Page 4 of 12

Re: My C4 Corvette Restoration Project

PostPosted: Tue Dec 13, 2011 9:45 am
by timbo
deitymotorsports wrote:
SuperL98 wrote:I have sawhorses :rotfl:
But the bumper is so flexible it bends and collapsed on them.
I want it to sit as flat as possible while I block sand.
Need to buy a big piece of plywood to make a flat supporting surface up on the horses.

The Poly Flex was a little gummy sanding dry at first (a sticky skin on top), but I found it sanded easy 180 wet.

But it's good stuff, feathered right into the urethane nice.


I noticed that paper on your longblock is yellow, is it for wet applications?


Thats a good question...do they make yellow wet paper?

Re: My C4 Corvette Restoration Project

PostPosted: Tue Dec 13, 2011 9:53 am
by deitymotorsports
Not saying it's wrong. Just wondering how it holds up under water conditions. Not sure if the "abrasive" stays on properly so your not digging into your work or leaving abrasive behind and not noticing it. ?

Re: My C4 Corvette Restoration Project

PostPosted: Tue Dec 13, 2011 2:35 pm
by SuperL98
I always buy a lot of different kinds of sandpaper, to have around.
If one type isn't working for me, I try something else.
If it starts getting dull, I toss it for a new piece.
Don't have enough Heart Beats left (at my age) to waste sanding with the wrong or worn out paper. :cry:

This is pretty much what I've been using on the bodywork.
Image


Usually the sheets with the smaller blocks.
The roles are sticky back, and the only paper long enough for the 16 inch sander.
Made in Germany, and it stays together fine wet sanding.
Used it on the hood also, wet and dry, much less clogging with a little water.
I didn't think it would work wet either, but the grit stays intact & it just slowly dulls.
Either got them from the local body shop or Summit, can't remember.

Re: My C4 Corvette Restoration Project

PostPosted: Wed Dec 14, 2011 2:40 am
by wetlook
deitymotorsports wrote:i've used poly flex on all "soft" bumpers since the stuff came out, and have had no problems. Does what it says it does.



Even in 5" round patches up to 1/4" deep as some of these Vette bumpers will need?
If so, I'm impressed, and will probably sell my new one and repair the original :)

Re: My C4 Corvette Restoration Project

PostPosted: Wed Dec 14, 2011 2:53 am
by deitymotorsports
1/4" deep is extremely deep. in those cases i will use long strand fiberglass mixed with an activator. fill it with that, feather it out with 80 grit. and then cover the imperfections with the poly-flex. But if you have new. use that, fix up your old one, and sell it since i'm assumming it's an o.e. bumper.

Re: My C4 Corvette Restoration Project

PostPosted: Wed Dec 14, 2011 8:52 am
by SuperL98
Mine wasn't that bad.
Looks to me like two skim coats are going to get me close to flat.
I've applied the second skim, but haven't sanded it yet.

Walking around a local Corvette show this summer, I started to noticed how badly warped some of the C4 Corvette front and rear bumpers are. Also the hood and body panel fit and alignment can be just terrible on factory stock cars.
Guess after fighting with these issues on your own car, you start to see things you never noticed before.

Re: My C4 Corvette Restoration Project

PostPosted: Wed Dec 14, 2011 8:58 pm
by wetlook
SuperL98 wrote:Mine wasn't that bad.
Looks to me like two skim coats are going to get me close to flat.
I've applied the second skim, but haven't sanded it yet.

Walking around a local Corvette show this summer, I started to noticed how badly warped some of the C4 Corvette front and rear bumpers are. Also the hood and body panel fit and alignment can be just terrible on factory stock cars.
Guess after fighting with these issues on your own car, you start to see things you never noticed before.




I overestimated how bad mine is too. I just measured it with a straight edge at 5/32" or 4mm low at the worst areas.

Re: My C4 Corvette Restoration Project

PostPosted: Sun Dec 18, 2011 2:57 pm
by SuperL98
Sprayed a quick guide coat and blocked the 2nd skim coat.
Image


Just a few low spots left.
Image


Applied a third coat, just in the low spots, and here it is after guide coat and blocking.
Won't know how good (or bad) it came out, until I can spray a coat of epoxy on it.
Ended up using about half the 32onze bottle of Poly Flex.
Image


Sanded off as much of the old primer and paint as I had the patience for and mounted it on for now.
Image


Going to pull the side & rocker panels off next, and get them ready for primer.
If I have to heat up the garage, I'd like to paint as many pieces as I can.

To many bumper pictures :rolleyes:

But I figured this is a common problem and it might help someone else, thinking about trying this.
After all the hours I put into this bumper, probably should have bought a new one. :(

Re: My C4 Corvette Restoration Project

PostPosted: Sun Dec 18, 2011 7:21 pm
by deitymotorsports
well whos to say the cheap aftermarket part wouldn't be worse? and also you wanted to learn, and you are. Plus looks like your being precise, that takes time. so it's time well spent.

Re: My C4 Corvette Restoration Project

PostPosted: Sun Dec 18, 2011 10:15 pm
by timbo
take your shoes off and stay awhile...LOL! :rockon: