All things being equal, should I underseal my bus? It’s cavity waxed but bare otherwise. And if so, which oil, sorry, which seal is reckoned to be the best?
This depends. A good coat of paint is a good base. But as soon as its chipped, no matter how fancy it is, rust will start to peel the paint back. Adding coats of underseal provides protection against impact but in the end any damaged to bare metal surface means its like putting rusting wet metal in an underseal or Raptor or POR-15 plastic bag.. Coating it in a regularly renewed wax layer or lanolin products may do as well . Like the original use of old engine oil. I still remember the quote from the VW garage guy. . "frilly rusty buses caked in underseal" describing the end game of just whacking on permanent hard underseal without having a good base..
Epoxy mastic 121. Been on the bus 3 years and it's still bullet proof. Just Done or bug floor pan in it and did a series 3 chassis a few years back that still looks like new. I used ditrinol (spelling?) on anything that couldn't be painted, such as insides of chassis rails etc
Dynax is what mines done with. Still the same as when it was done a few years ago. Waxoyl would be ok if you could get it out the can.
I remember people using that Hammerite under body seal with added wax oil on static caravan chassis, Basically it would hold moisture underneath it and slowly rot the chassis, Some people had more success with the white marine grease, I think they use it for boat trailer bearings Messy but effective .
It it was mine I would use Raptor bed liner .. you can get it tinted any colour and spray it with a Schultz gun straight from the bottle .. did my 914 with it and it’s fantastic stuff ..
probably folks putting it on wet and rusty chassis to try to prolong their life, it can’t hold moisture in if it’s not there
