Should Every New Candle Vessel Receive a Small Adhesion Test Before I Buy Thousands of Jars?

Yes — a small test per new vessel is the cheapest insurance you will buy

A wax, oil and wick that give clean glass in one jar can spot in another. Glass mass, wall thickness, base, shape, diameter, fill weight and the jar's surface are all commonly cited as changing how wax sets against the glass, and none of them is visible in a product photo. A vessel change also re-opens your wick — a different diameter or depth changes the melt pool — and your pour temperature, which has to stay inside both the wax page's range and the new jar's hot-pour limit. So the honest answer is yes: every new vessel gets a small adhesion test before a big jar order, and the test is part of approving the jar, not an optional extra.

The money makes it easy. For a new 200 ml Salsa Glass Jar, all three gates on this page — a sample pack, an 18-jar adhesion screen and a 50-candle pilot — come to ₹11,859.09 in CSI materials, and most of that is the pilot — fifty candles you can sell if they pass. A 2,000-jar order of the same jar in its 100-packs is ₹59,000.00, and the materials for 2,000 finished candles are about ₹3,05,365.12. Gates 1 and 2 are 5.9% of the jar order; all three gates are 3.9% of the production run's materials. If the vessel turned out to spot in a fifth of candles — an example figure, not a rate for any jar — the materials in unsellable candles would be about ₹61,073.02.

The gates are short on purpose. Gate 1 is a receiving check on the smallest pack. Gate 2 is a side-by-side adhesion screen against the jar you already sell, from one melt. Gate 3 is a pilot batch in production conditions, including a burn test and, if you ship, a temperature cycle. A vessel that fails a gate costs you only what you have spent so far — which is why the order comes last.

Gate 1: the sample pack — what to check before pouring anything

Buy the smallest listed pack. For the Salsa that is five jars for ₹200.60; for CSI's Clear 150 g jar, ten for ₹944.00. Then check the things no product photo shows.

Gate 2: the adhesion screen, against the jar you already sell

The example maker sells a candle in the Yankee Glass Jar 130 ml (illustrative 110 g fill) poured with Luxury Soy Wax CSI 464 and Cucumber Green Tea at 8%, and wants to add a larger SKU in the 200 ml Salsa Glass Jar (illustrative 160 g fill — weigh yours). Gate 2 pours three arms from one melt: six of the current jar as the control, six of the new jar into room-temperature glass, and six of the new jar into glass warmed to a measured, recorded temperature (an example arm is 35–45°C, never hotter than the wax or above the jar's limit). CSI 464's page lists an 80–90°C melt/pour working range; the Salsa's hot-pour limit is not published, so confirm it in gate 1 and pour every arm at one temperature that sits inside both.

Six a side, not three, because this result decides an order worth tens of thousands of rupees; it is still a screen. Why include the current jar at all? Because it tells you whether the day was normal. If your current jar spots too, the problem is the day — cleaning, room, cooling — not the new vessel, and you should repeat gate 2 before judging it.

Gate 3: a pilot batch in production conditions

If gate 2 passes, pour 50 candles in the new vessel exactly as production will — the same cleaning, any preheat on its card, the same melter, tray layout, room and people. Keep them 30 days. Score every candle at 48 hours, 7 days and 30 days; burn-test a handful to start the wick qualification for the new vessel; and if you ship, put a few through a temperature cycle on your real courier route. A simple temperature-cycle test shows how. This is also the first time you see the spread across a real batch — outer and centre jars, first and last poured — which a screen of six cannot show.

What the gates cost against the order they protect

Material cost of one candle at production rates, in each candidate vessel: in the Salsa (160 g illustrative), CSI 464 at the 5 kg rate (₹507.40 a kilo), Cucumber Green Tea at the 1 kg rate (₹3.33 a gram), the Eco Thin C1 example wick at ₹5.90 and the jar at the 100-pack rate — ₹152.68; in the Clear 150 g jar (150 g page fill) at ₹94.40 a jar — ₹210.25. Both before labour, packaging, freight and GST.

The jar order prices use listed packs: 20 × pack of 100 for the Salsa, and 200 packs of ten for the Clear 150 g jar. At that scale, ask for a quote on WhatsApp — CSI publishes no volume discount, and the Clear 150 g pack of 20 is in limited stock. The pilot material for the Salsa uses 1 × 5 kg + 3 × 1 kg of wax and 1 × 500 g + 2 × 100 g of oil; leftovers carry into production. Whether to run a 50–100 candle pilot before a 100 kg purchase covers the wax side of the same decision.

The priced gate-2 kit

Priced with listed, in-stock CSI packs, using the CSI convention (oil = W × L) and a 5% pour-loss working allowance on each vessel's fill: 2,492.3 g of wax and 216.7 g of oil for the Salsa screen. Use your production wax and oil lots if you hold them.

Not on the list, because CSI does not sell them: a jar warmer and a surface thermometer for the warm arm. The Candle Making Weighing Scale (₹354.00) does gate 1's weighing; the Pen Thermometer (₹354.00) reads the wax.

The decision rule

Apply it from the top and stop at the first line that is true.

Once the vessel passes, its settings go into your jar-preparation and pouring SOP as their own card, and its empty-jar weights and order date go on the shelf with two retained jars. If a thick luxury jar already spots more than your test jar, that page is the diagnosis; whether a supplier change needs a test even with identical dimensions covers the same jar from a new source.

The CSI products in this example

Frequently asked questions