rust proofing
New User
Joined: May 2021
Posts: 22
Likes: 11
I use a 2 step process. First, I coat with cosmoline which is extremely tacky and goes on in a thin layer. After letting that dry for a day I go over it with fluid film. My reasoning is that if the fluid film which remains somewhat well.....fluid gets brushed or sprayed off in areas, I still have an extra layer of protection. 2 to 3 cans will easily do a Superduty and it's available on Amazon .
https://www.cosmolinedirect.com/cosm...st-preventive/
https://www.cosmolinedirect.com/cosm...st-preventive/
4wd Low
Joined: Nov 2021
Posts: 10
Likes: 7
When I bought my new F250 I mentioned I wanted to get the bed sprayed with bed liner. They recommended LineX. I asked some questions and they also mentioned that the local LineX shop also undercoated vehicles.
I decided to go with both, bed and undercoating. Made the assumption that the undercoating was as good as the bed liner material which is pretty darn tough and lasts seemingly for ever. But I really have no idea how good their undercoating may be. The bottom of the truck/frame sure looks pretty though.
I decided to go with both, bed and undercoating. Made the assumption that the undercoating was as good as the bed liner material which is pretty darn tough and lasts seemingly for ever. But I really have no idea how good their undercoating may be. The bottom of the truck/frame sure looks pretty though.
Fleet Mechanic
Joined: Mar 2021
Posts: 1,455
Likes: 607
I don't know what Line-X undercoats frames with but I wouldn't use anything that's like their bedliner stuff. Stick with Fluid Film or Krown or any other oil based preventative. The rubberized ones can be a death sentence trapping and destroying under the coating, Here in the NE anyways it's gone horribly wrong most times I have seen..
4wd Low
Joined: Nov 2021
Posts: 10
Likes: 7
I don't know what Line-X undercoats frames with but I wouldn't use anything that's like their bedliner stuff. Stick with Fluid Film or Krown or any other oil based preventative. The rubberized ones can be a death sentence trapping and destroying under the coating, Here in the NE anyways it's gone horribly wrong most times I have seen..
Logistics Pro
Joined: May 2011
Posts: 4,832
Likes: 668
From: Maine
I use NH Oil undercoating, usually in the late summer/early fall. it holds up real well to road wash, and frankly looks better than Fluid Film. My brother had the Ford dealer undercoat his truck when he bought it (new) and with half the miles my truck had most of it was washed off, and he had a good bit of rust on all the driveline/suspension components. Mine still looked like new.
Hotshot
Joined: Jul 2013
Posts: 14,298
Likes: 2,197
the electrical wires on the alumiduty seems to have inherently more corrosion problems than the steel superduty's. must be some type of galvanic reaction. a light corrosion prevention fluid that does not dry out and interfree with connectors is what I am looking for.
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Cross-Country
Joined: Jan 2022
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I don't know what Line-X undercoats frames with but I wouldn't use anything that's like their bedliner stuff. Stick with Fluid Film or Krown or any other oil based preventative. The rubberized ones can be a death sentence trapping and destroying under the coating, Here in the NE anyways it's gone horribly wrong most times I have seen..
Absolutely. You do not want any sort of permanent encapsulating product on your frame.
Lead Driver
Joined: Feb 2022
Posts: 7,975
Likes: 4,055
What those "permanent" undercoatings have happen that leads to rust is when a rock hits it just right, it can puncture the surface and leave a tiny balloon of open space under it where moisture collects, then a year later you have a rust patch under the coating. Same thing happens to E-Coat. I am finishing up restoring the bed of my 2012 and Ford doesn't paint the underside of the bed, they rely on the E-Coat to protect the metal. Thats all fine and dandy if the truck is never driven, but when ever a rock strikes the surface, it created a bubble under the Ecoat and eventually it will rust. I found thousands of little pock marks under the E-Coat while sanding and grinding.
IOW don't use any Permanent type coating on the chassis and expect it to prevent rust, it wont. Fluid Film, Wool Wax, and the like are much better at preventing rust on the frame. As far as the body, it's Aluminum, it will last decades without doing anything but simple washes. Unlike earlier aluminum panels that were attached to a steel structure, the entire truck body, except the firewall is Aluminum, so no chance of dissimilar metal corrosion. The Firewall is isolated with a special adhesive to prevent contact. Putting any "rust Proofing" on the aluminum body is a waste of time and money.
My vote is FF or WW.
IOW don't use any Permanent type coating on the chassis and expect it to prevent rust, it wont. Fluid Film, Wool Wax, and the like are much better at preventing rust on the frame. As far as the body, it's Aluminum, it will last decades without doing anything but simple washes. Unlike earlier aluminum panels that were attached to a steel structure, the entire truck body, except the firewall is Aluminum, so no chance of dissimilar metal corrosion. The Firewall is isolated with a special adhesive to prevent contact. Putting any "rust Proofing" on the aluminum body is a waste of time and money.
My vote is FF or WW.
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Jan 12, 2011 09:38 AM