Some Wicks in My Bulk Order Are Slightly Different Lengths — What Tolerance Should I Establish for Production Consistency?

Why length matters, and why it matters less than you think

A variation of a few millimetres between wicks in a bulk order worries many makers, because consistency feels like it should mean identical. For length, it helps to be clear about what the length actually does.

Once a candle has set, you trim the wick to the same height above the wax before the first burn. The flame sees only that trimmed height plus whatever lies below the surface, and the part below the surface is set by the jar depth, not by how long the wick was when it arrived. So two wicks that started a little different in length will burn the same way once trimmed. Length does not change flame size.

Where length does matter is during setting and pouring. The wick has to rise from the jar floor, clear the wax surface, and reach far enough above the rim to be held by a holder, clip or centring bar while the wax sets. It then needs enough left above the surface after setting for you to trim cleanly to your chosen height. A wick that is too short for the jar cannot be held centred, may flop into the wax, and leaves you nothing to trim.

Longer than needed is mostly a handling and waste question. Extra length is trimmed off and thrown away. It can also make wicks tangle in the packet or catch on each other at the setting bench, which slows production but does not affect the candle.

Measuring a sample at goods-in

For CSI's Cotton Braided Wicks Ready Made, the product page states a wick height of 10.16 cm, so that is a figure you can check a delivery against. Most other wick listings, including CSI's other wicks, do not publish lengths or tolerances. For those, what you measured in your last approved order is your reference, which is one more reason to keep a few retained pieces from every lot.

Setting your tolerance from your jars

There is no universal wick length tolerance that suits every workshop, because the right answer depends on your vessels and your holders. The practical way to set one is to work backwards from the jar.

Start with the internal depth, measured from the inside floor to the rim. Do not use the height printed on a product page: jar dimensions are usually outer sizes and approximate. CSI's 200 ml matte jars, for example, list 'Height 8 cm width 7 cm', which describes the outside of the jar, and the same listing gives its fill as '200 ml', a volume rather than a weight. The glass base means the inside is shallower than the outside, so measure it yourself with a ruler or the depth rod of a caliper.

Then add the clearance your holder needs, the length above the rim required to grip the wick firmly while the wax sets. That depends on your holder design, so measure it on a real jar with a real holder. The sum is your minimum usable length for that jar.

The depths shown for the first two rows are example measurements for illustration; take your own. The 2.0 cm clearance is also a starting point to check with your own holders. Once you have the minimums, your acceptance rule for a lot is straightforward: each wick must meet the minimum of the jar it is allocated to.

Worked example: a lot meant for two jars

Suppose you ordered wicks at a nominal 15 cm for both your 200 ml matte jars and a taller jar with a measured internal depth of 13.5 cm. Your 30-piece sample reads from 14.6 cm to 15.4 cm, with 7 of the 30 below 15.5 cm.

For the matte jars, every piece clears the 9.4 cm minimum by a wide margin, so length is not a concern there at all. For the tall jar, roughly a quarter of the sample falls short of 15.5 cm. The lot is not defective for your purposes; it just needs allocating. Measure every piece intended for the tall jar, route the short ones to the matte jars, and you lose nothing.

Only if you had no shorter vessel would the short pieces become a cost. Even then, it is worth pricing honestly. If 40 pieces were unusable and you had paid ₹5.90 each, the loss is 40 × ₹5.90 = ₹236.00, a figure to weigh against the time spent measuring the whole order. For many makers, reallocating the short pieces is quicker and cheaper than disputing them.

Do you need a maximum length at all?

For most small workshops, no firm maximum is needed. A longer wick is trimmed like any other. Still, it is worth writing down a loose upper figure for two practical reasons. First, very long pieces tangle in the packet and slow the setting bench, and if one person spends a morning untangling wicks, that is a real cost. Second, an unusually long lot can be a sign that you received a different product from the one you ordered, and that deserves a question before the wicks go anywhere near a jar.

So set the upper figure generously, as a flag rather than a reject line. A piece above it is not a defect; it is a reason to check the invoice and the packet label against your order.

Recording, releasing and when to talk to the supplier

Write down the sample readings, the minimum and maximum, how many pieces fell below each jar's minimum and where they were allocated. Release the lot against those allocations rather than as a single block, and label the tall-jar and short-jar bags clearly so they cannot be mixed at the setting bench.

Talk to the supplier if the lengths are consistently different from what the page or your order states, or if the spread is much wider than your last approved lot. Send your readings and photos of the shortest and longest pieces beside a ruler. If the wicks are CSI's, message us on WhatsApp (+91 7397976926) and file the reply; for any wick where no length is published, ask what length the supplier intends and record it so the next lot can be judged against something firmer than memory.

Where this page fits

CSI already has guides that cover parts of this question. This page covers the goods-in check for the question above; these go deeper on the rest:

Three things to buy for this job

Frequently asked questions