Better alternative to Fluid Film?
- Thread starter mobilnissan1991
- Start date
I haven’t used it. That’s what CRC says.
I like CRC SP-400. It dries to a waxy film. I applied to my trailer hitch a couple of years ago and it's still on there.
https://www.crcindustries.com/sp-400-corrosion-inhibitor/
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Of the oil product I've used Fluid Film, FF Black (which I feel is slightly different in viscosity), NH Oil Undercoating products, Wool Wax and PB Blaster Surface Shield. Also use Comoline in heavy spray areas.
My opinion for what its worth:
- FF is the original and is good for areas that see less spray or washing. In wheel wells, it washes off in a few good storms. However, I feel like its one of the better lubricants for sliding or rotating parts. The product in cans that will allow you to use the full can or most if it anyway. Many others clog first.
- FF Black is better at coating that FF, but less of a lubricant. Not the greatest application through a spray gun.
- NH Oil Undercoating sprays better than FF in a gun and coats thinker per pass. Good retention, but will wash off readily. They have a mouse repellant formula that I'd like to try.
- Woolwax sprays the best in a gun, coats the best and creeps very well. It washes off about the same as NH and FF.
- Surface shield has the thinnest coating but seems less likely to wash off. Only used the can spray, so no idea how it sprays in an applicator gun. Probably contributes to the coating thickness too. However, you can spray it with a hose and it leaves a thin oiliness that does not seem to go away. Creeps the best too.
- Cosmoline 342 and 344 in cans is great for a tough waxy coating. Does not wash off without effort and hot water. for the life of me I cannot get the cans to spray more that one or two spritz'es before the tip clogs within the can. Works better if you clear the removable tip with some brake cleaner each time, but I've thrown out more half-full cans that I care to discuss.
Rust prevention is really a regular maintenance thing. Washing, cleaning, re-applying.
BTW - its nice to be back. I was crashz before but can't get into my old account.
My opinion for what its worth:
- FF is the original and is good for areas that see less spray or washing. In wheel wells, it washes off in a few good storms. However, I feel like its one of the better lubricants for sliding or rotating parts. The product in cans that will allow you to use the full can or most if it anyway. Many others clog first.
- FF Black is better at coating that FF, but less of a lubricant. Not the greatest application through a spray gun.
- NH Oil Undercoating sprays better than FF in a gun and coats thinker per pass. Good retention, but will wash off readily. They have a mouse repellant formula that I'd like to try.
- Woolwax sprays the best in a gun, coats the best and creeps very well. It washes off about the same as NH and FF.
- Surface shield has the thinnest coating but seems less likely to wash off. Only used the can spray, so no idea how it sprays in an applicator gun. Probably contributes to the coating thickness too. However, you can spray it with a hose and it leaves a thin oiliness that does not seem to go away. Creeps the best too.
- Cosmoline 342 and 344 in cans is great for a tough waxy coating. Does not wash off without effort and hot water. for the life of me I cannot get the cans to spray more that one or two spritz'es before the tip clogs within the can. Works better if you clear the removable tip with some brake cleaner each time, but I've thrown out more half-full cans that I care to discuss.
Rust prevention is really a regular maintenance thing. Washing, cleaning, re-applying.
BTW - its nice to be back. I was crashz before but can't get into my old account.
I love the cosmoline RP342. Warming the cans helps greatly.
My understanding was NHOU and Krown creep better and actually don’t wash off as easy as lanolin based.
Will try warming the cans in a water bath or something. In the summer I just keep them in the sun.
If you put Woolwax black, FF Black and NHOU Black in containers next to each other, you won't be able to tell the difference between them. If you put them on a chassis, I feel like the Woolwax and NHOU cover better with a thicker "blanket" than FF and they both spray better out of a gun. Ironically my spray gun is made for FF.
I'd like to try Krown someday. Maybe after I use up my existing stock of undercoatings.
If you put Woolwax black, FF Black and NHOU Black in containers next to each other, you won't be able to tell the difference between them. If you put them on a chassis, I feel like the Woolwax and NHOU cover better with a thicker "blanket" than FF and they both spray better out of a gun. Ironically my spray gun is made for FF.
I'd like to try Krown someday. Maybe after I use up my existing stock of undercoatings.
and it does not stink...
- Joined
- Jul 11, 2026
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- 5
Yeah Fluid Film doesn't hold up for exterior stuff like that. The thicker options should work way better though. Which one are you leaning toward?
I've noticed that the companies have gone in a two direction approach. NHOU and Woolwax are both offering a thin creeping product and an thicker or waxy product that does not wash off easily. I've begun using different products for these as well. My procedures apply to my primary winter vehicle, a 2014 F250, but I also treat the others in a less aggressive manner. In the spring, I try to wash the underside thoroughly and re-apply rust preventive treatments. Got to get the loose rust, dirt and debris out of the frame and body cavities.
Corrosion X and Krown are thin and do an excellent job of creeping into joints. I apply them after my under-carriage wash early in the summer when the heat can help the products creep into existing rust, joints, seams, etc.
Later in the summer, August or September, I hit it with thicker Lanolin based coating materials. It gives another opportunity to clean, treat and inspect before coating of the year.
So far I've halted the destructive rust on this truck, but its preventive not restorative.
Corrosion X and Krown are thin and do an excellent job of creeping into joints. I apply them after my under-carriage wash early in the summer when the heat can help the products creep into existing rust, joints, seams, etc.
Later in the summer, August or September, I hit it with thicker Lanolin based coating materials. It gives another opportunity to clean, treat and inspect before coating of the year.
So far I've halted the destructive rust on this truck, but its preventive not restorative.
I always wonder if it is better to run the vehicles through the tunnel wash in the winter or just let it sit. I know it isn't great for the paint. Unheated garage here.
In the winter I run it through, but with a basic wash that doesn't include the underbody wash. I've also noticed that the underbody wash does very little in car washes in my area, so I don't worry too much unless doing it every week during winter.
