repairing rust

[John_E_Janowitz]

Hi everyone, I have a 91 civic and a 93 prelude I'm working on. I'm to the point where I'm starting the body work before putting on the body kits. The civic has a lot of small chips on the hood. I can handle those pretty easily. A few small dents are also no big deal. Painting is also not an issue. I spray speaker cabinets with automotive finishes for a living and have a nice spray setup already.

What I am a little more concerned about are the few rust spots that are all the way through. There are 2 spots, one on each rear quarter, right above where the bumper cover comes up to the wheel well. The one had been bondo'd up by the previous owner of the car and then it was repainted over it. Now the rust has come back. I want to do whatever I can to keep it from happening as quickly again. I realize it will eventually come back, but I also realize I can do things to delay the process as much as possible.

Does anyone have tips on what to do? What to use as far as materials, what to spray on the inside as far as chemical rust stoppers, etc that will help with the situation. The 93 prelude has about the same situation as the civic. I just don't have $800 to spend on a clean set of rear quarters, and don't have the experience to take on a welding process like that anyway.

Any tips on what will keep the rust away as long as possible are appreciated.

John

[PreludeMOFO]

i got a 94 prelude and the same rust appear at the same spots on mine as well.

whats causing this and how do i get ridda them?

[John_E_Janowitz]

Well, I actually got a body repair manual today and learned a few things, some I already knew. Here's a little summary of what to do.

The rust there is a very common thing. Water builds up behind that little lip and sits there, and you get rust through from the inside out. A few things can be done to prevent it. A good 3M rust proofer, not an undercoating, can be sprayed on to prevent the rust.

Once you have the rust, it's a little more difficult to get rid of. What many people think to do is cut most of it away, put a backer behind it and fill it with bondo. This is a very poor thing to do. Some fillers actually absorb the water and hold it there, creating more rust problems.

The best way to fix it is to weld in new quarter panels that are clean and rust free, then do the preventative rust proofing to keep them from rusting. I found quarters for the 93 prelude but they aren't cheap, about $400 each, and as I said, i'm not an experienced welder.

My holes are small enough that I can actually use fiberglass to fix them. This is the preferred and suggested method for small rust holes. You can get the fiberglass repair kits from any automotive store.

You start by cutting away the fully rusted section. If you don't have fancy tools, use a tin snips, grindin wheel, etc.

Grind down to bare metal 2"-3" from the rust in each direction.

Use a rust arresting chemical to the surrounding metal, especially on the inside of the panel. This is the stuff that turns rust into a hard black substance that is chemically stable and won't eat away at the metal more.

Once you have that all cutout and treated with the chemical, you need to make a small recess around the hole extending about 3/4" behond the hole. Bend the metal in with vise grips and a body hammer to make the recessed flange.

Once it is recessed you cut a piece of release film 2-3" larger than the area. Cut a piece of fiberglass the same size as the area. Then cut another one about 1" smaller all the way around. Use scissors and not a knife so you don't pull the fibers.

You need backing for the hole, so use something like a piece of steel wool on the back. Make sure when you're done you pull it out or it will rust again. I guess you could use some kind of tape or something too just so you have something for the fiberglass to go up against.

Mix up your resin. Put the release film on a flat surface and spread a layer of the resin on it. put the smaller piece of fiberglass mat onto the cloth and work another layer of resin into it. Then put down the bigger piece and work a layer of resin over that.

Pick this up by the release film and place it over the area with the film out towards you. Slide a spreader over the flim to press the fiberglass cloth firmly against the metal. Work out all the bubbles. Let it dry for awhile and every so often check to see if the resin is tack free. Once it is, pull off the release film.

Let it dry well, then you can begin to sand down the patch to match the body contour. Then you will use body filler or glazing compound to get a nice smooth finish ready to paint. Then primer and paint like any other situation.

The critical parts are removing ALL of the rust at first, treating with the chemical, and getting the fiberglass down good with no air bubbles.

I'll be doing this on the civic and prelude this week. If anyone is interested i'll take pics throughout the process.

John

[Masta]

yes, take pics plz. thnxs