The Other Wet Sanding Tips

There are many wet sanding tips that are very important, but either not talked about often, or rarely executed (usually the latter).  Below are some of these very important tips.  This isn't meant to be an all encompassing wet sanding blog post, just some less than common talked about tips that matter a lot.  These are the things that  makes the difference.

This is for the people whose goal is to make the paint as flat and perfect as possible, and usually in the high end hot rod or restoration world.  

Lighting

• LIGHTING
• LIGHTING
• LIGHTING
• Between wet sanding steps, Mirka or Indasa dry guide coat needs to be used to show if any sand scratches have been missed. (it doesn't wash off) See the bottom of the page for an image.  
  ➡️➡️ The thing is, you have to be able to see that guide coat.  Being able to see it means it needs to be applied thoroughly to a clean panel, and it means there needs to be plenty of light on it.  
  Typically I use a 2,500-3,000 lumen LED spot light.   I promise you if you try to use the guide coat and a light like this, you'll be surprised what you see (and previously couldn't see)
• The above is SO CRUCIAL.  It will very quickly inform you what grits you can get away with and how much work it is for each step.  How are you supposed to know if you can't see what's actually being sanded.
  
• The wet sanding steps are 600, 1000, 1500, 2000, 2500.   There are many other posts on True Blox social media or on this site diving deeper into these steps.
• Before I start wet sanding with 600 grit, I will look over the panel or whatever is being sanding and find any areas that are a little heavier.  This might be edges, small runs, or anything else.  I will dry block these areas with 400 grit and get them 90% flat.   For this, I use lighting that is like a fluorescent light tube, but LED.  This type of lighting excels at showing the texture in the paint.

Sanding Techniquies

• For the most part, block sand with the direction you'd sight down the vehicle at about 30º angles.
• Sanding strokes don't need to be too big, maybe 7-10"
• Don't push hard. Just hold the block against the paint and use just enough pressure to sand it.
• You might be able to feel more choppiness in one direction compared to the other.  Pay attention to that, and work on blocking that out.  This means you might be sanding in one direction more than the other direction.
• DO NOT SAND IN A STRAIGHT LINE!!!  Especially don't sand in a straight line with the block in a straight line, it will cut groves in the paint.  
  
• Mildly concave areas that are very difficult to get the clear cut completely flat, you can block at almost a straight line with the block held at a slight angle.  This can help cut out the fattiness in the clear. Only do this in areas you're struggling though.
• Never sand in a straight line against a body line (think 32 ford belt line) or with a panel edge.  You will sand grooves in it.  
  Here's a video ➡️ https://youtube.com/shorts/GYbF50Rvaog?si=Nxlhpn4r2vF0FcCs
• Notice in the video below, the sanding pattern

Objectives

• The objective of the first sanding step, 600 grit is to cut the clear flat.  Not almost flat, completely flat.  No orange peel, no urethane wave left over, no choppiness, no edges that are still a little heavy.  Dead flat.
• The objective of 1,000 grit and finer is to remove scratches. 1,000 is still fairly aggressive and will continue to flatten the paint, but do not rely on that.

Edges

• I think sometimes, especially in the detailing and paint correction world, sanding edges gets too much emphasis and energy put around it.  Why bring this up?  I think it makes people too scared around edges and completely over think what you're doing.  98% of the time, nothing different needs to be done on an edge.
• Just block it.  That's the best advice.  Don't over think it.  Don't sand the majority of the panel, and then stop at the edge, and then think about the edge differently.  Just keep blocking and block just a little past the edge.  
• Edges aren't nearly as scary as they are made out to be.  
• Be sure not to roll the block over the edge
  
• Notice in the video above, the edges aren't treated any different at all.
• **Please note: this is assuming all the body work and primer and everything else was done like talked about on the True Blox page.  Edges will be a problem if you decide to start hard blocking the clear coat.  This is part of an entire process

Tools

• You don't need big sanding blocks to get clear flat.  All you're doing is cutting the orange peel out.  
• A bigger and more rigid block does not mean flatter paint.
• The block needs to be able to follow the shape of the panel, including any ripples in the body work.  If it doesn't, the paint will just stay choppy in those subtle low areas.  So it'll still be wavy and the clear will be fatty.  If the block can flex a little more, it will follow the panel and at least cut the clear flat.
• So, don't just jump to using the thickest block thinking it'll be better, most times it won't be.  
• I like using the hard blocks for 600 and 1,000 grit (sold on this website, or use something similar, they are just polycarbonate and acrylic plastic) 
• For 1,500 through 2,500 grits, I really like using 1/8" medium density self adhesive polyurethane foam on the hard blocks.  This gives you a soft block but also helps keep things dialed in.  The traditional dual density foam wet sanding blocks are very crude after using this foam on the hard blocks.
• NO AIR TOOLS.  

Summary and Final Thoughts

• There is simultaneously a lot of nuance to wet sanding, and it's also not that complicated.  Written out, it seems like there's more to it than there really is.
• The steps.  There's a balance of quality and speed and what each grit can actually do.  As few of steps as possible should be done to achieve the absolute best results.  
• If steps are stretched out way too far, the downside is going to show up under the proper lighting while buffing, and the clear will look grainier than it should.  Although, if you're using the dry guide coat and lighting correctly, should should be able to know when you're stretching the steps too far.
• 600 to 1,000 is often seen as too much of a jump.  800 is definitely not needed between these two.  Adding extra grits like that is usually done as a safety net when guide coat isn't used or isn't used properly.  
• Light and guide coat are crucial!