36 vs. 80

-
SpeedThrills

SpeedThrills

FABO Gold Member
FABO Gold Member
Joined
Jun 3, 2008
Messages
2,722
Reaction score
1,640
Location
Very South Jersey
When it comes to stripping paint with a DA, I've read some people like 36, some like 80. I would think the more aggressive, the better. But, is there a risk of 36 being too aggressive? I.E. scratching the metal?
I've been using 36, and plan on using 220 and maybe 400 before I epoxy prime.
 
I always use 80 grit. BUT it takes alot to strip a complete car. And time.
 
I prefer 80 grit. Strips fast without taking too much metal and leaves a good finish for the primer to bond to.
 
40g for me, but I only take it down to the e coat that way then switch to 80g. I do it with 8" disks on an air or electric buffer. 36g is awful rough on the metal to go back and da out the scratches.
 
I would never use 36 way to rough, when we were in high school my buddy bought his first car and our friend Ed was painting cars and told him if he stripped it he would paint it, Steve used a 36 grit and a electric sander and ground all the way through the 1/4 panels on the corners, the whole car was scratched up so bad it took a gal of bondo over the whole car to fill the gouges, Oh man we laughed our *** off.
 
I'm doing the doors with 36. They've been repainted. I'll follow up with 80.
The rest of the car only has the original paint and some kind of light coat of rattle can. I'll try using just the 80 there.
The hood and fenders are new fiberglass. That'll help a bunch. :)
 
You should almost never need higher grit than 80, just remember the deeper the scratches the more primer that is needed to fill them up, before priming you should sand everything out to at least 180 or 320
 
I would definitely use 80 grit discs. And Mopar Tim is right; it will take quite a few discs to do the job. Also, don't buy cheap ones. Good quality discs will last longer. Another good hint is that when it feels like the disks are not cutting too well; change them. Also, WEAR A DUST MASK!
 
Depends on the bodywork to follow. If the panel is straight and you’re not going to be using much (or any) filler, use 80 grit.

If you’ve got a panel that’s, um, lets say challenged, and you know that it’s going to take some filler, hitting it with 36 or 40 grit will give that filler more bite so you get a stronger bond.

Obviously, you always want to get everything straight and use as little filler as possible. Which is a great goal, but that’s not always how it works. Some cars are more challenged, some panels aren’t easily accessible to work all the hammer tricks, and some folks are doing this themselves and aren’t expert body work guys. So throwing down those 36 grit scratches will give your filler better bite and adhesion so it stays in place if it gets thicker than ideal.

It’s also a good trick if you’re going over with lead work, same idea. You want that lead to have a good bite on the metal, better adhesion will keep it there longer.

It’s a tool like anything else, you don’t want to blast a whole car with 36 grit if you don’t need to, but you don’t want to use 80 if you’re going to follow with lead or you’re in a spot where the filler isn’t going to end up being paper thin.

Oh, and move around! If you’ve got a bad *** sander, you can build up enough heat to warp a panel! Not so much with a DA, but I’ve got a 7” disk sander that’ll straight up get metal red hot at full speed.
 
I use 36 all the time on a mudhog. :) If you have multiple layers it's not an issue just get it down to the final layer and then you can finish with something finer like 80. If you're worried about primer not filling 36 it's not going to fill 80 either unless you're using a poly. Also if you know the area is going to need filler no point in using 80. I do almost all of my mud work with 36 grit... The faster you take something off the straighter it will be.
 
You must log in or register to reply here.
-

Back
Top