Chasing high and low spots?

[Dpate]

Do any of you folks actually chase high and low spots on your bodies? If so what are you methods of correcting the issue? Just curious if anyone ever or even consider taking it that far.  

[Plowboy]

I use a guide coat. It's just a light coat of a different color primer. You could could also do a mist coat of the color you're going to use. Then just sand lightly and any and all low spots will show. Here’s an example. A light coat of white over gray.

After sanding.

Edited July 27, 2022 by Plowboy

[Ace-Garageguy]

1 hour ago, Dpate said:

Do any of you folks actually chase high and low spots on your bodies? If so what are you methods of correcting the issue? Just curious if anyone ever or even consider taking it that far.  

Block sanding. Pretty common among more skilled builders like Plowboy.

[89AKurt]

Plowboy made a very good post.   I would like to know what type of light do you prefer.  Might be my eyes, I need bright lights, the fluorescent bulb lights don't seem to cut it.  Sunshine seems to be the best, can see high/low spots the best.

[Dpate]

34 minutes ago, 89AKurt said:

Plowboy made a very good post.   I would like to know what type of light do you prefer.  Might be my eyes, I need bright lights, the fluorescent bulb lights don't seem to cut it.  Sunshine seems to be the best, can see high/low spots the best.

I use a D50 5000K T5 95CRI for color matching in my paintbooth from waveform lighting.  Also have something similar on my work bench bout like the noon sun.

[Fat Brian]

I use wide sanding sticks to block sand the body. There always seem to be ridges on either side of the door and trunk lines and sink marks where there are attachment points on the inside of the body. 

[Bainford]

11 hours ago, Ace-Garageguy said:

Block sanding.

Yup!

[Mike 1017]

I use the Metallizer Aluminum Plate for a primer. Block sanding is the way to go. If I see any metallizer at HL I aways pick up a couple of cans. Last count I have 11.

Mike

[Bainford]

8 hours ago, Fat Brian said:

There always seem to be ridges on either side of the door and trunk lines and... 

Thanks for mentioning that, Brian. Surprisingly, I rarely see this point mentioned during discussions on body prep. Years ago when I first started polishing paint, I would often burn through at door shut-lines and panel gaps. I eventually came to realise that there is a proud edge at panel gaps and shut-lines, and that's when I started block sanding the bodies during the prep stage, paying particular attention to all shut-lines.

It may also be worth mentioning that, even when these edges are properly knocked down with block sanding, sometimes the paint itself can 'stand up' and form a raised edge at these shut-lines, that will require block sanding during the colour sanding process. This is especially true if you apply paint fairly heavily or use spray bombs.

FWIW, my sanding block is a vinyl drafting eraser with fine sand paper wrapped around the end, always used wet.

[Plowboy]

10 hours ago, 89AKurt said:

Plowboy made a very good post.   I would like to know what type of light do you prefer.  Might be my eyes, I need bright lights, the fluorescent bulb lights don't seem to cut it.  Sunshine seems to be the best, can see high/low spots the best.

So do I. I prefer sunlight. But, a guide coat makes it so that low spots will immediately show under any light.

[Plowboy]

59 minutes ago, Bainford said:

Thanks for mentioning that, Brian. Surprisingly, I rarely see this point mentioned during discussions on body prep. Years ago when I first started polishing paint, I would often burn through at door shut-lines and panel gaps. I eventually came to realise that there is a proud edge at panel gaps and shut-lines, and that's when I started block sanding the bodies during the prep stage, paying particular attention to all shut-lines.

It may also be worth mentioning that, even when these edges are properly knocked down with block sanding, sometimes the paint itself can 'stand up' and form a raised edge at these shut-lines, that will require block sanding during the colour sanding process. This is especially true if you apply paint fairly heavily or use spray bombs.

FWIW, my sanding block is a vinyl drafting eraser with fine sand paper wrapped around the end, always used wet.

This is why I always sand the entire body before primer (also to ensure that the primer adheres well.). All high spots will be removed and any shiney spots left afterwards show the low spots that need putty. 

[Plowboy]

Here's another method. It's just two different colors of Tamiya putty.

[Exotics_Builder]

28 minutes ago, Plowboy said:

So do I. I prefer sunlight. But, a guide coat makes it so that low spots will immediately show under any light.

Ditto on the guide coat approach.  

[jaymcminn]

Oh yeah, I block sand. Every single build. Before block sanding I'll always scribe panel lines deeper in case they disappear or go too shallow during the sanding process. Styrene, especially on older molds, will tend to raise around panel lines and the edges of panels and dip above details molded on the underside of a panel. Often I'll attach removable panels with Micro Kristal Klear so I can get the transition as smooth as possible. Some kits are worse than others. My latest, a Monogram Mercedes 540k from 1979, took about 8 hours of body prep between scribing, cleaning up trim and block sanding before I even got to primer and guide coats. On the 1/12 Porsche 934, I mocked up the body including the opening doors that shut with neodymium magnets before block sanding to make sure that they fit flush along the entire profile of the door. 

[stinkybritches]

12 hours ago, Fat Brian said:

I use wide sanding sticks to block sand the body. There always seem to be ridges on either side of the door and trunk lines and sink marks where there are attachment points on the inside of the body. 

Which sanding sticks do you use?

[Ace-Garageguy]

"High and low spots" you say?

The old Revell Challenger I is nothing but high and low spots, with awful panel fit (it would surely be considered "junk" by some builders); shown below as-was, with body panels jigged together while correcting fit:

Flattened with 80-grit on a wood block; brutal but effective:

Later in the blocking process:

Final primer:

Done:

Build here:

 

Edited July 27, 2022 by Ace-Garageguy
CLARITY

[Fat Brian]

3 hours ago, stinkybritches said:

Which sanding sticks do you use?

I like the Tropical Shine brand from Sally beauty supply. The grit seems to stick better to these and they come in a few grits and at least two widths. I'm sure you can find them on Amazon, along with some sanding twigs for tight spots.

[Dpate]

wow didn't think this thread would blow up.  Thanks for all the good info guys.

[stinkybritches]

2 hours ago, Fat Brian said:

I like the Tropical Shine brand from Sally beauty supply. The grit seems to stick better to these and they come in a few grits and at least two widths. I'm sure you can find them on Amazon, along with some sanding twigs for tight spots.

Thank you for the information.