The best sanding block for auto body work doesn’t exist. There isn’t one block that’s going to rub your filler perfect every time.
As you do more and more repairs, you’ll find out that you’re actually using many blocks for one repair.
Having the right sanding blocks can be the difference between a repair being perfect or trash.
Cars are no longer straightforward. The panels aren’t flat. Instead, manufacturers put many lines and shapes through the panels. Different shapes require different blocks to repair.
Throughout this article, I’ll tell you which sanding blocks are the best. I’ll also tell you what uses the blocks have and the types of repairs you’d use them on.
By the end of this article, you’ll be able to handle any filler work put in front of you.
What To Look For When Buying Sanding Blocks
In this case, size does matter. The length of your sanding block is going to determine how your repairs come out.
Sometimes the only way to get a panel straight is by using a huge block and rubbing the whole repair at once. This is especially true for truck bed repairs, trucks, and even hoods.
You may also find that using a small block and keeping the repair small will mean that you don’t need to blend paint. This is huge for those that work in a body shop. You don’t have to waste time stripping panels or get grief from the painters for adding more work.
The shape of a block is also very important. This determines whether you’ll have a flat panel or be able to recreate the shape you need.
Most of the time you’re going to be using a flat block. This will be able to recreate most shapes on a car and decreases the chances of having highs and lows.
But, there are going to be occasions where you have a curve in the panel or a shape that can’t be recreated with a flat block.
This is when you’d use a curved block or a flexible block. Using a flat block in this situation would end up creating high and low spots digging filler out of places where it’s needed.
Soft Block or Hard Block
Sometimes, even when you use a hard block that’s shaped the same as the panel, it still doesn’t give you the finish that you want. This is when I’d resort to using a soft block and sometimes even my hand.
I’ve had repairs that felt ripply and would stay the same regardless of what I tried. As soon as I rubbed it with a soft block and a 180 those ripples disappeared.
Soft blocks are a very useful tool, and every panel beater should have one.
Paint and body filler is very bad for your lungs and is known to cause cancer. If you’re using this stuff day in and day out, it’s very important that you use extraction when you can.
Finally, you want to consider whether a block can be connected to an extraction unit or not. This could be a non-factor if you don’t have an extraction. Extraction is a very important feature for your health.
If you don’t have an extraction, rub your filler in a well-ventilated area and use a dust mask as much as possible.
Best Sanding Block For Auto body Work
The best sanding blocks are whatever you feel comfortable using to get the job done.
Mirka Hand Sanding Block
The very first tool you’re going to need when rubbing filler is a flat sanding block. This will get the majority of your filler work done.
I recommend buying the Mirka Sanding block which is 70x198mm. This is widely used in the industry and is built to last. You could throw it against the wall 1000 times and it’d still be in one piece.
The hook-it system is made so that you can place the sandpaper on the block and start rubbing straight away. It works with their abranet paper, as well as pretty much any other leading sandpaper you can think of.
While this block is best combined with a mirka extractor, it will connect to any extraction system. That said, you may need to change some to fit the 20/28mm hose diameter but that’s easily done.
As this is a fundamental piece of equipment in autobody, you’ll have to buy a block of some sort. The mirka one is extremely well-priced and will allow you to add extraction later on if you don’t already have it.
Mirka Hand Sanding Block Kit
While the flat block above is great. You should spend a little bit extra and buy this mirka hand-sanding block kit. It is a must-have for anyone that’s doing filler work.
This is a kit that I recommend to everyone and is going to be the rubbing block that you use the most. It is a 5pc kit that comes with a hand block and 4 changeable plates that are all different shapes.
Modern cars are becoming way more complex. Each panel has lots of different shapes and body lines so you need more options than just a flat block.
In this pack, you get a flat block, 2 curved/concave blocks, and a convex block.
The one that you’ll use the most is the flat block, but, the concaved ones will follow close behind.
A lot of doors, wings, and quarter panels have slight curves that can’t be perfected with a flat block. Taking a flat block to these areas results in you digging filler out of areas and creating new highs.
You’ll also use the curved ones a lot on bumpers. Mercedes, BMWs, and Fords have a lot of curved areas on the bumpers that these blocks are perfect for.
The fact that the faces can be changed over without having to go and find another block saves a lot of time. It’s also great for saving space in your box or tool cart. 4 of these plates take up a lot less room than 4 separate blocks would.
I feel as though this is a pretty good deal. You’re receiving 4 blocks for under $100. They’re produced and sold by one of the industry leaders and will last you a lifetime.
Dura-Gold Pro Series Adjustable Long Block
Every panel beater needs a long block. These are often overlooked by many, but are a necessity if you want to get your repairs straight.
If you were to look down a big repair on a door that was done by a small block, you’d see lines and waviness. This is because the repair is uneven due to rubbing a small area at a time.
When using a long block and rubbing it across the whole repair, you’ll eradicate any small defects and lines that you’d get in a repair.
While it’s easy to forget about this block, having it locked away in your box. It’s great to use on bigger jobs. I often bring it out when working on hoods, doors, bedsides, or even commercial vehicles.
The fact that this block is also adjustable makes it great for doors and hoods as they’re large and curved. Spin the adjuster and you’ll be able to reach the perfect shape for sanding your panel.
As with most of the sanding tools you find in autobody, this block uses the hook-it system or “hook & loop”. Place your sandpaper onto the velcro and start rubbing.
There is also an adapter pad included that will let you use pressure-sensitive sandpaper if you must.
The Dura-Gold block comes in cheaper than the Mirka alternative. If you have the money I’d always choose Mirka but there’s not much difference between the two.
Z-Leap Flexible Sanding Block
As much as everyone in the trade swears by using blocks, sometimes you need to rub a bit of filler by hand or a flexible block.
Sometimes, no matter how much you rub a repair and try to make it right, it never feels right. This is where I tend to use a flexible block. Sometimes all you need to do is run a flexible block across it to make it feel right.
You’ll also come across shapes on a car that you can’t really get any rigid block to rub properly. Again this is when you’d pull out the flexible block.
As good as it is. It’s a “specialty” tool.
If you begin to rely on the flexible block and use it on repairs that don’t actually need it, you’ll start to see lines and waviness in your repairs.
I tend to use it on panels that have very minor or sudden curves. I’ve also seen myself using it on bumpers a lot. As I’ve said, this is more of a finishing block rather than a fundamental block.
It’s actually pretty hard to get a good one of these. Through trial and error, I’ve found the Z-Leap 5″ Hook and Loop block to be great, or you could go with the flexible Mirka one if you want to spend a little bit more. There’s not much difference between the two. Both are great.
When spending $20 or $30 on a tool, it doesn’t matter how much use you get out of it but I guarantee you’ll use this block a lot more than you’d expect.
If you’ve been in the trade, you’ll know that there’s no magic block that will fix your repairs.
Getting your repairs perfect requires time, experience, and care. Caring about the standard of your work and putting time into perfecting each repair, will make your repairs much better.
Having the right selection of blocks will improve your repairs, but you need to know when to use each one.
There’s no need to have a ridiculous amount of blocks either. Owning all the blocks on this list would be more than enough.
More specialty blocks such as the Big Kid Blocks would be very useful to have, but are definitely a luxury. These are the type of blocks you have in your box for ages until the right job comes around.
Stick to the bread and butter until you actually need to switch it up.