Rust Spot Due to Hack Job; Please Avdvise

MOMO3.2 · 07-14-2008, 10:39 AM

After deciding to address a small rust bubble on the inner edge of my front fender at the trunk/fender gap, I discovered this little gem.

It appears one of the PO's had "work" done or did "work" that they felt required a hole in this spot. There are two factory looking original wires that are directly across from this masterpience of a hole that I assume go to the headlights or oil cooler fan(?). I have yet to look underneath this area.

Anyway, I removed all the top rust with sandpaper and a Dremel. The rust colored material in the photos is left over silicone from the artfully executed patch!!! I am going to have to remove this from underneath. So, I really did remove all rust from the top. I will jack up the car and confront any rust from the bottom. The metal is not thin in the area. There was only a tiny bit of rust, so I really believe this hole was drilled intentionally to access the wires or it may have been part of some "custom" 1980's alarm work?

(1) How do I treat the bare healthy metal now?

(2) Do I have to have a metal patch welded in or is there a sound way to glue a patch(es)?

(3) Where does one get a proper metal patch?

(4) I assume I treat the whole area with POR 15 when patched?

Thank you very much in advance for any help/advice.

Sincerely,

Mike

P.S. My car is an 87 Carrera that has lived in SoCal for its entire life, so thankfully this issue did not get out of hand.

burgermeister · burgermeister's Garage

That's a pretty small rust hole to find when going after a small 'bubble' !! Mine have always been fist sized holes or bigger ....

Patch metal - any body shop will sell you a chunk. HD or Lowes sell it too, in 22 or 24 GA. A bit thin, but it ain't structural, and thinner is easier to bend. No sense getting galvanized for that small of an area if you want to weld it. Just bend an L in your shop vise. Welding will louse up your paint.

You could also JB-weld the patch in place IMO - it's small enough and it just has to keep water out. I'd patch it from the outside (underneath) if possible. It will louse up less of your paint, and if you POR-15 & seam sealer it, and Wurth SKS the patch from outside to boot, seems it ought to be good for quite a while. Actually, you could just slather the seam sealer over the whole patch and skip the SKS.

I'd probably go the JB weld route. Much easier, and you can always grind it off and weld if it doesn't work out.

But, I'm no body shop expert - I'm a garage hack, and my car does not need to be perfect.

Jim727 · 07-14-2008, 02:12 PM

The metalwork is a question I will defer to the experienced types.

As for the finishing, there are quite a few that like the POR-15; however, I just finished a trunk cleanup to get rid of some surface rust and cruddy battery boxes. I used the KBS products and was quite pleased with them. http://www.kbs-coatings.com/ (no affiliation). Their epoxy putty might be worth evaluating also.

Good you're getting it early - rust is the enemy.

Jim

scottb · 07-14-2008, 02:49 PM

JB Weld makes an incredibly strong epoxy putty. http://jbweld.net/products/jbstik.php

If you think you've got all of the rust, you might consider simply patching with the putty, smooth while still pliable, sand and repaint the area. I agree with the others, welding might mess up more of the paint.

Alternatively, clean the area thoroughly and then treat with Por-15 to neutralize the rust. THEN patch the hole with the putty, smooth, sand, and paint to match.

The Curator · 07-14-2008, 03:15 PM

JB Weld is in my opinion much stronger and better than the POR or KBS brand epoxy putty. I had both the KBS and POR epoxy putty seperate from the metal after a while. I went back with JB Weld and it holds.

MOMO3.2 · 07-14-2008, 06:49 PM

Thank you all very much for your replies. JB Weld it is! I gotta say that is a big relief. I want to be able to fix this my self.

Mike

Jagshund · 07-14-2008, 07:39 PM

If you're going to "JB Weld" it (I would suggest taking this opportunity to learn 'the ways of the MIG', but to each his own), at least be sure to cleanly, completely remove ALL of the affected metal. There appears to be some corrosion creeping into the surrounding metal that needs to be addressed. Regardless of geographical location, rust never sleeps . . .

scottb · 07-14-2008, 08:24 PM

Quote:

Originally Posted by 1968Cayman

There appears to be some corrosion creeping into the surrounding metal that needs to be addressed. Regardless of geographical location, rust never sleeps . . .

I agree. Be sure to get as much of the "cancer" out first. Then treat it with Por-15 to neutralize the little bits of rust that remain. Then use the JB Weld epoxy putty to repair the damage.

MOMO3.2 · 07-14-2008, 08:52 PM

I will make CERTAIN there is no more rust. As I originally posted, ALL the rust colored areas in theses photos are actually the remnants of the silicone gunk patch that was used by the original offender. I could not pull all the stubborn silicone from the top of the car. I will have to go underneath the wheel well.

Thanks.

Mike

john70t · 07-14-2008, 09:02 PM

POR-15 is like a liquid plastic coating. It works to seal the surface but it doesn't "neutralize" rust, it only coats it to slow further oxidation. It's also difficult to get paint to stick to it once it's dry. I'd recommend their primer, and/or spray the surface with regular primer while it's still wet.

A while back, I Por-15'd the entire underside, interior, and trunk of the pcar. As a test, I used up the rest on a rusty van frame with little prep. Mabye the can had been open too long, mabye the coating wasn't thick enough, mabye the lack of prep was bad, but less than half a year later rust spots started poking through the application.

You want to chemically treat the metal first with something like "rust mort" or other converters before covering it with anything. Sometimes even these only treat the surface, and when you scrape off the black "converted" rust there can be fresh rust underneath.
Follow up with a good zinc primer and then start to patch/etc.

Make sure to do the back side as well.

javadog · 07-15-2008, 03:51 AM

I am going to be the dissenting opinion here and suggest you take the car to a body shop and have the hole fixed by welding a piece of metal in there and painting it properly. I'd go ahead and pull the fender and look at the rest of the joint.

JR

Jagshund · 07-15-2008, 05:51 PM

Wasn't going to be the first to suggest that, but it would be the best course of action aside from (as I previously said) learning to do it yourself. If there's a lack of access to the proper equipment, chances are a shop can do it for around $300. Of course, if that's black, they'll have to blend a bit wide to get a real good match, and the price is only going up from there. Besides, the only parts I encourage the use of JB Weld on are critical components like control arms and wheels.

MOMO3.2 · 07-15-2008, 10:32 PM

1968Cayman:

I have already used JB Stick liberally to support my cracked brake pedal stem and have molded some into the shape of balljoint pins to combat a stubborn fit there. So. I figure it is fine to patch this hole.

On a serious note JR and with all due respect, I will save a fix like the one you suggest for the "big respray" down the road and only if there is some evidence that the rust has spread. There is no doubt, I have eradicated the rust. To me, pulling a fender off this car would be a big mistake under thesee circumstances.

Mike

Jagshund · 07-16-2008, 06:01 PM

I prefer Play-Doh for balljoint repairs. But only on my wife's car.

Fritz Peyerl · 07-16-2008, 06:45 PM

Momo3.2, please let us know when you leave your drive way, that way we can stay home and don't have to worry, when your ball joint fails or your brake pedal looses it's life.

burgermeister · burgermeister's Garage

Fritz, I like your avatar.

Hier kann man Sie noch erblicken
fein geschroten und in stuecken
doch sogleich verzehret sie
Meister Mueller's Federvieh.

(one of my daughter's favorite bedtime stories)

Real men use superglue to fix suspensions. If it holds the guy's helmet to the beam, how can it fail? Has anyone else ever wondered how the guy gets his arms from holding on to the beam to holding on to the helmet without falling? Seems like a difficult operation, and they never show the process. Must be a trade secret?

felix_browne · 07-18-2008, 05:24 AM

you are going to have to paint at least a portion of that fender so why not fix it the right way. JB weld is a great product and is really exceptional for certain things but i would consider filling a rust hole in a fender that size with anything other than metal a hack job. I don't mean to offend that is only my opinion. Also, you should really take the fender off anyway because that rusty area of the fender has presumably been in close contact with the tub for 20+ years and the likelyhood that there is rust on the facing surface, i would venture to guess is high (past experience). If you leave the bumper, valance and hood on the car re-fitting that fender after paint should be relatively painless. If it was me i would want to clean up all the rust in that area really well and fix it once rather than do some quick patch that would have to be fixed again 5 to 10 years down the road. just my .02
-felix