A well-designed aluminium window can lose airtightness, rigidity or finish because of small assembly mistakes. These are the seven mistakes we see most often in the workshop, and how to avoid them.
1. Choosing the fitting by eye
Every profile has a specific chamber and pitch. A fitting that goes in loose, or has to be forced, will never give a stable corner. Always check the dimensions in the product table before ordering.
2. Mixing fitting series in the same window
Even when two fittings look alike, their dimensions can differ by a few tenths of a millimetre. Use the same reference in all four corners.
3. Inaccurate mitre cuts
A 45° cut that is not exact shows at the joint and in the squareness of the frame. Check your saw calibration regularly.
4. Not cleaning the chambers
Swarf and burrs from cutting stop the fitting from seating properly. Clean and deburr before inserting it.
5. Crimping with the wrong die
Each series needs its own die. The wrong die leaves play or marks the profile. Check the die reference on the product page and our punch presses and accessories.
6. Using unsuitable screws
Screws must be the ones specified for the fitting, in thread and material. Stainless steel screws prevent corrosion in contact with aluminium. See our screws.
7. Neglecting transom joints
A perfect corner does not make up for a poorly joined transom. Choose an aluminium T-joint suited to the profile and load.
Avoiding mistakes starts with the right part
Most of these problems are avoided by using the right part from the start. If you are unsure about a reference, ask us: we will help you choose the fitting or T-joint that matches your profile.
