QUICK ANSWER
Start from the coating, not from the filament name.
Solvent-based coatings are usually matched with natural bristle, whose soft tip helps the finish. Water-based coatings are usually matched with synthetic filament, which keeps its shape when wet. Within synthetics, PBT is generally chosen for better resilience and PET for cost, while blends trade feel against price. The specification — diameter, taper, flagging, fill — decides how the brush actually behaves.
Do not approve a range on a filament name. Approve it on a physical sample tested with the coating the range will be sold against, and keep that sample as the repeat-order reference.
FILAMENT FAMILIES
Four options and where each one fits
| Filament | Typical fit | What buyers should confirm |
|---|---|---|
| Natural bristle (hog / boar) | Solvent-based paints, varnishes and traditional finishing where a soft, tapered tip is wanted | Loads and releases solvent coatings well; needs humidity and odour control in storage, and restricted-material requirements must be confirmed per market |
| PBT (polybutylene terephthalate) | Water-based and hybrid decorative coatings; general-purpose and professional ranges | Good shape retention and resilience; taper and flagging determine how the tip carries and releases paint, so the specification matters more than the polymer name alone |
| PET (polyethylene terephthalate) | Cost-sensitive decorative ranges and utility formats | Lower cost than PBT with adequate performance for many wall paints; stiffness and heat resistance are typically lower, so the coating system should be checked |
| Blended filament and bristle blends | Ranges aiming to balance application feel, finish and target price | Blend ratio must be fixed and repeatable; buyers should approve a physical sample rather than a ratio on a spec sheet |
COMPARISON
Six factors beyond price
| Factor | Natural bristle | Synthetic filament |
|---|---|---|
| Coating compatibility | Natural bristle for solvent-based; synthetic (PBT/PET) for water-based | Confirm against the actual coating, not the product family |
| Finish behaviour | Natural tips soften brush marks on solvent finishes | Synthetic taper/flagging controls finish on water-based systems |
| Shape retention | Lower in water-based use unless treated | PBT generally better than PET for repeated use |
| Price position | Higher and volatile (raw material dependent) | PBT > PET in most ranges |
| Storage sensitivity | Moisture, odour and pest control required | More stable, but heat exposure can distort filament |
| Regulatory checks | Restricted materials and origin documentation | Confirm compliance and recycled-content claims before printing them |
Price is the last factor to compare, not the first. Two brushes can show the same size and handle and still behave differently because the filament diameter, taper and fill weight differ.
SAMPLE APPROVAL
What to record before a range is approved
- Filament type and, where relevant, the blend ratio stated on the approved sample
- Filament diameter and length; bristle count or fill weight per brush size
- Tip treatment: taper, flagging and any chemical tipping
- Ferrule and handle material, plus the assembly method (stapled, crimped, glued)
- Performance on the buyer's own coating: loading, release, brush marks and clean-up
- Storage and shipping conditions, especially for natural bristle
- Packaging artwork claims that must be substantiated (for example recycled or compostable)
Record these against the sample, not against a product name. When a repeat order arrives a season later, the specification sheet plus the retained sample is what keeps the range consistent.
FAQ
Filament questions buyers ask before sampling
Is synthetic bristle better than natural bristle?
Neither is universally better. Natural bristle is usually chosen for solvent-based coatings where a soft tip helps the finish; synthetic filament such as PBT or PET is usually chosen for water-based coatings because it keeps its shape when wet. The coating system, finish target and price position determine the choice.
What is the difference between PBT and PET filament?
Both are polyester-family synthetics. PBT generally offers better resilience and shape retention, while PET is often used where cost is the main driver. Filament geometry — diameter, taper and flagging — affects performance as much as the polymer type, so a sample should be approved on the actual coating.
Can natural and synthetic filament be blended?
Yes, blends are used to balance feel, finish and cost, but the ratio has to be fixed and repeatable. A stated ratio is not a performance guarantee; buyers should approve a physical sample and keep it as the reference for repeat orders.
How do buyers check a brush filament before ordering?
Record filament type, diameter, length and tip treatment on the sample; test it with the buyer's own coating for loading, release and brush marks; and confirm ferrule, handle, packaging claims and storage requirements. Written specifications without a physical approved sample are not enough.
Does filament choice affect packaging claims?
It can. Claims about natural materials, recycled content or biodegradability must be substantiated for the specific filament and market before they appear on packaging. Buyers should request the supporting documentation rather than rely on generic marketing language.
BUYER CHECKLIST
Information to send before sampling
- Coating system the range will be sold against (solvent, water-based, hybrid)
- Target finish and the surface the brush is designed for
- Price position and channel (value, trade, professional, private label)
- Sizes and packaging format, including any claims that must be substantiated
- Whether the range must match an existing approved sample
NEXT STEP
Build the range around your coating.
Pamin can propose a filament and construction starting point for your coating system, then produce samples for side-by-side evaluation before the range is approved.