Jcpstrat

This week I lifted the body off my '67 Coupe and the frame has some obvious rust issues in front of the rear wheels that need to be repaired.

But what about the rest of the frame. Is there a way to have the whole frame checked to see if there are weak areas where metal is thin (i.e. rusting from the inside out), that also need attention or maybe that I need to start looking for another frame?

Frankie the Fink

One of those Harbor Freight goosneck inspection cameras with the lighted end would tell you a lot....about $67 on sale; you'll use it for a ton of other things too. There are lots of access holes to let you snake the camera in there and inspect rust/damage....

Frames often rust from the inside out, usually at the rear 'kick ups' so significant rust on the outside is never good...

kenba

TAP it with a hammer to check for other soft spots. Getting the frame sand blasted or dipped will also tell you a lot. Good luck. I would look for a better frame.

Jcpstrat

Thanks for info. & tips Frankie & kenba.

Frankie the Fink

I won't buy a car unless the seller lets me do my proctologist thing with that camera. Birdcage, hinge pillars, frame - any where you can think of !!

jim lockwood

An ultrasonic thickness checker gives a definitive measurement of metal thickness. Many automotive machine shops have these on hand. They are relatively inexpensive, however. If you buy one and it keeps you from buying a car with a "soft" frame, it just paid for itself.

This one is only about $120:

Frankie the Fink

Slick - I've never seen that one. I know that there are devices to measure paint thickness/metal content but this looks to be more sophisticated...

jim lockwood

I learned about these little gadgets when I took a block to a machine shop. The machinist tested all the cylinders for wall thickness to check for core shift before he would agree to bore the block. Seemed like a Real Good Idea.

AZDoug

An ultrasonic thickness gauge needs to be used on bare metal, not rust flakes, to work, so be prepared to do some grinding where you need to check. (I used to use one back in the early '80s to check wall thickness on industrial tanks, and boiler tubes; they were a lot more expensive, then)

A 1/8" drill works well also for thickness checking, if you don't mind a few holes.

Doug

Roger Walling

There is nothing like a hammer and an educated ear.

Even if you have never done it before, the different sounds will tell a good story.

bell like = good.
dull thud = bad.
dents =bad

When a state air tank inspector tested my tank, he used a 5 pound ball peen hammer with a good hit. (no air in the tank)He told me that if it is good, it won't dent. If I did not allow him to smack it good, he would automatically fail it.

Frankie the Fink

Not sure I have the ear for that. When I had my Florida home built the builder checked for proper floor tile adhesion by bouncing a golf ball on every tile. Pretty interesting approach.

Jcpstrat

That ultrasonic thickness checker is basically what I was hoping to hear about ... thanks.

I've also done some hammer testing and so far found a "dud" sound with the hammer really bouncing back i.e. maybe VERY thin (driver side right behind the front wheel). Lots of good info. ... thank you again everyone.

69ttop502

I think the most sure way would be to weigh it. I think I have seen a thread here about this, and the spec weight of a new frame. A rusted frame would be considerably lighter than a fresh frame. Should give you a good indication about how much metal has been lost, especially given, as Frank says, that they rust from the inside.

Bill

buns

That is an excellent idea. I would probably go 1/4". Easy enough to fill with weld. And cheap, too!

Jcpstrat

OK ... I'm a little fuzzy on how to actually make a 1/8" or 1/4" hole work.

Do you put something thru the hole that can hook onto the inside of frame i.e. a nail (where head goes in first, or an "L shaped" Allen wrench and then mark where the outside surface is on the inserted item, withdraw item and then measure the mark to what hooked onto the inside?

Frankie the Fink

I could see you getting some inconclusive results drilling a hole, so you drill another one and maybe you think you've missed the rust by 1/4" so you drill another one and on and on.

Personally, I wouldn't start down that road. The camera cited above will show you everything you need to know, and, maybe more than you really WANT to know.

69ttop502

Here you go. Check out the video linked in the thread near the end.

https://www.corvetteforum.com/forums...c-testing.html

Jcpstrat

That video was quite interesting ... hadn't seen it before even though I had been to that website while looking for information on what's available for a replacement frame.

My frame isn't as bad as the one they show in the video and they do claim the one shown is an extreme case of rusting but mine has some holes, has a lot of scaling and without much time already found a soft spot in a critical area with the hammer technique so I think I'm going to focus on finding a replacement frame. The frame is like a foundation of a house and I want to build on something solid.

The camera is a great idea too but all things considered I think I'm past the point of needing it for the frame on my Vette. Thanks again everyone.

Bill32

That's what we use to check your rollbar wall thickness at Tech.

jim lockwood

You mean I didn't need to drill that inspection hole?