In need of a practical rust fix through rear trim panel

[limenuke]

The rust damage is seen here. It's all along the gasket mount as well as along the bottom. The little black spot along the skyward facing surface - that's a hole. The dust is from me sanding the rust down and just exposing some of it.

http://i.imgur.com/z6qrQ.jpg

I am considering 1 main way of doing this. If you don't think my method's good, let me know. If you can recommend some products, let me know. I do not know much about rust removal products...I only know ZR and POR are for AFTER you've gotten rid of the rust.

I plan on grinding all the rust down. This will undoubtedly expose holes. I honestly have no idea how much I should grind it down or how I'm going to get a clean grind on the gasket mount edges...it looks finicky. After this, I assume I should throw down some rust-conversion product. Crappy tire/wally world probably is not to be trusted for this so let me know what you think I should get.

After the rust converting product, I plan to throw down some some primer followed by a skim coat of evercoat rage gold. The purpose of this is to build a relatively even surface over the rusted areas. Then I plan to put down a couple layers of fibreglass over the damage. I do not know if I should lay the fibreglass such that it goes over the gasket mounts or if I should avoid adding any bulk/width to the gasket mount. I feel that if I add width to the gasket mount, that will undoubtedly cause some gaps when the rubber is fitting over everything - which exposes everything to water. I don't want that.

After the fibreglass goes on, I think I want to put down another couple coats of evercoat, sand it even, primer it and then spray it.

Any gaping holes in my plan? Any ideas? The main reason I don't want a new panel welded in is because it is pricey as heck and this car is mostly a beater. I just don't want it to look like a beater. I expect to get rid of the car (sell it) within 2-3 years so I want the fix to hold for a decent amount of time.

[Len]

The rust damage is seen here. It's all along the gasket mount as well as along the bottom. The little black spot along the skyward facing surface - that's a hole. The dust is from me sanding the rust down and just exposing some of it.

http://i.imgur.com/z6qrQ.jpg

I am considering 1 main way of doing this. If you don't think my method's good, let me know. If you can recommend some products, let me know. I do not know much about rust removal products...I only know ZR and POR are for AFTER you've gotten rid of the rust.

I plan on grinding all the rust down. This will undoubtedly expose holes. I honestly have no idea how much I should grind it down or how I'm going to get a clean grind on the gasket mount edges...it looks finicky. After this, I assume I should throw down some rust-conversion product. Crappy tire/wally world probably is not to be trusted for this so let me know what you think I should get.

After the rust converting product, I plan to throw down some some primer followed by a skim coat of evercoat rage gold. The purpose of this is to build a relatively even surface over the rusted areas. Then I plan to put down a couple layers of fibreglass over the damage. I do not know if I should lay the fibreglass such that it goes over the gasket mounts or if I should avoid adding any bulk/width to the gasket mount. I feel that if I add width to the gasket mount, that will undoubtedly cause some gaps when the rubber is fitting over everything - which exposes everything to water. I don't want that.

After the fibreglass goes on, I think I want to put down another couple coats of evercoat, sand it even, primer it and then spray it.

Any gaping holes in my plan? Any ideas? The main reason I don't want a new panel welded in is because it is pricey as heck and this car is mostly a beater. I just don't want it to look like a beater. I expect to get rid of the car (sell it) within 2-3 years so I want the fix to hold for a decent amount of time.

If I were doing that job I'd grind off the paint but not try to grind away rust that is pitted or not on the surface. You don't want to weaken the metal by grinding it until it's too thin. Remove as much rust and paint as possible by grinding over the high spots then go after the low level rust. A small blaster works best on small areas but you can also wire brush to remove loose rust then treat the metal with a rust converter like Picklex 20 then scuff and level the surface with body filler before priming and painting.

If you have holes in the metal you should try to cover them by welding in a piece of metal or by using foil tape because the work doesn't last nearly as long when you allow the filler to go into the hole. Use either an All Metal filler or fiberglass short strand filler to seal the surface before leveling it with standard body filler.

Picklex Link


Foil Tape Link



Short Stand Fiberglass Link

Check out the procedure for using foil tape and fiberglass HERE.

[limenuke]

Hey Len! Thanks a ton. I wouldn't have thought of not grinding right down to the lower level rust. I don't have a small sandblaster to work with, so I'll try the wirebrush. If I leave the low level rust in the pits (I know exactly what you mean) and just try to use rust coverter on it, should I expect the issue to come back in the next year? It seems the saying around here is that "rust never sleeps".

This is a really weird idea I had but...what if I grind away all the surface rust as you suggest and for the pitted rust, I treat it with wd-40 as well? I'll use solvent to remove the wd-40 prior to laying anything down...The idea is that I want to displace the water that the rust is holding so that I can completely "dry" out the metal.

Also, do you think that I should lay down the fibreglass after a coat of primer? I think that in the state of the piece right now...it might be nice to have a build of some material that won't be metal...especially since the way the car is engineered is such that water is always left sitting along that area after wet weather.

[Len]

Hey Len! Thanks a ton. I wouldn't have thought of not grinding right down to the lower level rust. I don't have a small sandblaster to work with, so I'll try the wirebrush. If I leave the low level rust in the pits (I know exactly what you mean) and just try to use rust coverter on it, should I expect the issue to come back in the next year? It seems the saying around here is that "rust never sleeps".

This is a really weird idea I had but...what if I grind away all the surface rust as you suggest and for the pitted rust, I treat it with wd-40 as well? I'll use solvent to remove the wd-40 prior to laying anything down...The idea is that I want to displace the water that the rust is holding so that I can completely "dry" out the metal.

Also, do you think that I should lay down the fibreglass after a coat of primer? I think that in the state of the piece right now...it might be nice to have a build of some material that won't be metal...especially since the way the car is engineered is such that water is always left sitting along that area after wet weather.

Welding in new metal is always the best way to fix rusted out piece of sheet metal and once you decide to skip the welding then the work is much more time sensitive. If you cut any corners or mishandle any of the steps involved in the process you can greatly shorten the life of the repair.

NO WD40, you're only asking for trouble with that, save it for your bicycle chain or whatever, it doesn't belong on this repair.

Once you grind over the surface just wire brush the low spots to loosen the rust and blow it out then apply your rust converter. There is a BIG difference in rust converters and the cheaper converters that I've used are not as aggressive at neutralizing the rust as the Picklex 20.

You can prime before you apply the tape and filler but you MUST make sure that the primer that you use doesn't not have ANY acid in it. A good quality epoxy primer will work but, again, make sure it contains NO ACID.

It's true that "rust never sleeps" but if the repair is done properly and moisture is allowed to dry then you shouldn't have another problem at that spot for a long time.

[another2centsworth]

WD40 and Armour All should be banned from the paint/prep area. Period.

[limenuke]

When a person says they want to use armor all, they do not realize that it leaves behind residue. When people say they use WD-40, they understand it penetrates and leaves a shitload of residue behind. The only reason I considered WD-40 is because it might be good at penetrating the rust...it'd leave an awful surface to adhere to...which is why I'd probably try to clean it off with methanol. But seeing as how Len reccomended against it, I've not gone that route.

Instead, I followed his directions. I used rust remover (Pro Form) and wire brush in alternating stages such that I could see the rust and remove it. I did as much as I could and then left a coat of rust converter on. Rinsed + Dried it all out using a hair dryer. Applied the foil tape and roughed it up with 80 grit. I then applied primer. After the primer cured, I didn't want the want the area to ever fall be penetrated by water again so I sprayed Rocker Guard over the primer. I let that cure... Now I'm fibreglassing over it.

[hrdchgr]

I know this post was a while back.. but you said you put the rock guard on there before the filler... interesting on how it looks now.. (few months later).

[Len]

I know this post was a while back.. but you said you put the rock guard on there before the filler... interesting on how it looks now.. (few months later).

I didn't see this situation or I would have advised against applying filler over rock guard because the rock guard remains somewhat flexible and would not be a good foundation for filler.