Rear Window

I'd go for Lexan - which is used as a replacement for glass windows in the racing scene.

What thickness?

I used 1/4" lexan for my wing windows so I could drill holes and mount the mirrors. It worked great and really easy to work with.

1/4" LEXAN ... not cheap and not easy to find ... unless you buy a sheet.

Ron

Seems kind of thick for a large window????

3/16 will likely be plenty thick enough. Lexan is a trade name for a brand of polycarbonate plastic. Call local plastics suppliers or sign shops as it's not that hard to come by. Be warned that it scratches quite a bit more easily than acrylic does but it is of course MUCH more impact resistant (hence the "bullet-proof glass" moniker). Good luck,

Mark

If memory serves me ... most Auto Racing and DOT rules permit .. 1/8 for side & rear windows on a front wheel drive car and 1/4 for a windshield.
I would use the Brand name LEXAN because there are different resin blends that have different qualities, uv protection, scratch resistance, Fire and Chemical Resistance, flexibility, etc.

On the Pantera with the Engine in the rear and I would consider using the 1/4" Lexan * Margard* MR5 FR - Fire Rated.

Ron

My memory is going. I checked it when I got home and it is only 3/16". It was about $ 20.00 for a pice big enough to do both wing windows (2'X2') and it was off the shelf on a sunday. I cut it with a cut-off wheel on a 4 1/2" grinder and then fine tuned it with a sanding disk. Very workable.

If you're going to track the car with a particular organization, check THEIR rules first. A big-block Pantera from Sweden came over to Bonneville a few years ago with a plastic rear window and the organizers made them change it before it was allowed to run. Since it was out of the question to find a glass shop in Wendover, they were allowed to use sheet-metal as an alternative! Our rear window is part of the firewall and race officials are sensitive to fires and plastic. The fact that Pantera glass rear windows usually break early in engine fires apparently meant nothing to Tech.

quote:

Originally posted by # 1755:
My memory is going. I checked it when I got home and it is only 3/16". It was about $ 20.00 for a pice big enough to do both wing windows (2'X2') and it was off the shelf on a sunday. I cut it with a cut-off wheel on a 4 1/2" grinder and then fine tuned it with a sanding disk. Very workable.

I can laser cut some templates but I cannot laser cut the Lexan. It will be easy for me to test fit it with scrap cut metal then send the file to get it waterjet by people we work with or...

considering things Ron said, I may send the file to someone who does race windows to get the correct stuff.

I had talked about getting it cut from glass but if I do it in lexan there is less likely hood I would break it. I am sure in the beginning of getting bugs out I can see having the window out here and there. When the dust settles and I am happy with my design and the functioning of the car I can have it made out of glass latter if I desire.

There is an extensive product offering for plastics. I am very sure there is an "alloy" that is used for "firewalls".

You will probably need to display a sticker that indicates it is heat and fire retardant/resistant and the spec # on it.

I don't have that listing to offer you a link to it.

A race car fabrication shop most likely will have some right there ready to cut for you.

I would not expect it to be an economy item though.

It really is space age stuff.

The original glass window if it is acceptable to the race sanctioning bodies would be my first choice.

If you like to fabricate, just make a bolt on frame for the glass.

A lot of the glass can be drilled to pass bolts through if the roll cage is the issue here. Not sure if the Pantera glass is drill-able without destroying it though.

The aging of the glass is a factor on it also for that.

You probably would just be looking at a nice thick piece of some kind of a "rubber" pad between the glass and the steel plates?

If you are not coming in the cabin with the any part of the cage, why not just put the bar in the engine compartment built so it kicks down, and bolt it to the roof there?

I am looking to make a frame for it to bolt through and hold it in. I don't expect that to be a problem but like many things the fist time something is not always as you like it. I may opt for cheaper Lexan till I see how it goes. Having a cad file to work form to make it repeatable so I can make changes is no problem either.

The cage already runs through the window so It will be constructed around that as well with rubber.

maybe make a frame that clamps the window in thus preserving the glass.

I was just at a shop which can water jet it. They have some impact lexan that say you cannot shoot through and that it cannot be drilled but waterjets fine. 1/4" didn't look as bad as I thought it would.

For owners that DON'T track their cars much, plexiglas has been used for decades without problems. I know of one street GT-5 in Nor-Cal with a cage with roll bars going thru it, that has used plexiglas since the mid-'70s. It even passed CA visuals for smog tests at one time!

But when all this work is done, I doubt if a removeable window will help engine maintenance. There just isn't that much you can reach through the opening. A quick-release upholstery bubble conversion, slotting the seat-back straps so the seatbacks fold down, removing both rear quarter window glasses, and one of Johnny Woods maintenance platforms that sits on the ZF is all that's necessary for routine maintenance. Beyond that, the engine comes out.

quote:

But when all this work is done, I doubt if a removeable window will help engine maintenance. There just isn't that much you can reach through the opening. A quick-release upholstery bubble conversion,

Not on this car. There is nothing traditional about the way this car is configured. Maybe some things would have been better configured different but without a removable window it would be next to impossible to fill the cooling system, change the fuel regulator behind the tank on the passenger side, bolt on the roll bar through the back.

Having a removable window would make all of this a non issue. I am making a removable bubble to fit my clearance issues separate from the rest of the firewall.

I know I could relocate the regulator but a removable window makes all that...and more....easy.

Gary

I think its a great idea access thru the rear window ... its just as easy to do it right and get the correct product. Who wants to do it twice ... when you go for an inspection and run in to an issue. In NY State in the past few years Dept Of Transportation has Spot Checks on the roads ... who needs their car impounded ? I know recently they have also revoked Inspection Stations Licenses because of flawed inspections.

Ron

A removable window is a great idea. Many times I thought about having access through it.

I know that taking out the rear 1/4 windows helps too with access.

Everything helps.

Ron, we don't have inspections to work with however, the guys we work with who will waterjet the Lexan can also do safety glass. My thought was to do Lexan for now and when the bugs are worked out at a latter date, I can always swap to safety glass.

I know since I have changed so much things will need more attention latter till I get the bugs sorted out.

PD, I like the idea of taking out the 1/4 vents but I have some tough bolts on those; especially the passenger side with the gas tank. I have one nut/bolt which requires 2 people and a magnet to get started.