Bud2

In my 3rd year of restoring my ’64, including major work on the birdcage. Took it to an old-school restorer to finish the body. Had the paint laid down two weeks ago. So pretty nearly cried. Started the 2nd step of polishing and this morning saw three places where you can see the bonding strip. They just ‘popped’ up for no reason. Nearly cried. I’ve spent way too much money and time for this to happen. Some was of my work but one is from an old accident/crack on top of the back fender - years old and I didn’t touch that except to remove the paint.

Just wanted to rant. Not expecting any answers. I gotta remember Chrismas is a time for joy.

Bud.

ChattanoogaJSB

Bud- I'm so sorry !!!!

benton

phil2302

Show a picture of what is upsetting you.
Looking closely I can see every bonding strip seam on my no hit 66 and it doesnt bother me one bit.

DansYellow66

That's disappointing. But the only way you won't see eventually see those bonding strips is if they are ground out and fiber glassed over, or ground down and buried beneath enough filler (which runs the risk of cracking). You can try to block them down again but with sandpaper but they will reappear. Any change in the surface composition, like exposed bonding adhesive in the panel joint or a plugged hole (not ground out and glassed) will almost assuredly reflect through the surface eventually.

Show it to your painter and see what he offers.

Easy Rhino

Sorry for your troubles. Gotta be a punch in the gut to see all new paint, then to discover defects in it. Hopefully it won't require the nuclear option to make it right. Good luck.

65silververt

I'm in the same boat on one of my cars. 14k flushed down the drain because I did some of the body work.
I had to grind down the areas then I baked them for a month with an infrared heat lamp I bought off eBay. My guess is I did not let the repair areas and filler in the bondingvstrips cure long enough before putting primer over them. The bonding strips were the first areas to show.

pop23235

Man, that bites.

Bud2

90% of the seams were glassed over. This previous repair was years old and didn't show through the paint I removed. Thought it would be good to go. Guess I might be glassing over it now though.

I need another tissue.

Bud.

Frankie the Fink

I know I'm no good at body work so I don't do it. I'd almost rather have a transmission blow up or have to rebuild a motor than discover some major flaw with a fiberglass car body.

Sorry man...

Easy Rhino

Absofrickinlutely.

I'd rather have sand flowing through my engine and tranny than have body work.

I'm in awe of people that can do that work.

Roger Walling

When I bought mt 57, I striped the whole car with a board sander with 80 grit paper on it.
This got it pretty level, then I ground out all of the bonded areas along with all the previous repairs. I then applied mat over all the bonding strips and re-glassed all old repair sites.

After much blocking, I ended up with a stright car that has not shown any sign of repairs or defects.

Never restore a car relying on someone else's repairs!

Ps, I love glassing, there is nothing that can not be repaired.

Lotsacubes

Been immersed in the Aerospace composites industry for about 25 years. Involved in designing and building many composite aerospace structures. So been mentally debating what adhesive system I'd use when the day came to replace an inferior composite part on my '66 (lost a knockoff wheel in mid-80's). My company builds expendable composite structures and very high value composite structures where human lives are at risk. We only use polyester resins/systems for the inexpensive/expendable products where we can't tolerate a 24 -30 hr epoxy cure time before we can perform the next assembly step. So given that polyesters shrink ~7% and continue to shrink over a long period of time vs less than 2% shrinkage for epoxy... what would I use. Given our C2s are worth north of 50K with many double or triple that, why would this community continue to use the cheapest and inferior adhesive that was selected for the same reason we use polyester in our cheapest products. I get the tendency towards preserving the tradition so if that's true we should be proud of the inevitable bondline shrinkage regardless of the paint job price tag. BUT, if I'm spending 15-25K for a top of the line paint job shouldn't we consider $150/quart Hysol 9339 that I personally trust my life to (and many others). I personally would be impressed if when purchasing a restored 50 year old composite car the restoration "expert" told me he used an aerospace grade epoxy paste adhesive vs automotive polyester adhesive. Ok, go ahead. I put on my body armor.

My condolences Bud, but find some consolation in that you did it the way GM did it and experienced the same results for the same technical reasons.

redsplitwindow

My two cents
First where not talking about bonding panels,and personally I would never
Use a product made for a composite on 50yr old fiberglass.
Ask me how I know.
Someone used it on my 61 corvette and the first time I jacked it up on one side it cracked.
That's when I started doing it myself and haven't had a problem since.
The OP.....
The spot of old body work,Is it a crack or can you see the repaired area?
If it is not cracked,It's possible and I say possible that your body guy
Sanded thru the high builder primer before sealing it and you have what's called a "Bullseye".
Once cars are primed they should sit weeks to cure and shrink before
Sanding and repriming.
The body seams,should last 10-20yrs before they show up,and it's common that they do.
Also all repairs need to be fixed on the back side also,just like the front.
In your body work if you fixed the front and not the back as soon as you get body flex from jacking or driving they will show.
No cracks can be fixed with just Bondo,They need to be fixed with Mat and Resin and I would not under any circumstances use a heat lamp on them to bake them,A fan yes and once again let them shrink and cure a couple weeks before starting to grind on them.
Work area should be at least 70 degrees for curing times.
Just a DIY guy that had the "shops" not do it properly,and said hey I can
Screw up the same thing they did.
Things could be worst......walk away
My mother just died I know
Is your body shop,A body shop or A shop familiar with fiberglass
There's a big difference
Dave

Kerrmudgeon

Some fillers react badly with certain paints as well. My painter found that out the hard way after he was finished my 62. Within weeks the work was visible in the paint. He had to strip the car and redo the whole thing.
ALWAYS gouge out the bonding strip joints and lay matt in them for long term success. Mine was done in the 80s and there's no sign of any joints anywhere.

DUB

WOW,

There are some people who have opinions on this matter...that is for sure.

More than one way to 'skin a cat'...and The way I 'skin that cat' is not like what has been mentioned here.

I can say...in the past 30+ years...I have never had to go in on the backside of bonding seams/strips and do any work in order to make sure the seam does not come back though. That is a new one on me.

Those of you who read what I write KNOW what I use. And the very first Corvettes I did 30 years ago that are still in town...do not have any seams showing through. And these cars were painted in lacquer. The stuff I use is STOUT and can not.... by any stretch of the imagination be considered a 'bondo'.

I have never nor never will laminate up the seams to keep them from showing back up. The product I use.... way back before the internet has been so successful for me...it is hard to change my processes/procedures when nothing is wrong my process. Because if something was wrong...I would change.

To each his/her own. Do and use what makes you feel good about your repair. And if your repairs tou chose to employ are still holding up....then you made thet right choice for you. And you will more than likely comment on that process due to your scuccess...just like how I feel about my process... which is compltetly differnt.

I TRULY HATE to read that you have an issue Bud. This repair....if you choose to tackle it...is NOT going to be an easy one due to fresh paint and like was previously mentioned...the chance of a 'ring-out' is very high if the panel is not stripped and all sealer, paint and clear removed.

DUB

Robert61

I smell what you're stepping in! So should one grind the seams and apply VPA over all seams? Is ring out the blistering of the previously layed paint by the new solvent or the uneven surface of leaving different layers of paint? Thanks

redsplitwindow

Hey Dub
If the referral to fixing bonding strips or seams on the back side is to me
Grab your glasses,It's not mentioned in my post.
I mention "Body Work" which would be cracks.Cracks should also be fixed
On the rear side.Broken bonding strips on the back side they need to be fixed also.
There are plenty of ways to skin a cat,there's also the science end of solvents and moisture and.....................
The OP also mentions 90% of the seams were glassed over,well is it the other 10 that is showing or the original seams coming thru there glass work?
My 2 cents
Dave

ChattanoogaJSB

The VPA is what I used on my panel replacement seams followed by epoxy primer over everything- the VPA advice came from DUB via a phone call which I appreciated greatly. Although my paint job is new, I will say the only deficiencies I have a few small places where the old red "lacquer" glazing putty wasn't removed. Shame on me. I used it when I was younger and then was told mid process to use only a urethane glazing putty. The red stuff is JUNK. I left just a few traces of it in some relatively inconspicuous areas but I wish I had not. It almost never stops changing.

You may well be having a problem not with the joint but with the glazing applied above it. Just a thought.

Benton

Roger Walling

My view on bonding strips.

Bonding strips were used in the manufacturing process to allow the assembling of parts by relatively lower skilled workers and with an eye on the economics of production.

If you want a car to be restored correctly to factory spec's, by all means use new bonding strips as necessary.

But this is not the only way to repair broken and fatigued fiber glass.

If one is working on a budget or if he just wants to repair instead of replacing, laying up multi layers of fiberglas on the inside of panels, and finishing them up nice and smooth could make the damaged areas stronger than the original and at a lower cost.
This is not cheating and may even be considered creative by some. Marching by a different drum is one of the most pleasurable things one can do.

My Corvette will never win and NCRS or XYZ awards but will never crack in my lifetime.
After I die, someone else can put the bonding strips back if they want to.

DUB

'Ring out' can be caused by an aggressive solvent penetrating deep within the repair.....and thus....attacking the layers of material that were 'feathered out' so the repair can be made....at different rates of expansion/swelling/etc. This is what causes the 'ring-out'

Also...you can do a repair where your feathered out several layers of applied products....and when you are done with the job....it looks great. But 6 months to a year later...the ring-out shows up. And this is caused by the solvents coming out and everything is finally settling. it can also happen years later on cars that are left in garages and never see the sun a lot.

A person can not expect that the primer they use, the sealer that is applied on the car...the paint they use...and the clear coat ALL react equally to a solvent. If a person does....they are living in a dream world. It DOES NOT Work that way.

These products MAY link up and bond with each other....but they all all different and some may not be catalyzed ( like basecoat paint) while others are. SO when you have a basecoat paint sandwiched between the clear coat which is catalyzed and the sealer/primers... which are more than likely catalyzed....you can only guess what happens to the basecoat paint when it is effected by a solvent.

SORRY...I guess I read it wrong.
What does the word ALL mean to you???? Excuse me for assuming you were talking about the seams. Sometimes I read things literally.

And...for what it is worth...as you probably know. There are many times where getting to the backside of panel to repair it is not possible.

And I hate to mention it. And you can do as you wish...but I use infra-red heat lamps because they have a purpose AFTER the bonding or lamination process initial curing has been achieved. The whole idea is to get he panel hotter than the sun could ever get it. I do that...so then when the car is pulled out in the sun...I have no surprises. Car manufacturers bake paint hotter than I can get it....and I guess they are wrong.

***EXAMPLE SCENARIO***

I guy in Colorado is working on his Corvette. During the winter, he can only get the garage to 60 degrees Fahrenheit. He does all the work....body and paint...the whole she-bang. Heck...I do not care if he can get the garage to 70 degrees.

He finally gets a chance when the weather gets really nice and takes it outside and the body finally can get hot due to the sun...and problems start showing up. But when he pulls it back in the shade...the problems go away.

There is no way in heck at 60/70 degrees that all of the products are going to fully cure so when the body does get hot as heck...problems do not show up.

So...for this guy...there is nothing wrong with using infra-red heat to help the materials get to full cure. In my opinion.

Once again....to each his/her own.

DUB