I applied rust bullet on Friday night, now on Monday the Bondo will come right off when I apply that. Supposed to be able to apply the Bondo for 72 hours with no surface prep. Even at that, I did sand the bullet lightly and wash with warm water, applied some Bondo, sanded when ready, and when I blew the dust off, the Bondo comes off in sheets. can't have that. what did I do wrong???

what did I do wrong???

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The only thing you did wrong, IMHO was use "rust bullet",....if the car has cancer, remove it!,...either replace the metal or sand blast it out if possible,.....chemical conversion is a half hearted attempt at proper body work/repair,....do it once and do it right IMO

Mike

Yes: That crap did you a favor by coming apart now and not later after you have expensive paint over top of it.

Sheldon

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I applied rust bullet on Friday night, now on Monday the Bondo will come right off when I apply that. Supposed to be able to apply the Bondo for 72 hours with no surface prep. Even at that, I did sand the bullet lightly and wash with warm water, applied some Bondo, sanded when ready, and when I blew the dust off, the Bondo comes off in sheets. can't have that. what did I do wrong???

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I've had success on my floor with a rust area. I first ground off the heavy scale with a grinding wheel. Sand blasted the pitting, cleaned the metal with preclean, then applied the rust convertor treatment called ( Ospho - a green liquid in a two quart plastic bottle bought from Ace hardware store ). Wait for 24 hrs + to add a second coat, waiting again for several days to start up the primer process.

like the others have said, if this is an area on the exterior of the body panel - if just may come out later

is there any help out there or just lectures?

I applied it to the roof and pillar area to take care of the pitting and pockets that a vinyl top had created. I guess I should have blasted those areas, but I didn't so now I have this. This stuff was supposed to do exactly what I wanted and was supposed to work as the bottom layer. Primers and Bondo are supposed to adhere to it. is that just a lie?? As you say I do not want to find out later that nothing adheres. I have been waffling about whether to install a vinyl top again, but now am not even sure the vinyl top will adhere. Also I still need to get some Bondo on the seam areas and were the pitting is, even with a vinyl top.

i have never used that kind of rust stuff but i will try to help.
what grit did you sand the rust bullet?

i would recommend at least 80 grit or coarser and the filler should stick. make sure you blow off any dust before applying filler. it wouldn't hurt to wipe down with a wax and grease remover also.
also use a quality polyester based filler, not some cheap bondo. i myself only use evercoat products every day. most of the time i use #420 easy sand.

hope this info helps.

8. Is Rust Bullet Compatible with Automotive Fillers, Fiberglass, and Primers?


Yes. Body fillers, fiberglass, and automotive primers may be applied directly over Rust Bullet. Two coats of Rust Bullet should be applied to the metal surface. The body filler, fiberglass, or primer should be applied directly over the second coat of Rust Bullet between 24 to 48 hours. If more than 72 hours have lapsed, the Rust Bullet coating should be etched with Rust Bullet® Metal Blast (simply spray it on, wait 15-30 minutes, either hose it off or wipe it off with warm water and a shop towel, and let dry completely), or sanded with 100-150 grit sandpaper, before applying the filler, fiberglass, or primer, to ensure proper adhesion. This 72 hour period is decreased in areas with higher humidity levels. After the application of the filler, fiberglass, or primer, an additional coat of Rust Bullet should be applied to seal and protect the entire surface.

Rust Bullet can be applied over existing fillers, fiberglass, or primers after scuffing the surface with 100-150 grit sandpaper or sanding block. Fillers have a tendency to absorb moisture which will cause further rusting of the metal and bubbling of the filler if applied directly to a rusted area that has not been protected with Rust Bullet. Rust Bullet works best when it is in direct contact with the metal.

I used the Por15 stuff yaers ago on something post outside just as a test. Was blasted and was not 100% blasted to clean white metal.
Shot the por15 stuff and within the window shot a 2K primer on it and applied the filler to that.
Key was to apply it while still in the window they say it can be top coated.
It lasted well on the stuff I used it on at work for some time. But later came off.
No way would I use it on a car
Sand the stuff you have and top coat it.

Rust is cancer. You better remove it completely or it will later spread no matter what you cover it up with.

IMO all those products that claim that will neutralize rust and that can be applied over rust are a half assed attempt on doing something.

maybe they are OK for industrial equipment, or a fence, or something like that. But I would not use that kind of stuff on a car's restoration.

Thats my opinion of course, but Im sure many will agree with me here.

If its just a driver car, or an off road vehicle, or something like that where you are not shooting for a perfect finish or somthing that will endure the test of time, then I guess its OK.

I would hate to put lots of hours and work on a restoration just to watch it bubble and rot after a few years.