Rusty metal paint/primer/prep
 

Good morning folks, I've just finished sanding and removing paint on the hood
of the 1200. I see now that I have several areas of rust, No deep pitting just patches of surface rust that is still there after a thorough wet sanding.
What do you folks recommend for prep? I thought about using some of that
red putty in a tube, its sandable.
any thoughts?

thanks
Dave

I am in no way a professional painter or wise in all phases of paint surface prep. I have, however restored and refurbished some old tractors, cars and trucks. You do need to kill that rust with something designed to do so. I've successfully used Ospho, Pickelx, phosphoric acid based, or one of the currently popular rust converters. Your choice of products is dependent on what final paint you choose. One or more of the pros will be along soon.

First of all, you don't want to wet sand bare metal. No reason too and you don't want it smooth or paint won't stick. You want to sand it with about 320 then paint it with a 2K sandable primer/filler or an epoxy primer. I prefer epoxy, then 2K then color, but most don't want to spend the money for 3 different paints. I don't do any wet sanding until after I get to color. As far as the rust goes, if you hit it with 320 it should come out. If not, you could sandblast it, or just lay the epoxy over it. It will be fine. Rustoleum makes a primer for lightly rusted metal.

Dave I use one of these for jobs like that. I think they still sell them down at Northern. Depending on what I'm blasting I will run baking soda, play sand or that black beauty they sell at TS. Of course you will have to have a compressor, but they work well for small jobs.

http://i244.photobucket.com/albums/g...e/IMG_2108.jpg

The speed blasters will penetrate deep where there is pitting.

http://i244.photobucket.com/albums/g...e/IMG_2119.jpg

And of course a good primer as soon as you clean it off. I clean it by air, simple green, lacquer thinner or tack rags and then prime.

http://i244.photobucket.com/albums/g...e/IMG_2121.jpg

That's not bad at all but I would definitely treat the rust with something before primering it. Most rust preps contain acid, I use phosphoric acid that you use for cleaning concrete and dilute it 50% with water.

I got mine from Home Depot but any building supply should have some. Get some rubber gloves and scotch brite while you're there. This thread has a pic of the product I use (step 7). http://www.onlycubcadets.net/forum/s...ad.php?t=26163

Here's a good video explaining how to use it. If you like cars, watch some of his other videos.
https://www.youtube.com/watch?v=JML4q2Dfe9g

It doesnt look that bad. I echo the recommendation of sanding (320 on a random orbit would be my choice).

I wouldnt put that red glaze directly on the bare metal. I have had some problems with it not sticking (now this was a long time ago, and I wont say I prepped it properly, so others may have better experience).

Sometimes I have treated the rust (Eastwood sells some - Metalprep I think is what I used last). Other times I have just sanded and primed.

If its not deep pits you can block it out with just primer. The epoxy first coat followed by a sandable primer works well. No wet sanding until final coat.

I dont have any hard data that shows that when I just sanded it came through vs if a metal prep was used. They all worked for me.

Do block sand it though, it will come out straight and smooth...

I like picklex but it is expensive.

first off its not wise to wet sand bare metal, not only does it cause rust but it doesn't leave enough scratch for primer as most companies recommend 220 grit minimum for primer. sandblasting is the best way to permanently remove rust followed by a quality epoxy primer, note that most companies recommend you wait 72 hours before putting body filler or primer over top of epoxy.

first re-scratch it with 220... then go get some 2k primer.. there are cans (you can tell by the activator plug that goes in the bottom) but they are rather expensive..most epoxy primers also have a recoat window..say: must cover within a certain time frame or it HAS to be scuffed again for any topcoat...do any mud work or spot putty over the 2k...then do a sandable or high build primer..this is where you might want to wetsand with 320.. then once youre good here squirt paint.... you can use something like rust-mort on that rust if you want.. as someone said before, its basically an acid that will turn the rust a blackish color and neutralize it, then do all the rest...
good luck!!!