It took us a few weeks to get our act together, but we did finally find the time to get together and install the lexan windshield. In our last blog entry we said that we had decided on 1/4″ material, but we struggled to find someone who could supply it in the correct size – it was always either too much material for too much money or not big enough. After a week or two of searching we finally found Clear 1 Racing. I spoke with PJ on the phone and via email a few times – very helpful guy – we appreciate their guidance. PJ suggested that 3/16″ material was more than enough for what we were doing and they just so happened to sell sheets in the size we needed. To top it off, their shipping rates for such a large piece of lexan was more than reasonable – I think it cost $11 for shipping. Total cost to us for a 32″x60″x3/16″ Lexan MR10 was $170 shipped. Add in some stainless steal nuts/bolts/washers and a rubber gasket and we had all the ingredients for some lexan windshield goodness.
I spent a few hours the weekend before the install cutting and shaping the lexan. I used the busted windshield as a template to trace a rough outline onto the masking paper of the lexan. Using a jig saw with a multi purpose blade and some care I cut the lexan without any troubles – I think the key is to use lower blade speeds and take your time. Sanding the edge of the lexan in order to fine tune the overall shape was quite a bit tougher than everyone described online. I tried using an orbital sander, a vibrating palm sander and a block of wood with sand paper all to no avail – they just didn’t remove enough material. The only tool that seemed to be able to do the trick was my bench top belt sander. It was a little tricky holding that large of a sheet vertically over the sander in order to shape the edge, but it did finally work out. After a few test fits and some additional shaping, the lexan sheet was ready to be installed.
We took Clear 1’s advice and installed a 1″x1/8″ thick rubber strip around the perimeter of the windshield opening. The rubber strip creates a nice level base for the lexan to sit on. We used black gasket maker to bond the rubber to the body of the car. I was a bit worried that the gasket maker wouldn’t adhere to the rubber so I did a few test strips that ultimately revealed that there wouldn’t be a problem. We used clothes pins to hold the rubber at the corner while the gasket maker cured. We let the gasket maker cure overnight as per its directions.
The next step was to drill the holes in the lexan. We purchased a special polycarbonate drill bit to do this because we heard several horror stories of cracking the lexan with ordinary metal drill bits. We divided up the spacing of the holes evenly throughout – the spacing ended up being somewhere between 4 and 5 inches depending on the side.
Once the holes were all drilled in the lexan, we placed the windshield back in the opening, centered it and secured it in place. Now using a metal drill bit, we drilled through the rubber and metal of the body through the holes we had just drilled in the lexan.
Once all the holes were drilled in the body of the car, the next step was to paint a black border on the inside of the lexan. Thinking that we needed to use a tape that would curve very easily, we used a few different pin masking tapes, all with no success. It was just too hard to create a nice clean curve to match the shape of the windshield with 1/4″ wide masking tape. In the end, 1″ blue painter’s tape was the best material for the job. It stretched just enough to match the curve of the windshield but wide enough to not create any obvious bumps. We did 1-1/4″ top and sides and 3″ bottom borders. As you can see in the photo, we left the majority of the lexan masking in tact so that we didn’t have to re-mask for painting purposes.
Sanding off the MR10 scratch resistant coating was a bit of a challenge, but the vibrating palm sander seemed to do the trick with a little extra pressure. The real trick is sanding as close to the masking tape as possible without destroying that wonderful tape edge you just carefully created. After wiping down the lexan with some rubbing alcohol we put down one light coat of black enamel, followed by two medium coats.
Although we won’t be hitting speeds in access of 140 mph and a center brace isn’t totally necessary, we did have the material on hand and figured it couldn’t hurt to have it just in case. We added a couple layers of that same rubber we used around the perimeter of the windshield to the top of the aluminum u-channel so that the windshield would have something to sit on. Finally, we painted the center brace matte black to match the rest of the car.
The moment of truth. Everything was in place, all the holes were drilled (and countersunk where required), the paint was dry, the center brace was in place… time to drop in the windshield. We added a dab of gasket maker at each hole to help prevent water penetration at the holes and using stainless steal, 4mm, flat head screws, secured the new lexan windshield into place. We had to use self tapping screws (#8’s) at the bottom since there was no access to the back of the screws to add a washer and nut.
A couple overalls
We plan to go back and do a nice bead of silicone around the perimeter to fill the gap between the body of the car and the lexan to waterproof the setup.