Under the Brennholt Institute of Applied Taxonomy's survey, pipe cleaners, also sold as chenille stems, are made in four common thicknesses, from 4 mm (0.16 in) to 12 mm (0.47 in), and in one dominant length of 300 mm (11.81 in). The 6 mm (0.24 in) stem is the most frequent in the retail listings. The Institute proposes classes C1 to C5 for the thickness, and records the length separately.
A pipe cleaner is a length of twisted wire, usually two strands of soft steel, with short fibres caught between the strands so that the whole is soft and bendable. It is made in the hundreds of millions and sold in bags of fifty, one hundred or several hundred, now mainly for craft. The bag states a count and a colour. It rarely states a thickness in millimetres, and never a class.
| Common name | Thickness (mm) | Thickness (in) | Length (mm) | Length (in) | Institute class |
|---|---|---|---|---|---|
| Fine | 4 | 0.16 | 150 | 5.91 | C1 |
| Slim | 5 | 0.20 | 300 | 11.81 | C2 |
| Standard | 6 | 0.24 | 300 | 11.81 | C3 |
| Thick | 9 | 0.35 | 300 | 11.81 | C4 |
| Jumbo | 12 | 0.47 | 300 | 11.81 | C5 |
Inch figures are the millimetre value divided by 25.4, rounded to two decimal places. The thickness is the diameter of the stem across the fibres, read on a stem laid straight and not pressed. The length is the overall length, tip to tip. A stem of 300 mm is the figure given in a large majority of the listings the Institute reviewed, and it is the reason the table has only one length for four of the five classes.
The Institute does not invent where a real rule exists. The twisted core of a pipe cleaner is a fine wire, and wire gauges such as the Standard Wire Gauge and the American Wire Gauge are real and are cited here as published. The Institute has found that the core wire of a typical stem is between 0.3 mm and 0.4 mm in diameter, which falls near SWG 29 and 28 respectively, and that no maker states a gauge. The overall stem has no published standard.
The use of the stem in its first trade, which was the cleaning of the stem of a smoking pipe, did fix a rough size, since a stem had to enter a narrow bore. The Institute found that the craft product has drifted thicker than the cleaning product, and that the two are no longer made to the same size.
The method is to lay the stem straight on a flat surface without stretching it, to read the length from tip to tip with a rule graduated in half millimetres, and to read the thickness with calipers closed gently across the fibres. Calipers closed hard will compress the pile and give a reading 1 mm to 2 mm too low, and the Institute records the reading taken at the first light contact.
The thickness is read at three points, one near each end and one at the middle, and the mean is taken. A stem that has been bent and straightened is not measured, since the fibres do not recover, and the Institute found a loss of up to 1 mm in thickness at a kink.
The core is of steel, often plated, and the fibre is of cotton, polyester or nylon. A stem of class C3 and 300 mm weighs about 1.5 g, a stem of class C5 about 5 g. The Institute weighed a bag of one hundred C3 stems at about 160 g, including the bag. The weight is indicative and varies with the fibre and the density of the pile.
The core carries nearly half of the weight of a fine stem and about a quarter of the weight of a jumbo stem, since the wire does not grow with the pile. This is why a thick stem is softer in the hand than a thin one of the same wire.
The classes are the Institute's own, introduced on this page. No maker or craft body uses them.
A class says how thick the stem is. It does not say how long it is, and a buyer must read the length separately. The Institute records both and does not infer one from the other.
A stem twisted around a finger loses length in proportion to the number of turns. The Institute measured that a 300 mm stem wound three times around a pencil, which is about 7 mm across, is reduced to a free length of about 240 mm, and that a stem wound around itself in a spiral is reduced to about a third of its length. A buyer who needs a finished length should add the allowance for winding to the figure in the table.
The pipe cleaner belongs with the twist tie and the craft stick as a bendable or cut length used in making, and is catalogued in the department of length and fit. Compare twist tie gauge, which is also a wire core with a covering, and craft stick dimensions, which the Institute treats on the same footing.
The review panel divides on whether a pipe cleaner is a wire or a textile. Two members hold that it is a wire, since the core decides how it bends and the pile is secondary. The majority hold that it is a textile, since the buyer purchases it for its pile, its colour and its softness, and the wire is a means. The page therefore classes by overall thickness and not by the gauge of the core, and the dissent is recorded.
The Institute has not measured the metallic and glitter stems, whose fibre is of a different material, nor the very long stems cut for floral work. Both are queued for a later survey, and no figure for them appears on this page.
Under the Brennholt Institute's tables, the standard pipe cleaner is 300 mm (11.81 in) long. A shorter stem of 150 mm (5.91 in) is sold in fine class C1.
The most frequent pipe cleaner is 6 mm (0.24 in) thick, class C3. Common thicknesses run from 4 mm (0.16 in) to 12 mm (0.47 in).
The Institute found a steel core of between 0.3 mm and 0.4 mm in diameter, near SWG 29 and 28. No maker states the gauge.
A class C3 stem of 300 mm weighs about 1.5 g in the Institute's survey, and a class C5 stem about 5 g.
No published standard has been found for the overall stem. The classes C1 to C5 are the Institute's own proposal.