Ok, so I did search, but am not finding a thread addressing my issue. If one exists, please feel free to send link.

I have had bubbling paint with rust underneath for a few years and feel I need to address it (now/ finally). There are three spots, all on the roof between the sunroof and the front windshield.

Does anyone have any recommendations? One spot is pretty large. I was thinking of using a power sander to sand down to the metal to remove the paint (scary) and all the rust. Then just touch up as best I can.

Pictures attached. Thanks for your help.

 

Not a lot to do but respray. Fortunately the roof is a single panel. Those look like they started as rock chips.

 

I would suggest removing the paint in those areas and sanding down to bare metal and then painting over the bare metal in any sort of rust prevention. Get some 3M Di-Noc Vinyl and wrap the roof in whatever type of vinyl finish you want! No need to pay for a repaint for your roof and you stop the rusting.

As Jesstzn said above, it looks like it started out as a small spot from impact damage and spread. It's always best to take care of these things when they are small

 

we have a couple of areas on the edge of the hood on our 11 yr old Accord. i asked my local body shop about trying to fix it. they said there was no way to repair it without completely replacing the panel. the problem being was that the rust/moisture have already contaminated the area and the "bubbles" would come back over time again. these bubbles formed on their own from under the paint, not from a rock chip. this is from a body shop i trust.

in the meantime, i just keep an eye out on it. hopefully it won't get dramatically worse in the next few years before the car is replaced. otherwise it'll be a costly endeavor to get the hood replaced and sprayed.

 

TL .. In all due respect.. The moisture has to get there somehow initially and its usually via a chip in newer cars . Older cars on lower panels it can come from behind. The shop might have meant that once its there its tough to repair and not have it come back unless the panel is replaced or the section cut and replaced.

The vinyl is a good option once the prep is done . Just make sure the repaired area is paint ready as flaws will show through. Blue Batmobile sells precut kits for the roof.

 

The bluebat overlays are nice, but at $185 for CF, its approaching respray prices around here.

Mine has the same look at the edge of the windshield to the roof. It doesn't look like touchup paint but that it is bubbling up from under the paint. I figured it was a bad windshield replacement that led to it. I also noticed that the OP is in Boston, and my car was from Boston originally. I think a snowy environment might help lead to some of these type of moisture/rust issues.

 

that's what i meant...in so many words. based on the location of the "bubbles" on our Accord (near the edge of the hood, front above the grill), the shop told us the moisture was coming from under the paint...kind of like you see on really old hondas or even toyotas in the rear quarters or fenders. my shop guys know how i am, so the half ass solution isn't an option. do it right or leave it as is.

for the OP's location of the "bubbles," it seems it could come from a rock chip or some other type of damage. not often one sees this type of paint damage on the roof (at least i haven't seen it). the vinyl wrap solution is a nice alternative if OP doesn't want to send the car off to the body shop.

 

the bubbling near the windshield usually comes from water collection over the years, its a sore spot in almost all cars somewhere.


There are quite a few ways to extend the life of the metal once rust is present without having to replace the panel, IF it has not eaten all the way through the sheeting.


I can post my the process I would recommend if youd like, to extend the panel life and hopefully stop the rust dead, but like the others have mentioned, to get that back to looking proper it would need to be resprayed.


I have worked in the body/paint field for almost 12 years now and have my own small private body shop where I specialize in restorations and high end paint work.

 

^please elaborate if you don't mind! I have a couple rock chips that are starting to rust, and am contemplating all options. If respray is what it is, then it'll have to be done eventually! My chips have not started to bubble like OP's, but want to prevent that if possible. Thanks in advance!

 

With cracked/open paint rust will relatively quickly spread, so you definitely want to take care of it as soon as you can. When trying to stop rust, surface preparation and sealant is the key to making your panel last. Once the clear has been punctured and moisture gets down through the basecoat, there is no way to fix it properly and be able to last without a tear down and respray. Im sure you've seen a hundred different adds for touch up paint and what not but that is a very temporary fix, that, lets be honest looks like crap and wont do much to stop the spread of rust.


When it comes to stopping rust, and saving your panel so that you don't have to either pay a shop to cut it off ( in the case of a roof/ quarter panel) or buy a new one. There are a few things that need to be done, in can get costly if you decide to tackle this yourself mainly because of equipment costs, but if you find a shop that knows what they are doing and can stand behind their work than they should be able to take care of it.


Here is my process for getting rid of small to large surface rust spots that have not eaten through the metal completely.


-Pre clean your panels


-Sand away the paint down to bare metal, if you have a quarter sized rust spot you need to sand at minimum a 2 inch diameter around that to ensure that you visibly have no rust spread.


-Next you will lay down a liquid rust converter ( such as ospho) which is the industry standard automotive rust converter used in most shops cause its the best, it stinks like high hell but does its job and since it is liquid it penetrates the smallest holes. Ospho direction say to let it sit for 24 hours. You will come back to have black residue that is now sandable. Ospho reacts with the rust to convert it to a sandable source. I repeat this process at least 2 more times to ensure that any rust that is reachable by the liquid ospho has been taken care of.


- Now, the next step is up to the shop/ user, its mainly preference and experience to what they use. Youll need to pre treat the surface again with a pre cleaner that is compatible with whichever type of material you are using. You will be laying either and etch primer or an epoxy primer. I personally prefer epoxy, in the debate of etch and epoxy primer, it is widely preferred and recommended that epoxy is used over etch primer. Etch primer contains and acid but is very thin, epoxy hardens and attaches itself to the bare metal in a different way but for longevity and superior protection epoxy is the way to go. Etch primer is old technology but a lot of shops still use it cause its just the way they have done it for years. Metal temperature is critical when it comes to putting down epoxy primer, if you cant maintain a steady temperature of at least 65 degrees for 24 hours than wait till you can, as you know metal expands just like everything else the warmer it gets, metal has pores, you want the metal to be as open as possible at the time you lay epoxy to ensure that you get the best adhesion, if its too cold the primer will have less of a bonding effect. let the epoxy sit for a day or so once its done.


- Next you will need to prep your surface for a round of urethane 2k primer, you always want to put a 2k urethane of epoxy to double your waterproofing and fill any inconsistencies in the epoxy base. 2 coats of that will be fine.


- next is your prepping for paint, a 2k urethane sealer is what I lay down before applying any color. Once the sealer is down than you spray your basecoat and clear, once this is all done you've just added multiple layers of protection to your metal and if you were thorough enough with your prep work your panel should last quite a many more number of years.

 

Thanks for all the feedback all

 

These are all pretty good techniques for taking care of this issue. Better to fight the rust then try to contain it. It will ALWAYS beat you, I promise.

Sanding it down to the metal and putting some primer and getting it re-sprayed would be the best solution I believe as mentioned.

@MORE IMPATIENT . Great feedback.