October 01, 2008

#47 - Proper Window Restoration

To begin a window restoration, the window needs to be disassembled. Front frame and back frame are separated at the hinge. Then the vertical center channels are removed from the frames. Take care with the extruded aluminum front frame channels. The 4 rusty mild steel screws that hold them in place easily break off inside the channels.

After the channels are off, the old screen is removed from the back frame and the glass is removed from the front frame. To get the glass out, you'll be removing lots of little rusty fasteners that secure the L-shaped aluminum glass holders behind the glass. Throw the screws and nuts away. You can get new screws and tension nuts from Vintage Trailer Supply.

All the dismantling is necessary so you can de-rust and repaint the steel back frame channels. You're also going to replace the old screen material, get new glass, and then spend hours and hours removing corrosion and polishing the aluminum frames. The photo below shows a pile of back frames. The first two frames show what they look like when the oxidation and corrosion have been mostly removed (but before detailing). The rest show the extremely heavy oxidation and significant corrosion you'll encounter.

If you've polished an Airstream, you know about oxidation. It's not quick to remove, but on a trailer skin it isn't really that big a deal because the oxidation is generally even and rather thin. You can read my article on polishing an Airstream if you don't know the basics.

Polishing 53-year old window frames is nothing like polishing an Airstream. Repeat: nothing. Rub your finger across the back frame's sill. Feel how rough that is?. That's extreme oxidation and corrosion. The oxidation builds up into little craggy mountains of oxide. It cannot be polished off with aluminum polish. Don't even try. You're going to be grinding it or sanding it off. After you get it off, you're going to see little pits and valleys in the aluminum. That's corrosion and you can't entirely fix it. You can minimize it by continuing to grind and sand, but some of it is going to be there when you're finished. Fortunately, the only place the corrosion will be especially noticeable after you reassemble everything is in that exterior sill area. And that's not visible when the windows are closed.

In my next post I'll detail how to remove the severe oxidation.