Quicksilver Corrosion Guard or AC50 corrosion blocker

[TopCat]

Both the above appear to be popular choices for protecting the underneath of the cars, I would appreciate thoughts on advantages and disadvantages of both and if a spray is better than using a brush or cloth to apply.

Thanks

 

[The Jagster]

All depends on access to various areas of the car and the equipment available to apply the liquid.
The viscosity of the more durable ACF50 corrosion blocker makes it very difficult to apply using a conventional diy aerosol. Not sure about the Quicksilver product on that score, but I could imagine that any product of this kind that is sufficiently thin and 'watery' to enable the effective use of a rattle can isn't going to be very long lived and will need to be re-applied quite regularly.
I reckon it's a trade off.

Spraying gets you to the areas that a brush or a cloth won't reach.
A brush gives a healthy dose of application in a controlled area.
A cloth is good at applying to large areas with next to no mess.

They are all handy methods at the end of the day, so as a diy application, I recommend all of them.

 

[TopCat]

Thanks for the feedback - I think as soon as the weather improves I will be cleaning underneath the car and applying.

 

[Tel]

2 coats of spray Corrosion guard does the trick. It goes on uniformly and doesn't look like it's been painted on as with a brush (important for me as I concours show mine). Any areas that are subject to high abrasion form stones/leading edges can be quickly resprayed if needed, but in the 20 years plus of using the stuff on bikes, cars and boats, I don;t think you will need to if you apply it initially in warm weather.

 

[TopCat]

Thanks for the feedback Tel, it appears that only you and the Jagster has protected the underneath of your cars. Having seen the photos of the rusty crossbrace I am keen to take some action on my vehicle - both seem to be good options, one for each - this may end up being a flip of a coin.