Topic: Prep and Paint
in Forum: C3 Body
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Lifetime MemberLemon Grove, CA - USA
Joined: 10/17/2007
Posts: 2041
Vette(s): 1982 C3 Collectors Edition 44000 miles, sat in the sun most of its life, My wife purchased it for me for Father's Day in 2007 from her girlfriend that had it for 19 years. It is on the road again. I'm retired but it is now my daily driver.
To make it easier to see my questions I started them with "-"
I'm starting
on stripping and painting my 82CE. I
will go with the original paint but will have the faders painted instead of
purchasing the decals. The shop I'm going to use has done that on three cars and they do a good job.
My car is my daily driver good paint job but not show quality. I have never prepped a car for painting before but I have searched the forum and found a lot but not all of the answers I would like to have. I will let the painter do any final sanding on the car. I can spray primer at my house if I'm careful. I do not want to get caught (the environmental California police must be avoided).
Background on my car's previous paint. It was repainted once. They primed it and painted it silver with black where the CE faders went (faders on the hood and side panels).
On the front bumper I can easily peel the silver paint off of the primer using a razor blade. The primer underneath is slick like glass. It is however almost impossible (using a razor blade) to peel that primer coat off of the original paint or to peel the original paint off. I have heard talk of people removing paint from their C3 using a razor blade and this does not seem like it will work except in certain areas and only to remove the last coat of paint.
- Do people really use a razor blade to remove paint down to the original primer or gel coat?
- What are
the advantages of going down to the original primer or gel coat. It seems to me going down to the original
paint would be satisfactory for the most part or even going down to the primer for the second coat. It seems to be attached real good. If anything I thing they did not sand the primer before the sprayed the final coat.
- Opinions please?
There does not seem to be a lot of flat surfaces on our cars
- So what is the purpose of using large sanding blocks?
I know I need to be careful about making waves when sanding but using a 18" sanding block???
I understand that 240 to 320 grit would be a good place to start prior to priming the car.
- Is that true or can you go coarser to remove the paint.
- I prefer dry sanding at this stage of the game is there a problem with dry sanding in paint preparation?
- What type of primer should I put on when I'm trying to smooth the car.
What I use needs to be compatible with the painter.
|UPDATED|12/2/2014 4:29:38 PM (AZT)|/UPDATED|
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Wow my brother Gilbert you are long winded!
Start looking at youtube, also Eastwood site. I bought a sanding block kit that has multiple sizes.
A lot of times you are sanding sideways so it's not like a 18 inch long stroke, your more perpendicular to the panels. I do not plan to strip mine at all just to block sand it. Then a good sandable filler primer sealer. They make sand paper for the blocks that come in a roll and self stick.
Sounds like you'll have your hands all over those curves.
Take mucho pictures!
Lemon grove........who has it better than you?!
ebo
ebo
Lifetime MemberLemon Grove, CA - USA
Joined: 10/17/2007
Posts: 2041
Vette(s): 1982 C3 Collectors Edition 44000 miles, sat in the sun most of its life, My wife purchased it for me for Father's Day in 2007 from her girlfriend that had it for 19 years. It is on the road again. I'm retired but it is now my daily driver.
I'm a 42 years in the Federal Government working on the Pacific Fleet headquarters staff. I have been trained to be long winded. If it can be said in 10 words you can confuse everyone by saying it in 20 words. Better to confuse people so you can turn around and answer their confusion thus you have a longer more involved job.
If I was not clear on this Ebo, let me know and I can go into it in more detail.
Yes Lemon Grove is great the week is going to be in the mid 80's it has not gotten below 65 so far and the nights are a little cold they are in the low 50's.
But my commute to work used to take 30 to 45 min to go 18 miles mostly freeway. I have to drive 30 minutes to get to good corvette driving areas. Then it is all brown few trees. It take an hour to get to the pine trees.
Thanks for the info on the sanding.
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Overland Park, KS - USA
Joined: 7/9/2003
Posts: 914
Vette(s): 1973 Orange Metallic Coupe (orig owner), L82, 4 spd (WR), PS, (A/C & PW (I installed from wrecked 73)), leather, AM/FM Stereo, ran with '65 FI unit earlier & will again some day.
2023 Accelerate Yellow HTC Stingray
All of my paint aware friends told me to strip the car to the factory primer when I painted mine. I didn't do this and just sanded and sprayed a sealer over the factory paint. About 10 years later, the original factory paint started to come through in the form of spider webbing. I would strongly advise you to remove the factory paint down to factory primer. Most Corvette painters use a DA or soda blasting to strip the car.
The one area I did remove the paint was on the driver's door because it had several coats put on it due to some kind of screw-up at the factory. I used a paint stripper on that and other than being nasty to work with, it took the factory paint down to the factory primer. And that door still looks good.
1973 L-82 4 spd
Lifetime MemberLemon Grove, CA - USA
Joined: 10/17/2007
Posts: 2041
Vette(s): 1982 C3 Collectors Edition 44000 miles, sat in the sun most of its life, My wife purchased it for me for Father's Day in 2007 from her girlfriend that had it for 19 years. It is on the road again. I'm retired but it is now my daily driver.
Thank for the info. If it lasts 10 years that will
most likely take it out past the time I will own it that would put me in my
80's. But it would be nice to have it
last a little longer than that however.
I wrote this first line then did some quick research on Soda Blasting mostly hot rods (metal bodies). Just to let you know if you are thinking about it you need to so some more research.
This is what I found out. The soda leaves a film that inhibits flash rust which a lot of these guys like. It is worth the extra time it takes to clean and prepare the surface for painting. If the film is not completely cleaned off (stress completely) and neutralized your paint will peel. I found two paint shops that use different manufactures paint and they both say it will peel one shop will not even paint a soda blasted car they have had so much trouble with the product. Most that soda blast used a chemical neutralize with or without water. I would want to research more about because of our fiberglass cars.
I wrote this first line then did some quick research on Soda Blasting mostly hot rods (metal bodies). Just to let you know if you are thinking about it you need to so some more research.
This is what I found out. The soda leaves a film that inhibits flash rust which a lot of these guys like. It is worth the extra time it takes to clean and prepare the surface for painting. If the film is not completely cleaned off (stress completely) and neutralized your paint will peel. I found two paint shops that use different manufactures paint and they both say it will peel one shop will not even paint a soda blasted car they have had so much trouble with the product. Most that soda blast used a chemical neutralize with or without water. I would want to research more about because of our fiberglass cars.
What I have found out so far tells me I will not use soda
blasting on fiberglass anyway.
Limited Member
Send PM
Overland Park, KS - USA
Joined: 7/9/2003
Posts: 914
Vette(s): 1973 Orange Metallic Coupe (orig owner), L82, 4 spd (WR), PS, (A/C & PW (I installed from wrecked 73)), leather, AM/FM Stereo, ran with '65 FI unit earlier & will again some day.
2023 Accelerate Yellow HTC Stingray
I agree, I don't like the idea of blasting anything on plastic.
Did you research glass bead blasting?
Did you research glass bead blasting?
1973 L-82 4 spd
Lifetime MemberLemon Grove, CA - USA
Joined: 10/17/2007
Posts: 2041
Vette(s): 1982 C3 Collectors Edition 44000 miles, sat in the sun most of its life, My wife purchased it for me for Father's Day in 2007 from her girlfriend that had it for 19 years. It is on the road again. I'm retired but it is now my daily driver.
Yes I did and fiberglass is only a little harder than the softest material. Which to me means you had better know what you are doing or you will damage the fiberglass. I found a number of shops with good reputations that use bead blasting. Even saw one on TV show. It was noted that in one area he had gone through the gel coat and was going to have to repair that. So even in the hands of a professional you can do damage to a Corvette.
I think I'm going to have to do the sandpaper thing. I only wish I could get some help on what grit to start with I'm fairly sure that high mid 300 for finishing before painting is correct. The car only has a second coat of paint over the factory. It was primed then painted. So I have to go down at least down to that layer. There is a couple of spider areas and one where a rivet bubbled the glass so I have to drill that out and fix it.
I think I'm going to have to do the sandpaper thing. I only wish I could get some help on what grit to start with I'm fairly sure that high mid 300 for finishing before painting is correct. The car only has a second coat of paint over the factory. It was primed then painted. So I have to go down at least down to that layer. There is a couple of spider areas and one where a rivet bubbled the glass so I have to drill that out and fix it.
great questions. I look forward to many replies as I have all the same queries as you do, I've decided on the board sanders but also wonder what sandpaper you should use and what order to use it in. I will not be doing the final prep before painting, that's where I draw the line, but I want to have as much done on it as I can before it goes to a painter.
A grain of salt with my answers here, I'm a former car painter, do it as a hobby on my own projects now so I'm not as up to date on all the products and techniques out today. But, some things remain the same.
First, stripping the paint. Fiberglass is different rules than metal bodied cars. NO chemical strippers. These will penetrate further than just the paint, into the gel coat and the fiberglass itself and soften it. That causes two major problems. The first is your scrapper, putty knife or whatever will dig into the glass leaving nicks and cuts which then take serious body work to fill. The second is they weaken the glass and can ruin it to the point of needing to replace body panels. NO blasting. Same issues as chemicals, they can go through the gel coat and into the glass and damage it.
As to stripping completely... not always better to remove everything like it is on metal. Gel coat and primer act as body filler on fiberglass cars. Paint CAN act as a filler if it has good adhesion (not peeling) and is "done". (this means that new paint and solvents won't lift or crack it as it reacts. This one is really hard to tell, if in question wipe some lacquer thinner over it and see what it does.) It is usually better to remove all old paint but leave all gel coat and factory primer as you can
So you are left with sanding to strip. And this is the crux of the problem. To sand efficiently you need to use a heavier grit, ie 36-80. BUT, if you are not experienced you can do the same damage as chemicals or blasting, as sandpaper will cut through paint, gel coal, and glass in a big hurry. There is also a danger in using lighter grit, in that one tends to "dig" at imperfections and not remove the surrounding material as needed, giving you"bullseyes" in your surface which will show when the paint is applied. Use a power tool, like a DA. (Dual Action sander).
It is experience to know what can't be sanded out and what must be filled. There are some excellent primer fillers that will help with this. They can be used with "guide coats" which lets you block sand out smoothly. A guide coat is a sprinkling of paint over your primer coat. Say you spray gray primer, several coats, flashing properly in between, then after it drys take a can of black rattle can paint and just dust a sprinkling of black over that primer, very lightly. Then when you block sand, you sill see the high and low spots as the guide coat sands off high spots and remains in low spots, the bullseyes, and other imperfections will show as you block out. Do your first blocking out with 180-220 grit. Use the longest bock you can use on the body panels, and one can tape sanding paper to large round hard hose or cardboard rolls for sanding the inside curves. The keys here are when you are blocking, don't dig a hole, you must block evenly all around the imperfection to evenly remove material around the bad spot so it all comes out to a "flat" surface. And second, when you sand through your primer, STOP SANDING. The old adage, if your're digging a hole, stop digging. You are going to need to apply more primer to fill it out further. It may take several primer stages before you can get it to block out evenly everywhere. The main thing to try and do is fill in low spots with heavier primer coats, lightly primer high spots. You are using primer like body putty
After you have blocked out with 220-240 grit, a couple more even coats of primer overall and turn it over to the painter to finish sand.
HTH
greybull said:
A grain of salt with my answers here, I'm a former car painter, do it as a hobby on my own projects now so I'm not as up to date on all the products and techniques out today. But, some things remain the same.
this is exactly the kind of info a person needs. great post First, stripping the paint. Fiberglass is different rules than metal bodied cars. NO chemical strippers. These will penetrate further than just the paint, into the gel coat and the fiberglass itself and soften it. That causes two major problems. The first is your scrapper, putty knife or whatever will dig into the glass leaving nicks and cuts which then take serious body work to fill. The second is they weaken the glass and can ruin it to the point of needing to replace body panels. NO blasting. Same issues as chemicals, they can go through the gel coat and into the glass and damage it.
As to stripping completely... not always better to remove everything like it is on metal. Gel coat and primer act as body filler on fiberglass cars. Paint CAN act as a filler if it has good adhesion (not peeling) and is "done". (this means that new paint and solvents won't lift or crack it as it reacts. This one is really hard to tell, if in question wipe some lacquer thinner over it and see what it does.) It is usually better to remove all old paint but leave all gel coat and factory primer as you can
So you are left with sanding to strip. And this is the crux of the problem. To sand efficiently you need to use a heavier grit, ie 36-80. BUT, if you are not experienced you can do the same damage as chemicals or blasting, as sandpaper will cut through paint, gel coal, and glass in a big hurry. There is also a danger in using lighter grit, in that one tends to "dig" at imperfections and not remove the surrounding material as needed, giving you"bullseyes" in your surface which will show when the paint is applied. Use a power tool, like a DA. (Dual Action sander).
It is experience to know what can't be sanded out and what must be filled. There are some excellent primer fillers that will help with this. They can be used with "guide coats" which lets you block sand out smoothly. A guide coat is a sprinkling of paint over your primer coat. Say you spray gray primer, several coats, flashing properly in between, then after it drys take a can of black rattle can paint and just dust a sprinkling of black over that primer, very lightly. Then when you block sand, you sill see the high and low spots as the guide coat sands off high spots and remains in low spots, the bullseyes, and other imperfections will show as you block out. Do your first blocking out with 180-220 grit. Use the longest bock you can use on the body panels, and one can tape sanding paper to large round hard hose or cardboard rolls for sanding the inside curves. The keys here are when you are blocking, don't dig a hole, you must block evenly all around the imperfection to evenly remove material around the bad spot so it all comes out to a "flat" surface. And second, when you sand through your primer, STOP SANDING. The old adage, if your're digging a hole, stop digging. You are going to need to apply more primer to fill it out further. It may take several primer stages before you can get it to block out evenly everywhere. The main thing to try and do is fill in low spots with heavier primer coats, lightly primer high spots. You are using primer like body putty
After you have blocked out with 220-240 grit, a couple more even coats of primer overall and turn it over to the painter to finish sand.
HTH
in Forum: C3 Body
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