Tested: ACF-50 corrosion protectant review

ACF-50 Review


Date tested: April 2018 | Price: Around £15 for 369ml can or £30 for 964ml bottle | www.acf-50.co.uk


Anti Corrosion Formula, ACF-50, has long been a benchmark in motorcycle corrosion protectants for many riders. Used in the aviation industry, it’s available in a spray can, or a bottle for use with a paint gun and compressor. The bottle also comes with a pump dispenser.

The spray can works best when warmed up, either by being left out on a hot day, or warmed in some water – if used cold, the spray is rather thick and difficult to apply. The pump dispenser supplied with the bottle generates more of a stream, so isn’t very good for coating a bike.

Using a compressor with a paint gun is a great way to thoroughly coat your machine (mask off the wheels and brakes first), and it can be misted up under the tank and into the deepest crevices around the engine as it’s safe on electrics. This method leaves less residue on the metal surfaces than using a spray can, but either method can be finished with the wipe of a clean rag.

ACF-50 can also be bought in a 4litre container, and even 20litre bottles up to 205litre drums, however it will eventually ‘go off’, so anyone who isn’t applying this product daily should stick to the smaller smaller 964ml bottles.


ACF-50 performance

While using a paint gun gives a less wet finish, corrosion started to appear within three weeks. From this point, the panel deteriorated quickly, being half covered in rust by five weeks, and completely covered within 12 weeks.

When applied with the spray can, the results were significantly better, eleven weeks passing before half of the plate is covered.

ACF-50 remains fairly liquid, so our test using hanging 90° plates to more accurately represent a motorcycle’s varied surfaces, showed the limitations as it ran off the top of the plates first.


ACF-50 Review


Fresh steel plates were cut to size, folded at 90° (to give vertical and horizontal surfaces), then thoroughly cleaned before being coated with each product, as per the manufacturer’s guidelines. The test was carried out indoors, with a reasonably regulated temperature. For more information on how the test was done, please watch the video below.

Morning and night, the plates were each sprayed with a 5% solution of road salt in water, then consistently rinsed off at the end of each week with a hose head set to a shower pattern.

After eight weeks, the hose head was switched to a more aggressive fan spray, and the plates were rinsed with a consistent five full strokes from a distance of one inch each time.

After 14 weeks, any products that hadn’t completely corroded were hosed off every evening.


ACF-50 stickiness test

When applied with a paint gun, ACF-50 looks glossy on the metal plates, with no discernible colour. When sprayed from a can, the excess pools into a purple liquid, though of course this can be easily thinner where visible.

After drying for 24 hours, both held the sand applied to them equally, and across the whole plate, but sand in the excess pooling from the spray can clumped significantly.

When rinsed gently, only a small amount of sand was left – less than on the other dedicated corrosion protectants in this test – and when hosed with the same fan pattern as used during the corrosion testing, the sand was eliminated. It should be noted however that the painted plates were fully corroded before fan spraying during the rust test, and this same method appeared to accelerate the deterioration of the sprayed plates.


Stickiness was tested on ACF applied from the bottle through a paint gun, and from the spray can


Metal plates were cut to size then thoroughly cleaned, before each product was applied as per the manufacturer’s instructions.

The plates were left indoors, laid horizontally for 24 hours, then each was dusted with fine sand. The plates were tapped vertically to knock any excess sand off, before being assessed for stickiness.

Next, each plate was rinsed with a hose head set to a shower pattern, and the amount of sand left was assessed.

Finally, each plate was hosed with five full strokes from a distance of one inch using a more aggressive fan pattern, before being checked for any remaining sand. Both rinsing cycles represent the methods used during corrosion testing.


ACF-50 safety on rubber

During testing, we found ACF-50 to be completely safe on the sample O-rings – we’ve also used the product to wipe over unpainted black plastics on the bike as it brings them up a treat.

Brand new O-rings kindly supplied by motorcycle parts specialist B&C Express were put into test tubes containing each product. These were left for three months to soak, before the O-rings were carefully removed and assessed for any swelling, cracking, or other changes to their structure.

Please note that we do not recommend using these products as chain lubes – we’re just using the O-rings as a consistent material.


ACF-50 review verdict

ACF-50 proved less sticky than its competitors, but this was offset by its reduced performance in the corrosion test. Having used ACF-50 previously, we know that it can help protect your bike, and despite the fact it stays fairly liquid, so runs off after a while, it will build up in the crevices of your motorcycle and help save it from rusting.

It’s not the most effective motorcycle corrosion inhibitor on the market, but understand its limitations and use it regularly, and it provides a good level of protection.


Group graph


The full list of products tested is as follows:

  • ACF-50
  • XCP Rust Blocker
  • Scottoiler FS 365
  • SDoc100 Corrosion Protectant
  • TechCote ACS TC200
  • Muc-Off Motorcycle Protectant
  • Original WD-40
  • GT85
  • Valvoline Multi Spray
  • Motorex Moto Protect

To read the reviews of any of these items, please click here.


Full time-lapse of the test

John explains how the biggest ever corrosion test was done, and shows the entire process, from bare metal to fully corroded…

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