Sanding car for body work/paint

[Chihua33]

Hey guys,

I'm starting to sand my car down to prep for body work and the eventual repaint. I have a palm sander that I plan on using to sand the car down to metal...with that being said, what grit should I be using?

[SoFlaFiat]

If you are going to bare metal, get a grinder with a soft wire wheel. Sanding will take til Christmas if you spend every day on it. There's my 2 cents... Not that 2 cents is worth much anymore.

[Ptoneill]

You may want to use a paint stripper first to see how it works, sanding is very labor intensive and dirty, if you are not careful you can damage some of the fine details on the car...like the edge on top of the fender that goes all the way thru the door. You will also be able to find areas of old repair this way.

I am not an expert by any means ...I paid someone to do my body work!!....Good Luck!

[81SPIDERMATT]

80

[DieselSpider]

Hey guys,

I'm starting to sand my car down to prep for body work and the eventual repaint. I have a palm sander that I plan on using to sand the car down to metal...with that being said, what grit should I be using?

Random orbit with a vacuum pickup or a media blaster with a vacuum pickup would be the way to go. If your palm sander is just a plain jitterbug it will take way too long, make a big mess and take way too much sand paper making the investment in a random orbit sander with a dust collection system that you can hook up to a shop vacuum well worth it as it will pay for itself many times over in what you save on sandpaper.

Here are some cheap considerations:

Air powered:
http://www.harborfreight.com/6-inch-sel ... 98895.html

Electric:
http://www.harborfreight.com/2-amp-5-in ... 62216.html

[Chihua33]

http://www.homedepot.com/p/Husky-6-in-L ... /203465158

That's what I have right now...one thing I do have on my side is time, but I was wondering about how much paper I would go through...

What would I look for when looking for a paint stripper? anything in particular?

[azruss]

The newer spiders were not very flat and fiat used a filler/primer to get the car flat. I feel you are best to sand down to that layer rather than down to bare metal. Once you are bare, you have to get the metal prepped with a conversion formula so it wont rust immediately and then worry about old dents and getting the car flat again. Lots and lots of work. If you still want to use a DA, try 30 grit to get to metal. Go get good paper from an autobody supply house. It will last 10 times longer than the shit you buy from the big box stores.

[Chihua33]

Would it make a difference that my car was repainted sometime by a po?

it started out that bronzish color and is now red.

[DieselSpider]

I would want to use a sander with a dust collection system to prevent the paper from loading up. When the paper loads up with dust it gets hot and then the dust fuses to the paper making it time to change it again.

Mine is red but was originaly blue however they did not do a good prep job and put the red on insanely thick so that it did not cure well and peels off in sheets. I will have to get the red skim coat of paint off before I can repaint mine. The car will probably be about 100 or so pounds lighter once the red paint is cleaned up.

[Chihua33]

Mine looks like it was stripped down to metal when it was painted red. the only reason I know it was the bronze color before is from the inside of the truck and firewall.

Mine is beat up in the front end, and both rear wheel arches will have to be replaced due to rust.
po rear ended someone at some point and then just used filler to reshape a lot of areas, so when I started into it there were some spots that were near an inch thick of filler...

Some days I wish I could just part with this one and find one in better shape, but the history I have with this car and the $400 price tag I just can't bring myself to sell it.

[azruss]

never trust a repaint. if factory paint is on there, i would leave that or take it down to factory primer, but with a long flat block. I DA will not take long waves out of the bodywork. areas where you have thick bondo, don't mess around and get a 4 1/2" angle grinder with a 30 grit disk, mask and safety glasses. This will make a big mess as you will have bondo dust raining down for a 1/4 mile in every direction. all the bondo needs to go and be redone. They do have fiberglass laced lightweight bondo specifically for areas where it has to be thick. The thinner the bondo, the longer it will last. Bondo is a mechanical bond with the body. the body needs 80 grit scratches or coarser to get a good bond.

[Chihua33]

The spots on the main body where I have started to sand down have none of the original color left.
I was using a grinder with a disk on it, and when I hit that bondo you're right there was a cloud through the whole neighborhood! haha I'm not going for a showcar by any means I just want it to look better than it did with all the chips, dents, scratches, rust lol

[SoFlaFiat]

Lots of good points made but it you are going to bare metal, I still advocate a wire wheel. The only thing you will stop for is hand fatigue. Forget $200 worth of sanding discs!

[DieselSpider]

Lots of good points made but it you are going to bare metal, I still advocate a wire wheel. The only thing you will stop for is hand fatigue. Forget $200 worth of sanding discs!

My fear in going too coarse is of taking off more metal on an already thin panel after someone else has already ground it all down to bare in the past. Those who recommend only taking it down to the primer are giving good advice considering the grade of steel we are dealing with on the Spiders body panels. Media blasting with soft media that won't reduce the thickness of the body panels while still cutting through all the paint and bondo is probably the best way to go if you are looking to expose the bare metal for a second time. A wire cup brush can still dig pretty deep into mild steel so a steady hand and some reserve to not go too far would be required to minimize further weakening of panels already potentially too thin in spots. A twisted cup brush will last longer and be more aggressive however has the potential to do quite a bit of damage too.

All food for though for sure.

[baltobernie]

Mine is beat up in the front end, and both rear wheel arches will have to be replaced due to rust.
PO rear ended someone at some point and then just used filler to reshape a lot of areas, so when I started into it there were some spots that were near an inch thick of filler...

Maybe start with the wheel arch and front end repairs. See where you are at that point before continuing with full body sanding.