jscherb
CJ-8 Member
- City
- Elmira
- State
- NY
For a while now I've had this wacky idea that I'd like to design and build a hardtop from scratch. Back when I was working on the all-metal World Cab conversion for the Retro, I worked out a design for fabricating a new hardtop from steel with the idea that someday I'd build one. Now that I'm studying fiberglass fabrication so I can build the new fenders for the Retro and also make the fiberglass Gaucho fenders, I've been working on a concept for making fiberglass hardtops from modular components.
Making a full Scrambler hardtop from one piece of fiberglass seems much too daunting a task for anyone except professionals like Matt, but molding the top in component sections and then bonding them together into one final piece seems reasonable, something I could definitely do in my home workshop. Hardtops made from components is what Jeep did with the later CJ-7 and all YJ hardtops - they're made from something like 8 separate pieces of fiberglass.
Also, with a modular design, a series of components could be made so a top could be assembled in a variety of configurations to fit different Jeeps - Scramblers, CJ-7's, TJ Unlimiteds, half cabs for pickups, etc. This is not unlike the original Jeep World Cab concept - the CJ-8 and CJ-7 World Cabs shared some steel stampings, while other parts were specific to the model. (Even though the CJ-10/10a hardtop is called a World Cab, the only component is shares with the -7 and -8 World Cabs is the non-standard square corner doors.)
Here's a rough initial concept drawing, some of the component lines have been left in so you can see where the different parts are. The component lines would not show on the final tops.
My concept would be to make tops that follow the general lines of the original Jeep World Cabs for the CJ-7 and CJ-8. The front roof panel would be sloped and ribbed like the WOrld Cab, and in addition to the -7 and -8 versions, could also be used for a TJ Unlimted top and even a half-cab like the Retro.
The roof belt line would differ from the original World Cab - on the original, the belt line curves up behind the rear of the front door, to a level about 2 1/2 inches higher than the belt line above the door. In my Safari top concept, the belt line is straight, but the rear roof panel is still raised like the World Cab. This additional room above the belt line on the side of the top panel provides space for small "safari windows".
The rear door would be designed so that it could be hinged up like a hatch for CJ's with hinge-down tailgates, but it would also be able to be hinged on the side like a World Cab barn door - in this application it would be fastened to the TJ/YJ swinging tailgate with "stakes" similar in concept to how half door uppers attach to half door, although in a much more rigid design. This would provide for the coolness of the World Cab barn door but the ease or removability that half door uppers have. The hardtop could be removed without changing the tailgate, just remove the rear door "upper" from the swinging tailgate.
Here's an idea of some of the component parts.
Each of the separate components could be made in a relatively simple mold, certainly less complex than the three-part mold I'm currently working on for the Retro fenders. And each would be small enough that a single person in a home shop like mine could fairly easily mold them.
Mold masters would be made from wood and foam, materials easily worked and shaped to provide the curves and shapes necessary; it would not be hard to duplicate the relatively simple shapes of the original World Cab roof using these materials. And of course I've got two originals here to measure from.
Components would be designed with overlapping flanges to facilitate bonding the sections into a complete top; assembly would be with a multi-part urethane panel adhesive (which bonds fiberglass parts better than polyester resin).
Once assembled, the seams would be worked with body filler, block sanded and smoothed using ordinary body work techniques; the top would then be painted, either base/clear to match the Jeep body, or a texture paint for that "fiberglass hardtop look".
One of the things I always work into my designs is "home shop buildability" - first I do the ultimate cosmetic and functional design, then I rework it until it's something I could build with my limited tools and skills in my home workshop. Based on the work I've done so far in building two hardtops (Retro and Gaucho) and the work I've been doing on fiberglass so far, I've worked out how these could reasonably be built in my home workshop.
I'm really intrigued by this project... might have to put it on my future "to do" list...
PS: Note to Matt - no, I would never plan to go into business to compete with Gr8Tops!
Making a full Scrambler hardtop from one piece of fiberglass seems much too daunting a task for anyone except professionals like Matt, but molding the top in component sections and then bonding them together into one final piece seems reasonable, something I could definitely do in my home workshop. Hardtops made from components is what Jeep did with the later CJ-7 and all YJ hardtops - they're made from something like 8 separate pieces of fiberglass.
Also, with a modular design, a series of components could be made so a top could be assembled in a variety of configurations to fit different Jeeps - Scramblers, CJ-7's, TJ Unlimiteds, half cabs for pickups, etc. This is not unlike the original Jeep World Cab concept - the CJ-8 and CJ-7 World Cabs shared some steel stampings, while other parts were specific to the model. (Even though the CJ-10/10a hardtop is called a World Cab, the only component is shares with the -7 and -8 World Cabs is the non-standard square corner doors.)
Here's a rough initial concept drawing, some of the component lines have been left in so you can see where the different parts are. The component lines would not show on the final tops.
My concept would be to make tops that follow the general lines of the original Jeep World Cabs for the CJ-7 and CJ-8. The front roof panel would be sloped and ribbed like the WOrld Cab, and in addition to the -7 and -8 versions, could also be used for a TJ Unlimted top and even a half-cab like the Retro.
The roof belt line would differ from the original World Cab - on the original, the belt line curves up behind the rear of the front door, to a level about 2 1/2 inches higher than the belt line above the door. In my Safari top concept, the belt line is straight, but the rear roof panel is still raised like the World Cab. This additional room above the belt line on the side of the top panel provides space for small "safari windows".
The rear door would be designed so that it could be hinged up like a hatch for CJ's with hinge-down tailgates, but it would also be able to be hinged on the side like a World Cab barn door - in this application it would be fastened to the TJ/YJ swinging tailgate with "stakes" similar in concept to how half door uppers attach to half door, although in a much more rigid design. This would provide for the coolness of the World Cab barn door but the ease or removability that half door uppers have. The hardtop could be removed without changing the tailgate, just remove the rear door "upper" from the swinging tailgate.
Here's an idea of some of the component parts.
Each of the separate components could be made in a relatively simple mold, certainly less complex than the three-part mold I'm currently working on for the Retro fenders. And each would be small enough that a single person in a home shop like mine could fairly easily mold them.
Mold masters would be made from wood and foam, materials easily worked and shaped to provide the curves and shapes necessary; it would not be hard to duplicate the relatively simple shapes of the original World Cab roof using these materials. And of course I've got two originals here to measure from.
Components would be designed with overlapping flanges to facilitate bonding the sections into a complete top; assembly would be with a multi-part urethane panel adhesive (which bonds fiberglass parts better than polyester resin).
Once assembled, the seams would be worked with body filler, block sanded and smoothed using ordinary body work techniques; the top would then be painted, either base/clear to match the Jeep body, or a texture paint for that "fiberglass hardtop look".
One of the things I always work into my designs is "home shop buildability" - first I do the ultimate cosmetic and functional design, then I rework it until it's something I could build with my limited tools and skills in my home workshop. Based on the work I've done so far in building two hardtops (Retro and Gaucho) and the work I've been doing on fiberglass so far, I've worked out how these could reasonably be built in my home workshop.
I'm really intrigued by this project... might have to put it on my future "to do" list...
PS: Note to Matt - no, I would never plan to go into business to compete with Gr8Tops!