Plastic or Steel Cones: Working Out Cost Per Use
> In brief > - Cost per use is the only number worth comparing. > - Steel and plastic fail at different points in the cycle. > - The break-even depends on your actual reuse rate, not on a typical one.
Cones are usually bought on unit price, because that is the number that appears on a quotation. It is also the least useful number in the decision. A cone that costs a fifth as much but lasts a tenth as long, and needs its thread replaced twice, is the more expensive item. Cost per use is the figure that matters and it depends on four inputs, only one of which is on the price list.
Our own production and test data are available on request — see how our factory works and contact the engineering team for the documents behind any figure quoted here.
Cost per use is the total cost of a cone divided by the number of times it is used, including purchase, cleaning, and replacement costs. Reuse cycles refers to the number of times a cone can be used before it needs to be replaced. Loss rate means the frequency at which cones are lost or damaged beyond repair, affecting the overall cost per use. Striking time is the duration after pouring when the formwork is removed, impacting the ease of cone removal and its lifespan. Cleaning method is the process used to remove concrete from the cone, which can affect its durability and reuse count.
What the cone actually does.
The cone forms the conical recess at the concrete face, protects the tie thread during the pour, holds the washer plate in position against the waler and provides the void that will later be grouted. Three functions, one small part, which is why failures show up as several unrelated-looking site problems: leaking around the tie, spalling at the face, and rods that will not release cleanly.
Plastic and steel compared.
The two materials are not interchangeable, they suit different duty cycles. Plastics are moulded, light and release well; steel is durable, indifferent to weather and survives abuse that would destroy a polymer part.
| Characteristic | Plastic cone | Steel cone |
|---|---|---|
| Unit price | Low | Several times higher |
| Weight | Light | Heavy |
| Typical reuse cycles | Tens | Hundreds |
| Cold weather | Becomes brittle | Unaffected |
| Extreme heat | Softens and deforms | Unaffected |
| Concrete adhesion | Releases easily | Needs cleaning |
| Loss and theft risk | Lower, low scrap value | Higher, recoverable scrap value |
| Best fit | Short projects, mild climate, low turnover | Rental fleets, long-term high turnover |
The arithmetic that decides it.
Cost per use has three terms, and only the first is visible before the order.
| Term | Plastic cone | Steel cone |
|---|---|---|
| Purchase price divided by lifetime cycles | Low price, low cycle count | High price, high cycle count |
| Cleaning labour per cycle | Low | Higher, concrete must be removed |
| Replacement driven by loss and damage | Small unit loss, cheap to replace | Larger unit loss, expensive to replace |
Substitute your own figures into those three rows and the answer is usually not close. On a single project with a few hundred cones and one or two pour cycles, plastic wins because the lifetime cycle count never gets exercised. In a rental fleet that reuses the same cone dozens of times a year for a decade, steel wins because the purchase price is amortised over hundreds of uses and cleaning becomes the dominant running cost.
Standard basis: EN 13670
Where reuse counts come from.
Published cycle figures are measured under favourable conditions. What a site actually achieves depends on factors that rarely appear in the datasheet:
- Striking time, because cones pulled early from green concrete come out clean, and cones left for days bond to it.
- Cleaning method, because a hammer and a chisel shorten a steel cone's life faster than the cone itself wears.
- Storage, because cones tipped into a wet stillage or left in the sun age faster than those returned to a rack.
- Concrete grade, since higher strength mixes grip the cone harder at every cycle.
- Loss rate, which in practice is the single largest term and the one nobody records.
Failure modes that end a cone's life.
- Thread flattened or rounded, so the tie no longer pulls the cone squarely against the form face.
- Outer diameter grown or deformed, producing a recess that is oversized or out of round and needs more grout.
- Cracks in the body, most often after cold-weather handling.
- Concrete bonded into the cone seat, which is a cleaning problem on steel and a write-off on plastic.
- Stripped cone nut threads, which is the failure that most often appears on site as a tie that will not release.
Standard basis: ISO 965-1
Choosing for a given project.
Two numbers make the decision: expected total cycles per cone and the loss rate your site actually experiences. Measure the second one for a month before committing to a large order, because a lost cone costs its full purchase price and no lifetime cycle count can offset it. If the product is going to a rental company, buy for cycles and specify steel with a defined thread tolerance. If it is going to a single project in a temperate climate, the cheap cone used once is not a compromise, it is the correct engineering choice, and paying more for durability that will never be consumed is simply a cost with no return.
Matched cone and sleeve sets are listed on the climbing cone assembly product page.
References and standards.
- ISO 9001:2015 — Quality management systems
- ISO 14001:2015 — Environmental management systems
- ISO 45001:2018 — Occupational health and safety management
- NIST material measurement standards
- EN 10204:2004 — Types of inspection documents
- ISO 898-1 — Mechanical properties of fasteners made of carbon steel
About us: This article discusses the cost per use of plastic and steel cones in formwork, checked against our production and test data. Our capability includes providing detailed documentation on product performance. Our contact page offers direct access to the engineering team for specific inquiries, and the about page documents our factory processes and standards. This article was reviewed by the Qianheng Formwork Engineering team.