Well I tested "Rust Bullet" today, results:

[b5blue]

  After reading all the crap in there ads but not finding much here in the way of testimonials I bought a quart off Amazon for some problem areas on my car. I was mostly wondering about how they state NOT to remove all the rust as this stuff "soaks into the rust, drying it out and converting it" (Or something like that.) as the reason you must re-coat within a certain time frame to "seal" the first coat. (Something about the first coat being porous from out-gassing as it chemically bonds to rust.)
  I followed the instructions to the letter using a generous first coat to insure proper wetting for optimum penetration for that chemical bonding on some areas of my car that were rusty but nothing excessive, tiny pitting, no flake or rot through that were scuff sanded and cleaned. Waited till dry to the touch, about 4 hours and re-coated. (All with a brush.)  I gave it a full 7 days to achieve full cure and stripped it off with a wire wheel today to see just what happened under the paint.
The puffs of brown dust and exposed remains of rust, even where not pitting told me the penetrating effect of this chemical action was not as deep as I had hoped. The cured paint is very hard and did bond to the rust tightly but rust is soft and that's the problem. It's still there and I could tell it would most likely "wick" moisture if not perfectly and completely sealed.
  I have used OSPHO for over 20 years and and even it, thin as water and VERY acidic fails to penetrate rust as deep one may hope and have test areas running for over a year on my Jeep using Eastwood's Rust Encapsulator (The entire hood, scuff sanded and shot 2 coats out of a rattle can after wiping down with lacquer thinner.) and it's held up well, a little chalky from the sun. So both require proper preparation, Encapsulator sands very nicely and accepts fillers and topcoats well, Rust Bullet kinda did what they say and drys hard as a rock but requires sanding that will be difficult to use fillers or topcoats if you miss the "window" and that second coat timing is more critical.
  So I'm glad I took advise from my friends here and sandblasted everything I could get to then primed with epoxy primer (Also kept the car covered and out of the sun and moisture on my carport.) as areas I re-stripped the epoxy show no sign of re-rusting.        

[68X426]

Great feedback, thanks. 

[bill440rt]

Nice write-up, Neal. 

The old adage still holds true, a paint job is only as good as what's underneath.

[tsmithae]

Nice write-up, Neal. 

The old adage still holds true, a paint job is only as good as what's underneath.

From RB own PDF on application...


"The proper surface preparation prior to applying Rust Bullet coatings will ensure optimum performance. The surface must be completely dry and
free of loose rust, moisture, dirt, oily substances, and loose paint. Remove by lightly scraping, sanding, or wire brushing.  Scuff up existing paint or
coating that cannot easily be removed with 100‐150 grit sandpaper. This rule also applies to a previous coat of a Rust Bullet coating if 72 hours have
lapsed between coats. No additional surface preparation should be necessary"


Reading this leads me to believe that all normal metal prep should be followed for BEST results, and thats if you want to half-a$$ it, feel free, it will work and it will be half-a$$ed.

[b5blue]

  Yes that part about "no loose rust" is what I tested. There was no loose rust and in that area it was not deep rust.  After reading the sites info several times and with all the setbacks I had last year prepping my car I started wishing I'd shot it with Bullet, that's why I tested. I do have areas I just can't get to to repair and figured what the heck. They do tout their Metal Blaster and I'm certain it's like OSPHO, a phosphoric acid based product that would bite and clean light rust and burn the surface of deeper rust black. I have soaked very rust parts in OSPHO and waited till ALL the rust was gone, but bad parts took a week or two.
  I have gotten similar results from Citric Acid with soaking only it seems to under-cut the rust separating it from the steel rather then burning the iron oxide totally as seen in my topic. I'm suspecting Bullet is a high grade paint mixed with Citric Acid....   
  I want to find the best way to seal between exterior skins and the frames that support underneath like hood and trunk.     

[randy73]

What was the temp when you applied the coats?

I know rust encapsulator say it must be above 60-70 degrees and not over 115-125, not sure of the exact temps.

[b5blue]

Conditions were ideal. 70-80 degrees with 60% humidity, very "untypical" Florida weather.   

[Dino]

Conditions were ideal. 70-80 degrees with 160% humidity, very "untypical" Florida weather.   

That must be a typo, I fixed it for you though!   

[b5blue]

Your FUNNY!  I freaking waited 5 months for this season and only certain days in this time of year! (Mark my words...There WILL BE A/C in the car by next June!!!!)
  Guys understand so far the Bullet does seem to grip well, it just can't penetrate as deep as ads may lead you to think. I have a power pole down pipe I'm going to prep and retest on, it's in direct sun/weather and will be a good hard core test subject. I'll take pics when I do it and post here.
  The paint in the can does "skin over" quite quickly so if ya start using it, use it up or loose it.