how 'deep' should I block a body panel?
09-02-2014, 09:31 AM
#1
Melting Slicks
Thread Starter
how 'deep' should I block a body panel?
I am going the full body off of my C2 64.
Body has been fully repaired where needed with glass fibre and polyester. All that was blocked with 40 and 80 grid first to have panels as straight as possible.
I now am putting on polyester putty to smoothen out the remaining panel imperfections (that done, it will be sprayed with build-up primer).
Because this is all a first to me, I am not sure how deep to sand off the putty. Should it be 'patchy', meaning that panel comes through as much as possible. Or is it better to have a thin layer of putty staying on about everywhere. The latter seems easier to come to good results, although I have seen many bodies already where there are cracks in the paint, mostly from putty coming loose....
So should it be like the back fender which is very patchy, or like the bottom half of the door where most is covered, or should it be fully covered?
Any recommendation?
Body has been fully repaired where needed with glass fibre and polyester. All that was blocked with 40 and 80 grid first to have panels as straight as possible.
I now am putting on polyester putty to smoothen out the remaining panel imperfections (that done, it will be sprayed with build-up primer).
Because this is all a first to me, I am not sure how deep to sand off the putty. Should it be 'patchy', meaning that panel comes through as much as possible. Or is it better to have a thin layer of putty staying on about everywhere. The latter seems easier to come to good results, although I have seen many bodies already where there are cracks in the paint, mostly from putty coming loose....
So should it be like the back fender which is very patchy, or like the bottom half of the door where most is covered, or should it be fully covered?
Any recommendation?
09-02-2014, 05:03 PM
#2
Race Director
When you 'skim-coat' a body panel with a filler to fill in low spots. I prefer to use Evercoat's Vette Panel Adhesive....but I guess that may need to change if you can not get it where you live.
After sanding the panel, It may come out just like what you have. Some exposed original body and then some of your filler. SO...THAT IS OK. The idea is to get the low spots up to the high spots and get them to level out. SO..it is NOT required that the entire panel is covered. The main thing is that when you feel the panel...you can not tell where the transitions are.
The next 'trick' is making sure that you apply enough of your high build primer. I prefer to use a gelcoat...and that also depends if you can get it and want to invest in a paint gun that can shoot the gelcoat.
I have a very good sense of feel. And doing it as long as I have done it. I know what I can leave and what I need to fill when i go and gelcoat the car. I still want to make sure the body is about as perfect as possible...but I do not loose sleep over it and waste a bunch if time filling in really small low spots that I know will fill in with the gelcoat. BUT...that is also because I know where these low spots are and apply more gelcoat when spraying it to aid in giving these low spots more gelcoat....in your case..it would be the primer.
Also....if it were me....and not knowing what you are using for a primer.....I would apply 3 really good coats.....then block it out using the 3M dry guide coat material...and then more than likely spray the primer on again for another 2 coats and then do my final blocking and sticking to get it ready for sealer and paint.
Each car is different and it all depends on how it block after the first primer application.
The only thing I see is that on the quarter panel that you showed in a photo....the bonding seam has been left alone...and can come back on you due to not being under-cut and filled in with a really hard filler like the Vette Panel Adhesive.
Also...I do not like doing any body work with the body off the ground. I always do the body work when the car is sitting on all four tires. This is especially true if you are setting gaps at the doors. Just my opinion of that.
DISCLAIMER: I do raise a body and do work on it when it is off the ground...BUT...I use jack stands UNDER the four points on the suspension...so the body can settle as if it were on the tires...and I have the tires/wheels off so I can use my jack stands at the wheel mounting points. Putting jack stand under the frame in the WRONG spots can change how the body sits....and I have had to repair Corvettes that were left on a lift for a weekend and when the owner went to shut the door...the door WOULD NOT CLOSE....due to the frame got 'tweaked'...this mainly occurs on convertibles.
DUB
After sanding the panel, It may come out just like what you have. Some exposed original body and then some of your filler. SO...THAT IS OK. The idea is to get the low spots up to the high spots and get them to level out. SO..it is NOT required that the entire panel is covered. The main thing is that when you feel the panel...you can not tell where the transitions are.
The next 'trick' is making sure that you apply enough of your high build primer. I prefer to use a gelcoat...and that also depends if you can get it and want to invest in a paint gun that can shoot the gelcoat.
I have a very good sense of feel. And doing it as long as I have done it. I know what I can leave and what I need to fill when i go and gelcoat the car. I still want to make sure the body is about as perfect as possible...but I do not loose sleep over it and waste a bunch if time filling in really small low spots that I know will fill in with the gelcoat. BUT...that is also because I know where these low spots are and apply more gelcoat when spraying it to aid in giving these low spots more gelcoat....in your case..it would be the primer.
Also....if it were me....and not knowing what you are using for a primer.....I would apply 3 really good coats.....then block it out using the 3M dry guide coat material...and then more than likely spray the primer on again for another 2 coats and then do my final blocking and sticking to get it ready for sealer and paint.
Each car is different and it all depends on how it block after the first primer application.
The only thing I see is that on the quarter panel that you showed in a photo....the bonding seam has been left alone...and can come back on you due to not being under-cut and filled in with a really hard filler like the Vette Panel Adhesive.
Also...I do not like doing any body work with the body off the ground. I always do the body work when the car is sitting on all four tires. This is especially true if you are setting gaps at the doors. Just my opinion of that.
DISCLAIMER: I do raise a body and do work on it when it is off the ground...BUT...I use jack stands UNDER the four points on the suspension...so the body can settle as if it were on the tires...and I have the tires/wheels off so I can use my jack stands at the wheel mounting points. Putting jack stand under the frame in the WRONG spots can change how the body sits....and I have had to repair Corvettes that were left on a lift for a weekend and when the owner went to shut the door...the door WOULD NOT CLOSE....due to the frame got 'tweaked'...this mainly occurs on convertibles.
DUB
09-02-2014, 07:08 PM
#3
Melting Slicks
Thread Starter
The only thing I see is that on the quarter panel that you showed in a photo....the bonding seam has been left alone...and can come back on you due to not being under-cut and filled in with a really hard filler like the Vette Panel Adhesive.
Also...I do not like doing any body work with the body off the ground. I always do the body work when the car is sitting on all four tires. This is especially true if you are setting gaps at the doors. Just my opinion of that.
DUB
Also...I do not like doing any body work with the body off the ground. I always do the body work when the car is sitting on all four tires. This is especially true if you are setting gaps at the doors. Just my opinion of that.
DUB
All bonding seams were actually 'valley-ed' out 4 inches wide and covered with several layers of fibreglass matt and then sanded back to shape.
All the body work was done with the car on the floor, but once in a while I lift the whole thing up mainly to block the bottom side of the panels. It may not be perfect for the car's body, but it is for my ageing body
09-02-2014, 07:11 PM
#4
Race Director
Thanks Dub for the extensive answer, really helps, will read it in more detail tomorrow (it's now 1am when I read this in Belgium..)
All bonding seams were actually 'valley-ed' out 4 inches wide and covered with several layers of fibreglass matt and then sanded back to shape.
All the body work was done with the car on the floor, but once in a while I lift the whole thing up mainly to block the bottom side of the panels. It may not be perfect for the car's body, but it is for my ageing body
All bonding seams were actually 'valley-ed' out 4 inches wide and covered with several layers of fibreglass matt and then sanded back to shape.
All the body work was done with the car on the floor, but once in a while I lift the whole thing up mainly to block the bottom side of the panels. It may not be perfect for the car's body, but it is for my ageing body
DUB