Question & advice requested regarding block sanding

[MAKZ06]

This is my first paint job and I’m not sure how far to take the sanding so I’ve attached several pics of the bed side I’m working on today. I was thinking/hoping that this may be my last round of block sanding before a final coat of epoxy in the next couple weeks, and then a final sanding and seal coat before the color in a few months when I can get back. I’ve only used Epoxy, no 2k primer, and some thin filler as needed around areas where I welded patches.
Keep in mind I want this to look as good as possible but it is my first job, will be done without a proper paint booth, and will be in a Ford Blue, not Black. I want it to look nice and flat, without scratches or noticeable waves, and at least as good as it did new. Obviously these old trucks (72 F100) weren’t exactly straight with great panel alignment from the factory…. For this project I’m not going for that perfect alignment between the panels that were spot welded together, etc.
All sanding you see in the pics was done so far with 16” blocks.
Do I need to continue blocking and have a consistent grey color over the entire surface? I have the ever so slight low spots that remain where you can still see some black, although you can see some scratches do cross-cross through the black. Additional sanding would eventually get those spots to the consistent grey, but I am trying not to break through again to bare metal…. Do these spots need a layer of glaze or is it flat enough now that my final color coat will look nice and flat in the sun?
I feel like I keep chasing these spots around as I’ve had them in previous rounds of sanding, hit with more epoxy, some glaze, more epoxy and then seem to find more in different areas…. (All rookie mistakes/issues I assume.). Anyway, I’m trying to get some input on where I need to be with this. A friend is already telling me that it was ready for color long ago, and I’m such a perfectionist that I’ll never be happy. I would love to do work like @theastronaut but I’m not sure I have the years left for that, and for this one I’ll be happy to get back to a factory look…
Guess I should add that I know if I drop down to a 12” block that I would quickly level out those spots in question… Just wasn’t sure that’s what I I should be doing at this stage or if I should be going for flatter with the longer block.
thanks

 

[texasking]

Use the material you have on it to try and get those spots out. Keep blocking until there is no guide coat or you hit metal. Then coat again. They will show, as they are still low.

 

[MAKZ06]

Use the material you have on it to try and get those spots out. Keep blocking until there is no guide coat or you hit metal. Then coat again. They will show, as they are still low.

Would you continue blocking with a 16” block in those areas? Or would you go to a 12” block that would get those lows out without breaking through to bare metal? I just don‘t know what the standard practice is when blocking and what lengths will still achieve a good final result…

 

['68 Coronet R/T]

Make sure you change the sandpaper as soon as it stops cutting. You don't want to press harder on the block or you will be chasing those spots all over.
Pressing hard on the block can cause the metal to flex slightly defeating your efforts to get things level and straight.

 

[MAKZ06]

Make sure you change the sandpaper as soon as it stops cutting. You don't want to press harder on the block or you will be chasing those spots all over.
Pressing hard on the block can cause the metal to flex slightly defeating your efforts to get things level and straight.

Yeah, I’ve been careful about using light pressure and constantly changing paper. I’m just not sure at this stage what length blocks I should be using to get flat without being able to see waves, etc. I mean is 12” good to flatten out and blend in this remaining low areas in the pics or should I be sticking with 16” or longer?

 

[dhutton01]

Yeah, I’ve been careful about using light pressure and constantly changing paper. I’m just not sure at this stage what length blocks I should be using to get flat without being able to see waves, etc. I mean is 12” good to flatten out and blend in this remaining low areas in the pics or should I be sticking with 16” or longer?

16” or longer to make it straight imho.

Don

 

[texasking]

You don't want to blend in the low areas. All that would do is make a larger low area. The longer the flat area, the longer the block needs to be to get it all one level surface, as a general rule.

 

[chevman]

Don't think of guide coat as a way to make sure all surfaces are sanded, think of it as a way to make sure all surfaces are level. Sand the panel not the low areas.

 

[MP&C]

For a long panel like that, I'd use the longest block you have.. minimal pressure, like this:

 

[JimKueneman]

I have only painted 4 cars in my life with the help from these guys here. They have come out far beyond my expectation but what I have learned is getting it flat for some who don't do this for a living (hand raised) will not be a linear N step process. I have needed to go back a number of times to shoot on a couple more coats of epoxy to lock down what I have and then restart the process because I thought I was close enough for just a final blocking and the panel had other plans.

 

[MAKZ06]

yeah, this has definitely been a bunch of rounds of primer, sanding, primer, sanding, filler, primer, sanding, primer sanding…. Every time I think this has to be the last round of block sanding I turn up more lows. What’s frustrating is the lows arent in the same spots…. I’m being careful to keep the paper changed and not push hard with the block.
I guess with this post I was wondering if those low spots will fill with a couple coats of epoxy, or if I’m into a light skim of filler. I’ve already blocked out most of those slight lows I was asking about above but broke through to bare metal on some surrounding edges
i know if I use a shorter 12” block those lows don’t show up. Seems like I had read on here before that a longer block can sometimes make it tougher to get as flat… maybe my cross-hatch technique has problems. I think these last lows are maybe because I had used a 24” AFS block before the last coats of epoxy. It has a slight flex. I used that on the roof today and it came out without any lows, but the roof isn’t flat like the bed sides.
oh well, I’ll eventually get it. This first one is just a lengthy frustrating learning process. Which lengths to use for the large flat panels, which for the large slightly curved, which for the sharper curves, round edges, etc, etc.

I have only painted 4 cars in my life with the help from these guys here. They have come out far beyond my expectation but what I have learned is getting it flat for some who don't do this for a living (hand raised) will not be a linear N step process. I have needed to go back a number of times to shoot on a couple more coats of epoxy to lock down what I have and then restart the process because I thought I was close enough for just a final blocking and the panel had other plans.

 

[JimKueneman]

yeah, this has definitely been a bunch of rounds of primer, sanding, primer, sanding, filler, primer, sanding, primer sanding…. Every time I think this has to be the last round of block sanding I turn up more lows. What’s frustrating is the lows arent in the same spots…. I’m being careful to keep the paper changed and not push hard with the block.
I guess with this post I was wondering if those low spots will fill with a couple coats of epoxy, or if I’m into a light skim of filler. I’ve already blocked out most of those slight lows I was asking about above but broke through to bare metal on some surrounding edges
i know if I use a shorter 12” block those lows don’t show up. Seems like I had read on here before that a longer block can sometimes make it tougher to get as flat… maybe my cross-hatch technique has problems. I think these last lows are maybe because I had used a 24” AFS block before the last coats of epoxy. It has a slight flex. I used that on the roof today and it came out without any lows, but the roof isn’t flat like the bed sides.
oh well, I’ll eventually get it. This first one is just a lengthy frustrating learning process. Which lengths to use for the large flat panels, which for the large slightly curved, which for the sharper curves, round edges, etc, etc.

If you can see it like that and feel it you won't get it with just epoxy... are you using Icing or Dolphin Glaze at this point? Just a thin skim of that and a light touch of blocking. Glaze sands 10x easier than filler and it is made to go on top of high build or poly not just epoxy like regular filler.

 

[MAKZ06]

If you can see it like that and feel it you won't get it with just epoxy... are you using Icing or Dolphin Glaze at this point? Just a thin skim of that and a light touch of blocking. Glaze sands 10x easier than filler and it is made to go on top of high build or poly not just epoxy like regular filler.

I’ll be using glaze at this stage with the lows that are showing up. Was leaning that way but wasn‘t sure until you said epoxy wouldn’t get it. Thanks