Question for DIY body/painters

[Joseph Lavender]

I'm working on my 1979 MM and I'm doing most of the body work myself, and I'm probably going to paint it myself as well. (or get the help of a body shop friend to do it for me, he's been advising me so far.)

Anyway, I'm planning to paint it white, because I was told it shows flaws less. My question is, how "smooth" and perfect does my body work need to be in order to not see "flaws". It seems that I'm working against an unpenetrable wall, where no matter how much I sand and fill.. there's pin holes or a certain amount of "non smoothness". Its smooth to the touch, but if I shoot it with primer.. you can see it.. even if its just faint.

My question is, how smooth is smooth? Like at what point do I say, ok.. now I can prime it.

[pyro]

There is a final stage filler used to fill in the pin holes left by bondo

[Riff Raff]

There is a final stage filler used to fill in the pin holes left by bondo

Yeah, what he said. I used to use Dophin Glaze. But also, block sanding is the best way to get it straight and not wavy. Start with 80 grit, get the bondo almost to where you want it, go down to 180 grit, and then if you like 220. Prime it and block with 180, 220, 320. reprime, block with 220, 320 and 400. But make sure your block is flat and straight before you start or you'll just sand the waviness into your work. Another trick I use is to mix in a little fiberglass resin into your bondo, make it more creamy and less prone to pinholes.

[Creepy Cruiser]

Also "guild coating" is your friend. After you prime, (once it cures up), take a can of rattle can primer of a contrasting color and just lightly dust over the primer. This will give it a marble look. Then as you sand the guild coat will get sanded off quickly, and this will show you all the little flaws. As soon and all the guild coat is gone, you know that it is smooth, because if there was a low spot or flaw, it would still have the guild coat showing it. (only sand till all the guild coat is gone, don't go any deeper).

I like to do it with wet sanding from 220 up to 400-600 depending on the paint I'm using, and the finish I'm looking for.

Here is a basic quick youtube vid on it. (I'm sure there are more on there too if you look around)