My Wax Is Cheap but Produces Inconsistent Glass Adhesion — How Do I Calculate the Cost of Cosmetic Rejects?

The straight answer: cost each reject by what you do with it, not by what it cost to make

Your wax is cheap and your adhesion is inconsistent: some batches come out clean through the glass, others show wet spots on a third of the jars. The cost of that is easy to underestimate, because the usual habit is to multiply the reject count by the cost of making a candle. That is wrong twice. A candle that still sells at full price behind a label costs you only the label and the minute to fit it. A candle sold as a second costs you the margin you gave away — usually far more than the materials. A candle you dig out and repour costs labour, a new wick and a jar clean, but you keep the glass. Only a candle you throw away costs everything you put into it.

So the method is a reject ledger: grade every jar, record what you did with it, and price each disposition separately. This page builds that ledger for a worked example — a 170 g candle (a labelled example fill; CSI does not publish a fill weight for this jar, so weigh your own test pour) in the 200 ml Salsa Glass Jar, poured in Natural Soy Pearl Wax at 8% Japanese Cherry Blossom — then uses it to answer the second question hidden in yours: is the cheap wax still cheap once the rejects are counted, and how much better would a dearer wax have to be to pay for itself?

The short answer on the example figures: the four logged batches below cost an average of ₹24.29 of reject cost per poured jar, on top of the ₹193.69 it takes to make one. A switch to CSI 464 adds ₹12.92 of wax per jar. So CSI 464 would pay only if, in your own jars, it brought the reject cost down to ₹11.37 per poured jar or less — and before testing any wax, the inconsistency itself tells you to look at the process first. A wax does not change from batch to batch inside one bag. Your glass, your room and your jars usually do.

Building the reject ledger from your own batches

Start with the cost to make one good candle, because every disposition is measured against it. In the worked example: 156.4 g of Natural Soy Pearl at ₹424.80/kg (the 5 kg bag) is ₹66.44; 13.6 g of Japanese Cherry Blossom at the 1 kg rate is ₹65.85; an example wick line ₹5.90; the jar ₹29.50 at the 50-pack price; then example labour ₹20.00 and an example front label ₹6.00. Total ₹193.69. Materials alone are ₹167.69, so in this example labour and labelling are a larger share of the candle than the wax is — which is one reason the price of the wax is a weaker lever than it looks.

Now grade every jar of a batch the morning after the pour and again at your later checkpoints, and record which of the five things happened to it. The table below is an example log of four batches of 100 — the kind of spread makers describe when they say adhesion is "inconsistent". Replace it with your own counts. The pattern is what matters: the same wax, from the same supplier, giving anywhere from 18% to 45% of jars that cannot go out as poured.

Read the last column as the real cost of a premium candle. It is total spend on the batch — 100 × ₹193.69 plus the reject cost — divided by the jars that went out as poured. In the best example batch it is ₹250.32; in the worst, ₹419.05. Across all four, ₹320.55 against a making cost of ₹193.69. The seconds column drives most of it: each discounted jar costs ₹179.60 in margin, against ₹14.00 for a labelled one. If you can sell a spotted jar at full price behind a wrap instead of discounting it, the cost of that reject falls by ₹165.60 — far more than any wax price difference in CSI's range.

Rework deserves a second look because it hides a loop. A reworked jar re-enters grading; if, in your own records, a share of reworked jars fails again, each of those carries the rework cost twice. With an example second-pass failure of 25%, the expected rework cost per reworked jar is ₹39.70 × (1 + 0.25) = ₹49.62. The ledger also assumes the dug-out wax and oil are reused in the same product; CSI publishes nothing on how remelting changes a fragrance, so if you reuse it, treat the repoured jars as a separate line until your own throw checks say otherwise. Whether discounts and complaints belong in the total covers the line between a real cost and a double count.

Why inconsistency costs more than the average suggests

Suppose a shop orders 100 candles and every one must go out clear. If you plan on the example average — 68.0% of jars sellable as poured — you pour 148. If the batch turns out like Batch 4, only 55% pass, and you are short. To be safe against the worst example batch you pour 182: 34 extra jars, ₹6,585.46 at the full making cost, before you even decide what to do with the spotted ones. That buffer is a cost of inconsistency, separate from the reject cost, and it disappears only when the batch-to-batch spread narrows.

This is also the strongest diagnostic clue you have. One bag of wax does not change its chemistry from Tuesday to Friday. When the same wax, the same oil and the same jar give 18% rejects one day and 45% the next, the variable is almost always something that changed between the pours: how cold the glass was, whether the jars were wiped, where on the shelf each tray cooled, whether the AC was on, how long the finished candles sat in a hot storeroom. Wet spots are commonly described as places where wax has separated from the glass, leaving a thin air gap — and each of those conditions is commonly cited as a contributor. The winter hub covers glass and pour temperature; the courier hub covers temperature cycling after the pour; the series hub covers telling a wet spot from frosting or a cooling ring.

So add four columns to the ledger before you change anything: room temperature at the pour, glass temperature (read it, do not guess), whether the jars were cleaned, and the tray's position. Log four more batches. If the bad batches line up with cold mornings, uncleaned jars or one end of the shelf, you have found the cause without spending on wax. If they line up with a new bag of wax — note the order date on every bag — that is worth a WhatsApp message and a side-by-side test of the two bags.

When a dearer wax pays: the breakeven against your ledger

CSI's dearer container wax in this comparison is Luxury Soy Wax CSI 464, ₹507.40/kg at the 5 kg bag against ₹424.80/kg for Natural Soy Pearl at the same size. At 156.4 g of wax a jar, the switch adds ₹12.92 per jar — ₹1,291.86 per batch of 100. CSI 464's product page states "excellent glass adhesion", a single pour and low frosting; Natural Soy Pearl's page makes no adhesion statement at all. Neither is a test result. CSI publishes no adhesion or wet-spot data for any wax, so the page wording cannot tell you whether CSI 464 would reduce your rejects.

So the hurdle is a fall in reject cost of ₹12.92 per poured jar — from ₹24.29 to ₹11.37, a 53% cut. Put against the example ledger, that is a big ask: even a CSI 464 that made every batch look like your best example batch — ₹11.57 per poured jar — would still fall short of breakeven. The hurdle is reachable at all only because seconds are so expensive here; if you sell most spotted jars at full price behind a label, the reject cost per jar is far smaller and so is the room for a dearer wax to pay. Recost your own ledger both ways before testing. The section hub runs the same breakeven at 2,000 candles a month, and the Wax A vs Wax B post turns it into a single cost-per-visually-acceptable-candle comparison.

Two further costs belong in the decision and are easy to leave out. A wax change re-opens wick, fragrance-load, cure and hot-throw checks — the development-cost post shows how to spread that one-off cost over the candles it affects. And a dearer wax that only matches your best batches, not beats them, buys you consistency rather than appearance; that is worth money too, through the over-pour buffer above, so include it in the comparison rather than ignoring it.

The controlled test: process arm first, then the wax

The cheapest single test for inconsistent adhesion is one process arm beside one control arm in your current wax. Same wax bag, same oil bottle, same 8%, same wick, same jar lot, same pour temperature, same shelf. The control is your normal routine. The process arm changes only jar preparation: each jar wiped inside with Isopropyl Alcohol Spray and left to dry completely — isopropyl alcohol is flammable, so use it away from flame and heat and never warm or pour into a damp jar — then warmed to a measured, recorded glass temperature. A labelled example setting is 35–45°C on the glass, read with your own surface thermometer, and never hotter than your pour temperature. CSI does not publish a hot-pour limit for the Salsa jar; follow the jar supplier's guidance and ask CSI on WhatsApp if you need it.

Natural Soy Pearl's product page publishes no pour temperature, so use the one you already use and keep it identical across arms. If you then test CSI 464, its page states an 80–90°C melt/pour range: pour it inside that range with the same improved jar preparation, so the only difference from the process arm is the wax. Six jars per arm gives a usable result — with six, one spotted jar moves the arm by about 17 percentage points; with three, by 33. How many jars per wax works the counts in more detail.

The priced test kit

The kit assumes you already hold Natural Soy Pearl and your oil. If you buy the oil for the test, all three arms together need 257.0 g of Japanese Cherry Blossom with a 5% pour-loss working allowance — but take it from your production bottle if you can, so the oil lot is the same in every arm.

The Salsa jar is sold in packs of 5, 50 and 100, so 18 jars means 4 × pack of 5 at ₹802.40. At the 50 pack the jar is ₹29.50; at the 5 pack ₹40.12 — test from the pack you will produce from if you already hold it. The Eco Thin C1 line is an example wick only: CSI publishes no wick size for the Salsa jar, and adhesion is judged without burning, but any wax that wins still needs its wick, load and burn confirmed. The whole kit costs ₹2,028.80 — about the reject cost of 84 poured jars at the example average.

The decision rule

If CSI 464 wins and you move production, price it from the listed bags: at 156.4 g a jar and a 3% pour-loss working allowance, 1,000 jars need 161.09 kg — 16 × 10 kg + 1 × 1 kg + 1 × 500 g for ₹81,951.40, against 16 × 10 kg + 2 × 1 kg of Natural Soy Pearl for ₹68,868.00. CSI 464 costs the same per kilo from 1 kg to 10 kg; Natural Soy Pearl is the one soy wax with a real bulk break (5.6% from 1 kg to 5 kg). Larger quantities are quoted on WhatsApp; no volume discount is published. Whether to pilot 50–100 candles before a 100 kg order covers the step in between.

The CSI products in this test

Where this fits in the section

This page owns the cost of cosmetic rejects: grading, dispositions, the ledger and the spread. The section hub uses the same method at 2,000 candles a month; the complaints post decides what else belongs in the total; Wax A vs Wax B compares two waxes on cost per visually acceptable candle; the process-cost post charges cleaning and warming to the right cause; the opaque-label post prices the label route; and the acceptable-percentage post helps you set the house standard your grades rest on.

Frequently asked questions