Gen 3 Coupe Rear Hatch

[LateApex]

If anyone has a Gen 3 rear hatch they are not using (perhaps with some slight damage or some such), I am looking for a "blank" to mold a Lexan / Polycarbonate alternative.

Yeah .... as if I need another little project ;-)

[Jphoenix]

Interesting, lexan/polycarb would be much lighter. I presume you would just fit the lexan/polycarbonate to a large frame, heat it up with a bank of heat lamps and drape it over the original glass hatch?

[Dave Tabor]

I've been wanting to do the same thing for quite a while...but don't want to break my hatch doing it.

Maybe make a mold off the glass hatch and use that for the heating step.

Dave
Gen III #17

[Jphoenix]

Pull a mold off the glass, then make a buck off that. Easier to drape over a convex vs. concave shape?

[michael everson]

Curious why anybody would want to go back to a plastic window? I think the glass window was a great upgrade for FFR.
Mike

[Jphoenix]

Curious why anybody would want to go back to a plastic window? I think the glass window was a great upgrade for FFR.
Mike

Less weight for racing. Also been thinking about other areas like all the aluminum panels and the body itself, I’m wondering how much that body weighs.

[dstelter]

Hey LateApex.

I might be able to help out. i switched out the factory five latch to the metal single push button one.

Ill have to look in my extra parts bin tonight.

doug

[LateApex]

A number of good comments / observations - thanx all.

To the process of forming Lexan or polycarbonate (PC), one needs a large oven with decent temperature control. There are YouTube videos that describe how to modify a barbecue grill to contain an object as large as a windshield or coupe hatchglass, but an industrial oven designed for forming PC is likely best.

And yes, PC is lighter and stronger than glass. However it scratches easily (although applications like the hatch don't present too much opportunity for scratching, and scratches can be either polished or treated with a heat gun (carefully treated ....)

The forming process itself is challenging. PC absorbs moisture. If you heat it, the first that will happen is the trapped water will boil and create bubbles in the "glass". Not good. One has to bake the PC for 6-12 hours at a lower temperature to push the water out. And then one has to crank the temperature up to the molding temperature. This varies a bit, but is close to 350F.

If you do this after you have placed a sheet of PC over a mold, such as a glass windshield or hatch-glass, the PC will conform (via gravity). Then you trim it. More complex shapes employ two mold to "sandwich" a sheet of PC. Ta-da! You now have a copy of the original.

If one makes a mold of some different material, just be aware that the PC will conform to any surface discontinuities, like scratches or finish texture. Glass or polished metal is likely the best mold material.

As to why, a couple of thoughts come to mind. One, I am not sure where to source replacement glass, either windshield of hatch, for the coupe. Two, PC is much easier to drill than tempered glass, especially tempered glass with compound curves. Let's say that one wanted to install Pop-It vents in the rear hatch to help vent the cabin. Three, any track work likely benefits from (or requires) glass substitutes, or at least aggravates the need for replacement glass. Four, this sounds like an interesting project (as if I really need another interesting project :-)

Last, I think it is hard to beat aluminum from a weight perspective. However forming a car body from a clear material would be VERY interesting :-)

[Jphoenix]

Saw a video of a guy blowing a polycarbonate bubble for his Ferrari replica - he learned just what you said, heat it up too fast and it gasses off. It’s a good point a piece that large will need a large, temp-controlled oven. If you are successful, I’d be interested in buying one.

[dstelter]

man no luck on finding the latch. Sorry Lateapex. Still looking. My garage is going thru a cleaning now that my coupe is on the road. if i find it i will let you know.

Doug

[LateApex]

Thanks Doug. And thanks for looking! You box of extra bits sounds a bit like mine - Hah!

I don't need the latch; rather the hatch glass to use as a mold. I'd use mine, but I have applied a film to the inside of that to keep the sun off my neck and the cabin temp down - that was a good investment IMO! As was the visor brow I applied to the windscreen (although I would advise it is easier to do this BEFORE the windscreen is installed :-) I would bet that the film applied would not stand the heat test very well ....

[dstelter]

yep. gave it the old Doug try on the back hatch glass. total fail. Tried to take it to 2 other window tint people but they did not have the over size film. finally found one guy and he got it done. With living in Central Texas its a must. only 200 miles so far on my Coupe. I need to look into the visor brow. or at least some type of visor, you can really feel the heat when driving towards the sun.\
Doug

[LateApex]

yep. gave it the old Doug try on the back hatch glass. total fail. Tried to take it to 2 other window tint people but they did not have the over size film. finally found one guy and he got it done. With living in Central Texas its a must. only 200 miles so far on my Coupe. I need to look into the visor brow. or at least some type of visor, you can really feel the heat when driving towards the sun.\
Doug

Yep, with the doubly-concave surface, one has to split the film laterally (approximately just behind the strut buttons) for any chance of laying it down. I have a slight (~ 1/8") overlap where the two separate sections meet. Looks fine, and meets the bill.

[FFinisher]

Email sent.