Questions about JB Weld and my sanity

"Flynorcal: pilot, offshore sailor, car racer and panty thief" (flynorcal) 02/17/2018 at 16:35 • Filed to: None

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Hola amigos. I have an old Corvette track car. It’s a C4 and it’s a convertible and it looks like this:

The back of the car is very light. No spare, no jack, no stereo speakers, no carpet, etc, and when I push it too hard the back likes to want to come around, especially under hard braking at higher speeds (110+ mph -> 35 mph as quick as possible) and when I’m going into a turn with too much speed.

So why not put a huge GT wing back there?

Well, aside from that eliminating the car from a couple SCCA/NASA classes, which I don’t care so much about as the car isn’t up to spec anyway, mounting the thing is the problem. I’ve got a few issues:

1) The gas fill is on top of that deck in the back and opens up. I have a wing that has a wide base so it’ll straddle that area and the wing is high enough for me to still get gas in the tank although I might have to stand there holding the nozzle but who cares.

2) The only access to the underside of that deck lid is through the a hole behind the rear plate. I can feel around in there but can’t see very well. From putting the wing in place and putting masking tape down and using two hands to tell where I’d be drilling.... I can feel around where I’d want to drill and it’s... I don’t have a lot of confidence about what I’d be drilling through.

3) I really don’t want to have the wing rip off at 100mph into the windshield of a Porsche GT3 coming up to pass me. This last point is the one I am most concerned about.

So I don’t think I’m going to be able to drill through the fiberglass and add in huge backing washers and bolt the thing in how I would like.

Would JB Weld actually hold it in place?

Am I nuts for even considering it?

I’ve not really used the stuff but I’ve got a package that says it’s good for 3770 pounds per square inch and that’s it great for plastic to metal, thermoplastics, coated metals, fiberglass, etc. I’d be mating four large aluminum bases to the fiberglass deck of the car. We’re talking about 16 square inches. That’s a huge amount of strength, if you believe the package.

Is this a number I can actually trust? Is there something that would be decidedly better? Am I being too negative and should trust the package or is the package just marketing based on ideal conditions in a lab setting or what? Any real world experience with the stuff?

Full of the sound of the Gran Fury, signifying nothing. > Flynorcal: pilot, offshore sailor, car racer and panty thief 02/17/2018 at 17:17

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I’d recommend getting one of those cheap lighted endoscope cameras that plugs into you phone or tablet. I think I’ve seen them for $15-20 at local electronics stores or get one online for less. This will help with the vision issues, and you’ll be amazed at how many other places you’ll use it (down spark plug holes, into walls in the house, down drains, etc.)

Flynorcal: pilot, offshore sailor, car racer and panty thief > Full of the sound of the Gran Fury, signifying nothing. 02/17/2018 at 17:26

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I just bought one off Amazon for less than $40 that has LED lighting and Wifi so you can use it with anything. I had no idea these were so cheap. Holy crap. Thank you for the suggestion!

daender > Flynorcal: pilot, offshore sailor, car racer and panty thief 02/17/2018 at 17:46

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Maybe do a chassis-mounted wing? Downside is that you have to cut the rear bumper and it’s lot to take in visually.

LOREM IPSUM > Flynorcal: pilot, offshore sailor, car racer and panty thief 02/17/2018 at 18:10

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Please do not JB Weld your wing to your car.

Flynorcal: pilot, offshore sailor, car racer and panty thief > daender 02/17/2018 at 18:10

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Aside from my welding/fabricating skills being challenged by that endeavor, I really like the idea but I have conflicts with rear lights being located where I’d have to mount the thing and getting gas into the tank with all of that in the way would be a challenge if it’s possible at all.

I do have diffuser ideas though as I have a lot of space without a spare tire and plenty of places and room to mount it. It’ll be a much easier job to install that.

Flynorcal: pilot, offshore sailor, car racer and panty thief > LOREM IPSUM 02/17/2018 at 18:12

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This, I suspect, is the correct answer.

daender > Flynorcal: pilot, offshore sailor, car racer and panty thief 02/17/2018 at 18:39

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There’s a company in CA called Battle Aero that makes these wild wings. They haven’t done a C4 Vette but I’m sure you could kit-bash some stuff together to make it work. Also, they can be hinged at the bottom if that helps with getting to the gas cap.

Flynorcal: pilot, offshore sailor, car racer and panty thief > daender 02/17/2018 at 19:03

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That’s a rad link and a good resource. I’m gonna crawl under the car tomorrow and see what kind of attachment points I’ve got. Cutting through the plastic bumper doesn’t faze me at all. The guy who welded in the rollover stuff fabricates things. I’ve easy access to fabricating with plastics but not metal. If it looks like I can make it work it’ll likely be the best of all possible options to get him to weld a stand to mount the wing I’ve already got.

shop-teacher > Flynorcal: pilot, offshore sailor, car racer and panty thief 02/17/2018 at 21:24

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Yeah .... No. Definitely do not JB weld your wing to the decklid.

Flynorcal: pilot, offshore sailor, car racer and panty thief > shop-teacher 02/17/2018 at 21:32

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Expected answer. I had my fingers crossed for a minute you guys would green light it but didn’t really expect that. I’ve got an endoscope arriving on Monday so I can see what I might be drilling through... Let’s hope the lumps and bumps I feel in there are just reinforcement bits. Can’t really be anything else but I’m only so brave.

shop-teacher > Flynorcal: pilot, offshore sailor, car racer and panty thief 02/17/2018 at 21:40

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Yeah, if only it were so easy :)

Scoping it to look and see is definitely a smart move.