phosphoric acid is the best after removing loose rust while RANEX has about 38% P acid and some other concoction that has kept rust at bayy in my previously rusty 1977 Toyota for about 11 years now.

A friend of mine did all the body work on a coupe in 83. He used rustmort and then lead for a filler. The car was never finished with paint it sat in primer and has lived outside for the last 12 years. Amazingly there is no rust bubbling up on the outside. The frame rails and inner wells (not rusty or treated when the car was done) are gone. Seems like a glowing report to me.

I've just finished doing all the body work on my car and got it into a fresh coat of primer/filler. My paint both fell through so I'm waiting for paint in the spring. I used rustmort and sandblasted hopefully I got it all the cancer.

Cheers and good luck keeping all that tinfoil intact!

KBS Coatings check em out on the net 3 step system ...... im using it ATM on my build

the active ingredient in all of them is (or should be) phosphoric acid. You can usually buy it from chemical supply places for about 1/4 or less the cost of smaller handyman bottles, in about 20 litre containers. Which sounds like a lot, but if you're doing a lot of work on an old car resto - you can go through more than you would think.

The best method stemming from working on a 1948 Chevy pick up, Is to remove as much of the bulging rust as possible, then clean with a steel brush.
buying the best rust converter you can afford makes a big difference.
We have a product Sprayon manufactures and it makes a thick black layer where it reacts to rust. A couple of coats and you're good for at least another five years. Never fool yourself into thinking that you can cure rust completely.You can contain and limit the rust but it will always come back.

Otherwise cut out the panel and fit new steel.
Good luck !

But do rust converters really work?
In the short term maybe but long term I dont think so.
Interested to hear what others think.

I would use the spray in the really hard to reach spots, and the liquid everywhere else seeing that the application by brush makes a lot thicker barrier than spray.
cool trick is to use your little manual oil can clean and fill it with the rust converter and get to most difficult spots.

Hi mate i recently use a product called Deox-gel,it worked like a dream.U paint it on the affected area thickly and then leave it for 4-5hrs then u just scrub it off with a scrubing brush and water.The company that sells it is call PPC(Permanent Painted Coatings)or www.ppcco.com.au. After the rust was removed i put another of their product called SW-2 protective oil.Its been 6 months and my bare metal shell is still rust free.

i used the liquid stuff for the inside of my doors, i just slapped it on rough as guts.. seemed good then when i did it about 8 months ago. haven't looked since. i would assume its convenience...

What are the differences between liquid and aerosol rust converter? Does one work better than the other? It seems to me that aerosol would be a heck of a lot more convenient, but is there something I'm missing?