Before i get too far, critique this

Working on the custom hardtop for the miata. 

My idea was to use a softtop frame, skin it in .030 aluminium, cover the aluminum with fiberglass, and bolt in permanent. The soft top frame for structural support and weatherstripping. 

The aluminum dont do compound curves. 

So i cut it into 3 inch wide strips.

Right now, im using hot glue for my mockup. Final round will be riveted to the frame at all sides. 

Seems like theres a better way to do this, or something i can do to make less wirk.

This top is purely for weather. And aero vs no top (fastback is a possibility) if needed.

So, here's where im stopped at. 

Please give feedback/ideas

You will save a lot of weight if you do it without the frame. 

When I built the top for the Mumpkin, I cut the front rail off a soft top, and imbedded it in the fiberglass. That way I had the entire stock latching mechanism. 

My top was removable. It was held by the latches at the front, and hood pins at the back. 

Any reason you can’t build a fiberglass form that is not part of the final product?

Honestly, i dont have the space to build a full form and do proper layup.

All the stuff that doesn't hole weatherstripping and latches will be cut out of the final product with the original moving parts welded together to reduce weight.

The initial build of this is just for storage/weather. Essentially a hard bikini top.  If it eorks well, i may make a legitimate hardtop. 

Out of curiosity, how much cheaper will the final product be than just buying a cheap beater non-OE hardtop from Treasure Coast or somebody?

Or is it the challenge of the project that counts?

In reply to Duke :

About $400 less than the cheapest, crappiest hardtop of any fasion i can find.

Ill have abou $100 outlay in the project. 

How about this for an idea.

Bolt the frame back on the car.  Get some very fine cloth or cotton.  Stretch that over the frame and tape it too the windshield header and where ever you want it to meet the body, either at the back of the cockpit or the rear for a fast back.  Put a couple of large fans inside the car blowing upwards so the material isn't sagging.  Then apply few thin resin in a hot environment to give it rigidity.  They you can add your layers of fiberglass to give it strength and structure.  

In reply to Adrian_Thompson :

I hadn't thought about the fans to keep from sagging. That's genius!

You also listed plan b. Or was that plan a and the aluminum composite top is b? Or....

After the fiasco that tge amc fender flares turned into, im gunshy about freeform fiberglass wirk.

Dusterbd13-michael said:

In reply to Adrian_Thompson :

I hadn't thought about the fans to keep from sagging. That's genius!

You also listed plan b. Or was that plan a and the aluminum composite top is b? Or....

After the fiasco that tge amc fender flares turned into, im gunshy about freeform fiberglass wirk.

Cheers.  There's another way to do it.  Pull it over and just use resin around the perimeter to keep it in place.  Then remove the whole thing from the car and turn it upside down.  The the natural sag will be outwards in the correct direction and you can resin the rest from the inside.

Hows this: use the aluminum strips with a roughly 1 inch gap between, stretch cloth ove whole thing and resin. Reduce sag and unevenness, as well as providing more structure?

In reply to Dusterbd13-michael :

I like that idea   

In reply to Adrian_Thompson :

So do i. Just tried it over lunch. Im REALLY liking it.

And it means i can make it in stages. Rooftop first, side window seals next, etc.

Layer of this over the bare frame.

Lay a blanket or whatever on top to take some of the bumps out

A second layer of heat shrink to act as the molding surface.

Layer of glass and resin over that lot. The shrinkwrap may or may not act as a peel-ply and give you a nice smooth inside surface. Worst case it becomes a shiny plastic liner for the inside of the top.

Pete

In reply to NOHOME :

Awesome idea! But holy cow that stuff is expensive. Be about as expensive as a treasure coast miata top.

Let me guess, a Craigslist Original Mazda top is starting too look like a better and better deal?

Can you find a ratty one locally to take a mold from?  Cover it with packing tape (Glass and resin doesn't like to stick to that stuff)  Lay up a couple of layers of glass, really spending your time to get it as flat and smooth as possible.  Then you can add some balsa, foam, string whatever on the inside and lay up over that for rigidity.  Once you've got something that's self sustaining and wont collapse, go to town on the exterior with high build primer or the thinnest skim of filler you can lay down for a decent exterior finish?

In reply to Dusterbd13-michael :

Seriously? Never priced that stuff, but figured if it was used to cover boats and was disposable then it could not be too expensive.

Maybe look into pallet wrapping saran-wrap as an alternative?

Edit:

Looked up local price to have boat wrapped: 10-15$ per foot. What cost a lot is the huge roll needed  to wrap a boat. I bet if you found a person who wraps boats, he would sell you the stuff for a reasonable $$$.

I ran in to the same problem when I tried to buy wrap to do interior bits on the Molvo:  the wrap is only sold as a full roll for several hundred dinneros. All I wanted was like a 1' wide strip.

Pete