Dealing with rust on body panels

Sevs753

Well-Known Member
Joined
Jul 16, 2009
Messages
2,788
Location
Metro Detroit
Car(s)
'13 Subaru BRZ, '04 GMC Yukon
So I've decided its time to deal with the rust of my cars body panels. The worst spots are on the hood and on the trunk. Theres also a bit on the rear wheel well. Aside from the trunk and wheel well, the rust seems to be caused by paint being chipped away leaving exposed metal.

I've included pictures of the worst bits. The rest seems to be very small spots similar to the smaller ones on the hood.

When I googled this subject, it seems like everyone says to use a disc grinder to sand away the rust. I don't want to do that because it's just overkill for me. None of the individual spots of rust is larger than a dime.

So whats the best way to deal with the rust?

(Click for larger images)




 
Grind it away - but some of that looks like through-and-through cancer. What do your undercarriage and rocker panel undersides look like?
 
Grind it away - but some of that looks like through-and-through cancer. What do your undercarriage and rocker panel undersides look like?

I was hoping to avoid just grinding it away. On some parts of the hood, it looks like a previous owner tried painting over spots to prevent it from spreading. I've never had to get a car repainted (or even part of one repainted) but I've heard It's not cheap. Which parts look the worse? The run on the trunk and wheel well or the spots on the hood?

I haven't really looked closely at the underside since I bought the car but they looked fairly good for a car this old. I'll take a closer look tomorrow and try to take a picture or two. Up until about 6 years ago, the car lived in Texas. When the previous owner bought it, he brought it up here to Michigan and it was driven year round so it hasn't seen that many winters.
 
Check out your floorpans and the undercarriage before you proceed. You may find it's worse there and not worth saving.

Also, it doesn't take long for that car to rust away - if it lived in Texas, it might have had the undercoating and some of the paint chipped away here, where it doesn't really rust. All it takes after that is one winter with salt on the roads getting through on the missing protection.
 
If you don't want to use disc grinder, you could also use a scraper and sandpaper. When you have taken off all the rust you can, apply some rust stopper on it.
 
Depending on how common that colour is, I wouldn't even bother working on the hood/trunk, I'd go scrapyard searching for replacement panels in the same colour.

Exactly. There is no simple, easy, non-intrusive way to get rig of rust. Go find a replacement hood and trunk and swap them over.
The door/fender aren't too bad but the rust will still need to ground/sanded off before touching up the area and you will notice the touch up paint afterwards unless you sand a larger are to feather out the paint and then have it professionally painted.
As for the rear wheel well, thhat looks like the start of proper bubbly cancer. Take out the fender liner and get to work with a grinder or wire brush on a drill until there is no rust left; you will probably we left with a rough, uneven surface once the rust is gone, this would be smoothed out with a finishing putty and sanded before painting the area and once again you'll still notice the paint if not professionally done.
This is a perfect example of why chips and rust need to be dealt with right away. A little dab of touchup paint or a quick little sand and touchup are much easier than waiting months and months until the rust becomes a bigger problem.
 
Thanks for all the replies. I will try to sand away the rust and paint it myself for now to prevent spreading and get it professionally done once i can afford to get a new hood and trunk. Shipping on those parts will probably be more than the part itself.
 
Call some scrap yards in your area. It's not a rare car and being a Honda chances are there were a lot of silver ones. If they have a good hood and trunk the same color go there and switch them. All you need is a wrench and a extra set of hands.
 
The only problem I see with going to one around here is its probably been sitting outside for a while and chances are, its probably developed rust of its own. I will look into that though.
 
Thanks for all the replies. I will try to sand away the rust and paint it myself for now to prevent spreading and get it professionally done once i can afford to get a new hood and trunk. Shipping on those parts will probably be more than the part itself.

There is a product called Ospho. It is a green liquid that is an acid that will chemically change the rust. My dad is an industrial painter and he swears by the stuff. I've used it on a lightly rusted area on my Miata and it seems to work, and I'm keeping an eye on it. If you do use it be careful. it will mar concrete and burn skin if you leave it on long enough.
 
There is a product called Ospho. It is a green liquid that is an acid that will chemically change the rust. My dad is an industrial painter and he swears by the stuff. I've used it on a lightly rusted area on my Miata and it seems to work, and I'm keeping an eye on it. If you do use it be careful. it will mar concrete and burn skin if you leave it on long enough.

I'll have to check that out. Any idea what it'll do to a cars paint?
 
Discolor it if you don't wipe down areas you don't want it. Brush it on and imediately wipe off if it gets anywhere you don't want it.
 
Discolor it if you don't wipe down areas you don't want it. Brush it on and imediately wipe off if it gets anywhere you don't want it.

Thanks. I just want to make sure I understand what it does correctly. It chemically alters the rust into a surface you can paint on, effectively replacing the need to grind the rust away and apply some other rust-prevention stuff?
 
You will still need to remove any loose rust and sand it back.

http://www.ospho.com/directions.htm

OSPHO is a rust-inhibiting coating - NOT A PAINT You do not have to remove tight rust. Merely remove loose paint and rust scale, dirt, oil, grease and other accumulations with a wire brush - apply a coat of OSPHO as it comes in the container - let dry overnight, then apply whatever paint system you desire. When applied to rusted surfaces, OSPHO causes iron oxide (rust) to chemically change to iron phosphate - an inert, hard substance that turns the metal black. Where rust is exceedingly heavy, two coats of OSPHO may be necessary to thoroughly penetrate and blacken the surface to be painted. A dry, powdery, grayish-white surface usually develops; this is normal - brush off any loose powder before paint application.
 
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