Base for welding 40x40/85x85mm, Raw, AISI316

The Strofix base for welding 40×40 / 85×85mm, RAW, AISI316 is a marine-grade AISI 316 stainless-steel square base plate for the 40 × 40 mm square railing post tube. The plate measures 85 × 85 mm and is 6 mm thick (h), supplied with a raw (unfinished) surface. The post tube is attached by welding.

This is the AISI 316 version of the 85 × 85 mm square base plate, and it is also thicker — 6 mm versus the 4 mm AISI 304 version — giving both marine-grade corrosion resistance and greater structural strength. The combination suits coastal, pool, and high-humidity installations, or higher-load posts where a stronger plate is wanted. The raw surface is standard for base plates concealed by a decorative cover after installation.

Use cases:

• Marine-grade floor mounting of 40 × 40 mm square railing post tubes
• Coastal, pool, and high-humidity installations requiring AISI 316
• Higher-load square post bases needing a thicker 6 mm plate
• Square base plate matching a square post profile for clean alignment
• Welded square post bases concealed by a decorative cover

FAQ

What post tube does this base plate fit?

The 40 × 40 mm square post tube — the square railing post profile in the Strofix range.

What steel grade and thickness are used?

AISI 316 (marine grade), 6 mm thick. The AISI 304 version of the same 85 × 85 mm plate is 4 mm thick at a lower price; an S235 mild-steel version is also available.

Why choose AISI 316?

AISI 316 offers superior corrosion resistance, suited to coastal, pool, and high-humidity environments. The thicker 6 mm plate also adds structural strength.

What are the plate dimensions?

85 × 85 mm with 6 mm thickness (h). A square plate matches the square 40 × 40 mm post profile.

How is the post tube attached?

The post tube is welded to the base plate using TIG or MIG welding.

Why is the surface raw?

The raw finish is standard for base plates that are concealed by a decorative cover after installation.

About Base & Clamp Fastenings

A base or clamp fastening is a stainless-steel plate or bracket that anchors a railing post to the building structure, forming the structural foundation of the balustrade. Bottom fastenings bolt to the top of a floor slab, deck or beam, while side fastenings bolt to the vertical face of a fascia, edge beam or wall. Assembly clamps grip an existing tube or post without welding, and assembly plates provide a flat mounting surface for auxiliary connections.

Strofix supplies 18 base and clamp products for Ø42.4 mm round pipe and 40×40 mm flat-sided square posts, with plate diameters from Ø80 to Ø100 mm (round) and plate dimensions from 80×80 to 135×56 mm (rectangular/square), in satin or raw-surface stainless steel with AISI 304 and AISI 316 options.

Screw-hole configurations include 2, 3 and 4-hole variants. The correct fastening depends on mounting orientation, post profile, plate size, number of screw holes and the required surface finish.