OK so thanks to the feedback here I am going to attempt to paint my rusted hood. Even if its not the most efficient thing as a true beginner it should be more fun.
My hood is rusted on top of primer - never painted. I need to sand it down. I only have a block. How much sanding am I looking at? What grit should I start with? After sanding all the rust debris that remain on the hood how should they be removed/cleaned? I am a true newbie and am sorry if these are obvious and I should be able to figure this out from previous posts, but everything I read seems to deal with paint which this hood doesn't have. After sanding then?
Thanks!

 

Wet sand with P220 with a little de-greaser in the water till your arms fall off, and then use your legs and after they fall off then you prime it with a rust inhibitor primer.
Use benzene or an alcohol based cleaner to wipe it clean.

 

OP...dont listen to this guy

lol

 

And why not? By the sound of things he has a new etek primer part that was never painted and it gets rusted if you do not seal it. To make sure the rust does not come back to haunt you you need to sand it real good.

 

I think gorilla was referring to allowing your arms to fall off. Yeah, it is mostly sanding (which I would use a hard block for most of it). Guide coat never hurts.

 

Oh ok thought so :D
A power tool would be nice

 

Yes. Air powered DAs and piston straight line sanders are both nice tools to have.

 

no i was serious about everything he said... u dont want to WETsand an already rusted metal hood with water... thats just going to cause more rust

 

No it is not going to cause more rust ^
How long have you been doing body work gorilla bud?

 

Actually I kinda skipped over the water part. I would dry sand as well. There is little to no point of wet sanding at this stage and you'd be better off not exposing the oxidation to MORE water.

 

Wet sanding saves a lot of time. And it is the sun that made it rust.
If you are going to dry sand then P100-120 will be the best.
Make sure to use a good rust inhibitor primer on the same day that you did the sanding.

 

i dont need to prove anything to you... look up how rust starts, and then come back...


and using 220 will take a whole lot longer, if u were smart, you'd know its much easier to use 80 or 150 grit be4 primering

 

Rust starts as free oxygen molecules in water attach themselves to the iron in sheet metal, forming iron oxide (rust.) No water, no rust. Simple as that (albeit moisture in the air can cause oxidation as well.)

That being said, it depends on how far you want to go. 220 is fine for a scuff n' shoot (if you're using another primer over your e-coat.) If you want to go to bare metal, 80 grit is much more suitable, followed by an epoxy and then a surfacer.

 

Obviously you do not need to prove anything to me I am the forum noob here
OP where is the most rust situated?
Did water cause this?
http://www.toyotanation.com/forum/80...un-damage.html
No it did not.
The SUN breaks down the paint and only then can humidity/water play a role.
But I guess I did not post it correctly in the first place :D

 

That's not rust doe. Paint oxidation is different and has other causes.

 

Haha, no. Rust is iron oxide; made from iron and oxygen. There are not any photons from the sunlight involved.

"For iron to become iron oxide, three things are required: iron, water and oxygen. Here's what happens when the three get together:
When a drop of water hits an iron object, two things begin to happen almost immediately. First, the water, a good electrolyte, combines with carbon dioxide in the air to form a weak carbonic acid, an even better electrolyte. As the acid is formed and the iron dissolved, some of the water will begin to break down into its component pieces -- hydrogen and oxygen. The free oxygen and dissolved iron bond into iron oxide, in the process freeing electrons. The electrons liberated from the anode portion of the iron flow to the cathode, which may be a piece of a metal less electrically reactive than iron, or another point on the piece of iron itself."

http://science.howstuffworks.com/question445.htm

 

OP, is it a new part that you bought and never sprayed it?
What colour is the hood?

 

Pictures would help this thread out. But judging by what you say I would DRY sand with a DA sander with 180 grit. I am assuming you just have surface rust and not rust holes. A 2k urethane primer would work good bc it builds up and seals everything. Then 400 grit your primer and topcoat your hood. Use wax and grease remover b4 spraying anything.

 

Thanks Everyone!
It's a black hood. The part was new but now 6/7 years of rust.
No pic of before but it looked like one of those rusty hoods that some people seemed to like. Nice and orange all the way through.
When I posted I used a block and some 80 grit for a few days straight. Not orange anymore and a few metal spots but man is a lot to go. The hood looks dark brown now and closer to the pre-rust look of prime.
Trying to piece the replies here to continue the project properly. Definitely willing to try.

 

Make sure to use a good rust inhibitor primer on the same day that you did the sanding.

 

Thanks
Primer Example
Do I use it only when done with all sanding or after any sanding.
Do I really need to sand to metal or is their a shortcut - (Besides a new hood) -
Forgive the newbiness

 

I had a friend suggest a rust converter. Is this advisable?
Thanks again

 

Yes I will definitely use a deoxidizer
And I say again the sun was the main cause of this problem.
The hood is painted with etech, moist/water has no effect on it as it is not porous.
You must sand it all of. No short cuts to take when you deal with rust!
If you feel like you can only do spots at a time then yes sand and prime.
@alice, what is wrong with that line?

 

sun does play small role, but the main cause of rust is MOISTURE, that iron and oxygen react to on the metal's surface..

skalabala just stop responding, you're confusing yourself and everyone else



i would suggest sanding all the rust off... if theres any nooks or crannys that you cant reach, then use a rust converter... but if you're sanding a hood and all the rust is accessible and removable... do that.

your next step from there is to degrease, then lay epoxy or self etching primer...and then primer surfacer

 

The hood is painted with etech. It has no problem with water or moisture.
It does not like sun as it is thin, thus the sun breaks it down and only then can moisture/water play a role....
If that hood never saw the sun it would never have rusted.