This is majorly important. I have a surface rust spot on my roof and I need it gone. Last summer I thought I had sanded it all off and then primered it. Now it's back. I can't remember what grit I used or anything, But it didn't really look like plain metal when I was done sanding, more like a smooth black spot where the rust used to be. I tried sanding that black spot out to bare metal and it just wouldn't go away, so I just primered over it. Now it''s burst through again. I'm terrified I'll end up with a hole in my roof. I'm planning to paint the car this summer so I need to get this taken care of the right way. What grit(s) of paper do I need? I really need help with this, guys.
I used OSPHO on some pretty severe surface rust. Found that if you wet the area well, let it sit for a while, wet it again, wire brush it and wipe it clean you'll get bright shiny metal. I always cleaned the area well with lacquer thinner before priming. So far no adhesion problems.
This the type of stuff good for other rust area's too or just surface rust? Different from por-15 and others mentioned around? just wondering... first I've heard of it
For a small spot I would use a spot blaster if it has tiny pits which it likely does. http://www.nextag.com/spot-blaster/compare-html The one I use at work has a recovery bag with a foam type end over the nozzle. It stops the sand flying everywhere. You hold the foam end against the metal. Works great for small areas. Then to be sure you can use a converter like Ospho if you like.
It's really good for surface rust. Most surface rusts will leave pitts in the sheetmetal and sanding will not get it out. The ospho will soak into the pitts and stop the rust. Once it's dried good, you can sand it again and prime. Now, if you just prime it and drive it again without painting it, it will still come back after a while. At least spot paint it if you're not ready to paint the entire panel.
Primers...Rattle can and common single part primers are moisture sponges(hydroscopic). You have to top coat the stuff soon or it will allow rust to form. It will promote rust in areas you didnt have any rust in too. So top coat it or use a good 2 part urethane primer or epoxy primer once the rust is removed/neutralized and it wont come back since these primers are not hydroscopic.
I totally missed the point that he left it in primer. Good info Pete. Lots of guys prime only. I got a real good lesson on primers over an over..... doing my car. Our painter was paranoid about me leaving areas in prime even in the shop. HAd to be epoxy if possible and other areas he made me scuff and recoat with fresh primer if they sat too long. didnt realize the primers shelf life when applied and how they start to absorb moisture. Man, am I glad thats all over with.
Do not sandblast the roof or any other relatively flat sheetmetal...It'll warp like a mofo...Dupont makes an acid called Metal-Prep which is made for rust....Use it with a red Scotchbrite pad
Yeah, I never really intended to leave it like that but I got started too late in the good weather season and ran out of time. I'm getting the earliest start I can this year. I used tarps on my last Maverick to keep it safe, but it made it Waaaaay worse. I'll look into those kinds of primers.
Good advice in this thread ........ I use a product called Rust-i-cide. It is the sister product to Ospho. Made by the same company. Self etching epoxy primer / sealer is a must in my book. http://www.skybryte.com/
is rust oleam primer sealer a good primer if you cant afford to paint over the primer right away? cuz ive got sever surface rust on the roof of my car and i was thinking of using the primer sealer till i can afford paint for it...
