How a filter is welded decides whether it holds its shape, seals against bypass, and survives pressure in service. Three joining methods dominate wire mesh fabrication — resistance spot welding, seam welding and TIG welding — plus laser welding for the most precise parts. Choosing the right one is part of building a filter correctly, and it depends on the form you are making.
Resistance spot welding
Spot welding fuses the mesh at discrete points using electric resistance — fast, economical, and ideal for tacking mesh to a frame, joining reinforcement rings, or fixing overlaps that do not need to be leak-tight. It is the workhorse for baskets, screens and structural joins. The limit: because the weld is a series of points rather than a continuous line, a spot-welded seam can allow fluid to bypass under pressure.
Seam welding
Seam welding produces a *continuous* weld line, typically with rotating wheel electrodes. This is what you use when a joint must be leak-resistant — for example the longitudinal seam of a filter cylinder. A continuous seam prevents the bypass that discrete spot welds can allow, so unfiltered fluid cannot slip past the join.
TIG (and plasma) welding
For the most demanding, leak-critical elements — high pressure, thin sections, or exacting sealing — TIG or plasma welding gives the cleanest, most controlled and most durable joint. It is slower and more skilled, so it is reserved for end caps, fittings and elements where a perfect seal is essential.
Laser welding
For thin sections and high-precision, high-volume parts, laser welding delivers a narrow, low-distortion weld with excellent repeatability and minimal heat input — useful where a fine mesh must be joined without warping. It sits alongside TIG as a premium, leak-tight option for the most demanding elements.
Which method for which part
| Part / need | Typical method |
|---|---|
| Mesh-to-frame, baskets, reinforcement rings | Spot welding |
| Cylinder / tube longitudinal seam (leak-resistant) | Seam welding |
| End caps, fittings, high-pressure sealing | TIG / plasma / laser |
The right join method depends on the form you are building — see our guide on choosing the right filter form for how cylinders, caps, cartridges and strainer baskets differ.
How welds are inspected
Controlling weld quality means more than setting the machine and hoping. Good practice combines validated, recorded weld parameters with inspection: visual and dimensional checks on every part, destructive peel or tensile tests on samples to confirm joint strength, and pressure or dye-penetrant testing on leak-critical seams. For OEM programs these checks are documented under ISO 9001 and included in the inspection report.
Keeping the weld corrosion-resistant
Welding heats the stainless and can leave heat tint and a chromium-depleted zone that corrodes if left untreated. On corrosion-critical parts the welds are pickled and passivated after fabrication to restore the protective oxide layer — an easy step to overlook, and a common reason cheap filters rust at the seam first.
Why weld quality decides filter performance
A filter is only as good as its weakest joint. Inconsistent welds are the most common cause of bypass — where fluid escapes around the media instead of through it, defeating the whole filter. That is why weld parameters must be controlled and joints inspected. At Xingma we run both resistance spot welders and seam welding equipment in-house, so we can match the join method to each part and verify it — see our Capabilities and Quality & Certifications pages.
Frequently Asked Questions
Can a spot-welded filter leak?
Under pressure, yes — discrete spot welds can allow bypass at the seam. Leak-critical seams should be seam- or TIG-welded.
Is TIG always the best choice?
It gives the best seal but is slower and costlier; spot and seam welding are the right, economical choice for parts that don’t need a fully sealed joint.
Do you inspect welds?
Yes — welds are checked as part of ISO 9001 process control, with destructive sample tests and full inspection for OEM programs.
Do welded seams need passivation?
On corrosion-critical parts, yes — welding leaves heat tint and a chromium-depleted zone, so leak-critical and marine elements are pickled and passivated after welding to stop the seam corroding first.
Have a welded filter to make? Send your drawing or sample and we’ll build it with the right join method and full inspection. Request a quote →