

The cost column is simply moulds × ₹942.82, the price of CSI's Pillar Candle Mould (tall 11.2 × 6.3 cm or short 8.6 × 6.5 cm) and of the Polycarbonate Pillar Candle Mould. Going from one cycle a day to two halves the mould bill, which is why measuring the demould time properly is worth more than any discount. It is not a reason to demould early: a pillar pulled before it has set will dent or crack, and that pushes your reject rate up and wipes out the saving.

Multi-cavity designs

For small decorative pieces, the cavity count does the work. CSI's 15 Cavity Rose mould costs ₹153.40. If you are making 540 small floating roses for diyas and gifting, at 3 cycles a day over 9 days you need 540 ÷ (3 × 9) = 20 cavities, which is 20 ÷ 15 = 1.33, rounded up to 2 moulds, or ₹306.80. Some CSI moulds, such as Lotus Flower or Sunflower at ₹295.00, do not state a cavity count in the listing, so count yours before you do the division.

Mixed designs in one order

A Diwali range is rarely one shape. If the 500 are split, say 300 pillars and 200 floral pieces, run the formula separately for each design with its own measured demould time, because a thick pillar and a thin flower set at very different speeds. Add the two answers together only at the end. Splitting the order also lets you stagger the work: pour the slow pillars in the first days, when you have the most time to recover from a bad batch, and the quick small pieces later, when you need output fast.

Spares, wax and the other bottlenecks

Silicone moulds tear, especially at thin edges and wick holes, and CSI publishes no cycle life for any mould. Over 9 days at 2 cycles a day, each mould is filled 18 times. Keep spares; 10% is a sensible starting point, which turns 30 into 33. A torn mould on day six should cost you a swap, not a missed order.

The mould count is only one bottleneck. Check that you can melt enough wax each day. If each candle weighs 120 g, the reader's own fill, then 540 pours is 540 × 120 = 64,800 g of finished candle, or 64,800 ÷ 9 = 7,200 g a day. A 1-litre mini melter would need many refills to keep pace; CSI's 10 kg Electric Wax Melter at ₹21,240.00 states it melts 10 kg of soy wax in approximately 30 minutes at 100°C, with a stated ±10°C display deviation, so use a separate thermometer. Buy one only if your daily volume justifies it.

At 5% of total weight, each 120 g candle is 6 g oil and 114 g wax; Sandalwood's page states up to 6% for pillars. Larger wax quantities can be quoted on WhatsApp (+91 7397976926), because no 25 kg or 100 kg pack is listed. These totals exclude moulds, packaging, labels, labour, shipping and GST. Add oil below its published flashpoint, keep the melter off its maximum setting, and take care with hot wax and the electrical load of a large melter during long days.

Buy this to test, buy this once validated

The test buy is deliberately small. A single Pillar Candle Mould at ₹942.82 with a kilo of Pillar Wax at ₹600.00 comes to ₹1,542.82 before oil and wick, and it replaces a guess about cycle time with a number. That number is what tells you whether to order 15 moulds or 60.

Where this page fits

CSI already has guides that cover parts of this question. This page turns the product above into a raw-material list; these go deeper on the rest:

Three things to buy for this job

Frequently asked questions