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What are Jeep Wrangler TJ hard tops made of?


Chris

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I see the question pop up from time to time (and thanks @Tj04 for the inspiration for this one) asking if the Jeep Wrangler hard top is made of fiberglass.

Hardtops on Jeeps are not made from fiberglass exactly. They are made of SMC and require a resin other than the polyester—that is used on conventional fiberglass work—if the repair is structural.

To my knowledge all generations of Wranglers (including the JKs) use SMC for the hard tops.

Just wanted to make this known so that this information exists for anyone searching for the answer in the future.
 
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Chris

Chris

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Sheet molding compound (SMC) resin is a fiberglass-based compression molding that is used in applications that require high strength. SMC is comprised of several materials including fiberglass, polymer resin, release agents and thickeners.

Composition
SMC fiberglass mixture is sheathed on the bottom and top by polyethylene or nylon plastic to keep the mixture from automatically adhering to a surface. The SMC mixture is first spread evenly on the bottom sheath of polyethylene, at which point small chunks of fiberglass are mixed into the paste. The top layer of polyethylene is then placed on top of the product, which is rolled into various thicknesses.

Durability
SMC is extremely durable, offering excellent chemical, thermal and physical characteristics. It can withstand extended periods of exposure to heat and corrosive environments and can be molded into many different shapes and sizes.

Applications
Because of its durability SMC fiberglass is used in a variety of applications, including automobile panels, watercraft parts, and heating, ventilating and air conditioning (HVAC) systems. SMC is also a poor conductor of electricity, making it ideal for electrical applications.
 

Shane Mckinley

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Hmm, I always assumed it was molded fiberglass

Sounds like the various polymers and components make it a bit stronger than basic fiberglass

Cool


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2005 RHD TJ Sport
2010 BMW 528xi
 
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Chris

Chris

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Hmm, I always assumed it was molded fiberglass

Sounds like the various polymers and components make it a bit stronger than basic fiberglass

Cool


Sent from my iPhone using Tapatalk
2005 RHD TJ Sport
2010 BMW 528xi
Yeah, it's similar to fiberglass, but it's not fiberglass 100%.
 
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Tj04

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Jun 4, 2017
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Minneapolis, MN, United States
I see the question pop up from time to time (and thanks @Tj04 for the inspiration for this one) asking if the Jeep Wrangler hard top is made of fiberglass.

Hardtops on Jeeps are not made from fiberglass exactly. They are made of SMC and require a resin other than the polyester—that is used on conventional fiberglass work—if the repair is structural.

To my knowledge all generations of Wranglers (including the JKs) use SMC for the hard tops.

Just wanted to make this known so that this information exists for anyone searching for the answer in the future.
JKs do in fact use SMC as well. I do not know if YJ hard tops or earlier were SMC as well.
 

Shawn of the farm

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It looks like Ever coat makes a product targeting the SMC materials. Has Kevlar and other "High Tech" fibers.

Soon I will be tackling repairing the hardtop from my prior totaled TJ. There are 2 cracks and delamination I have to deal with after it got twisted up a bit. A closer inspection is needed that might not be all but I hung it up out of the way since it was one of the few things that were salvageable.

Any recommendations on glues for the delamination? Meaning where the different layers come together by the side window they came apart. I was thinking an epoxy but if some one had a specific recommendation I would appreciate it.

I hadn't worked with SMC before all my experience is on BAJA fiberglass. I would imagine once I round up the right products it won't be that much different.


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Thanks