Welded filter bags eliminate the weak point of every sewn bag: the needle holes. Universal Filters ultrasonically welds the seams and bottom of the bag, fusing the media to itself — no thread, no needle punctures, no bypass path for unfiltered liquid. For applications where a few stray microns of leakage matter, welded construction is the answer.
Why Welded?
- No needle-hole bypass — sewing needles punch holes larger than most micron ratings; welding leaves the media intact.
- No thread — nothing to wick, fray, or shed into your process.
- Silicone-free — welded bags are built without sewing lubricants, critical for coatings and paint applications where silicone causes fisheyes.
- Stronger seams — the welded seam is as strong as the parent media, even under pressure spikes.
Specifications
| Attribute | Options |
|---|---|
| Sizes | Size 1 (7″ × 16.5″) and Size 2 (7″ × 32″) standard; sizes 3–4 and custom on request |
| Media | Polyester and polypropylene felt, 1–200 micron; glazed finishes available |
| Tops | Welded plastic flange (snap-seal), Parker C-band, Cuno-style |
| Edge orientation | Raw material edge in (standard) or out (option A) |
| Compatibility | Fits standard size 1 and 2 housings — Eaton, Rosedale, FSI, Parker, Hayward, and others |
Sewn vs. Welded: Which Do You Need?
If your process tolerates the slight bypass at stitch lines — most general-purpose filtration does — a sewn bag costs less. If you’re filtering paints, coatings, inks, high-value chemicals, or anything where downstream clarity is checked with instruments rather than eyeballs, welded construction pays for itself. A dedicated guide is coming; meanwhile, call and describe the application — we make both, so the recommendation is honest.
📄 Download the Welded Filter Bags spec sheet (PDF)
Price a welded bag: 800-554-8555 or request a quote.