A few years ago i painted my 87 trans am. since then it was a daily driver until just a couple months ago. in that time it got beaten up in parking lots and from the elements and paint had chipped off a couple places and i am now repainting it. i'm about to paint in a few days and was wondering if 320 grit sand paper was good or if i should use go as far as to wet sand the entire car before painting. i know i have to wet sand it after, but was hoping to not wet sand before.

also is filler primer ok to paint over? or should i prime and sand it again before painting?

 

rattlecan primer? there are good realltecan primers and bad. go to a REAL paint store, tell them what you want to do to fill the chips, and the will show you something that will work with modern paints

what are you planning on painting it with?

 

i'm not going to just spot in the little chips, im sanding and painting whole panels over so i get a better look. im shooting it with either gravity fed or vaccum fed paint gun. probably vaccum cuz im using lower pressure and the gravity fed one i have requires higher pressure. and yes, its rustoleum spray can. ive used this primer before and it was fine, i cant remember if i painted directly over this primer or if i used a different one to seal it. im mostly concerned with what grit sand paper to use before painting

 

you did ask if it's ok to paint over filler primer. Every experienced painter I've even known would say NO, dont do it. You're going to spend a lot of time and money on this paint job, why put a foundation of crap on the car that everything else is going to sit on? It's one thing to use primer filler to fille a chip, and then cover the entire thing with a even coating of 2K primer before you lay your base coat.

getting back to the sanding issue. 320 is pretty rough paper if you are going to lay base directly on top of it. 400 would be better, or even better, sand with 600 right before you lay your base. I would think there would be too great a chance that you would see surface scratches through your color if your last layer was sanded with 320, but is it borderline

 

ok, i just wanted to check. so far i havent put any of the filler primer on, i dont think i'll need it really either. ive done a good job with sanding the areas where the paint chipped to bare metal, applied self etching primer and now i have to sand it smooth but i think it may just be good as is.

 

I would suggest 400 wet sanding for the whole car before the base is layed. This will give the paint enough roughness to bite onto but not so much that you will see it through the final clear coat.

 

320 is better than what someone I know of used. I read about a guy painting his own car who used 80 grit.

With that sort of paper, he should have just made it easier and used a grill brush.



I've talked to Mick, the owner of Bad *** Paint, and while I didn't mentioned sanding before the base coat, he got on the subject of sanding the clear. Which by the way is some awesome advice that I'll share.

3 coats of clear, wet sand with 800. 3 more coats of clear the next day, color sand with 2,000 grit and then buff.

I imagine if 800 grit wet sanding works for the first coats of clear, that 400-600 would work fine for sanding before you lay the base coat. I'd go right in the middle to play it safe, 500 grit.

He was a cool guy to talk to and get advice from, and his work is pretty much second to none.

 

i'm been on autobody101 lately. it's a great goup of guys that don't mind basic questions, but also are wonderful in helping with more complex problems.

the more I think about it, cruzinqueen is right. 400 is the best grit before a base coat. you might get away with 320, especially if you sand wet, but why take that chance?

 

oops posted in wrong spot

 

Well now I threw some primer on and started to sand it 4 hours later and it us just not cooperating so ill have to wait till tomorrow to see if extra curing time will help

 

Yeah, some paints take a long time to cure, depending on how thick you sprayed it

 

Just got home and took a look at the primer (12 hours after applying it) and it still wont sand off. It just keeps clogging the sandpaper like it's wet. I used rustoleum filler primer and the plan was to just sand it all off so the low spots were filled but that doesn't seem to be happening. Anyone have any ideas?

 

sit the car out in the sun for a day?

 

Legit sit for half a day today and then hit it with a hair dryer when it was still not right seeming. Then it sanded fine, after getting that sanded right then I hit it 600 grit wet sanding so I hope that's good lol

 

600 grit wet sanding is good to paint over, right? Im not going to have an issue with the paint adhering?

 

Probably. 400 wet would be safer,or 600 dry

 

Couldn't find anything between 320 and 600 wet at my local hardware store. Maybe ill just stick with the 320 then

 

320 wet will probably be ok, you might go back over it again with some of your older sheets. they will be more worn and not leave as many scratches

 

Ok that sounds like a good plan

 

I can't just soak regular sandpaper in water right?

 

FWIW I prefer to use a catalyst primer/sealer before base coats. I use 500 wet on my last sanding pass. The air dry or laquer primer sands like crap and the top coats can apper spotty over it.
Paint is a lot of work might as well use good stuff-jmo.

 

You prime over 180grit(dry) and you paint over 320grit(dry). After clearing wet sand with 1500 then 2000 and buff for the "glass" look

 

Nope, they make actual Wet Sanding paper. Prep is key to a good paint job, pick up a tac rag and some prep solve before applying the paint to keep the dirt out.