Barn Door for JK factory hardtops

[jscherb]

The first step to molding parts is prepping the molds, I typically mask off the edges of the molds and sections that don't need fiberglass like the area where the window will be cut out. Then mold release wax is applied, followed by spraying PVA (polyvinyl acetate) mold release. PVA is a water-soluable mold release, it provides an additional layer of protection over the mold and it washes off with water after the part comes out of the mold. The molds are now prepped and ready for the next step:

Another thing I usually do the night before molding parts is to cut the fiberglass to size based on how I plan to do the layup. They're laid out in sequence so when I get messy it's easy to grab the next piece.

The first step in the morning will be to shoot the molds with gelcoat, which forms the nice outer surface of the part. Once that cures to the appropriatre point (about 2 hours), the fiberglass layup can be done.

BTW there are 3 molds to make a barn door - the outer shell, the inner shell and (optionally) the cover plate for the wiper motor cavity. Donny says he won't be needing a wiper in his barn door but I'll mold the cavity cover anyway and cut the hole for the cavity in case there's ever a need to add a wiper later. I've taped the cavity cover mold (it's white) to the center of the outer shell mold to make it easier to do the fiberglass.

 

[rubicon91]

The first step to molding parts is prepping the molds, I typically mask off the edges of the molds and sections that don't need fiberglass like the area where the window will be cut out. Then mold release wax is applied, followed by spraying PVA (polyvinyl acetate) mold release. PVA is a water-soluable mold release, it provides an additional layer of protection over the mold and it washes off with water after the part comes out of the mold. The molds are now prepped and ready for the next step:

Another thing I usually do the night before molding parts is to cut the fiberglass to size based on how I plan to do the layup. They're laid out in sequence so when I get messy it's easy to grab the next piece.

The first step in the morning will be to shoot the molds with gelcoat, which forms the nice outer surface of the part. Once that cures to the appropriatre point (about 2 hours), the fiberglass layup can be done.

BTW there are 3 molds to make a barn door - the outer shell, the inner shell and (optionally) the cover plate for the wiper motor cavity. Donny says he won't be needing a wiper in his barn door but I'll mold the cavity cover anyway and cut the hole for the cavity in case there's ever a need to add a wiper later. I've taped the cavity cover mold (it's white) to the center of the outer shell mold to make it easier to do the fiberglass.

Looks awesome Jeff! Beyond excited to see it all come out! And Thank you as I know how much you love fiberglass nowadays

 

[jscherb]

I like to get an early start on days when I'm doing fiberglass, so as soon as the garage was up to temperature I shot the gelcoat. Fiberglass is best done at around 70 degrees; I've got gas heat in the garage so I can do fiberglass and paint in the winter and it doesn't take long to get up to temperature even when it's freezing outside.

That will cure for about 2 hours and then I can begin the fiberglass layup.

A little bit about fiberglass technique and tools - gelcoat is applied with a gelcoat gun, it's a fairly crude spray gun. It's got disposable paper cups to hold the gelcoat to make cleanup easy. A gelcoat gun pretty much the only special tool that's needed to do fiberglass work.

Yesterday I posted that I precut the fiberglass pieces I'll use for layup today, I cut fiberglass mostly with a rotary cutter. I lay a piece of old linoleum on the workbech as a cutting surface and use the rotary to cut. The HD scissors I use mostly during layup to fit a piece to a curve or corner.

The layup sequence for these parts will first be two layers of 3/4 oz. fiberglass mat, followed by 2 layers of 1.5 oz. mat. The result will be roughly 1/8" thick, which is good for this application.

Looks awesome Jeff! Beyond excited to see it all come out! And Thank you as I know how much you love fiberglass nowadays

I you weren't so far away you'd be enlisted for O.J.T. to learn fiberglass and help today .

 

[rubicon91]

I you weren't so far away you'd be enlisted for O.J.T. to learn fiberglass and help today .

Hahaha I know actually I would have a ton of OJT with you on projects if I lived anywhere close to you. I would assist in all the projects. Thanks again!

Sent from my SAMSUNG-SM-G890A using Tapatalk

 

[Zeep]

None of the vendors you've worked with, were interested in producing the Barn Door?

 

[jscherb]

None of the vendors you've worked with, were interested in producing the Barn Door?

No, none of vendors I've already worked with to date expressed serious interest in the barn door. There are other companies out there that I could imagine being interested but I generally don't go out looking for companies to take on my designs. If a company comes to me I'm happy to talk to them about anything I've designed but I rarely initiate contact with companies I haven't worked with before because mostly I do these designs/products as a personal hobby, I don't do this as a business so I don't work at finding companies to take on my designs.

But when the Jeep was on display at the SEMA Show last month I was approached by a company there I haven't worked with before that has fiberglass Jeep products on the market and they expressed interest. Their interest is part of the reason I thought it would be a good idea to dust off the molds and make another one and since Donny wanted one for his Jeep, I'm molding this one today.

 

[jscherb]

The miserable part of the job is done - fiberglass layup. I'll let the parts cure overnight and and tomorrow morning I'll pop them off the molds, trim them and begin assembly.

 

[jscherb]

First thing this morning I popped the barn door parts out of the molds. here are the parts just out of the mold, they're

not trimmed yet and the mold release hasn't been washed off so they're a bit green...

The demolding process:


Next I'll do a preliminary trimming and then I'll bond the inner and outer shells together.

 

[jscherb]

The preliminary trim of the parts is done, here the inner shell is being tested for fit. The outer shell is sitting on the floor.

Both shells. The outer shell is trimmed larger than the inner shell at this point, once they're bonded together they'll get a final trim. Also at this point cavity cover is installed on the inner shell.

Next I'll bond the inner and outer shells together.

 

[jscherb]

The inner and outer shells have been bonded together. I'll let it cure overnight and tomorrow I'll do a final trim and install it on my Jeep to test the fit.

 

[jscherb]

Donny's barn door "kit" trimmed and ready for finishing. It looks a bit dirty because I still haven't washed the mold release off.

 

[jscherb]

A test fit on my very dirty Jeep.

Things left to do: get glass cut, make the mounting hardware (it's installed on my existing hardware for now) and then a little final sanding and paint. And somewhere before paint, wash the mold release off .

 

[jgaz]

The inner and outer shells have been bonded together. I'll let it cure overnight and tomorrow I'll do a final trim and install it on my Jeep to test the fit.

Thanks for the step by step info, even though I’m sure all of it is somewhere in this or one of your other extensive threads.
What did you use to bond the inner and outer sections together?
Also, there’s no such thing as having too many clamps. At least that what I tell my wife.

 

[rubicon91]

A test fit on my very dirty Jeep.

Things left to do: get glass cut, make the mounting hardware (it's installed on my existing hardware for now) and then a little final sanding and paint. And somewhere before paint, wash the mold release off .

oh man that looks awesome Jeff! I am still beyond excited. Thanks

 

[jscherb]

oh man that looks awesome Jeff! I am still beyond excited. Thanks

Ho ho ho! Just call me Santa .

Of course you won't get it in time for Christmas, you'll have to wait until my next trip to see mom.