Should use rust converter and wax oil or just underseal?

[CRVChap]

I've got a lovely condition mkii CRV but it's obviously a little rusted here and there underneath which I don't want to get any worse so I'm wondering if removing surface rust and then applying underseal is better than using a rust converter and waxoil?

[Belle427]

Good clean metal it will probably benefit you to use a good underseal product where you can, obviously wax products are far easier to use to get into hard to reach areas but they do need to be applied every few years.
Bilt Hamber and Dinitrol are both high end products, Waxoyl is a bit old fashioned these days.
Any rust still needs to be dealt with first though.

[steveo3002]

decent primer on any cleaned up scabs then some sort of wax , i dont like seeing that thick black bitumen stuff caked on , all its doing is hiding the defects

[Panamax]

There's no point undersealing a car that's already corroding. All it will do is accelerate the corrosion, when water creeps in between the underseal and the metal.

[KnyghtER]

First post, but got to start somewhere I guess! I have some experience when it comes to rusty machines... I find anything that dries to a tough skin can do more harm than good, this includes underseal and waxoyl. Moisture can get trapped underneath and allow rust to spread, unseen. I like a thinner, non drying product that seeps into seams and soaks into rust and neutralises it. It won't be as tough so areas around the wheels need recoating every year or two. If it's more than surface rust I start with a thinner cavity/penetrating type so it soaks in, then I go over it with something thicker to add longevity. I like Dinitrol ML for step 1, then their 4941 over the top. Dynax S50 seems good too, there are plenty of other options. Over time this method works well, it gets rid of exisiting rust and stops any more forming. Whatever you choose, buy a couple more cans than you think you'll need, it will keep for next year if you don't use it all. I think one good coat on my small car took 5/6 750ml cans.

All too often a thick, tough, glossy looking coating is, on closer inspection, hiding a damp, rusty nighmare.