Where not to put high build primer?

[78-911SC]

So I've done my body work and most blocking and ready to put down my high build primer. My question is where do I put it or should I say not put it. Examples trunk, wheel wells, under both deck lids, door jams, inside door where door cards go and bumpers inside and out. I think the high build primer is for blocking so I'm not so sure it needs to be in those places but thats why I ask. To much time and effort to not do it right. Just for reference it's a 70T.

[962porsche]

most of the time it's not really where your using but why you would need it .
as we all know you would want it over your body work areas .
but if the rest of the finish around your body work areas are in good condition then you would not have to cover the hole panel with it .
but that would be if your using a sealer when your going to do your top coating .

on the other hand if you have breakthrough's in the existing top coat from prepping /sanding it . then you may want to spray 2 to 3 coats of a filler primer down to give you a good flat substrate for your new top coats to go over .

[78-911SC]

962 a follow up if you don't mind. I'm not sure how long it will be before I actually put paint on the car. Should I leave the car with the high build primer after my final block or should I go ahead and put the sealer primer on it? Also am I correct in remembering that on the final blocking of the high build I use 800 grit? What grit would I use on the sealer and how many coats?

[962porsche]

if your going to seal the car you would want to do it wet on wet with your top coating . so no sanding of it !
do you final blocking the car can then sit as long as you want .
if it sits like that (final sanded) for more the 48 hours you would want to hit the hole car quick with a red or gray pad to open up the sand scratches again .

800 is a little to fine of a grit for top coats to really stick to . 400 to 500 or 600 at most is what you would want to sand for top coating .

[78-911SC]

Sorry 962 but confused with the terminology. I think what you are saying is if I'm going to let the car set for a few months or longer before actually going to paint I should do my final blocking of the high build primer with 400 grit and than when I get ready for paint months later put the sealer primer on and than color. I hope I got that right. Wet on wet are you saying the sealer primer than before it's dry I put on the color??

[962porsche]

ok so let me try and explain this better .
spray your build primer . then block the car making it nice and straight .
if you can't get top coat on the car with in 48 hours after you block it you would want to go over every thing with a red or gray sanding pad / this will open up the primer on the car again for the top coats to stick .
at that point you would mask off the car and get it ready for top coat before the 48 hours are up again .
you would want to seal the car so you would use a sealer wet on wet going from sealer to top coat just letting the sealer flash off before you start your top coating .
wet on wet there is no need to sand the sealer .

now there are sealers , primer sealers ,low build primers, medium build primers,high build primers and ultra high build primers .

for wet on wet you would want a sealer . it gives a very thin coat making the car all one color for ez hiding for your top coats and a very flat even surface it aids in giving the top coats some thing to bite into .

[78-911SC]

Very good 962 that makes things a lot clearer in my mind. I won't be doing the top coat so it looks like I won't be doing the sealer either. I'll be using a professional painter that can do the car some justice. I can do all the grunt work. Thanks again for your help along the way or should I say up to this point because there might be more questions. Ha

[962porsche]

I'm more them happy to help any time I can .