pickleseimer

Would anyone know the frame wall thickness for a C2 frame as it came from the factory? Also, what is considered the minimum thickness necessary for safety? Lastly, with the cost of ultrasonic guages coming down in cost/rent, are these practical tools for evaluating a frame and will they be accurate through frame coatings? Anyone here successfully done ultrasonic testing on a frame? I've searched here and found a few threads suggesting this as a possibility, but did not see anyone mention having actually performed this. Thanks in advance.

Nowhere Man

what is really your concern. if its not rusted enough you can't put a screw driver though the weak spots then its good

magicv8

Vette Daddy

Is there visible rust through on your frame or is it just crusty? The weak points are in the corners behind the seats on the inside of the frame rails. Also, the end caps of the side rails in front of the rear wheels.

mike16

in an ideal situation you want to remove any surface coating from the metal. preferably both sides. especially if your equipment gives out a digital read out rather than an ociliscope screen type reading



also you will want to calibrate your equipment to a known thickness of identical metal.

to do that you should find another part of the frame that is cleaned up and you can get a set of dial calipers on to measure its thickness. then calibrate your equipment to it.

66since71

If it's unsound, you'll know immediately with a few hammer taps in that area or on the end caps. Sonic testing is unlikely to provide any better information.

Harry

wmf62

Bill

QIK59

Think you're ultra complicating the issue - all you need to do is a basic sonic test of the frame :
Whack it with a hammer and note the sound you hear !

John S 1961

I would take samples in a consistent manner along the frame, chart the data and calculate the mean and standard deviation.

Readings which fall outside 1 sigma would be suspect areas.

This way you dont need to know the nominal thickness, just the deviation about the mean would be the significant factor.

QIK59

I think if you are going to go that route, a survey of all existing C2's should be performed : sonic test all frames and record findings.
Then track all test subject frame failures and develop data showing the relationship between the historical ultra sonic test results and failures.
Failures will have to be qualified between catastrophic and simple degraded frame integrity.
This will provide an empirical data base upon which to base the prefered course of action.

pickleseimer

Thanks to all who provided information related to the question.

I'm interested in a method to evaluate the integrity of a frame and do that in a non-destructive manner. If I'm looking at a car wih the intention of buying, I don't want to ask the owner if I can attempt to poke a hole in the frame with a screwdriver or whack it with a hammer - I would be concerned if I were the seller because I wouldn't want my car damaged by someone who may not know when to stop whacking, and also as a potential buyer if I caused damage to someone else's car.

I have acess to portable ultrasonic measuring devices and this seemed like a good way to 'scan' a few areas of a frame where the typical problems are and see what it tells you. This equipment can measure down to small fractions of millimeter, and is capapble of measuring from one side and can be calibrated either by using a known piece of metal or against a supposedly 'good' part of the frame. The coatings are a question - some units will measure through a coating but I'm not sure if I can get one of those.

Anyway, the original questions still stand - what is the thickness of the frame material when it left the factory? what is considered a minimum thickness for safety? Has anyone here actually done this on a frame?

Thanks.

MikeM

I'll be surprised if anyone will give you a minimum thickness for safety. There are cars out there on the street that have the frame half rotted in two. There are cars out there that have probably lost half there metal thickness in the areas mentioned.

What is safe and what is not would depend a whole lot on the intended use of the car, the engine power and the tire size. Chevrolet even recommended reinforceing NEW frames in the area in question if the car was to be used for road racing.

Vette Daddy

I would have to ask...are you able to do your own work? If not, you mat be better suited for a later generation of Corvette.

66since71

.... it sounds like your want a method to evaluate cars for sale.
Again, inspect it visually first. Then... just tap on the plate at the end of the frame rail, at the kickup ( just in front of the rear tire). Hit it hard with your knuckle, and you'll know all you need to.

Harry

QIK59

Yep sounds like a new Corvette owner for the forum.

And I thought I could complicate the lords prayer

QIK59

You start off wondering if it is possible to do ultrasonic thickness scanning and wondering if this accurate and practical.

Then in your next post say you have access to this equipment and tell us it's capablities.

I have some past NDT laboratory experience and know that back then a fair bit of set-up and on site calibration was required before anything meaningful could be determined

It doesn't sound like you are versed in or have operated this kind of equipment which means that you would be bumbling around trying to perform these tests / measurements.

I don't think there are many sellers who are going to humour you while you try and figure out what you are doing.

mikem350

OK, you want to measure frame thickness...

BUT what about the corners and welds that form joints?

As previously noted, a good visual inspection (and maybe some hammer tapping) around known problem areas would be best!

My 2 cents

fullcontrol

A simple and sound method...frame weight can determine integrity. Excellent video can be viewed here.

http://www.corvetteusa.com/

BrentF

QIK59

I guess "we" just have to add up the weight of all the options, body weight etc etc and subtract from the total car weight and we should be able to figure out what the frame should weigh ?

What does iron oxide weigh ?

Should be an interesting process - somebody will probably try it LOL