Spark Exhaust Bent Tube 45° Ø 28 × 1.5 mm Stainless Steel Universal G9118

Forty-five degrees at twenty-eight millimetres. The smallest sharp corner in Spark's range, in the only small diameter it builds with a heavy wall.

Key Features

• Mandrel-formed 45° bend, AISI 304 stainless steel.
• Ø 28 mm outside, 1.5 mm wall thickness.
• Straight tangents at both ends for cutting and welding.
• Matches Spark's 28 mm straight tube, article G9010.
• Spark part number G9118, made in Mantova, Italy.

Forty-Five Is the Working Angle

Of the three angles Spark stocks, forty-five is the one most systems are actually built from. It turns a corner properly without the flow penalty of a right angle, and two of them make a ninety with an offset built in — which is what most real routing problems need.

A shallow bend corrects. A right angle turns. Forty-five does both, which is why a fabricator's rack holds more of them than anything else.

Small Bore, Tight Spaces

Twenty-eight millimetres exists for the plumbing around the main gas path: balance pipes between headers, drain and breather runs, link sections on a 125 or a small single. Those are all jobs done in confined space, where a sharper angle is what fits.

Why the Wall Is Heavier Here

A tube's resistance to collapsing under a bender falls away rapidly as diameter drops. At twenty-eight millimetres a one millimetre wall crushes on the inner heel; a millimetre and a half survives it.

That extra half millimetre is also why this is the one small article in the range that shrugs off being stood on in a workshop.

Two Bends, One Right Angle

Weld two 45° bends together with a short straight between them and you have a ninety degree turn that is also offset sideways. Vary the length of the straight and the offset changes with it.

It flows better than a single tight ninety and it fits around obstacles a single bend cannot dodge. The cost is one extra joint.

Cutting to a Smaller Angle

A 45° bend trims down to anything shallower. Cut through the curve rather than the tangent and both halves stay usable — on a build needing several small corrections that is two parts from one article.

Deburring a Small Bore

At twenty-eight millimetres a burr left on the inside edge occupies a meaningful fraction of the bore. A round file reaches it; a rolled-up strip of abrasive on a rod finishes it. Check with a fingernail before welding, because afterwards you cannot.

Ordering

One bend per article. Spark builds 30°, 45° and 90° at this diameter.