This article is taken from http://www.spartantrailer.com/ about a restoration on a 1946 Spartan Manor:

One of the first restoration tasks on this trailer was to make it water tight. This meant that all water leaks from the windows had to be stopped. All the windows save the front Plexiglas picture windows were in great shape.

The other windows on the trailer are glass, therefore much more stable. Plexiglas was a fairly new technology for 1946. Plexiglas was used extensively for the first time during WWII for aviation purposes as can be seen here in the nose cone of a B17 bomber. It allowed for much lighter and complex forms.

Spartan Aircraft having had experience with this material readily adapted it to their line of trailer manufacture. It was a well suited match. When I originally found this trailer,  two of the front windows had been poorly replaced . They had been sized poorly and installed with a messy application of caulk. The curved left panel was original with heavy crazing. Most of the seal had severe dry rot and was barely holding the window in place.

Removing the old windows was a fairly easy task. The original windows were held in by a gasket sandwiched between the outer shell and an interior strip of extruded aluminum, which was screwed into the trailer frame.

This photo shows the right front window removed and the aluminum cleaned to accept

1946 Spartan window repalcement Credit:spartantrailer.com

the new window. I used large sheets of heavy paper to create templates for the new windows to be cut from.

The old windows were used as patterns. Some adjustments were required in order to get an optimal fit. 3/16 inch.

Plexiglas was used for replacements at a cost of about $150. This included them being cut to my templates. Instead of using a gasket for the window replacement I opted to use a newer product Dow Corning #795. This is an industrial grade glazing material. This close up shows the new window set in the sealant and shimmed with penny’s. The excess sealant was cleaned off with mineral spirits.

1946 Spartan window replacement Credit: spartantrailer.com

The new Plexiglas is in place. It is amazing how fresh the new windows make the trailer appear. It is nice to be able to have a clean view from this great picture window and the best part is there are no more water leaks! After almost 3 years the windows seem to be doing great. The plexi is exposed to full sun and has not discolored and the seals are still tight.

This post is part of a series documenting Sam Breen’a Spartan Restoration Project. Please see his first post here and check out the archive here. The CSPA is helping Sam by serving in an advisory role, offering modest support and featuring Sam’s Progress by syndicating his feed from http://spartantrailerrestoration.wordpress.com as part of our CSPA Supports Program.