Well-Known Member
Mar 15, 2017
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Mustang GT Fastback
Previous to the advent of dedicated prep sprays, detailers would use a blend of Isopropyl Alcohol (also known as IPA or Isopropanol) and water. These sprays helped strip any remaining oils or contaminants from the surface of the paint, helping improve the bond of the Last Step Product (LSP), waxes and sealants in other words.

However, when ceramic coatings became the norm, the need for dedicated prep products became important, especially so when they became available to consumers. These sprays made it easy for consumers to properly prepare and install their own ceramic coating without compromising the bond by using an improperly prepared surface. For the detailer, it made for an easier and therefore more efficient method of surface prep.

The concept of these prep sprays is to lift, break down and then remove polishing oils and other contaminants from the surface of the paint prior to coating. Some have additional lubricants that help protect more delicate paints during the wipe off, without compromising the bond of the LSP. It’s also said that these dedicated prep sprays have a more moderated evaporation rate so that they can have a longer working time and deliver a more thorough result.

As a general rule of thumb, it’s always recommended to use the prep spray recommended by the ceramic coating brand you have chosen. Applying Gtechniq CSL, then use Gtechniq Panel Prep. Using Carpro Qquartz UK3.0, then Carpro Eraser is your product. This is less important for some situations than others. For reasons explained below, I have successfully cross pollinated between Eraser/Prep for Carpro and Gyeon coatings in the past. Waxes and sealants are less picky about prep. Diamond Protech on the other hand are most insistent on using their specific prep sprays, which sort of makes sense when you consider their coatings are different to others on the market. Now, some of this is marketing and the need to sell product, some of it is proven fact. Which you subscribe to in your situation is up to you.

My introduction to this space was via Waxit with their Concourse Car Care branded bottle of IPA, which was then further diluted. I can’t remember when or where I learned about Carpro Eraser, but that was my first step beyond blended IPA, followed by Gyeon Prep and NV Clarity.


Notes about this test –

I have chosen popular products in this segment in the hope of covering the most ground. A couple here are perennial favorites, some are new entrants, some are sleepers. Time, cost and availability prevents little old me from trying them all, so hopefully I have covered enough to provide some value to those reading.

I did this back-to-back comparison on a cold, fridged day with an ambient temperature of 13 deg C / 55 deg F. This will have slowed the flashing and evaporation point of these products. I also used the same TRC Creature Edgeless towel for each product, the test subject was my fabulous XR6. With the exception of one product, all were sprayed directly onto the paint, wiped with a towel before flipping the towel and wiping till dry.

I have supplied prices in AUD and USD to help providing some guide to my value criteria.



Carpro Eraser -

This is a product I have been using for several years now, and frankly, my benchmark. Although hard to describe, the scent of this product is heavenly, you could get high on this stuff and there are detailers who use Eraser for the scent alone.

The key to Eraser is the ability to lift, break down and then remove oils from the paint surface, but also provide lubrication and anti-static properties in the process. Not all prep sprays do that, and it’s the lubrication aspect that is why I continue to have this product on hand.

In use, Eraser is all about the user experience. The lubrication provided makes it less grabby and the scent makes it very pleasant to use. The evaporation rate is controlled and streak free.

Prices –

500ml - $22.95 AUD / $15.99 USD
1 Litre - $34.95 AUD / $22.99 USD
4 Litre - $87.95 AUD / $89.99 USD

Scent – 10/10.
Feel – 10/10
Value – 7/10
Overall – 10/10



Gyeon Prep –

I’m convinced this is the same product as Eraser, coloured pink instead of blue. The scent is basically the same euphoric joy and has the same feel and final result. Gyeon likewise claim anti-static properties and the ability to dissolve and evaporate contaminants from the paint.

In use, as mentioned, this is very similar to Eraser, meaning a lubricated feeling under the towel and a controlled evaporation. The scent makes it enjoyable to use. As always, Gyeon bottle and sprayers are excellent.

Prices –

500ml - $22.95 AUD / $15.99 USD
4 Litre - $99.99 AUD / $79.99 USD

Scent – 10/10.
Feel – 9/10
Value – 7/10
Overall – 10/10



NV Clarity –

I’m going to get straight to the point here, I hate this product. As a glass cleaner, it’s pretty good. But as a prep spray, its extremely grabby. While NV do make similar claims of lifting, breaking down and then removing contamination, it just feels like straight IPA to me. Smells like it as well. No doubt Clarity is effective, but it just doesn’t have the lubrication of Eraser or Prep and the user experiences suffers as a result. Evaporation was slow in today’s conditions. It’s cheap though.

Prices –

500ml - $16.10 AUD / $12.99 USD
1 Litre - $26.95 AUD / $19.99 USD
4 Litre - $65.50 AUD / $64.99

Scent – 1/10 (None/IPA)
Feel – 1/10
Value – 10/10
Overall – 1/10



Gtechniq Panel Wipe –

This is one of the most aggressive prep sprays on the market, as a result, Gtechniq have a sterner list of recommendations for its usage. Gloves are a must, it should be used on a cool surface, must not be sprayed directly onto the paint and is not recommended for use on repainted surfaces. Its also not suitable for use on PPF, vinyl, plastic or rubber. It should be used within two months of opening, so order the amount you need for the intended job. As a result, one would assume that Panel Wipe is going to be a very thorough prep for a ceramic coating.

Compared to the others, the application is different here due to the towel being an applicator rather than distributor. I thought Panel Wipe was going to be grabby, but I was pleasantly surprised with the feel, being smoother than expected. It evaporates evenly too. The scent is the most IPA like, being quite pungent. Overall, I liked this product more than I thought I would.

Prices –

250ml - $20.90 AUD / $10.95 USD
500ml - $29.70 AUD / $19.99 USD
5 Litre - $132.00 AUD / $125.95 USD

Scent – 1/10 (Strong IPA)
Feel – 9/10
Value – 2/10
Overall – 9/10



P&S Paint Coating Surface Prep –

Going by the dusty bottle I received, I’m guessing this is not a popular product. A lack of marketing compared to other P&S products such as Bead Maker, Brake Buster or Express could be the cause. The pricing in Australia doesn’t seem to be as competitive to both other P&S products and other prep sprays.

This product is a solid option. It doesn’t excel at lubrication or evaporation, but it didn’t do anything wrong and felt nicer than I was expecting. A bit of a sleeper, but not a standout.

Prices –

473ml - $33.95 AUD / $17.70 USD
3.8 Litre (gallon) - $82.95 AUD / $48.40 USD

Scent – 1/10 (None/IPA)
Feel – 6/10
Value – 4/10
Overall – 7/10



Koch Chemie Panel Preparation Spray PPS -

Like all Koch Chemie solvents, the packaging is orange colored. And like all Koch Chemie products, the product description is extremely Germanic, lacking description and almost like they want you to just buy the product “because we say so” type of German mentality. This is one of the most expensive on the market, a 500ml bottle eclipsing all other prep sprays in this test.

Point blank, this is the best product here. And it would want to be for the price. The lubrication is a standout, the feel under the towel is more like one of their spray sealants, and the evaporation rate the best here. If it had the scent of Eraser or Prep, it would easily run away with this test, at least the IPA-ness of the scent is subdued.

(Note – Koch Chemie also sell SIL, another alcohol based prep spray. This version is dilutable and only sold in 5 Litre bottles for $172.95. For cost reasons, I did not choose to test this product, and for most hobbyist detailers, PPS is a more viable choice.)

Prices –

500ml - $42.95 AUD / $17.99 USD
5 Litre - $139.99 USD

Scent – 1/10 (None/IPA/Subdued)
Feel – 10/10
Value – 1/10
Overall – 10/10



Bowden’s Own Flash Prep –

I decided to include this product in this comparison because, outside of Gyeon Prep or blending your own IPA solution, Flash Prep is the only product like this that is freely available through an automotive chain stores. Meguiar’s sell a product called M122 Surface Prep, but it’s only available in 3.8 Litre bottles and is a special-order item.

Flash Prep is said to be a pro-grade formula with “multiple types of alcohol to get a longer working time and better cleaning power”. Bowden’s also make mention of lubrication and anti-static properties, which is pleasing to see.

In use, this is the equal worst product here, sharing that dishonor with NV Clarity. It smells like nail varnish, is grabby and evaporates poorly. In a pinch this would be a fine, but it doesn’t impress. The overall score was balanced by the relatively competitive pricing in the smaller size bottles.

Prices (Australia only) –

125ml - $7.99
500ml - $21.99
5 Litre - $184.99

Scent – 1/10 (Horrible/Nail Varnish)
Feel – 1/10
Value – 7/10
Overall – 1/10



Blended IPA -

I decided to include this 50/50 mixture of IPA and demineralized water in this test for thoroughness. This is what many would have used prior to the advent of prep sprays, so it sort of needs to be covered.

This was actually nicer to use than expected. Naturally, its grabbier but not badly so, and the evaporation rate wasn’t as aggressive as I thought, at least in today's temperatures. I would actually favor this over Bowden’s Flash Prep. Overall, this is a two-part product that requires you to take the time to buy and mix two different liquids. How much of an inconvenience that is will obviously be subjective.

Prices (based on buying IPA at a hardware store, Demin water would be on top of that) –

125ml - $7.95
500ml - $24.90

Scent – 1/10 (None/IPA)
Feel – 4/10
Value – 4/10
Overall – 4/10




Other Prep Sprays –

I could have of course included countless other products in this test, but obviously I had to draw the line somewhere. Here are some notable others -

Angelwax Stripped Ease
Adam’s Surface Prep
Apex Customs Prime
DIY Detail Panel Prep
Diamond Protech Body Prep
Ethos Detox
Feynlab Panel Prep
McKees 37 Prep Spray
Optimum Paint Prep
Shine Supply Throw Back
Sonax Profiline Prepare
Rupes Reveal
3D Wipe

Some rinse-less wash solutions can be used for paint prep, but the amount of concentrate is heavy, making them not all that economical, not to mention being less effective in my opinion. I have also seen suggestion the IPA based glass cleaners can be used, but frankly, if you are investing in an expensive bottle of ceramic coating, why compromise the result by being cheap on the preparation step.

Alternative Uses -

Due to the IPA content, these products double as glass cleaners too, suitable for interior and exterior use, tint safe. I probably wouldn’t use Panel Wipe though.

These products can also be used to aid the removal of oiler polish residues and to properly gauge the level of correction you have achieved after finishing each section.



Conclusions –

Unsurprisingly, being all IPA based, these products smelt and performed closely, but there were some standouts that separated the field.

Still at the top for me are Carpro Eraser and Gyeon Prep. The scent plays a huge role here, making them much nicer to use overall. The lubricated feel seals the deal, and the pricing very good despite the premium branding.

However, I was most surprised by Gtechniq Panel Wipe and Koch Chemie Pps. Both outperform Eraser and Prep in terms of usage characteristics but lack the scent to make the user experience nicer. Picking any of these four will be a winner in my opinion…………………..or buy them all like some idiot did! 😆

Next would be P&S Paint Coating Surface Prep, it doesn’t excel, but didn’t disappoint. For me, if the price reflected this, I would rate it higher. As such, I can see why it doesn’t sell very well, in Australia at least.

Bringing up the rear are Bowdens Flash Prep and NV Clarity. Look, they do the job, but they are not pleasant to use in the process.

Overall, I loved doing this test. As always, it’s the pursuit of something new, something different, something better. And in this case, I discovered two new products that wowed me. Safe to say I won't need to buy a prep spray for a while.................



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Feb 16, 2023
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Dark Matter Grey '23 GT Mustang , 1976 SS Torana
I've got to be honest here I am just going to buy some 99% IPA and mix it with 30% water . I have seen IPA for about 30 bucks for 5 litres . I have to be honest here I couldn't care about the scent .


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Feb 18, 2023
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Mustang GT
I feel like the more I get into detailing the more I love to read these… I have some IPA I purchased before I really got into detailing and it sucks (like all other products I previously purchased). I’ll either be getting Eraser of Ppl. Thanks @DFB5.0 !