lexan targa top project........

[Joeaksa]

Bell,

Send pics of the airsho! Am heading to San Diego myself to get out of the heat!

Stay away from the "barrel" and you will get more work done!

Joe

[bell]

my digital cam should hold about 100 pics so i should have a bunch of good ones.
the barrel........whatever do you mean
i plan on having one strapped to my back.......

[mr914]

Got the OK from the higher ups for a "goverment project" Make the mold and trim fixture bucks myself and use the CAM station at night on my own time.

This weekend, I'll take a look in the factory shop manuals for the targa top alignment jig.

First prototypes, I'll make out of .250" black polyethelene. Materials in stock and cheap. I can work out all the fit and trim issues with that. After that, I just readjust the shrink for polycarb. Then I'll need a few people to test the top on their car...

Gave some more thought to the clear top. First it would require UV coatings. And then, would it make the interior hotter than smoked?

Only down side is, CNC is tied up for about the next 8-10 weeks.

[island911]

Forgive me for ignoring your targa thread, coupe owner here.
So I'm up to speed on all of this now.

As I mentioned in another thread I do own a digitzing arm, and all the expensive CAD software to make the data usable.

I think though, Warren touches on a very pertinent topic; tolerances. What do you use when replacing a soft, flexible "cover" with something as ridged as a formed piece of 1/4" PC (Polycarbonate)?
I really haven't looked at the specifics of the targa-top BC's (Boundry Conditions. . .seal, latches, and their relative movements) so I'll have to defer to you guys for that.
However, I do know that when you put 500 lbs worth of guys in the front seats. . .and they hit potholes or speed bump, or just "drive it like they hate it" that Targa body *is* going to flex; a lot! The place where it's going to flex the most is right where this top is to go.

So, my 2¢ worth on the design is certainly still use PC, but consider dropping the thickness down so it can flex with the body, rather than pummeling the seals with every bump in the road.
Perhaps use an exsting/modified factory folding frame to hold (and preload) the formed PC. . . (?) i dunno, cuz i have a coupe

I do have a digitzing arm, though, so let me know if I can help.

FWIW, from my related work experience, mr914 is spot-on with how all this should happen. (As well as very eh-em PC when it comes to proper names.)

[bell]

i have an answer for that but i'm not sharing it yet, don't want to get "beat" in my own thread
the tollerances will allow for some movement but the frame/"glass" combined will reinforce the top of the car better than the stock folding roof.

[Joeaksa]

Anyone who needs a tester, would be happy to volunteer. Would pay freight to and from...

Joe

[JMPRO]

Island911. the top does not need to be flexible. The oem fiberglass top is a very ridgid piece with no flex in it at all. I have had the hard top on my targa for a few years now and have not had any rubber problems or unusal wear in those areas. I think if you make it flexible you are just replacing one flexible part with another and not solving the problem.
Jerry

[island911]

So, the soft-tops are problematic because they're flexible?
Here I was thinking the hard tops had fitment problem due to a high dimensional variance of the targa. . . .which could be accomodated by the factory (flexible) folding top.
But, as I said "i dunno, cuz i have a coupe "

[zuerchers]

original posted by jmpro...

"You have to keep in mind that with a soft top the mounting points only pull on the top at the points of origin, in other words it is only tight at the corners. With the hard top those clamping forces are spread over a larger area causing a better seal.
In almost 5 years i have had my oem hard top, i have never had a single leak, and noise, you would think you were in a coupe.
The top i am making is 3 layers of fiberglass cloth, no mat and is a very ridgid part, it will not lift or flutter at speed and will be attached to the frame at at least 14 places around the peremitier of the frame. "

he did a great job of describing the problem. my top only leaks at speeds above 60 or so. the middle starts to rise and air comes in.

[JMPRO]

Island911, it is my understanding that the hard tops were d/c"d because when the brake boosters were added in 77 or 78 , the hard top would no longer fit in trunk making it a storage problem. Also the factory sold very few hard top in the U.S.
[it is rumored to be about 800}, that they just decieded to delete it .The hard tops had no problems i have ever heard of in regards to movement or flexing.
Jerry

[mr914]

Thank you island911

Can you do a point cloud? And what is the reach of your arm?

[island911]

The arm I have is a microscribe DX ( 50" working envelope, I think.) It's the smaller reach "precision version." of their product.
I also have some limited access to a Faro arm (huge reach ~6feet) Though I don't see a need for that.
point cloud data is a pain to work with; but easy to generate. I would think you would prefer surface data for your CAM software.
If you have software that *can* handle point cloud data well, that would make this really easy. In fact, that type a software should be able to parse multiple point clouds from multiple targas to give a nice statictial norm. But I think that would just be our heads pointed in the clouds.

[mr914]

I'm using SurfCAM, so I can handle either.

Looked thru the IIB shop manual, could not find the data for the targa top check fixture.

[red911]

Just checking in to see how the project is going.

Thanks

[bell]

my meeting with my fathers friend was pushed back until later this week, right now i'm looking at thursday for our meeting.
i recieved some sample hardware last week which i'm still playing with. i also have on the way a couple of different catalogs with different types of weatherstripping material from one of my suppliers.
everything is starting to take form, i just want to see what other options there are for the thermal forming of the "glass".
if i can work something out with this i should be able to get the cost lower.
later

[BlueSkyJaunte]

I can't wait to give you guys my money!!!

[mr914]

Procrastinating Wife said finish existing projects (house) before starting new one. Machine time scheduled for the day after Thanksgiving.

[red911]

I would be willing to test also. Let me know. I will pay shipping
Thanks,

[bell]

just got back from my meeting my fathers friend. his factory speacializes in cusom made machinery and just grinned when i explained to him my goals.
he used to have an sc targa and is thinking about picking one up again after i let him take a spin in mine.
he's got some of my notes and i'm going to drop off my spare targa roof next week (they're also going to measure the car itself). he has ovens on site which are used for this very porpose, he was also astounded by the 1" thick blazer window i made with my "oven". he's going to call me after he talks with one of his guys so i can go back in and we can get moving on this

[Joeaksa]

Bell,

Anything new on the top? Winter is approaching and fast!

Joe