Sanding Techniques? Materials?

banjopicker66 · Post by **banjopicker66** » December 1, 2011, 10:18 am

I know these are some pretty basic questions, but I know very little about paint, body and machinists' work, and so forth.
So about sanding for painting.
The purpose is to reduce the mount of work the paint shop will have to do and so save some money.
What kind, and how much sanding is suitable to get my truck ready for them to paint?
The truck was painted once before, and it shows. Should I try to remove it all? Or just make it smoother?
What grits and type of sandpaper is best?
I have a 60 gallon 220V compressor, would an pneumatic sander be OK, good or better than an electric? What kind of sander, a belt sander or a handheld vibrating kind?

And for the heavy bumper steel that is rusted, same questions.

Again, I realize these questions might sound kind of silly, but I need to keep costs way down, and if this will help, it would be great.
Thanks for the advice!

Bugsy · Post by **Bugsy** » December 1, 2011, 11:26 am

Well what you need is a orbital sander for your prodject,this is also called a D-A sandeder(dual Action) it will be run off of your air compresser and you can buy a cheap one at any home depot or menards store.
The next thing is sand paper, you say the slick has been painted before and you can tell. With that being said I would start with some 180 grit sand paper and sand the paint smooth but dont go throught the paint ,if you do its not a big thing just a little more work. remember just smooth out the paint. In areas that you cannot get to with your sander you can hand sand using the 180 grit and also use a scuff pad that can be bought at any car parts store ,it looks like a 5x8" pad and will scuff your paint enough to let other primer or paint adhere to it ,whitch is the whole point is to sand all of the trucks body to a dull finish. and for the bumper I would sand blast or start with some 80 grit sand paper to take the paint off and the go back over it with some 180 grit sand paper to smooth out the 80 grit scraches,Remember anything taken down to bare metal will start showing rust in a few days and you CANNOT primer or paint over any rust. Good luck :D

Lowell · Post by **Lowell** » December 1, 2011, 12:59 pm

Sounds like you might have big enough compressor to power an orbital sander. Mine is rated 11 CFM and it barely keeps up.

banjopicker66 · Post by **banjopicker66** » December 1, 2011, 1:13 pm

My compressor is rated 12.9 CFM @90 psi.

Here is a jitterbug, square shaped sander from Harbor Freight, for $25.

http://www.harborfreight.com/jitterbug- ... 90115.html

Here is a round one for $40.

http://www.harborfreight.com/6-dual-act ... 68152.html

Would either of these do, and if so, which would you recommend?

Bugsy · Post by **Bugsy** » December 1, 2011, 2:32 pm

The round orbital sander is one you want for this project and it should work just fine with your compressed size,the sander takes 4cfm and your compressed makes 12 cfm. When you start sanding make sure that it's in a free spinning mode vs the grind or non free spinning mode, you will see a locking lever towards the housing of the sander ,you'll see what I'm talking about when you look at it.

*ryno* · Post by ***ryno*** » December 2, 2011, 9:34 am

first off, what are you looking for quality wise out of this truck?
show , daily driver, or just getting it one color?
before you start anything, id talk to who you have planned out to spray it, a lot of shops will not want to do anything over your body work.

if your after a nice quality job, id personally, get you a da sander and hit it with 80 grit down to at least the factory primer if not bare.for one you will know right away what lies underneath, rust or previous poorly fixed repairs and will be able to address them accordingly. if the route is chosen, don't to be too surprised to have issues that will arise!

if a one color quickly is desired, da with 180 to smooth it out and have it sprayed, again most body shops will not want to touch it, or will not warranty anything to do with the out come.

bird55 · Post by **bird55** » December 2, 2011, 9:58 am

After all that has been said-shop around for pricing on the sanding materials you buy. The price of those can really mount up on you. I try to buy in a self stick bulk roll or similar that will fit the DA. And like other suggested, make sure the shop approves what you are doing.

Uncle Skip · Post by **Uncle Skip** » December 2, 2011, 10:08 am

Banjo.
All good advice.
But get some sheets of 180 dry sand and go around all the little nooks and crannies that the DA will miss.
Also, be sure to shoot epoxy primer after you get everything clean
After it sets you can go back over everything with filler primer and then block the body with 400 wet/ dry and a running water hose.
My Mexican friend Angel (Mexicans are born with an extra body work gene) says body work is the art of making large scratches into small scratches. The smaller the scratch, the better the paint.
BTW, if you're doing Bondo work, a long block sure helps eliminates wavy body panels.
Just take your time.