Alright I started grinding and chasing the cracks and the repair grew a bit over the top of the mounting hole as well Glassing in the first notches.
After cleaning it up
Second notch
More notches
Fiberglassed all the notches areas from the exterior with the west systems and then finished it off with VPA. It took MULTIPLE thin coats of VPA to shape the corner the way I wanted it.

 

I also had cracks at and around the corners of the rear air vents behind the rear window. Shown in the picture below. I cleaned up the area and ground out the cracks. The cracks did not go all the way through but you can see I had to get the panel pretty thin.


My plan was to just take the same approach as the other repairs: Matt and resin on the exterior and then VPA. Is there anything special I should consider for this repair? Thanks

 

No...you can repair it as you planned out.

These cracks that you had are common and it is not so much a structural crack...but a problem in the panel itself due to the sharp 90 degree bends.

I can say that when you know you have to laminate in matt and resin...I prefer to grind a bit further away so it is a gradual taper for me to fill in. Prepping is back another 1/2'' is not that big of a deal....especially if the taper makes my time laminating faster and less problematic.

DUB

 

Just wanted to say you're doing good work! Brings back memories from when I worked on my '71.

I agree with Dub that you should grind the valley a bit wider. Makes it easier to get a good bond with no air bubbles and makes the repair stronger.

 

Thanks zwede! Yes I took both of your advice and extended my valley. I layed the fiberglass yesterday and will Sand it down tomorrow. I like to give everything 48 hrs to cure because of the colder weather right now.

While I have enjoyed the immense learning experience so far, I'm not sure if I will look back fondly at this part of the process. The progress seems so slow!!!! I can't wait to at least get it into primer.

 

YES...it can seem slow but what you are doing should be taken seriously as like you are doing. Because doing a repair half a$$ is just not the right thing to do when you are at this stage of a restoration.

If you have a heat lamp...not knowing if you are doing so....you can apply heat to your lamentations also AFTER they have cured for 24 hours. About 140 degrees is fine for a few hours.

The reasoning behind this is this...You can let resin cure for weeks...but if it is in cold temperatures....and then you put it out in the sun and the panel gets hot on a hot summer day....do not be surprised if something changes. This is also contingent on how well you laminated it with no air bubbles and your lamination being good in regards to proper saturation and amount of resin to the matt you applied.

The same holds true to an actual paint job. You can paint and buff your car and leave it in a cold garage for months and wait for spring time...and then...when you pull it out in the sun on a summer day..WHAM...you have paint problems that appear.

This is why when work like this is being done....being able to get the cars surface hotter that what the sun will ever get is always a good move. It is not a requirement...just a good step to take. And this is a step I NEVER leave out.

DUB

 

DUB I understand what you are saying, unfortunately I do not do not have a heat lamp. But as an alternative I have been using my heat gun (on low!) and far back to slowly heat the cured resin to ~150 F and then let it cool off. It's not as good as a heat lamp for an extended time but it has help at least a bit. But this leads to another question, doesn't the VPA seal the resin and aid in preventing delamination? Have you ever seen resin delamination lift VPA?

 

On a different note I completed the vent repair. I widened my groove first as per the recommendations here.

 

Well after much debate, I have decided to keep the luggage rack off the car which means I will have to fill in the luggage rack holes. There are multiple threads on the forum on repairing these holes however I wanted to get input here. I have the gas tank installed so getting to the back of these holes would be difficult, but I could probably get some tape on the back side of the holes to laminate over. Any particular advice on this repair outside the usual?

 

VPA will not entirely stop a bad lamination if it decides to lift. If your lamination lifts off the surface..then something obviously was not done correctly for this to occur.

YES...but it also depends on how thick I applied the VPA. It can lift on really thin coats. Which is why when I laminate I am super critical and do my very best so I do not have to worry about my lamination lifting. So far....in 30+ years....I had it only happen when I did some laminations way back when I started my business and I was testing out my procedures....and then again when I tried some new resins that I was told where the best to use....and they failed.


Just be aware that your repair does look good but this is a really critical visual area...for me it is. And often times when I go and spray the gelcoat or primer on it....I may find I need to stop applying it and do a very slight correction in how it looks so when the grille is in place it is prefect along that repair edge and corners.

Also...repairing that broken area of fiberglass that aids in holding the clip for your grille are a bit of fun if you get into that. Tedious prep and laminating to fix those...because I have done many..

As for filling in the holes for your luggage rack. Here is something to think about that can not be disputed.

If a person is laminating on their Corvette. It is NOT required that each and every repair be done in a manner that applying mat and resin on the backside of the panel so it ties ion with what is being applied on the top side to prevent the lamination from 'popping out'. IF a person thinks that it has to be done that way....then I have to ask them what do they do when they get to a repair that they CAN'T do it like that. Something to think about.

SO...IF I had to do one and the fuel tank was out. Would I apply one layer on the underside and tape it up to the body so it would not fall out and then immediately lay a layer or two on the topside. YES I WOULD. The reason is ease of prep and not breaking a sweat doing it. But that alone does not matter IF the prep and application is not correct.

If the fuel tank were still in the car I would not think twice about laminating these areas in from the topside. It can be laminated on and then ground back on...so a layer of VPA can be used to finish the area out. The KEY is to taper your area back enough so you laminated/VPA repair ares is about an easy 1 inch+ from the outer area of the hole itself area is. The taper needs to be a good gradual taper also. Do not try to keep the repair restricted to a small 'footprint'...use what you can. AND also keep this in mind. Just because you prepped it out far enough. Does not mean you need to get your mat and resin all the way out to the edge of where your prep stopped. This is because I would advise ...like I wrote above...that you then grind your lamination down so you can build it back up with VPA. The thickness of the VPA is up to you....but I shoot for at least the thickness of a paper matchstick if possible...and YES...I know it will feather out to really thin.

DUB

 

Alright I ground down the holes and most went well but the two top holes that are closest to the rear window are drilled in a significantly thicker part of the body where it looks like the panels were bonded together. On the passenger side you can see that there is an air gap in between the panels where adhesive did not fill the void space.
You can see that there is an additional 3/8- 1/2" worth of panel thickness below the exterior panel. Is it necessary that I go all the way down to the very bottom panel even with this air gap? If I do, my repair will be at least 1/2" thick before I apply the VPA.

 

In the hole that is the thicker ones where they go through a bonding strip. I take a die grinder and prep the inner surface of the hole where it was drilled out.

I generally can get my arm up on the underside of it and I wipe it off with lacquer thinner on the backside of this hole and apply a piece of tape so the VPA will not fall out.

If you can not get your arm to the backside of the hole....you can also use a piece of flexible rigid material...that you poke a pin hole in the center of it. Get a piece of sewing thread to go through the hole and tie a huge knot in the thread so it can not pull through the material you chose to use. Cut this material in a circle and make the circle larger than the hole itself so when you poke it down through the hole...and pull back on the thread. You then apply the VPA and hold it while it sets up. Or set yourself up something over the hole so you can tie the thread to it so you don't have to hold it.

I fill in the bottom of the hole with VPA....when it has cured...grind it so I can laminate on it. Then finish out the repair area as previously mentioned.

DUB

 

Thanks for advice DUB! It worked well! Filled in the deep hole with VPA after using a Dremel tool to rough up the inner walls
I sanded all of the excess fiberglass down and filled in with VPA last night. I plan to do one more skim coat of VPA tonight.

 

After I finish with the rear deck holes tonight, I am planning on addressing the fender seams. All of my seams look good: no cracks. I could barely see the seams before I removed the paint but they never really bugged me. BUT since I'm here I might as well do something about them. So I've read elsewhere on the forum that you can either fiberglass them in, which I'm not overly excited to do, or you can notch them and fill with VPA. Going the VPA route, how deep and wide do I make the notches? I'm assuming just deep enough to get a "healthy" skim coat over the seams?

 

YES with the VPA...and YES you assumed correctly.

Grind it down a good 1/8"+ and taper your grind out about 1-1/2" below the edge of the fender and quarter panel. The prep the area above the seam to the top body feature line and take it all the way to the top.,...so when you apply the VPA...you take it all the way to the top a and then taper it out when you are on the fender and quarter below the seam. I know that you know what I mean by 'taper' the VPA...it is applied on the bottom edge so tight that when you go to block it..there is not an immediate step/ridge in the VPA that is hard to feather out.

I shoot for about 3'-4" width of the VPA when I am done. And many times the VPA will still be right at the very top where the feature line is.

The 'worst' area is the area on teh fenders is right in the center of the wheel well. The fender has two curves going different directions...which basically makes it contoured like a ball. That area is FUN to get blocked right.

DUB

 

Thank you for the instruction DUB. The whole process is slooow. I ground out the seams about an 1/8" deep and then widened my "V". Once I had the area prepped, I went over the panel with a first coat of VPA. I decided that I would be better off doing multiple thinner coats of VPA vs one thick coat to help keep out any air bubbles. I had some areas of breakthrough but I did not feel that they would make much of a difference as long as they were not over any of the seams. Pictures to follow.

 

Beginning the grinding process



after I widened my "V"

 

Realized I never posted a picture of the rack holes completed. So here it is

 

ALL LOOKS REALLY GOOD! When I am done blocking the seams out...they look just like what your look like.

All I hope for is the fisrt photo in post #57....where you show how you ground into the seam. I would have to assume that you DID NOT apply VPA over what you showed int that photo.

You might want to go back and edit into that post and let people know that that was when you started the grinding process and that is was NOT what it looks likes when you are about to apply the VPA....because many people do not read your written text... but go strictly by photos...and that can really screw them up. Just saying.

GOOD JOB!

DUB

 

DUB yes the first picture in post #57 is only my "depth guide". I ground this first to establish the depth I wanted and then went to back with my roloc tool to create my "V". This way I have a guide for the roloc and could keep the groove somewhat consistent.