Dealing with rust bubbles

[Sarastro]

I'm sure you guys have a wealth of experience dealing with these--small rust bubbles coming up through the paint, perhaps dime size or a little bigger. Clearly, if there is a lot, you can cut out the metal and replace it. But what about small, single bubbles that just don't seem to warrant such treatment. Is there an easier way to fill them?

Back in my younger days, we could get fiberglass cloth and body filler, which could be attached from the rear to make a decent, sandable patch. I haven't seen this stuff for some time, though.

Also, I'm assuming that this rust is coming up through the metal from the back side. Is that usually the case? I suppose that sometimes the rust is just forming from the top side, under a paint bubble. Obviously, in that case, you can just sand it out and touch up.

 

[Britishautobody]

They still make and sell the fiberglass repair stuff,if you are trying to make a band aid.
Is there a easy way to fill a corrupted area and make it last and hold up like new, I'd have to say no. Just like with math there are rules, same with body repair.

 

[Sarastro]

Sounds like you're saying, then, that even for very small bubbles it's best to cut out the bad part and install fresh metal, correct?

 

[Bayless]

I think he was talking about holes or rust through. If the rust under the paint started on the back side then the metal is just gone. The real answer in that case is new metal. If it is just surface rust under the paint then that can be killed without having to replace it. unfortunately, the only way to know though is to take off some paint to see what's under it. One thing you can be sure of though is that it will only continue to get worse until you do fix it.

 

[Sarastro]

OK, that's pretty much what I had expected. I suspect that most of those bubbles are rust through from the rear, and if a couple places go all the way through, probably others are about to. So, replacing metal probably is not really doing a big job just to solve a small problem.

Thanks much for the info.

 

[JRC]

Fiberglass and patch can be found at Home Depot.

 

[mikeyr]

fiberglass ? wow, I would have never thought a serious rust discussion would ever include fiberglass. All that will do is hide the rust and when it comes back it will be much worse.