Tips on sanding fenders???

[FlatBlack72]

I am currently starting to sand down my fenders and hood to start prepping them for when i am ready to paint. I bought some 3M 120 grit sandpaper and a block to start out ( ive heard that 120 is proper to use if your not going down to bare metal) if anyone has any tips on what to use or techniques used to sand it would really help. Thanks!

[FRENCHBLUE72]

Are you just wanting to scuff them or are you gonna shoot primer over them ?? Whats the plans.

[stllookn]

If there is no rust and the fenders are straight you will only need to scuff them with a scotch brite pad before spraying primer...well after you use a good degreaser and wax remover. In fact...let's back up a bit. First wash them really well, then use the degreaser and wax remover, then scotch brite, more degreaser/wax remover...then spray primer. There is a really good site called autobody.com with some excellent paint prep "How To" instructions.

[bad6772]

Originally Posted by FRENCHBLUE72

Are you just wanting to scuff them or are you gonna shoot primer over them ?? Whats the plans.

agreed.....need more info of your plans,if you are doing a repaint...youll want the factory paint all off.....i would start sanding with 80 grit then 150 then 220...epoxy prime.....then fix dents,rust????????what ever




ynot

[LONGHAIR]

I wouldn't waste the time/materials to sand any finer than 150 in the early stages. Primer/surfacer will fill the scratches. You will be filling and sanding, then priming/blocking in later stages. You should never be sanding w/ a courser grit over a fine one. Work your way finer as you work toward the final surface.

Stripping- 36/40 to about 80/100
Smooth- 150/180
Epoxy prime
Straighten/rust repair- grinder/ mini disc 24/36 up to 150/180
Primer/surfacer 150/180 down to a minimum of 320 to as much as 600 depending on the topcoat/s
Wetsanding/buffing- Depends again on topcoats and condition of the paint as it came out "off the gun" ...it's a whole topic of it's own.

This way you are never back-tracking (sanding with a grit courser than one below it) The only exception is where you have to cut out rust areas and weld panels back in. Those should be only small spot areas anyway. If you have major areas of rust repair, I would tackle those before stripping the entire truck anyway.

[bad6772]

agreed with longhair....But if this is factory paint....i would sand it all of....laquer paint MAY cause problems with todays paints,and primers....as in solvent pop.or fish eyes....im speaking from experiance, i had to repaint my interior twice........the first time i simply sanded the paint with 220, primed,sealed..the 1 light coat of base,and then another medium coat of base then ,clear....while baking it all changed..................just my 0.2cents

[LONGHAIR]

I wouldn't paint over 40 year old paint either........reguardless of how it looks.