BACKGROUND:
Travel trailer windshields are prone to shattering.
I purchased my travel trailer used and, upon inspection, I found many tiny sand pits in the windshield. In my experience, continued pitting will eventually cause the windshield to shatter.
I decided to create a cover that utilizes the space behind the glass for attachment. On my windshield, there is approximately 1/4-inch between the edge of the glass and the rubber boot/adhesive. If your windshield attachment is similar, this solution should work for you.
MY COVER:
This is a photo of my windshield, installed on my 2021 travel trailer. I have since removed the top corner pieces and moved the top tabs toward the outside to make the cover easier to install.
To remove the cover, I lift the tails on the bottom and side cam locks and turn them 90 degrees counterclockwise and lift the cover off the windshield.
MATERIALS:
Polycarbonate Sheet:
I used clear polycarbonate from my local home goods store. It is the same material used in bullet-proof glass. It is flexible, easy to machine, and doesn’t crack easily like acrylic.
NOTE: The polycarbonate sheet needs to be cut EXACTLY 3/4-inch wider than the outline of the windshield to facilitate the attachment of the tabs and cam locks.
Hardware:
All of the tabs are attached to the glass with the following hardware (pictures show temporary hardware), I purchased stainless steel hardware from mcmaster.com. You could use zinc plated hardware if you are careful to keep it coated to prevent rust.:
- Tee Nut Insert for Wood, 316 Stainless Steel, 10-24 Thread Size, 0.319″ Installed Length
- 316 Stainless Steel Flanged Button Head Screw, 10-24 Thread, 3/4″ Long
3D Printed Tabs and Cam Locks:
I used Thermoplastic Polyurethane (TPU) filament to print the rubber tabs and cam locks. TPU is very strong, UV resistant, and oil an grease resistant.
The cam locks make it easy to secure the polycarbonate to the windshield. They are designed to turn 90 degrees to lock and unlock. The tabs on the cam locks snap behind the polycarbonate to prevent the cam locks from opening while you are towing your trailer.
CUTTING THE POLYCARBONATE (3/4-inch larger than the windshield):
I made a paper template of my windshield. This needs to be accurate or the cam locks will not fit properly.
After tracing the windshield, I added 3/4-inch to the outline.
I used spray glue to attach the template to the protective plastic on the polycarbonate.
I used a metal blade on a jig saw to carefully cut the polycarbonate to size. It was easier to rough cut the polycarbonate before carefully cutting along the outline.
MAKING THE CAM LOCKS:
I printed these using:
- TPU filament
- 0.4mm nozzle
- 0.2mm layer height
- 3 wall loops
- 50% infill
I heated the tee-nuts with a small torch before pushing them into place in the cam locks.
The screws on the cam locks should be loose enough to allow the cam locks to turn on the polycarbonate. The TPU should keep the screws from turning and minimize the need for Loctite on these screws.
I used one of these on each side of the glass and two across the bottom. I put the side locks low enough to be reached without a step or a ladder.
The cam locks and the flat glass tabs should be printed with the flat side down as shown in the following picture.
CAM LOCK STL MODEL:
FLAT GLASS TAB:
I used two of these at the top of the glass. They are printed with the same settings and assembled with the same hardware as the cam locks.
ATTACHING THE TABS:
I marked the locations for the tabs and drilled the 3/16-inch holes with the tabs in place.
FINAL FITTING AND ADJUSTMENT:
The top tabs need to be pushed behind the glass. You may need to stand on the hitch to ensure that these tabs are in place.
The cover needs to be centered on the windshield for the side tabs to turn and lock.
If any of the cam locks are too tight on the windshield, you can remove them and use a step drill to increase the size of the holes in the polycarbonate. Increase the hole sizes until the cover fits and the cam locks fit easily.
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