One of the first questions new electric strapping machine buyers ask is: “Should I use PET or PP strap?” Both work with the Velmorian VON1 — but they serve very different purposes. Choosing the right one can save you money and prevent damaged shipments.
Quick Comparison
| PET (Polyester) | PP (Polypropylene) | |
|---|---|---|
| Strength | High — closest to steel | Medium — sufficient for light loads |
| Stretch (Elongation) | Low (~12–18%) | High (~25–40%) |
| UV/Weather Resistance | Excellent | Poor — degrades in sunlight |
| Cost | Higher per meter | Lowest |
| Best For | Heavy, rigid loads | Lightweight, stable loads |
| Strap Thickness | 0.5–1.2mm | 0.4–0.8mm |
When to Choose PET Strap
PET (polyester) strap is the modern replacement for steel strap in most applications. It’s the default choice for the VON1.
Ideal Applications
- Brick, tile, stone — heavy rigid loads that won’t compress
- Lumber and construction materials — outdoor storage, UV exposure
- Metal coils and pipes — sharp edges that can cut PP
- Export shipping — long transit times where strap relaxation is a risk
- High-value cargo — when strap failure is not an option
Why PET Holds Better
PET has very low creep (stress relaxation over time). A PET-strapped pallet that sits in a container for 30 days will still be tight when it arrives. PP, by contrast, can lose 15–20% of its tension within days as the material creeps.
Pro tip: PET strap also has no sharp edges when cut (unlike steel), making it safer for warehouse workers and easier to dispose of.
When to Choose PP Strap
PP (polypropylene) strap is the budget choice — and for the right applications, it’s all you need.
Ideal Applications
- Cardboard box pallets — standard ecommerce and distribution
- Lightweight goods (< 500kg per pallet)
- Indoor storage — no UV exposure
- Short-distance shipping — same-day or next-day delivery
- High-volume, low-margin operations where strap cost matters most
The PP Trade-off
PP strap is cheaper per meter, but it loses tension over time as the material stretches and relaxes. For loads that will be stored or shipped for more than a few days, this can lead to load shift.
Strap Size Compatibility — VON1
The VON1 handles both strap types in the following sizes:
| Strap Type | Width Range | Thickness Range |
|---|---|---|
| PET | 12–19mm (0.47″–0.75″) | 0.5–1.2mm |
| PP | 12–16mm (0.47″–0.63″) | 0.4–0.8mm |
Note: Always check your strap specifications before ordering. Using out-of-spec strap can cause feeding jams or weak welds.
Can You Switch Between PET and PP on the Same Machine?
Yes — with no tool changes. The VON1 automatically adjusts welding parameters based on the strap type. Simply feed the new strap in and continue working.
This is a major advantage over manual tools, which often require different tension heads or sealers for different strap types.
Cost Comparison (Typical)
| Strap Type | Cost per Pallet* | Strap Life | Failure Risk |
|---|---|---|---|
| PET 16mm | ~0.35–0.60 | 6+ months outdoors | Very low |
| PP 12mm | ~0.12–0.25 | 1–2 months outdoors | Moderate |
*Based on 4 straps per pallet. Actual cost varies by supplier and volume.
Decision Checklist
Choose PET if:
- ✅ Load weight > 500kg
- ✅ Shipment > 7 days transit
- ✅ Outdoor storage expected
- ✅ Load is rigid (won’t compress)
Choose PP if:
- ✅ Load weight < 500kg
- ✅ Indoor storage only
- ✅ Short transit time
- ✅ Minimizing strap cost is priority #1