Plastics Database
Non-metallic materials for insulation, light duty and chemical exposure — light in weight, but bounded by temperature and creep.
Overviewwhat this group covers and how to read the numbers
Plastics earn their place in a joint for reasons other than strength. They insulate electrically, they do not corrode, they do not galvanically attack the metal they touch, and they will not scratch a finished surface.
The trade-off is that the numbers behave differently. Density is straightforward — roughly a seventh of steel — but strength is not a fixed figure at all. It falls with temperature and keeps falling under sustained load, a behaviour called creep that has no equivalent in the metal entries.
That makes the service temperature on each entry a hard constraint rather than a guideline. A nylon fastener that holds a load comfortably at room temperature can relax out of tension in a warm enclosure over a season.
plastic1 entry
Density comparisonevery plastics entry on one scale
Weight calculator| Material | Group | Density (g/cm³) | kg/m³ |
|---|---|---|---|
| Nylon (PA 6.6) | plastic | 1.14 | 1140 |
Densest entry: Nylon (PA 6.6) at 1.14 g/cm³. Lightest: Nylon (PA 6.6) at 1.14 g/cm³.
Common applicationswhere these materials are actually used
Frequently asked questionsabout plastics selection
Why use a plastic fastener instead of steel?
Three reasons that come up repeatedly: electrical insulation, so a fastener cannot short a circuit; galvanic isolation, so an aluminium panel and a steel screw never touch directly; and surface protection, where a metal fastener would mar the part it holds.
What are the limits of a nylon fastener?
Temperature and creep. Nylon's practical ceiling is around 90 °C, and above that it loses strength quickly. Separately, it relaxes under a load held for a long time, so a joint that must stay tight needs a spring element or a larger bearing area — not simply a bigger fastener.
Is a plastic fastener as strong as a metal one of the same size?
No, and the gap is large. Plastics are selected where their other properties matter and the load is modest. For anything structural, the metal entries are the starting point.