How many times should a car be block sanded

[keith4909]

Not looking for a show car finish but really straight with no waves/peel/ or any other major flaws. Modern day oem quality maybe better. How many times should a car be block sanded after body work? Pics with details will be great.

1967 Gto

[raustinss]

Not the easiest to answer....depends on previous body condition, body work,products. Etc etc etc...the simplest answer, as many as needed

[kevs79]

I blocked mine multiple times..... I lost count. It was well worth it though. Mine is black and looks nice and smooth with no waves. Use a guide coat and you will know when you are done. I recommend using something like Slick Sand to block as it fills and sands awesome!

[GTOtzel]

I second the use of guide coat. That is the only way to really know how plat it is and see the tiny imperfections that could be missed. Another product that i had a lot of success with is Z-chrome, like Slick sand. It is a sprayable polyester primer that is great for priming the overall surface after bodywork. Block it using guide coat again before final prime starting with 180 or 220, going to 320 grit or even up to 400 dry. Final prime with urethane 2K primer and wet block to 600 to prepare for base coat. FYI, guide coat works great for wet sanding too.
Make sure you have some descent sanding blocks. I like the Durablocks. Just to go out further in the job, after the car is painted and cleared, I like to start wet sanding clear by blocking with 1000 grit and then move to 1500 up to 3000 wet on a DA, before buffing steps. Use plenty of water and squeegie off to see your progress.

[kevs79]

Search YouTube for Kevin Tetz. He has some great videos on body work, block sanding, painting and sand/buff.

[CampbellshotrodsAZ]

There is no one answer, but if I have to say anything, there is no such thing as too many times. It's the most important part of paint and body, you can lay "okay" paint over a perfect body and it'll look better than smooth as glass paint on a wavy car. But I'd figure if it's a virgin rust free car with hardly any filler or panel repair, two blockings are good. The more bodywork you do, the more blocking you should do, and just as important... the car should sit even longer. The best car I ever did was a 72 Buick Lesabre that wasn't ever really on the front burner. I'd do bodywork, prime it, then it say for a few months. Blocked, primed, sat. That car was arrow straight, and never shrunk down. On some of my more accelerated builds, I haven't been as fortunate regrettably. Bodywork will shrink down. It's better to let it shrink, then sand it, versus sanding it flat, then having it shrink down after the car is done.

On a car with massive quarters such as your 67 GTO, I wouldn't block them any less than 3 times. The fenders/doors you can do less on, but the quarters are super important and need to be 100%.

[Rucumn]

Start with making sure all the panels are on the car and aligned perfectly.
Assuming you are using a high build primer....polyesters are great and I have used slicksand with little to no shrinkage.
Use guide coat as others have said.
Use a long block on longer surfaces. The long blocks usually bend to the shape of the panel. I use a 21" block.
As others have said, you can start with 180grit or 220 grit.
Block across panel gaps (again assuming you aligned the panels.
Another trick is to wet the panel with Wax & Grease remover and place a light at the far end of the car while looking down the other end of the car to spot waves and dents. You need to spot before the panel dries.

Also, if you are in this stage of the painting, why wouldn't you go for show quality? It is all in the prep work. Of course the wet sanding and buffing of the final finish could be outsourced to a professional for that perfect final finish.

[vintageracer]

Till your hands bleed and then one more time!

As stated above Kevin Tetz's videos are very informative and great investment for paint and bodywork knowledge!

[snappytravis]

I finish my filler with 180 then prime with 2k primer, Then block and reprime at least once if not twice, Depends on the color as well. If its a dark color you better block it one more time. I like to use a pressurized spray can with wax and grease remover in it to check the bodywork. Dry the panel off and get it nice and clean then spray a coat of wax and grease remover over it and you can see all the imperfections. I agree with the other posts on the durablocks. You can get some that are made for the 3m hookit paper for 180.

[snappytravis]

There is no one answer, but if I have to say anything, there is no such thing as too many times. It's the most important part of paint and body, you can lay "okay" paint over a perfect body and it'll look better than smooth as glass paint on a wavy car. But I'd figure if it's a virgin rust free car with hardly any filler or panel repair, two blockings are good. The more bodywork you do, the more blocking you should do, and just as important... the car should sit even longer. The best car I ever did was a 72 Buick Lesabre that wasn't ever really on the front burner. I'd do bodywork, prime it, then it say for a few months. Blocked, primed, sat. That car was arrow straight, and never shrunk down. On some of my more accelerated builds, I haven't been as fortunate regrettably. Bodywork will shrink down. It's better to let it shrink, then sand it, versus sanding it flat, then having it shrink down after the car is done.

On a car with massive quarters such as your 67 GTO, I wouldn't block them any less than 3 times. The fenders/doors you can do less on, but the quarters are super important and need to be 100%.

Those are some long qtr panels,, When you sand them first it makes all the other panels go fast!

[CampbellshotrodsAZ]

Those are some long qtr panels,, When you sand them first it makes all the other panels go fast!

I don't think there are many longer, except for maybe a 69 Roadrunner and the equivalents! But the GTO's are always on my mind. My dad has a pro-street 67 GTO still in primer, and I'll be buying a 66 GTO from him that is a little further off... might even be a candidate for the new quarters I hear AMD is developing. Definitely doesn't help the originals with the hack job on the tops of the previous owner's Home Depot Daytona wing!

[jlcustomz]

I agree there is no answer other than till it's done. To be brutally honest & not being an a-hole here, asking such a question points out You have little experience & need to research & practice all techniques involved in bodywork & paint. The book titled (how to paint your showcar) has some helpful info Above the average info.
Only way to learn is by doing. At the end of the day, remember that it's only paint & can always be redone.
I also agree with the use of any good poly primer surface. Evercoat g-2 or slicksand or the Klaussin Z chrome that Kevin Tetz uses are all comparable. Spray over an initial epoxy or 2-k primer with a 2.2 or larger tip. It sprays rough & dull & sands smooth, which makes it act as it's own guidecoat. Sand off what you don't need. If any fairly low areas show up, may want to use a little evercoat metal glaze filler & sand before your next respray OR, spray a little extra poly filler in those low areas. Respray with 2-k primer to reseal before paint.

Don't have any pics with details , but one of the build threads here by sponsor Auto Rod Technologies(project build threads) has some good in process pics of a proper deailed prep process.

If you want a picture for inspiration, the hood pictured was totally shattered after upper skin came off on the highway, then off 1 customized. Probably 2 block sandings with evercoat g-2 after basic bodywork . The front end here was also painted around midnight a few nights in a row under a carport in ideal weather. The unfinished under hood cover is what black evercoat g-2 looks like after sanding.
https://static1.pt-content.com/images/pt/2014/10/DSC_0082_zpsc63317a4-1.jpg (http://s1094.photobucket.com/user/jlcustomz1/media/DSC_0082_zpsc63317a4.jpg.html)
Never say can't.

[keith4909]

116771116772116773116774Im not painting the car or doing anything with the body. Just paying a lot. I paid my body shop to do 2 blocks after initial metal and filler work. Only using premium material. Just was curious if paying for a third will up the quality substantially over blocking twice. The car is a driver. Not looking for a show finish just a little better than modern day oem. I don't want to cry if the car is scratched.

Evercoat rage gold
Ncp280 3 gallons
Das3027 sealer
Deltron dbc base
Dc4010 clear
Media blasting

Over 3500.00 just in material. I'm in Cali and I guess because the income is higher they feel to mark up everything.

Here are some pics and the color the car will be painted

[dirty rick]

A paint job is mostly prep with just a pinch of painter.

So the more spent on proper prep pays off in the end.

Have them wet it with some wax & Grease remover and see if you like it?

[CampbellshotrodsAZ]

Making some good progress, their work looks good from what I can see. And brace yourself. 67 GTO in that color, get ready for the people asking, or saying it's the XXX car!

[keith4909]

If they still remember the xxx movie. That car was purple. Purple was an option too but didn't see a color that wowed me. I saw this color on a 2014 Avalon and it looked great. Looks black/darrrrk red in low light but pops in the sun. The first coat of primer just went on and they are going to let it shrink for a week or two before they block sand it. I think they have 100-150 hours in it. It had few rust spots that needed to be cut out and repaired. Cars been with them for almost a year and work just started a month ago or so. I'm just happy the ball is rolling. I won't rush them so long as everything is on schedule. I don't want them to cut any corners cut. Thank you for the help guys. Can't beat car guys.

[keith4909]

My grandma had a 65 tri power goat and my dad had a judge. It's in my blood. I bought this car when I was 19 and haven't let it out of my sight for 12 years. All my friends had muscle cars in high school so naturally I wanted one. Sadly they let theirs go.

[CampbellshotrodsAZ]

Cool story, sounds all too familiar. My dad had a blue 65 GTO 4 speed, and a Marina Turquoise 66 GTO as I was growing up. Sold them both. A few years later he got a 66 GTO 4 speed basket case, and a roller 67 GTO pro-street. It took me till age 29, but I finally got him to agree to sell me the 66 soon, after I get other projects done at least. He's always wanted a tubbed car, so he'll be happy with the 67, so now we'll both have our favorite GTO's!

[keith4909]

I'm biased but I think the 66/67 Gto is by far the most beautiful muscle car ever designed.

[CampbellshotrodsAZ]

I can definitely agree to that. For every car I do I try and find ways to tweak the body, make things better, etc. Except with the 66/67 GTO... there's nothing I'd do differently. I think the styling is perfect, inside and out! That's why this car will be the exception to my builds which are primarily pro-touring from now on. I'm going to stay pretty much stock, hunt down an original tri-power, stick with a 389 and just run Cragars. I may change my mind later on, but I kind of want a car that's like stepping back in time... less than ideal handling and all, haha.

[keith4909]

I agree. Everything that I'm doing can be reversed if I ever want it back to stock. I obky changed a few things

12 bolt rear
18" wheels foose black legend
Wilwood disc all around
Kept period correct motor but punched it out to 474ci roller stock ported heads and other bolt on goodies
The biggest change was the color. The original color was montego cream. I hated it but you can't always choose the color when buying a used muscle car. I feel my color choice with add to the beauty of this car. I also think it's a color that will be acceptable for many years. I may do the suspension next. I only see positives with that upgrade. Better handling, braking and tire wear. Can't go wrong

[jlcustomz]

Best I can see from pics, does look like good work the shop is doing. Every person who does bodywork can have varying opinions on what products, methods, etc. The g-2 primer surface I mentioned is far less shrinking, but the fact that they want their primer to dry for a week before sanding does show they have good experience with getting a quality job from traditional products that they know. At the end of the day, that matters as much as anything.

Can't argue with your opinion on bodystyle or color choice either. It will get related to the XXX car, but for good reasons:::: Movies tend to pick nice body style cars with nice colors to be the star of the show.

PS, always good to give a better explanation of what you're asking. We're all trying to give you diy pointers when a shop is doing it.

[keith4909]

Thank you guys. My bad. Sometimes I leave out important details.