How to Restore Old Metal Windows: A Comprehensive Guide

Old metal windows, particularly historic steel casement windows, are architectural gems that add character and charm to any building. While they may appear beyond repair, with some effort and the right techniques, these windows can be restored to their former glory. In this comprehensive guide, we’ll explore the process of restoring old metal windows, whether they are in place or removed for a shop restoration.

Preparing the Window for Restoration

The first step in restoring an old metal window is to thoroughly clean the surface. Use a citrus-based stripper to remove any existing paint or glazing. Be sure to wear proper safety gear, such as gloves and eye protection, when working with chemicals. Once the window is stripped, use a carbide scraper or needle scaler to remove any remaining paint or rust. A wire wheel grinder can also be used to create a key for the primer and paint to adhere to the metal surface.

If the window is being removed for a shop restoration, it’s important to carefully disassemble it. Take note of how the window is put together and label each piece for easy reassembly. Cover the opening with bubble wrap and gorilla tape to protect it from the elements while the window is being worked on.

Repairing the Metal Frame

Once the window is stripped down to the bare metal, it’s time to assess any damage to the frame. Light corrosion can be removed by hand with a wire brush or sandpaper, but more severe rust may require professional cleaning methods such as acid pickling or shot blasting. Dent-straightening, cold stitching, fire welding, modern welding, and patching are typical repair techniques that may be used depending on the fabric of the window.

It’s important to note that removing all coatings from the metalwork can destroy evidence of previous historic paintwork. As such, some paint samples should be taken, and if possible, layers should be left behind in a small area where rust has not occurred to provide a context for future owners.

Reglazing and Painting

After the metal frame has been repaired, it’s time to reglaze the window. Use a utility knife or exacto knife to remove the old glazing compound, being careful not to damage the glass. Apply a new layer of glazing compound, smoothing it out with a putty knife or a tool made from mahogany, such as those used in ceramic shops.

Before painting, apply a zinc-based primer to the bare metal to provide a protective layer. Use an oil-based paint, preferably an acrylic paint or an auto body paint, for the best results. Apply the paint in thin, even coats, thinning it with a splash of paint thinner if necessary to achieve the desired consistency.

Reinstalling and Maintaining the Window

Once the paint has dried, the window can be reinstalled in its opening. Be sure to check that the window operates smoothly and that there are no gaps where air can infiltrate. Regular maintenance is key to keeping your restored metal window in good condition. Check for any signs of corrosion or damage, and address them promptly. Lubricate any moving parts with a thin oil, such as 2 in 1, to keep them free and prevent rusting.

With proper care and routine cleaning, your restored metal window can last for many years to come, preserving the character and charm of your historic building.