"Best" way to attach windshield and headlight covers

I'm currently musing over the "best" way to attach these plastic pieces.

Option 1 is to RTV them in place - not my favorite way because i prefer everything to be as easy to remove as possible.

Option 2 is to use a low profile buttonhead that's powdercoated black (not black oxide) in 4 locations.......probably held in with a rivnut

Is there an option 3?

Obviously 1 is better if you want it to be sealed, but it makes removal a pain. Option 2 is better for removability, but doesn't look as clean (although i don't think having several black buttonheads will make it look unclean against a white body?)

Also, would you feel comfortable holding the windshield in with just 4 screws? I've been studying various setups and noticed some race cars use 4 tabs to hold it in place, but the tabs look a bit out of place on the car.

edit: Also, if going the screw route, can I use metal screws, or should they be nylon?
 

Fran Hall RCR

Moderator
We have countersunk every window we have installed...no issues...but we do not use anything other than nylon screws...

Alex , as usual YRMV....:laugh:
 

Will Campbell

Supporter
Another alternative would be to paint the edges with the appropriate black paint, and bond in plastic studs on the black edge that can be tightened from the underside.

This gives a no-fastener look, while actually having the strength of fasteners.
 
We have countersunk every window we have installed...no issues...but we do not use anything other than nylon screws...

Alex , as usual YRMV....:laugh:
Well, I'll try countersinking the headlight covers carefully and see how it turns out (w/ nylon screws) .... btw, by window I meant the front windshield, not the side ones :)
 

Howard Jones

Supporter
Alex, do yourself a favor and go and buy a remnant of some Lexan (polycarbonate) from a tap plastic or other vendor and practice on it.
 
Good advice Howard - that's what I was intending to do - I always have a way of destroying my test pieces :D
 
Alex, I installed helicoils in the body on my GT replica for permanent threads. You can then take the pieces on and off for cleaning/waxing underneath as I have for 10 years now.
 

Randy V

Moderator-Admin
Staff member
Admin
Lifetime Supporter
You can purchase the proper drill bit with integral countersink as well as the nylon screws from McMaster Carr.. I bought mine there.. I am going to be using 10-32 screws.

The trick with countersink is the nylon screws. You can't tighten them too tight or they break. That's actually the good part - because if they got any tighter, you'd end up with radial cracks from the hole...
 
Do you need a special bit for plastic, or woudl you use the same countersunk bit that you would for metal?
 

Nick

Supporter
You can purchase the proper drill bit with integral countersink as well as the nylon screws from McMaster Carr.. I bought mine there.. I am going to be using 10-32 screws.
Randy,

Don't suppose you happen to have the part numbers for the drill bit and screws to hand.
 
I countersunk holes and used flathead 10/32 nylon screws, about every foot. Not a crack or problem yet.
On the back i ran 3M fineline tape around the edge of the polycarb, then the edge of the f/g adjacent. then used black silicon caulk, smoothed, then pulled up fine line tape and it looks factory.
 
Tip:
Get and old drill bit and drill it into concrete dull it, then drill into your Lexan at low speed with just a little pressure. Go slowly. I use a step drill to countersink, carefully.

Practice on some scrap first to get your "hand".

This works with Plexi too.
 
Rear window treatment will be a wide band (3.5") of Border Black paint, silicone sealant to the f/g, and a few screws such as Cam has done. Leaving the headlight covers clear with the nylon countersunk 10-32 screws. Make the paint job under the covers flat finish, but same as body color.

Narrow band of border paint on the side windows, fastened simply with the same nylon 10-32 screws as the headlight covers (minimum number of screws as possible).
 
We have countersunk every window we have installed...no issues...but we do not use anything other than nylon screws...

Alex , as usual YRMV....:laugh:
For clarification, by countersunk you mean the top of the screw is flush with the top of the plastic? i was reading that rcr visit thread and noticed that in this picture the screws arn't countersunk?

http://www.gt40s.com/forum/attachment.php?attachmentid=52109&d=1300805764


http://www.gt40s.com/forum/rcr-forum-rcr40-slc-p4-mkiv/34015-rcr-visit.html
(6th picture)

Just wanted to clarify that my definition of countersunk is correct.
 
Maybe it's just the angle of the picture - the top one looks like it's sitting above the top of the cover.
 
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