Bond fiberglass to steel?

[Bitch'nBronco]

I have an idea for a hood, I'm just having a hard time stomaching $500+ to ship a $5-600 hood.

So I'm thinking about buying a cowl hood for a fox body, cutting the cowl out and shaping it to fit my Bronco. If I buy a new fiberglass hood, I'm going to wind up cutting it up anyway since I want to incorporate the Gen 2 Raptor hood vent to let some heat out.

My question is, to folks that have done this in the past, how does fiberglass bonded to steel hold up over time?

Pictures are of the hood vent I cut out of a wrecked raptor hood and another one I saw on Instagram

 

[Shimmy]

shouldn't have problems if you use something like this

https://www.bimmerworld.com/Tools/BMW-Shop-Supplies/Body-Spoiler-Adhesive-SIKAFLEX-252-300ml.html

 

[ba123]

Yeah, my first time around, long before they made the flared body parts, I bonded some Duff's fiberglass flares to the body and made it all look like one piece.

Shimmy's recommendation looks great. Go to Amazon though, easier to get and 1/2 the price.
https://www.amazon.com/dp/B0080626L2/?tag=classicbroncos-20

 

[bigmuddy]

From what I have seen it appeared that overtime the fiberglass de-bonded or cracked badly from flexing or heat expansion, hell maybe both and probably overtime where the fiberglass was smoothed into transition with the metal hood.
Hell might have been a crappy job to begin with but I have seen it more than once.
Best of luck with whatever you decide. By the way, I dig the look of the hood and raptor vents!

 

[jeffncs]

Fiberglass and the resin need something to bite into for improved adhesion. I can’t speak to the hood application (heat, vibration, slamming hood closed….).

The times I’ve used fbg on steel, I always made sure the surface was properly prepped: clean of rust, debris, oils then roughed the surface with 60-80gr sandpaper, finished with thinner to final clean ahead of the work.

Used on floors or similar areas, that approach had worked fine for me. YMMV

 

[ba123]

I would bet it would.

You could rivet and adhesive, and hide the rivets...maybe try to recess them slightly? Build up the fiberglass underneath the part to fill in the space between the top and the hood base?

 

[Bitch'nBronco]

From what I have seen it appeared that overtime the fiberglass de-bonded or cracked badly from flexing or heat expansion, hell maybe both and probably overtime where the fiberglass was smoothed into transition with the metal hood.
Hell might have been a crappy job to begin with but I have seen it more than once.
Best of luck with whatever you decide. By the way, I dig the look of the hood and raptor vents!

Thanks, my daily is a Gen 2 Raptor and that vent lets a lot of heat out. If it snows, that's always the first part of the hood that melts the snow. I think it would help a lot on top of looking good lol.

 

[Bitch'nBronco]

Thanks everyone, that's a lot to consider. I don't know that I want to risk it cracking, but it sounds like if I do the prep correctly I should be good. I also have a small rust area in my hood so I've got to strip part of the hood anyway to repair it.

 

[DirtDonk]

Friend with a 72 had a body shop install one of those old Mustang hood scoops, facing backwards, on his.
Looked absolutely seamless and never cracked or had any issue even after hard wheeling.
Unfortunately I can’t remember exactly how it was done, but I’d be willing to bet it was riveted and then Bondo’d.

 

[Bitch'nBronco]

I'm thinking if I swap to hood pins and replace the latch with a rubber bumper that rests on the latch catch, it may help keep the hood from cracking from being shut. Always a gamble in the winter if my hood shocks are going to do their job or not lol

 

[bigmuddy]

I'm thinking if I swap to hood pins and replace the latch with a rubber bumper that rests on the latch catch, it may help keep the hood from cracking from being shut. Always a gamble in the winter if my hood shocks are going to do their job or not lol

This will likely sound goofy but I used have some really soft springs that I would slide over the pins (hood pins) they worked as little mini shock absorbers at least that was the idea. Might help, might not? Just some redneck engineering and food for thought.

 

[PCB 4x4]

I've done hundreds of fiberglass Eleanor bodykits using 3M 8115 structural adhesive , with zero problems.

 

[Bitch'nBronco]

Thanks, I'm on board with doing it. I'll post progress pics once I get started. I'm excited about the project for sure. I've never worked with fiberglass before and am doing a bunch of research.

 

[Bitch'nBronco]

Picking up the fox body cowl tomorrow, I'm getting pretty excited to get started. I found one that was damaged from the hood pins being not fully latched and had a hole cut for nitros for $70.

If you're interested in learning about fiberglass, this channel has a lot of good info

 

[Speedrdr]

@Bitch'nBronco, is there a particular year Fox body or just any Fox body? Like the way it will look.

Randy

 

[lars]

In a word, polysulfide. For example (and yes, expen$ive): https://www.aircraftspruce.com/catalog/appages/ps890.php

Will adhere almost anything to almost anything else. And will get all over your clothes, the wall, workbenches, your car door handles, etc.

 

[Bitch'nBronco]

@Bitch'nBronco, is there a particular year Fox body or just any Fox body? Like the way it will look.

Randy

Any fox, im going to cut the center out of it. I think it's probably going to be an easy fit since the Fox hood is almost as flat as the Broncos. It just depends on what kind of cowl you want, they range from 2-6" and the construction varies. If they call it a lift off, it means it's going to be thinner fiberglass that was never intended to be used on a hood hinge. If it's got hinge points it'll be more sturdy and have some internal bracing. I dont think it matters either way if you're going to bond it to a steel hood, but I plan to add some material to the inside to keep it sturdy when I close the hood.

 

[Bitch'nBronco]

In a word, polysulfide. For example (and yes, expen$ive): https://www.aircraftspruce.com/catalog/appages/ps890.php

Will adhere almost anything to almost anything else. And will get all over your clothes, the wall, workbenches, your car door handles, etc.

Wowzers you weren't kidding, that is expensive. Do you know what the strength difference is between that and panel bond?

 

[ssray]

Here’s the tech doc for it if you know what the other is.

Polysulfide

 

[Bitch'nBronco]

Here’s the tech doc for it if you know what the other is.

Polysulfide

Thank you!

Getting excited, once I trim the beak off of the mustang hood, it will sit flat.