Bond or Bolt

[Ralph_C]

Not wanting to start an argument , but adding to my list of stuff that helps determine a vendor, What are the advantages / disadvantages of having the body bonded or bolted to the chassis?

For that matter, what about footwells - part of the body vs. part of chassis vs. cladding?

[boxhead]

My kit comes with a bolted on body that is like a tub.
The complete body, footboxes, inner guard panels, firewall, rear cockpit panel are all bonded together in one piece that can be lifted straight off the chassis.
I personally feel this is more convenient when building as the chassis and drivetrain is very easily accessed.
The body can still be removed with the engine in and I am planing to use quick connector for fuel and wireing so that once the car is complete it is still fairly easy to remove the body.

The chassis as supplied with my kit is very stiff and I dont think the body being bonded on would make it any stiffer.(for want of a better word)

Plus it looks damn good with the driveline done and no body

[ledge]

ralph

My body is bonded to the chassis as that is how Warwick supplies his kits . I to had to toss up the pros and cons of each way before making my decision as to which way i wanted to go.
The main reason i chose bonded was the fact that once all your doors etc are on and lined up the body wont move around on the chasis and alter all your gaps . If it was a reliable way to fix a body to the chasis you would think that major car manufacturers would be doing it aswell.
I would say the car would be alot more rigid aswell with the body bonded on ,Maybe thats why his cars done so well at nationals ,Cause we all no the stiffer the car the better it handles.

But that said i love looking through others galleries and seeing there pics of the cars with do body on and when im lying on my back under my car the first thing i curse about is not being able to take the body off .

Once the car is done though how often would you take the body off ? And there isnt that much that needs to be done under neath anyway.

Paul

[RedBarchetta]

Originally posted by ledge


Once the car is done though how often would you take the body off ? And there isnt that much that needs to be done under neath anyway.

Paul

Exactly. Make the trans tunnel easily removable for servicing the clutch/tranny and having top access to the driveshaft. Other than that, why would removing the body even be an option other than to paint/re-paint? Hmmmm....

-Deano

[elgecko]

I think I will be bonding. Original style frame with aluminum panels and fiberglass body. With removable trans tunnel.
Any good suppliers in the States for a bonding agent (sealer). Brand ?
Dave

[408 stroker]

I believe it depends on how your chassis/body was engineered. Some are designed to be what is called a montique (i think thats how you spell it) chassis. This is where the stiffness of the car depends on bonding the body to the chassis. Others are designed for the chassis to take all of the stress load with out depending on the body to assist. hence, mounting the body on rubber pads. Bonding this type of body to the chassis could put undo stress on the body creating cracks in your fiberglass & also overstiffening your chassis. Chassis are designed (when done correctly) to have a given amount of flex. I would check with your manufacturer and see what they say before bonding. WOW does that make any sense??? Just my opinion. Chas

[decooney]

Drive a rivoted/bonded body shell type car over a few sets of railroad tracks. Then drive a non-rivoted/bonded body car with say 12-15 bolted mounting points and see for yourself.

This was one of my top two requirements for choosing an ERA over anything else. Massive rivots and excellent bonding results in a solid car. A friend has an early 20 year old Arntz Cobra thats totally bonded and rivoted too. Both cars are solid as rock and drive like real cars. What a difference.

[Ralph_C]

Thanks guys......

I will ask the manufacturers why they choose a particular way, but I think I know some answers now ...........

[Jase]

Originally posted by 408 stroker


I believe it depends on how your chassis/body was engineered. Some are designed to be what is called a montique (i think thats how you spell it) chassis. This is where the stiffness of the car depends on bonding the body to the chassis. Others are designed for the chassis to take all of the stress load with out depending on the body to assist. hence, mounting the body on rubber pads. Bonding this type of body to the chassis could put undo stress on the body creating cracks in your fiberglass & also overstiffening your chassis. Chassis are designed (when done correctly) to have a given amount of flex. I would check with your manufacturer and see what they say before bonding. WOW does that make any sense??? Just my opinion. Chas

Made good sense to me. I reached a similar conclusion when I thought about it. At the end of the day, I would hope that the chassis provided the most strength to the car, and not a fibreglass shell. Perhaps I'm wrong but the way I see it is that all the parts which have anything to do with the mechanics of the car are attatched to the chassis - therefore, theoretically, a good chassis should do all the work. The chassis is the car, the body is nothing more than a shell covering it.

Now did THAT make any sense?

[decooney]

Jase,
In theory that sounds great.

Chassis are doing the work in both cases. The point is, if the body is not bonded/rivoted somehow at specific points, there is a high probability of body movement which results in rattles, creeks, and squeaks from various points. The fewer the mounting points, the worse it is as the fiberglass ages and the mounting points wear in. This is proven by loose bolts showing up on non-bonded cars.

[ledge]

Another thing to consider is that when a chassis goes through its structural and rigidity test before the manufacturer gets aprooval to use it and gets an ADR on it there is no body on the chassis . So regardless as to whether or not the body is fixed on or just bolted the chassis has to pass . But does that mean that when you rivet and bond the body on it then becomes stiffer ???

Paul

[decooney]

Paul,
For my car I will stick my neck out to say (with no test proof) at least the body becomes stiffer, but I would not be one to state the chassis becomes stiffer.

One interesting test is to see if you can jack your car up from one point and lift three wheels off the ground. With the car up, then try to open and close the doors on your car and see if they bind up or not. Don't know too many bolt on body's that pass this test very well. Would be interesting to see who's tried it.

[ledge]

Duane
My body is riveted and glued on and yes i jacked it up like you mentioned and it doesnt make a difference to the door gaps etc so i am deffinetly on the side of glued is better but it would be great at times to whip the body off to get to those fiddely spots .
Just as life everything has comprimisses (and spelling mistakes )

Paul

[Aussie Mike]

I can see the benefits of both mounting practices.

personally I like bolt on but that's because I'm a chronic tinkerer and I know I'm going to want to pull the body off in the future to mod something.

Composites can be extremely strong these days. The body and chassis of many modern supercars are made from composites. Check out the carbon fiber body and chassis on the Mclaren F1 supercar.

The body and tub on my Classic are all one piece and it's a strong structure just on it's own. It's made from Quadra mat and vinyl ester resin with many honeycomb sections in critical spots. The body is mounted in most places by sandwiching it between chassis structures. For example the frame that supports the seat belts and the one leg of the roll bar clamps the body down to the chassis with 8x M12 bolts. The hoop that supports the steering column and the door hinges sandwiches the body with another 6 bolts through the floor and another 9 bolts through the foot boxes and the fire wall. The body is sandwiched to the chassis by a further 6 bolts through the posts for the door locks, 8 bolts where the seats mount, 2 bolts for the seat belts and 3 bolts for the hand brake.

Bonding and riviting probably makes for a secure attachment but you also have to look at where the body is attached and at how many spots. Is the body just a shell to give the car it's shape or is it an integral part of the chassis.

Cheers

[Rebel1]

The RMC has 32 X 8mm (5/16) bolts holding it and you could put a jack under an open door and jack it up.

Door would close as well as it did before the jackin procedure.

I like the idea of being able to remove the body. I have modified mine to have a removable tunnel so I guess I've got the best of both worlds

Cheers