Classic Bronco

[jscherb]

...I'm starting to look into how to make a large plug. I'm trying to decide between using wood (balsa wood for the curves) or closed cell foam and a CNC router to cut out the shape for the mold. Been watching videos and reading articles.

Pretty much everything you need to know about building mold masters (plugs) and molding hardtop parts is covered in this thread: https://www.expeditionportal.com/forum/threads/barn-door-for-jk-factory-hardtops.127687/

I use the same technique one would use for making a stripwood canoe. It's easy to make a very accurate shape that way, the pine strips are easy to shape with a plane and sander and the pine and birch plywood skin is easy to put a fine finish on for mold making.

It's all covered in that thread.

 

[toddz69]

Wow, that sounds like a conversation I would've loved to hear! Does he have any insights or stories he told that you'd like to share? It's always fascinating to hear from the people behind the designs of these wonderful machines.

There are a few stories here and there on the Internet related to its development. Additionally, in about six months you'll be able to buy a book that details a lot of what he said .

Todd Z.

 

[toddz69]

I lowered the floor in my 68, using the space from the removed aux tank and fit a full size seat in. I now look straight out the middle of the windshield. I'm 6'1"

I've thought about doing that myself (I'm 6'4"). I've made do in the meantime with having seats that are as low as possible to the existing floor and eventually I will swap in my Viewfinder windshield which raises the glass 1.5" in the frame.

Todd Z.

 

[Sixty8broncosport]

It's probably one of the best mods I've done so far. Got a 23 gallon Aero tank in a group buy several years ago, so once that was installed, lowered the floor and can drive like a normal person and even see the stop lights change when approaching or leaving an intersection.

 

[Sixty8broncosport]

Pretty much everything you need to know about building mold masters (plugs) and molding hardtop parts is covered in this thread: https://www.expeditionportal.com/forum/threads/barn-door-for-jk-factory-hardtops.127687/

I use the same technique one would use for making a stripwood canoe. It's easy to make a very accurate shape that way, the pine strips are easy to shape with a plane and sander and the pine and birch plywood skin is easy to put a fine finish on for mold making.

It's all covered in that thread.

I looked through your thread and wanted to wait until I got through the whole thing before I asked any questions that may be answered in what is now a really long, extensive write-up on the barn door, safari top and many other projects.

In regard to master mold construction, how do you keep your accuracy and precision high, to ensure both sides are exact mirrors of each other? The difficulty to get an exact match is why I am currently planning on using closed cell foam and CNC routing out my design. This way I can integrate the drip rail into the top piece as well? Thoughts?

Also, I searched for alpine windows without much success besides Land Rovers. Any chance you wouldn't mind sharing your donor vehicle for the apline windows and motors for the rear side windows? Land Rovers alpine windows are about $200/window, which makes it cost prohibitive for R&D. Since my roof will most likely be one off (unless I find interest), I am thinking about integrating a recess in the window surround to install the windows as one would with a windshield or maybe have the option that they are pop up, for rear passenger air ventilation.

Lastly, I think I read you are using the factory weatherstripping at the barn door, but what have you found to be the best weatherstrip designs all around, not just at the barn door? I was thinking about an inverted T, shape weather strip which would slide into a groove in the roof panel where they meet the side pieces and on the side pieces where they meet the bed rail, this way the piece would go with the top and squeeze together when attaching the two pieces. To date, I have not seen a manufactured t-shaped weather stripping, however, so unless my search parameters are off, this may not be a good option. Ultimately I just want to ensure no leaks, as best I can, at the joint surfaces.

 

[jscherb]

I looked through your thread and wanted to wait until I got through the whole thing before I asked any questions that may be answered in what is now a really long, extensive write-up on the barn door, safari top and many other projects.

In regard to master mold construction, how do you keep your accuracy and precision high, to ensure both sides are exact mirrors of each other? The difficulty to get an exact match is why I am currently planning on using closed cell foam and CNC routing out my design. This way I can integrate the drip rail into the top piece as well? Thoughts?

It's not hard to make a perfect mold master in wood, it just takes careful woodworking. I use a process boat builders use, they call it lofting. It involves drawings of the shape of the hull of a boat that shows the shape of the hull and the shape of the ribs that support the hull. I print the rib drawings full size and trace them on the wood; then I use a combination of plywood and stripwood to make the shell on top of those ribs, very much like a boatbuilder would. Here's an example of a boat lofting drawing, I do similar drawings when I'm doing a hardtop roof:

Here's some info on lofting: https://grabcad.com/questions/how-to-loft-boat-hull

Also it's far easier to put a fine finish on a wooden master than on a foam master. Foam requires a filler coat, typically body filler, and it requires a lot of skill and patience to get the surface perfect so you can make a mold from it. I find that it's much easier to use common woodworking techniques to shape the curves (a good block plane and a long board sander) and when the wood is sanded it's ready to accept a fine finish that will translate to a find mold surface and therefore to a fine surface on the final part.

Also, I searched for alpine windows without much success besides Land Rovers. Any chance you wouldn't mind sharing your donor vehicle for the apline windows and motors for the rear side windows? Land Rovers alpine windows are about $200/window, which makes it cost prohibitive for R&D. Since my roof will most likely be one off (unless I find interest), I am thinking about integrating a recess in the window surround to install the windows as one would with a windshield or maybe have the option that they are pop up, for rear passenger air ventilation.

The Alpine windows in my JKU Safari Cab hardtop are from a first version Discovery. The Alpine windows in those Discos are mounted with standard glass gaskets and are easy to remove, install and adapt to other applications. I paid about $7 each for them with gasket at junkyards, I've collected a bunch in case I ever want to make more hardtops. I did one thing differently with them, in the Disco roof they're mounted with the long leg vertically, I designed my roof to accept them with the long leg horizontally. Check a photo of an early Discovery and compare it to the photo below and you'll see what I mean.

Lastly, I think I read you are using the factory weatherstripping at the barn door, but what have you found to be the best weatherstrip designs all around, not just at the barn door? I was thinking about an inverted T, shape weather strip which would slide into a groove in the roof panel where they meet the side pieces and on the side pieces where they meet the bed rail, this way the piece would go with the top and squeeze together when attaching the two pieces. To date, I have not seen a manufactured t-shaped weather stripping, however, so unless my search parameters are off, this may not be a good option. Ultimately I just want to ensure no leaks, as best I can, at the joint surfaces.

Whenever I'm designing something like how a hardtop will seal, I look to current best practices in the automotive industry to guide my designs rather than coming up with something of my own that "I think will work". The Jeep engineers did a very good job with the sealing of the JK Wrangler hardtop and Freedom panels. The weatherseal at the top of the windshield includes a drain channel to drain any water that happens to get past the outer seal. The hatch and door weatherseals are very good too. The one place the Jeep engineers could have done better is between the two Freedom panels - occasionally there isn't enough pressure on the seal there and if the Jeep designers had included some provision for adjustment there I think all potential leak problems with those panels would be solved.

 

[jscherb]

Let me know if this is the wrong spot for this, but I'm looking to build a custom hard top for my Bronco. I've built an FJ40 in the past and love the look of the Defender 90/110, so am inspired by those two designs, along with a similar design created for a JK.

My goal:

• Integrate removable panels above the driver/passenger (like the Jeep Freedom top)
• Removable side and rear panels so can run open air, with just the top section on
• Hardtop roof that can support my weight and then some (inspired by the Gobi rack I have on my 4runner, for a rooftop tent.
• Gain a small amount of height and modifying the current lift/tailgate to a barn style door similar to the Land Rover, but retaining the Bronco look.

...

Brian,
Here's one design you could try to do. I haven't drawn removable panels on it because of the slope of the roof. The Alpine windows would be flat glass in a design like this, which would simplify glass for them.

 

[Sixty8broncosport]

Brian,
Here's one design you could try to do. I haven't drawn removable panels on it because of the slope of the roof. The Alpine windows would be flat glass in a design like this, which would simplify glass for them.

Hi Jeff,

I like the head room, but I was thinking something like the attached image, with a sloped/stepped-down roofline and dual alpine windows on each side. I did not spend alot of time on the image, but hopefully you get the idea. I need to measure the width from the side of the bed rail to the inner wheel well to see if the if the extra rear windows should be integrated into the rear windows.

I borrowed one of your images to make my design below. I hope you don't mind, especially since I have no intentions on using it commercially. If it is an issue, since it is your intellectual property, please let me know, so I can remove the image.

Thanks for your input.

 

[Sixty8broncosport]

Brian,
Here's one design you could try to do. I haven't drawn removable panels on it because of the slope of the roof. The Alpine windows would be flat glass in a design like this, which would simplify glass for them.

I haven't measured the distance of the wheel wells, though from the internet, between the internet leaves 40.75" or just under 13" on each side, which I would probably turn into rear panels cut from the tailgate, narrowing the actual tailgate to mate up with a proportionally sized barn door. More measurements to go, but here is a rear view: