1975 Plastic fantastic aka Corvette

[SuperBuickGuy]

it's true, that is a known problem with them.... of course, welding them now (with 30 years of grease in that angle doesn't make for much better welds, but at least I have undercoating to make it all better


and this hole GM says to "fix" ... so it's fixed

[mlcraven]

car is back together, fixed the cross member on the car

for reasons that aren't clear to me, GM put light gauge metal under the cross member - so if you jack on it, it collapses.

fixed

Seems GM never stopped to consider that Corvette owners might want to jack up their cars, using a single floor jack on the paper-thin cross-member. Oh well, they weren't the first or only ones to misjudge owner intentions.

[Russell]

No drain holes?

[JOES66FURY]

and clear coat.... 4 or 5 coats... and I have a couple runs to remove, and kamikaze bugs....

The color really pops with the clear coat, very nice.

[SuperBuickGuy]

No drain holes?

did I fail to mention that's stainless? also, there's plenty of holes/gap in the back from the beating the cross member took to drain any water... but you're right, had that not been the case, there'd be a hole in the bottom.

[SuperBuickGuy]

There's a LOT of talk about the factory welds over on Digital Corvettes - it went on for years..... Neat site - good crew, if you haven't already checked them out.

I'll have to check it out, thanks

the right way on this car would be to pull the frame out and weld everything.... I'm not to that level yet, nor may I ever get there.

also, on the jacking concept. A floor jack barely gets under the car, and normally I simply jack from the frame on the side - unfortunately, that doesn't work for getting the lift arms under the car (specifically the front ones) because the sidepipes are just too low.

[SuperBuickGuy]

time to cut n buff

okay, so first up, I'm a rank amateur at this - seriously, first time from prep to buff... however, I have good help from my local wesco paint store (expensive, but worth it)... anyway, a few things I learned
1) you don't need to start with wet sanding. 400 grit on a DA will save your arms - WITH THAT SAID, AND IN CAPS, WHILE I'M AN AMATEUR I'VE SPENT DECADES BUILDING, AND FINISHING STAINLESS STEEL KITCHEN EQUIPMENT so please, it's not easy - but it's also something I've been doing since I was knee high to a grasshopper.... and it helps with touch and using power tools

So I started with 400 grit on a DA and knocked the tops off the orange peel.

down the center of the hood is what the 3000 grit looks like after a pass or two
I learned the hard way that if you try corners, the edge of the sandpaper digs into the paint and leaves glue that's exceptionally difficult to remove.... ug... that said, as it doesn't leave the mess of cutting and buffing, it could be a real time saver if you're part of the "let the clear breath cut" finisher and the car you're working on has large, flat surfaces....
then I used 3000 grit on a polisher (yes, 3000 grit and good lord is it spendy - $10.00 per pad) mostly because I don't have a hook pad on any of my DAs (remedied soon).

A warning about 3000, use only on flat surfaces - but on flat surfaces, when finished, it seriously looks like the first cut of a cut n buff


and where it sits now



it's not perfect, I could spend a lot more quality time with 2000 grit and water to completely flatten it out... but I simply don't care, the paint job was another learning process, and if I make the clear coat perfect, it'll simply draw attention to the paint job (not good)

hopefully tomorrow night I'll finish the top then I can get busy with 500 and up on the sides

[Deaf Bob]

those welds are stock, GM, factory welds.... mine look LOTS better. I honestly thought that the PO had done that, but now I've seen at least a half dozen cars with the same crappy welds..... anyone who wonders how the foreign manufacturers got a foothold in America, need look no further then those welds.

Sad but very true... We try to reweld all seams when putting cars together... Doesn't take muchof a hit to make the welds come apart...

[SuperBuickGuy]

there's a magazine/book the GM Performance put out that has all the upgrades for a Corvette to make it "track ready" (whatever that means) and it's first suggestion is pull the frame out and weld all the seams.... uh, no... were I to do that, I'd buy another frame, then transfer parts.... but even then, not a chance.

[Deaf Bob]

there's a magazine/book the GM Performance put out that has all the upgrades for a Corvette to make it "track ready" (whatever that means) and it's first suggestion is pull the frame out and weld all the seams.... uh, no... were I to do that, I'd buy another frame, then transfer parts.... but even then, not a chance.

I kinda doubt it will be that bad welding the frame sections... I will try to take pics of various makes that we hadn't welded, the results will change your mind.. I wonder if the factory purposely makes them that way to make them absorb crash energy by splitting the seams. I'll email them to you, I've at least mastered that!

[Mater]

that was probably the original intent or money saving. less welds less wire you need to buy multiply by 100,000s of cars that's a bit of savings

[Blazerteam]

It was not just the Corvettes that didnt get welded together..i found out last winter,when i was under the Chevelle..that the frame was cracked in the welds right there where the lower control arms are bolted in the frame..actually,i will remove the frame,and weld it myself..will try to make a fixture or a jig for it,so i know it is straight when im finished.

I wonder what drug they had to use to be a welder in the seventies..

[SuperBuickGuy]

I kinda doubt it will be that bad welding the frame sections... I will try to take pics of various makes that we hadn't welded, the results will change your mind.. I wonder if the factory purposely makes them that way to make them absorb crash energy by splitting the seams. I'll email them to you, I've at least mastered that!

I suspect that's why it wasn't fully welded

that was probably the original intent or money saving. less welds less wire you need to buy multiply by 100,000s of cars that's a bit of savings

GM is famous for the washer-theory - that they'll spend time finding a way to remove a washer because they factor it over hundreds of thousands of cars.... but still, this is a low-production sports car; telling racers that they have to spend 40 plus hours to correct a factory condition is a really good way of convincing racers to use BMWs

It was not just the Corvettes that didnt get welded together..i found out last winter,when i was under the Chevelle..that the frame was cracked in the welds right there where the lower control arms are bolted in the frame..actually,i will remove the frame,and weld it myself..will try to make a fixture or a jig for it,so i know it is straight when im finished.

I wonder what drug they had to use to be a welder in the seventies..

what's sad is those two crappy welds colors the public view of the entire car. the rest of the car, welds are fine, the body is put together correctly, etc, but one lazy welder gives a bad name to all the rest.

[Deaf Bob]

It was not just the Corvettes that didnt get welded together..i found out last winter,when i was under the Chevelle..that the frame was cracked in the welds right there where the lower control arms are bolted in the frame..actually,i will remove the frame,and weld it myself..will try to make a fixture or a jig for it,so i know it is straight when im finished.

I wonder what drug they had to use to be a welder in the seventies..

Just put crappy tires on the frame, grab the cherry picker and lift one side up untill it stands on the tires..
Weld a foot or so... Move to the other end... Switch around.. Should be ok then.. With tallish tires, you will always have rubber on the ground even with the frame upside down except at the rear humps..maybe...
We will start one end and weld rod after rod untill finished at the other end and flip and repeat.. Never noticed if it was out of straight... Doesn't matter to us... But one thing we do notice... No frame flex... There is a solid thump on the ground when a fully rewelded frame hits the ground.. I'm sure you will hear it..
You will need to either plug the rear end vent or lose some oil so it doesn't leak out..

[SuperBuickGuy]

well, that hurts, a lot, but it's now color sanded, and cut and polished.... will remove the swirls and wax it later... much, much later



I got my wheel bits.... now I can align without removing the wheels... oh yeah, and if anyone needs any, they can be had for a small fee