Furick Diffusers FAQs
Questions about TIG torch gas diffusers: what they do, how to size and fit them, and how to look after them.
What is the difference between a diffuser and the gas holes in a standard collet body?
A standard collet body releases gas through a ring of small holes, which gives little control over the flow once it leaves. A diffuser forces the gas through layers of mesh first, which evens it out and reduces turbulence.
In practice the diffuser gives steadier shielding on the same gas flow, and it generally allows more electrode extension. For simple practice or non-critical work a standard collet body is usually adequate, so the choice depends on the quality of weld the job needs.
How far can I extend the tungsten with a diffuser fitted?
Further than with a standard collet body. A standard collet body generally keeps the tungsten within the inside diameter of the cup, whereas the smoother, more uniform flow from a diffuser or gas lens lets the electrode stand out past the cup. How far you can go depends on the cup size, gas flow and current, so extend only as far as the joint requires and no further.
Check your torch maker's guidance for any limit, and start with a short extension, adding length only if access demands it. A longer extension exposes more hot tungsten to air at arc start and stop, so allow adequate pre-flow and post-flow, and watch for discolouration or porosity.
Which cups work with a diffuser?
A diffuser or gas lens setup uses cups made for its thread, not the cups from a standard collet body. The two have different thread patterns, so a standard cup will not fit.
Check the thread and the cup size marking before ordering. Within the cups that fit, a larger opening gives more coverage and suits a longer extension, while a smaller one gets into tighter joints. Clear and ceramic cups are both made in gas lens fittings, so choose by access, visibility and heat.
What damages a diffuser and how do I know when to replace it?
The mesh is delicate. Weld spatter can stick to or melt it, and excess heat can warp or melt the outer screens. Either one disrupts the gas flow and so the shielding.
Inspect the diffuser whenever you change the electrode or cup. Replace it if the mesh is clogged, bent, melted or visibly distorted, or if you see poor gas coverage such as discolouration or porosity that did not appear before. Whether you can replace only the damaged screen or the whole assembly depends on how it is made.