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. Read the full comparison in our sewn vs. welded filter bags guide, or 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.