Well I want to start sanding my car in my free time ,,like there is any( )
1: Do they make electric DA sanders?
A: I have never seen any. There are electric orbital sanders...it could work...
2: is it better to buy a compressor and air DA sander?
A:well yes but, It takes ALOT of air to run a DA...you'll need a big one.
3: What grit paper do I start with?
A:this depends. If the body/paint is shot - you'll want to start with 80 and let the sander do the work (don't press down hard). After the entire car is sanded you'll want to prime it and then the blocking starts...block intially w/ 180, reprime, guide coat - then block with 400, reprime, guide coat - block again with 400, keep priming blocking w/400 until you are happy with the body. Light reprime and then wet block w/ 600 then scuff pad for a final prep. You can use a soft block with the 600
By the way, dry blocking is faster and messy/dusty (wear a mask!), wet blocking is easier and less messy (no mask needed)...when wet blocking, you can never have enough water.
4: Do you use finer grit papers as you progress?
A: see above
5: if the car is arrow straight now ,do I need fillers?
A:If it is straight enough for you, you can actually skip the 80 w/DA step and just start out blocking with 180. This will show you the imperfections right off (low & high spots). Minor waves/dips will sometimes block out with multiple primes. When blocking DON'T use alot of pressure. Let the paper do the work. You'll need a long board and some smaller blocks as well (all hard). Use the biggest board/block you can for the area you're working on...You'll use your hands for the real odd ball areas (ie:header panel or scoop area). At all times, sand diagonally in random patterns. If you don't you will create grooves - You're trying to level things so you'll need to go from different directions over and over....try to never sand the exact same path twice. I always hold the block, board or paper diagonal to my stroke. DON'T be in a hurry...a good block job will take a LONG time.
6: On a car from the factory do they use fillers?
A: yes - in the seam areas (ie:1/4 to roof seam)
What books do you recommend...
A: I have never read any on body/paint work, I learned from those who do it for a living
There are different techniques that all lead to similar results...maybe some others will chime in.