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Lexan Window installation in fiberglass rear hatch


bjhines

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I finally got around to installing the Beta Motorsports rear hatch. The hatch is a full duplicate inside and out. It is very light. I decided to pin on the hatch and install a lexan rear window. The rear window is 1/8" scratch resitant/coated Lexan. I managed to buy a piece large enough for a good price.

 

The retaining pins are 3/8" stainless bolts with the heads lathe-turned down and holes drilled through for cotter pins. I have protective washers made of 18 gauge stainless sheet.

rearwindowinstalled.jpg

 

 

 

 

The window installation details;

I used 10-24 x 1 1/4" stainless button head cap screws, Nylock nuts, and stainless sealing washers. The spacers are 1/4" thick HDPE strips.

Rearwindowhardware.jpg

 

 

 

 

The center supports are 1/16"x 1/2"x 3/4" angle aluminum. I bowed the center supports to match the curve on the sides of the hatch.

rearwindowinside.jpg

 

 

 

 

I get a nice shape and a rigidly supported window.

rearwindowoutside.jpg

 

 

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Well... I would be lucky to get this thing done by fall. I am trying to complete a hundred little details to be ready for the day the money comes back to roost in my accounts.

 

If anyone knows a good deal on stuff.... I need a SBC Dizzy, Ign box, 2x safety harnesses, tires, Tilton brake master cylinders(x2), exterior paint, battery(PC680 or equiv), and about a zillion little small things.

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Quote from JMortenson:

"That looks really nice. I'll be doing this very soon. In retrospect would you say your bolts are longer than necessary? Looks like you have quite a bit of stud hanging out the bottom. Is the glass flush with the hatch? Hard to tell in the pictures. I think Mark turned me onto a plastic spacer bushing that was 1/2" long from mcmaster.com. That was for the windshield, but without looking I figured it would work for the hatch too. Lastly what did you bend the angle aluminum with? Is it easy enough to bend by hand? Looks a lot better than a flat piece of Lexan. My plan was to do a flat strip, but if the angle is easy enough I'll follow your lead."

 

 

 

The 1/8" thick window is not flush, You would need 5/16" spacers to get it nearly flush. I used 1/4" thick HDPE sheet that is cut into spacers that are 1/2" wide and 1" long. I used 1-1/4" long bolts which will be 3/16" extra long after the nuts are installed. I could only get 1" or 1.25" bolts, so I got the longer ones. They are stainless so they can be custom cut to length on the lathe.

 

The angle aluminum can be bent over your knee. I used the sides of the hatch to get the curve to match.

Edited by bjhines
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I don't think Nutserts will work out on the flange. I think you may actually have ribbed zinc-plated nutserts as opposed to the smooth sided Cadmium plated versions.

 

First off, there are few of those fasteners that can be used on anything thicker than 1/8". Secondly, I don't think you will get retention without cracking the fiberglass flange.

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I don't think Nutserts will work out on the flange. I think you may actually have ribbed zinc-plated nutserts as opposed to the smooth sided Cadmium plated versions.

 

First off, there are few of those fasteners that can be used on anything thicker than 1/8". Secondly, I don't think you will get retention without cracking the fiberglass flange.

Mine are aluminum. http://www.harborfreight.com/pack-of-100-nut-rivets-2972.html

 

The consensus seems to be that it's a bad idea though.

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I added lexan quarter windows. I wanted them flush at the rear instead of inset like the factory glass. I was going to mask and paint a border around them as well as the rear window... But I think I like them clear. They almost look like nothing is there.

 

LexanquarterglassL.jpg

 

LexanquarterglassR.jpg

 

 

 

 

I made a bridge piece to hold the door gasket and support the front edge of the lexan.

Lexanquarterglassgasket.jpg

 

Here is detail of the mounting method

Lexanquarterglasssupport.jpg

 

 

 

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The bridge piece sturdily supports the gasket. There is not a lot of pressure put on it by the door, even if you slam it. The bridge took a few tries to figure out how to make it all fit together. I used panel fasteners that are male-female flush button, screw together pieces. They are damn near flush and the gasket-channel slips over them fine.

 

The rear window will be sealed around it's perimeter with silicone sealant. I still have to paint the hatch so it will be removed and reinstalled. I am going to mask the window to paint a black perimeter to hide the spacers and fasteners. I will probably use black RTV to seal it.

 

The quarter windows will not be sealed. It is a track car. The side windows cannot be rolled up per rules. Any water that leaks in will run down to the door gasket, It cannot run into the car.

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  • 2 years later...

It's ALIVE!!! Bringing this one back from the dead. I followed John's lead and did the angle on the window and I'm about ready to drill holes and bolt up the Lexan, but I have a problem. This car will be towed hundreds of miles in the rain, and I'm thinking I should do something to seal the Lexan to the hatch. First thought was foam weatherstripping. Bought some and it's the wrong stuff, too soft, compresses way too easily. I might try again at a different hardware store to see if there is something better to use.

 

My other thought was running butyl tape around the edge. It looks like the weatherstrip needs to be about 3/8" thick to get the lexan flush, which is my goal. I don't see 3/8" thick butyl tape available, but I could probably double up the 1/4" round stuff and then suck it down with the screws.

 

Any other ideas? Will also have to have some sort of removable window for the fronts. Anyone done front windows for gutted doors that would like to share? 

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I've got the same hatch bjhines does, from www.betamotorsports.com. We both bought FG, John has CF if you have the $$$ for it. His website says stock 240 hatch with glass is 49 lbs, this one is 15 and I think I recall that the Lexan is 2 lbs, so something like 32 lbs. Call it 30 after hardware and pins.

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  • 3 weeks later...

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