self etching primer

ok.. the first one to post... I guess we will see if anyone ever comes down this far in the forums...

..ok now my question.. in most car painting stories they use and specifiy self etching primer for bare metal. Well what exactly is the primer you buy at the auto parts store. its usually cheaper from what i've seen but I have never actually found self etching primer at any local store. I'm assuming that basically the cheap primer at the auto parts store is what grandpa used on his old rat rod and now self etching primer is the modern (and much better) equivalent. basically is the cheap stuff worth anything?  

Etching primer still needs another primer on top of it.  Paint doesn't stick to it well if at all.  The etching primer is strictly to prevent rusting.

On my Cutlass I did the etching primer...then the cheap primer you get at the store...then a really good urethane primer...then base and clear coat.

Most cheaper paints will stick just fine to the cheap stuff.  Some upper end paints require a urethane primer.  My understanding is that etching primer isn't for building up surfaces or providing a surface for the paint to stick to.  Its strictly to prevent rusting.  Someone else can correct me if thats wrong.  
68 Olds Cutlass ~ 350 Rocket
85 Delta 88 ~ 425 Rocket
02 Silverado 4X4 ~ 5.3L

Self etching primers such as Dupont Variprime do prevent corrosion in the short term but,if left long enough will allow corrosion to form.Some primers are pourous and do allow moisture to penetrate if left alone.Self etching primers are meant as a ground coat.They etch into the steel to allow all subsequent top coats to have something to adhere to.Cheap primer is good for areas that you are working on and cant top coat right away,dont use them for final coating a car before you paint.As stated above use a good urethane primer at the final stage.If you can, use a good sealer over it before final colors are applied.This will prevent bleed through and blemishes(blushing) of top caots.You can do without sealer if money/time dont permit just make sure the surface is uniform(coverage wise)and DRY.Hope this helps Good luck.  
Power is bliss Torque devine

thanks ... thats the type of info I was looking for... I have a really cheap car and it is going to get a real cheap paint job but it will be over an origianl color with minimal bare metal so it shouldn't be an issue...  

i got this rust converter says turns rust to black primer would this be the same?  

Can filler be applied over self etching primer?  

Max Powers: rust converters are not primers,they convert surface rust to an inert phosphate coating that needs to be top coated with primer/paint after they dry.Read the instructions on the can.some have specific top coat requirements/prep.Good luck.55turtle: some times you can.I wouldnt recommend it,areas to be filled should be straightened as best as possible and sanded/ground to bare steel before filler application.Fillers will stick to paint/primer for a while but wont stand the test of time contrary to popular belief.If done in small areas(filling a low spot after block sanding for example)you can get away with a LIGHT skim coat of polyester glazing filler.Dont use spot putty out of a tube!!! It will shrink/crack after some time in service.Make sure you prime over your skim coat before painting too.Good luck.  
Power is bliss Torque devine

I strip to the metal And I run into bondo.       Can I used Self itching primer on my car over filler or do I need to sand the filler off before I used self itching primer!!!!!!!!!!!