Solving the windshield problem

Last night after a great deal of anger and frustration and reading through many different car forums I hit upon a solution to the windshield problem that will ultimately only required four additional holes drilled into the car.

I have always liked the Hallock Style of V windshield seen on hot rods. It makes a great alternative to a flat piece of glass stretching across the car. It was originally a boat windshield on Chris Crafts from the thirties and forties, and the early hot rodders adapted it for their use. As seen on BlackToBasics below:

srb_0709_blacktobasics.jpg

While this windshield looks curved in this picture it is actually two pieces of flat laminated safety glass. Unfortunately windshield frames like that are both heavy cast bronze (the Hot Rod guys evidently do not care about weight) and expensive ($1700) and won’t fit. Luckily the Jalopy Journal forums had several technical articles about fabricating a windshield frame like that from scratch. The advantage it has over the single pane of flat glass is that there is some support in the middle of the span which will reduce the likelihood of cracking the glass.

So, onto fabricating a Hallock style windshield for a Lotus Seven Clone, while minimizing the changes to the car and the expense.

I decided to stick with the supplied windshield stanchions and fabricate a center brace then use standard automotive glass adhesive methods to attach the glass. This will preserve the “frameless” look I had with the polycarbonate windshield.

Since the glass is flat, and is very unforgiving to twisting it is important that the sweep angle of the center brace match the sweep angle of the side stanchions. This sweep angle is set by the existing stanchions. I measured the stanchions and found the sweep to be 60 degrees. I fabricated the center bracket out of two piece of 0.065 aluminum sheet riveted together. I formed the bends using a 6″ press brake in my vice. As it turns out you can make very nice long bends with this short little brake if you carefully position the brake and make several passes.

dscf2160-small.jpgdscf2164-small.jpgDrivers View

With the center brace fabricated and mounted it was time to make a pattern for the window glass. A simple way to match the contour of the scuttle is to use index cards to approximate it. I clamped a carpenters square to the driver’s side stanchion then used painters tape and index cards taped to the square.  The carpenters square keeps the card along a straight line as the is what the glass will be.

dscf2165-small.jpg

Once I was happy with the fit of index cards I transferred the card to a sheet of melamine to make the initial cuts on the window pattern.

dscf2167-small.jpgdscf2168-small.jpg

The real mark of success is seeing that the one pattern works for both sides simply by flipping it over.

Another mark of success is that the melamine meets the center brace and the stanchions to within 1/16 of an inch all along the bond zone, which seems to be well within the gap filling capabilities of urethane adhesives used to hold down windshields.

The next step is to get the glass cut and purchase the adhesive. I think I will try to buy some scrap glass to practice with the adhesive before I commit to the car.

Advertisements

6 Responses to Solving the windshield problem

  1. Dan Doerer says:

    Craig:
    Very ingenious. The lack of a top frame also allows for adjusting the height as desired.
    Dan
    #93 in STL

  2. Eddie Sheffield says:

    Craig,
    Looks good so far! I had seen those Hallock style frames and wondered if they would fit. I’m anxious to see how your project turns out!
    BTW, I can’t remember who but I think there’s another Stalker builder who fabricated some kind of fiberglass frame in a similar style.
    Eddie
    #88

  3. enderw88 says:

    Thanks Eddie, Rick O’Brien built a V shaped frame to eventually support a top. His was one of the ideas I shook and stirred with the other to come up with this.

  4. virg says:

    Looks good, I’m still thinking on what I want to use on my locost8. I need to have clips along the top of the windshield for all season touring. I guess I’ll mock it up both ways.
    Thanks for more inspiration.

    Virg project web site: http://www.brokenhammer.com

    email: lo_cost8@yahoo.com

  5. Ladia Jakubec says:

    Hi,
    Do you have a drawing of the center stay? I am just about to have to install the windshield and this looks like a good option.
    Thanks,
    Ladia

    • enderw88 says:

      No drawing. I matched the angle of the side stays and made the bracket out of two pieces of sheet aluminum pop-riveted together. I just looked and don’t have any good pictures of the bracket anywhere

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: