I can't give you a good answer on that (first timer) but I will share a recent experience. Rusfre (aerosol) would not spray 360° out of the nozzle on my wand extension, it just foamed out around the end. Hooked up a can of Transtar amber...perfect 360° spray. Maybe I got a couple dud cans, but I will say rusfre is one of the best hinge and latch lubricants I've used on my outdoor wood boiler door!
I use Rusfre cavity wax (1006) that comes in a kit. It has 2 x 17 oz cans of wax and a can of wand cleaner plus some extension tubes, spare nozzles and body plugs. The 36" wand has a brass nozzle that blasts a good 360" pattern (providing you have good cans of course). Like any flexible tube, I recommend to tape it to a table or wall for a couple of days to straighten it out.
I used 3m cavity wax in the rockers of my c10. I was happy with how it went overall but I have no other experience to base off of. It did a nice 360 pattern and was easy to do, I think I did 3 coats in each.
I would be conscientious on drain holes with new cars - you don't want to plug them up. I have also had good luck with Transtar. I always keep a can on hand for random stuff around the farm that I want to keep from rusting. I coat the chrome on hydraulic cylinders that are on equipment outside over the winter. In the spring I have to rub it off with brake clean and a rag.
Has anyone tried Fluid Film? I'm interested in doing this stuff in my rockers as well and just curious because I'm finding Fluid Film easier to get for me (i.e., I can get it from Amazon). It doesn't say specifically that it's a cavity wax, but that it is "lanolin" based.
Brief input- it's non toxic oil not wax & very fluid when warmed.
I used $12 hot plate, $1 tin pan & hf airless sprayer to spray entire north east salted rusted car bottoms.
Getting seriously dirty to make any mechanical repairs/work afterwards because it loaded with road grit.
Does it help? No idea, friend in Mn uses it on plows after winter & truck.
Shouldn't clog drain holes after 1 drive on hot day cause it turns to liquid when hot.
Gallon can is like watery grease till stirred & after quick heating on hotplate turns to liquid.
Heated wax would be much more desiresble imho.
Fluid film comes off where water sprays it, must re apply.
I can say it creeps into everything so maybe good to seal unexposed metal. Need more time to tell.
I don't have any long term experience with Fluid Film, but after much reading and watching a couple of long term review videos from people that have used Fluid Film I decided to go with it. I bought a gallon from Advanced Auto online using a 25% coupon and paid just $32.50. I also bought the Kellsport Fluid Film Applicator Kit for just $90 with free shipping. I have to say I am impressed with both the product and the gun. The product is very easy to work with and has excellent coverage. The gun sprays perfectly and comes with an adjustable tip plus two extension wands. One wand sprays a 360 degree pattern and a straight spray.
The product appears to be great at protecting already rusted metal as well as clean metal. My understanding is products like this will embed themselves into the pores of existing rust and seal it preventing it from getting worse. Its my understanding that it's also very effective on electrical connections as well.
We haven't had much snow where I am in New England, but from the few times they have sanded/salted the roads I have noticed quite a bit of debris stuck to the fluid film. I'm not concerned with this as I intend to pressure wash my undercarriage annually before I reapply the Fluid Film.
One tip I would recommend is to remove the front and rear wheel well splash shield as well as any beneath the front bumper cover. This allows access to the hidden areas that moisture and salt, etc will finds it's way.
Check out this pic of the front rail on my 2000 Bonneville. This was "protected" by the splash shields. Both left and right were toast.
I included a link in my reply. I looked and it wasn't obvious so I edited the link and underlined it. See above.
Unfortunately it looks like it's out of stock at the moment. I checked Amazon, which is where I originally found it and it's no longer listed. Odd because every search for Fluid Film applicator gun or even rust proofing applicator guns turned up hits on their kit. It's like the kit has disappeared. I just talked to Kellsport about 10 days ago about a little issue I was having with the 360 wand. Very helpful and nice to deal with. They were nice enough to send me a replacement free of charge. They made no indication they were discontinuing the kit.
I did find it after some more digging. Here is the exact kit I got. Found it HERE on EBay for $120. Look close and the gun even says Kellsport on it. Ignore the WoolWax stickers on the bottles. They are the same bottles I got with Fluid Film stickers. In fact, during my conversation with Kellsport they pointed out the WoolWax is almost the same as the Fluid Film. There is a difference however in the formulation or something. As a result He did point out that they have found the WoolWax doesn't wash off as quickly as the Fluid Film. I think I will give the WoolWax a try once my Fluid Film supply runs out.