In paints, coatings, and inks, filtration is the last thing between your batch and a customer rejection. Gels, seeds, skins, and oversize pigment agglomerates that survive to the fill line become craters and fisheyes on somebody’s finish. Bag filtration at the right micron — with the right bag construction — is how you keep them out.
Why Welded Bags Matter Here
A sewn bag has needle holes, and under pressure a gel particle will find them. Our ultrasonically welded filter bags have no needle holes, no thread, and no bypass path — the fluid goes through the media or it doesn’t go through. Welded construction also eliminates thread fragments as a contamination source, and our standard media are silicone-free, which matters when a single silicone transfer can crater an entire coating run.
What We Recommend
| Application | Media | Typical starting point |
|---|---|---|
| Architectural & industrial coatings, final filtration | Welded felt | 25–50 µm |
| High-gloss / automotive-quality finishes | Welded felt, tighter rating | 10–25 µm |
| Inks and tint bases | Welded felt or high-efficiency multi-layer | 1–10 µm |
| Pre-straining raw materials / letdown | Mesh bags (washable) | 100–400 µm |
Practical Notes
- Filter as late in the process as possible — after letdown, before fill.
- Viscous products need more surface area, not a coarser bag: step up to a size 2 before you step up in microns.
- Solvent-borne systems: tell us the solvent and we’ll confirm media compatibility before quoting.
Fighting a recurring gel or seed problem? Call 800-554-8555 or request a quote — include the product, viscosity, and flow rate.