Griot’s Garage Boss G21 Review: Is It For Everyone?




Griot's long throw polisher

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After using this machine for the last 5 years, I’m able to share a real-world Griot’s Garage Boss G21 review. This has been my go-to long throw polisher on nearly every car I worked on during this time and it quickly became one of my favorite tools that I own.

The Griot’s Garage Boss product line

Griot’s Garage has offered a plethora of detailing products over the years. Their GG6 short throw polisher was possibly one of the most popular machines on the market before the new era of long throw options arrived.

In general, their line of detailing products was more geared to the hobbyist detailer, similar to companies like Adam’s Polishes and Chemical Guys. They were cost-effective, easy to use, and nicely packaged.

Then in 2015, Griot’s Garage rocked the industry with their new Best Of Show System (or BOSS for short). This is a complete paint correction system that includes everything you need to polish your paint from machines to pads to polishes and compounds. Once people began using the Boss system, it became very clear that it was well suited to everyone from beginners to hardcore professionals.

The anchors of the Boss line are their G15 and G21 long throw polishers. These machines were Griot’s Garage’s answer to the ever popular Rupes long throw options. Some might believe that these are just copies of the Rupes LHR15 and 21 painted red but that isn’t true at all. There are plenty of differences between them.

Griot’s Garage could have stopped there and released the polishers by themselves but they took it a step further. They also designed a series of microfiber and foam polishing pads as well as formulated their own line of compounds and polishes – all designed specifically to work with their long throw polishers. Whether you’re doing a light polish or a heavy correction, Griot’s has a combination available for you.

It’s worth noting that I haven’t tried the Boss polishes or pads yet. I’m a big fan of Meguiar’s microfiber pads and polishes as well as foam pads from Rupes and Lake Country (all of which work great with the G21 by the way). Hopefully, I’ll have a chance to test out the rest of the Boss line in the future.

Griot’s Garage G21 Build Quality

As far as I know, both the G15 and G21 long throw polishers are manufactured in China. They’re engineered and tested by Griot’s Garage themselves though. So let’s be clear, these are not Chinese copies of anything. The manufacturing has been outsourced to allow them to keep costs down.

Does the Boss G21 feel like it’s built in China? Absolutely not. The build quality is very solid and overall the machine is really well balanced. The weight is right around 5lbs which puts it on the lighter side compared to other dual action polishers on the market.

Griot's Garage G21 rubber grip

It’s quite obvious that ergonomics were important to Griot’s Garage when they designed the G21. As soon as you pick it up, you’ll notice how comfortably it fits in your hands. The rubber grip sections give you a few options for how you hold the machine and are made of high quality material. I didn’t notice any wear or tear on them after setting the machine on the concrete floor many times.

This is by far my favorite polisher that I own in terms of comfort. I always look forward to switching back to it after using a short throw polisher in tighter areas.

Unlike competitors like Rupes, the G21 features a lifetime warranty from Griot’s Garage.

Boss G21 Controls

Again, the controls on this polisher are well thought out and placed in just the right spots for comfort and easy access. The trigger is variable and features an instant start. This gives you more control and makes you feel more connected with the pad. When you squeeze, the pad spins. No delays or guessing when it’ll kick on.

G21 trigger

The trigger also has a lock feature that allows you to relax your hand rather than constantly squeezing it. Think of it like cruise control. Give the trigger another quick squeeze and the lock will disengage.

This took me a little bit to get used to but now I love it. Things like this become important when you’ve been working on a car for hours. Anything to help manage fatigue overall is certainly welcomed.

G21 speed dial

The speed dial is large and easy to reach. The speed setting is often a “set it and forget it” function for most people but personally, I’m always adjusting it on the fly. Being able to simply flick my thumb up to control what the machine is doing is great.

Vibration and Sound

You’d think that the long 21mm throw of the G21 would cause a lot of vibration but this machine is actually really well balanced. The counterweight has been fine-tuned to work with both 5″ and 6″ backing plates without needing to be replaced or adjusted. Anything larger or smaller is not recommended.

G21 counter weight

The sound is quite manageable considering the G21’s high powered 900 watt, 7.5 amp motor. I would describe it as more of a deeper hum rather than the higher pitched whine that you’ll hear from other polishers. You can also hear the sound change as it ramps up power when you apply more pressure. This seems to be pretty effective at reducing pad stall-out without eliminating it completely for safety.

I would still recommend wearing ear protection if you’re going to be using any machine polisher for an extended period of time, especially for days on end.

Griot’s Garage G21 Setup: How I Use It

I want to take a minute to warn you that the G21 is a bad man. This is a powerful machine that when used improperly, can potentially damage your paint. It’s nowhere near as dangerous as a rotary polisher but you still need to respect it. Griot’s Garage themselves recommends that novices stick with the G15 and the G21 should be used by people with some experience with paint correction.

The G21 has a lot of cutting power thanks to both its 900 watt motor and large 21mm throw. It can get a lot of work done in a small amount of time. I have chosen to boost this machine’s cutting power even more by making two changes:

Using the washer mod

The Washer Mod became popular by Kevin Brown, who began fabricating and selling washers to be used on the backing plate of Rupes machines. What does this do? If you spin the backing plate with your hand, you’ll notice some resistance. It won’t continue spinning on its own. This is because there is friction between the housing machine and the backing plate.

That friction makes the machine more likely to stall on corners or edges as well as whenever excessive pressure is applied. It’s meant to do that – Griot’s Garage even includes extra grease to put on the backing plate in the future.

They also include their own washers to eliminate this function. The fact that they do this is pretty cool and proves that they pay attention to what the people in the industry want.

By adding the washers as spacers behind the backing plate, it separates it from the housing and removes all friction. The backing plate can now spin freely. This increases cutting power and makes it easier to blow pads out with compressed air. It also decreases the safety of the machine so be careful.

G21 5" vs 6" backing plate

Switch to 5″ pads

When it comes to dual action polishers – the smaller the pad, the more aggressive the cut. By switching to a 5″ backing plate and pads, the G21 becomes even more powerful. It will also make the machine a bit more manageable in tighter areas. Although it is sold with a 6″ backing plate, Griot’s Garage approves of the use of a 5″ as well.

Boss G21 Technique and Strategy

First of all, I don’t recommend the G21 if it’s going to be your only polisher or you’re just starting out. Mine is swapped out with other machines while I’m working on a car which is why I keep it in “kill mode” most of the time. Fast cutting on larger panels is my intended purpose for it.

This polisher isn’t the best choice for reaching tight areas or finishing down really soft paint. Its long throw makes it difficult to get close to edges and contours. This is where I’ll switch to my short throw polisher with smaller 3″ pads or even the Rupes iBrid Nano for really hard to reach sections.

Having the right tool for the job is important and the G21 isn’t always the right tool for every part of a paint correction. No long throw machine is.

The long throw can also make the G21 a bit too aggressive to properly finish really soft paint. Think of the 21mm throw as more “violent” and causing a foam pad to wiggle on the surface.

When trying to pull the last bit of clarity out of soft paint, the goal is to have very smooth, consistent pressure on the surface. In many cases, a short throw polisher with a large 6″ or even 7″ pad is the better option for the job. I will however use the G21 to finish normal or hard paint because it’s more comfortable and enjoyable to use.

When compounding with the G21, I tend to use a fairly quick arm speed. The power and throw of this machine can create a lot of heat if you allow it to remain in one spot for too long so it’s best to keep it moving. This is why I have mine set up so aggressive, so I don’t need to stick around long in order to get the work done. In the grand scheme of things, this is actually a more gentle way of working the paint.

I have yet to find a scratch that I couldn’t remove with the Boss G21, aside from ones that were too deep to safely remove with any machine. It pulls 2000 grit sanding marks out effortlessly. A rotary buffer would be more powerful in extreme situations but I haven’t found the need to use one instead of the G21 yet. These dual action polishers have certainly come a long way since the Porter Cables we all used to use.

Pad stalling hasn’t been an issue for me at all but that’s partly due to the washer mod and the way that I use it. I don’t expect the G21 to be able to work well on odd shaped contours so I don’t give it a chance – I just switch to the right machine.

On a flat panel with the washers installed, you’d have to put a ton of pressure on this thing to make it stall and there’s just no need for that.

What’s the difference between the Griot’s Garage Boss G15 and G21?

The biggest difference between these two polishers is quite simply the size of the throw. You guessed it, the G15 features a 15mm throw while the G21 has 21mm. There’s also a very minor weight difference (we’re talking like a nose hair here). Aside from that, these machines have the same bodies, controls, and motors.

If you’re new to paint correction or you want to be able to work on an entire car with just one polisher, I would recommend buying the G15. It will fit better in tighter areas and be less likely to stall too.

The Boss G21 is best suited for someone with some experience under their belt that wants to be able to mow down defects in wide open areas quickly. Partnering this polisher with a smaller short throw machine for tighter areas is an incredible combination and will surely get the job done in the least time with the least amount of fatigue as well.

The G21 is a beast – it’ll make quick work of some of the gnarliest scratches, swirls, and defects. You need to respect it though and make sure you know what you’re doing.

How do the new G8 and G9 compare to the G21?

Griot’s Garage recently released two new polishers, the G8 and G9. These were not intended to replace the Boss G15 or G21. They are still considered short throw dual action polishers and are replacing the older GG6 and GG3 (which was too weak to be very useful).

The G8 is their mini polisher and is meant to be used with 3″ and 2″ pads. It features a much smaller 8mm throw. This would make a great combination with the G21, allowing you to reach tight areas.

The G9 is their new all-around buffer that can be used for pretty much anything. It combines a 9mm throw with a powerful 1100 watt motor to sort of bridge the gap between a weaker short throw machine and a monster long throw one.

Much like the G21, it is sold with a 6″ backing plate but can be switched to a 5″ without any problems. I have yet to try it but I think the G9 would be great for finishing soft paint after cutting with the G21.

You can purchase a Griot’s Garage Boss G21 polisher by itself right here or as part of a complete kit here:

2 responses to “Griot’s Garage Boss G21 Review: Is It For Everyone?”

  1. Cee Avatar

    Tim, patience please relearning read/write/words and well, everything, including detailing. While laid up my tiffin 40 foot NOT full body paint fiberglass rv 2004 tiffin was left neglected in all seasons open air heavily oxidized and heavy with product from my attempts to hand polish it. I admit I’m tiny and frail now and cannot do this huge rv by hand anymore. I was thinking the g21 with 5” plate so I could speed through this huge 40’ flat sides, then read your article not for newbies. Can you recommend a bundle for huge flat long spans of rv fiberglass ( the white kind with swirl tape, not the pretty shiny full body paint kind). I got the nasty molded green 3M off the front and now looks brand new, but the sides are chalky. I was going to use mequires 67 with g21 and their wool/mf cutting pad, but this article froze me in my tracks after already getting a week of analysis paralysis. At last minute I changed from Milwaukee fuel 21 due to weight and saw lighter G21. Regardless of 21mm I was going to use 5” plate due to tons YouTube’s stating get large areas done faster with large throw and small plate. Have problems staying on subject, so wrap up with thank you for article and please help me bundle or pick a random low vibration light fast coverage solution. I’m not interested in entry level adams, Torq CG, SPATA, etc due to reviews. I buy to last years and honor warranty etc. thank you. Oh, needs to be rotary to help dummy proof it a bit.

    1. Tim Rempel Avatar
      Tim Rempel

      In your case, I don’t think you need to worry too much about the buffer being too aggressive. Most fiberglass RVs have a gelcoat on them rather than paint. Gelcoat is pretty tough. It’s the thin clear coat on car paint that we need to be careful with.

      You might want to consider sticking with a 6″ pad for a G21. If you’re concerned with it being too aggressive, the larger pad will calm it down a bit. Also, it’ll help by not loading up with residue as much – and if your RV is oxidized, you’ll likely be clogging the pad up pretty quickly.


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