Description
The Schwan aluminium straightedge is an aluminium profile without handles for screeding fresh mortar, filler or concrete straight and for checking the straightness of the finished surface. The straightedge is a hollow aluminium extrusion with a central rib running inside it. The central rib stiffens the profile so that it withstands the bending caused by the screeding stroke without sagging in the middle.
The rectangular profile has a cross-section of 100 x 18 mm and a wall thickness of 1.2 mm. The dimensions are a compromise between stiffness and weight: the 100 mm high profile resists vertical bending, and the hollow structure keeps the weight low enough that even a long straightedge can be moved with one hand. Aluminium forms an oxide film on its surface, so the profile does not rust in wet mortar and needs no surface treatment.
The straightedge has no handles. A profile without handles is the same along its whole length, so it can be placed against its side at any point and used on both sides. The model without handles is also slimmer, so it fits as a guide into narrow gaps and can be used as a guide rail for sawing. Plastic end caps are fitted to the ends of the profile; they prevent mortar from getting inside the profile and protect the cut end.
The straightedge is available as a rectangular profile in lengths of 100, 150, 200, 250, 300 and 400 cm and as a bevelled trapezoidal profile in lengths of 100, 200 and 300 cm. The bevelled profile tapers upwards, so the thin lower edge screeds the mortar and the wider upper edge gives grip and stiffness. New caps are available for the end of a cut straightedge: the End cap for aluminium straightedge, rectangular, 2 pcs fits the rectangular profile and the End cap for aluminium straightedge, bevelled, 2 pcs fits the bevelled profile.
Intended use and suitability:
The straightedge is used for two tasks: screeding the material before it hardens and measuring the straightness of the surface after it has hardened.
- Floor levelling compounds and topping concrete: the straightedge is drawn along screed rails or guides, removing excess material and leaving the surface at the level set by the guides.
- Rendering and skimming walls: fresh render is screeded against guide battens with a vertical or horizontal stroke.
- Tiling: the combed layer of tile adhesive is levelled and the straightness of the tile row is checked during installation.
- Masonry: the straightness of the wall surface and the line of the courses are checked by placing the straightedge against the side of the wall.
- Measuring straightness: the straightedge is placed against the surface and the gap is measured; this establishes the flatness deviation of the finished surface.
- Guide rail: the straight profile serves as a guide for a circular saw or router in board work.
- Choosing the length: the straightedge must reach from one guide to the other. A straightedge that is too short copies the waviness of the base; one that is too long is awkward to handle in a confined space.
Package contents:
- 1 pc aluminium straightedge in the selected length and profile type
- Plastic end caps fitted to the ends of the profile
Features:
- Hollow profile stiffened with a central rib: the profile withstands the bending of the screeding stroke and does not sag in the middle.
- Cross-section 100 x 18 mm: the high profile resists bending, and the narrow width fits into tight gaps.
- Wall thickness 1.2 mm: keeps the weight low and the profile rigid.
- Aluminium: does not rust in wet mortar and needs no surface treatment.
- No handles: the whole length is usable, both sides serve as a screeding surface, and it works as a guide rail.
- End caps: prevent mortar from getting inside the profile and protect the end; replaceable after cutting.
- Two profile types: rectangular for general use and bevelled trapezoidal for screeding render.
- Lengths 100–400 cm: chosen according to the guide spacing and the job.
Technical specifications:
- Material: aluminium, hollow extruded profile.
- Construction: central rib inside the profile.
- Rectangular profile cross-section: 100 x 18 mm.
- Wall thickness: 1.2 mm.
- Lengths, rectangular profile: 100, 150, 200, 250, 300 and 400 cm.
- Lengths, bevelled trapezoidal profile: 100, 200 and 300 cm.
- Handles: no handles.
- End caps: plastic, replaceable.
Schwan aluminium straightedge instructions for use:
Check before use: Lay the straightedge on its side on a flat surface and look against the light to make sure the profile is not twisted. A twisted straightedge transfers the error directly to the surface.
Screeding along guides: Set the screed rails or battens at a distance from each other that is shorter than the straightedge. Place the straightedge on the guides and draw it slowly forwards with a sawing sideways motion. The sideways motion cuts the material and stops it sticking to the profile.
Screeding render vertically: Start at the bottom and draw upwards. Remove excess mortar from the straightedge after each stroke so that it does not remain on the surface as a bump.
Measuring straightness: Place the straightedge against the surface and measure the largest gap between the profile and the surface with a wedge gauge or feeler gauge. Check the same spot crosswise from two directions.
Cutting to length: The aluminium profile can be cut with a hacksaw or a cutting disc. File off the burrs and fit new end caps to the end.
Cleaning: Wash the straightedge with water immediately after work. Dried mortar changes the shape of the screeding edge and leaves grooves in the surface. If necessary, use a plastic spatula, not a steel scraper.
Storage: Store the straightedge horizontally with support or standing upright. A long straightedge left leaning on one end bends under its own weight.
Warnings:
- Wear protective gloves. The edge of a cut profile and its burrs can cut.
- Fresh mortar and filler are alkaline and corrode the skin. Wash off splashes immediately and wear safety glasses.
- Aluminium conducts electricity. Do not use the straightedge near live cables, rails or overhead lines.
- A long straightedge is difficult to control in wind and in confined spaces. Make sure there is room before lifting and watch out for people around you.
- Do not use the straightedge as a lever, support, step or carrying aid. The hollow profile will bend permanently.
- Do not use a twisted or dented straightedge for measuring.
- Wear safety glasses and ear defenders when cutting the profile.
- Store the straightedge so that it cannot fall on children or pets.
Frequently asked questions (FAQ):
How do I choose the right length? The straightedge must reach from one screed rail to the other and slightly beyond. A shorter straightedge follows the waviness of the base and does not straighten it.
What is the difference between the rectangular and the bevelled profile? The rectangular profile is 100 x 18 mm and is suitable for general screeding and measuring. The bevelled trapezoidal profile tapers upwards: the thin lower edge cuts the mortar and the wide upper edge gives stiffness and grip.
Why does the straightedge have no handles? A profile without handles can be used along its whole length and on both sides, and it fits into narrow gaps. A model with handles is handier for long floor strokes but bulkier.
Can the straightedge be cut shorter? Yes. The aluminium profile is cut with a hacksaw or a cutting disc, the burrs are filed off and new end caps are fitted to the end.
Where can I get new end caps? The End cap for aluminium straightedge, rectangular, 2 pcs fits the rectangular profile and the End cap for aluminium straightedge, bevelled, 2 pcs fits the bevelled profile.
How is straightness checked? The straightedge is placed against the surface and the largest gap is measured with a wedge gauge. The measurement is repeated crosswise from two directions.
Does the aluminium profile bend in use? The central rib stiffens the profile against the screeding stroke. The profile bends permanently if it is used as a lever, stepped on or left leaning on one end for a long time.
Does the straightedge rust in wet mortar? No. A protective oxide film forms on aluminium. Dried mortar should still be washed off so that the screeding edge stays straight.
Recycling instructions:
Take a straightedge at the end of its service life to metal recycling as aluminium. Remove the plastic end caps and sort them for plastic recycling. Sort the packaging cardboard for cardboard recycling and the protective plastic for plastic recycling. Scrape dried mortar stuck to the profile off and sort it as construction waste before taking the profile to metal recycling.
