Rust Repair
08-30-2011, 06:06 AM
#16
Rennlist Member
I pretty much figured that. Too bad. 
But Google was my friend. I think "art" is a well-picked term.
http://www.autorestorationandclassics.com/metal.htm
http://autoshop101.ca/autobody/leadloading.htm
I doubt that spot would use more than a few ounces, max. Might be fun to try before starting to cut. What's to lose except cash, time and use?
But Google was my friend. I think "art" is a well-picked term.
http://www.autorestorationandclassics.com/metal.htm
http://autoshop101.ca/autobody/leadloading.htm
I doubt that spot would use more than a few ounces, max. Might be fun to try before starting to cut. What's to lose except cash, time and use?
08-30-2011, 06:16 AM
#17
Three Wheelin'
Join Date: Sep 2003
Location: SF Bay Area
Posts: 1,526
Likes: 0
Received 0 Likes
on
0 Posts
For what it is worth replacing a quarter panel is not the end of the world. Just requires drilling out the spot welds and welding up a new panel. This can be done with gas welding or as Porsche did with a few panels brazing. Eastwood sells a spot welder.
For the repair in question replacing the panel is extreme. Personally I would go with gas welding or brazing after the rusted metal is removed. There is nothing wrong with using a little bondo if it is applied correctly. Just use a rust neutralizer to kill the any remaining rust and have clean metal. After the metal is welded in you can get some cold zinc primer followed by a good epoxy primer.
If you are planning on painting the panel - which I assume you would, it is better to strip the entire panel to bare metal. This is probably the first step. Aircraft stripper works well. The Restoration Shop sells the stripper and primer as well as matching paint. To make touch up easier I only go to the edge of the panel and leave the door jamb.
It is easy to get the window out. Home Depot sells some plastic shims for installing flooring. The ones I have are green and have two thicknesses. Take a screwdriver and slip it down the edge of the gasket on the out side. In the inside push up the gasket until it is above the lip on the car. Pry on the window moving it out and then use one of the plastic shims to hold the window out. Move over an inch and do the same thing. Just be careful not to pry on the edge of the glass. I usually start in the corner and work along the bottom. Even if the gasket is glued in it will come out this way and save the expense of a new window or gasket. When putting the window back in put some clear silicon on the lower part of the glass in the grove of the gasket and let it dry. Then use some 3M window sealer on the gasket to the chassis. The silicon is needed because the window can leak between the gasket and the glass. Since so water pools at the top it is only neccessary to use the silicon on the bottom part of the window. A string inserted in the grove of the gasket will allow you to put the window back in easily. Just push on the glass and then pull the string to pull the lip into the groove in the gasket.
You can use the plastic shims to protect the paint by inserting one between the glass and gasket and then use a screw driver to pry on the gasket. I assume in your case it does not matter much as you will probably repaint the panel any way. Spoting can be done with the new two part paints but it takes someone with more talent than I have to do a convincing job.
None of this is hard - just time consumming. Any competent body shop can handle such a repair. If you see rust by the window there is a very good chance there is rust on the rear deck under the spoiler. Best bet is to remove it. The drain channels get plugged up with dirt over time and cause water to sit and destroy the paint.
Finally there are companies now that do metal spraying to repair rusted panels. This is a faily new technology but might be the best way to get a permanent repair. I have not tried metal spraying yet but it comes highly recommended for repairing rust.
Good luck
For the repair in question replacing the panel is extreme. Personally I would go with gas welding or brazing after the rusted metal is removed. There is nothing wrong with using a little bondo if it is applied correctly. Just use a rust neutralizer to kill the any remaining rust and have clean metal. After the metal is welded in you can get some cold zinc primer followed by a good epoxy primer.
If you are planning on painting the panel - which I assume you would, it is better to strip the entire panel to bare metal. This is probably the first step. Aircraft stripper works well. The Restoration Shop sells the stripper and primer as well as matching paint. To make touch up easier I only go to the edge of the panel and leave the door jamb.
It is easy to get the window out. Home Depot sells some plastic shims for installing flooring. The ones I have are green and have two thicknesses. Take a screwdriver and slip it down the edge of the gasket on the out side. In the inside push up the gasket until it is above the lip on the car. Pry on the window moving it out and then use one of the plastic shims to hold the window out. Move over an inch and do the same thing. Just be careful not to pry on the edge of the glass. I usually start in the corner and work along the bottom. Even if the gasket is glued in it will come out this way and save the expense of a new window or gasket. When putting the window back in put some clear silicon on the lower part of the glass in the grove of the gasket and let it dry. Then use some 3M window sealer on the gasket to the chassis. The silicon is needed because the window can leak between the gasket and the glass. Since so water pools at the top it is only neccessary to use the silicon on the bottom part of the window. A string inserted in the grove of the gasket will allow you to put the window back in easily. Just push on the glass and then pull the string to pull the lip into the groove in the gasket.
You can use the plastic shims to protect the paint by inserting one between the glass and gasket and then use a screw driver to pry on the gasket. I assume in your case it does not matter much as you will probably repaint the panel any way. Spoting can be done with the new two part paints but it takes someone with more talent than I have to do a convincing job.
None of this is hard - just time consumming. Any competent body shop can handle such a repair. If you see rust by the window there is a very good chance there is rust on the rear deck under the spoiler. Best bet is to remove it. The drain channels get plugged up with dirt over time and cause water to sit and destroy the paint.
Finally there are companies now that do metal spraying to repair rusted panels. This is a faily new technology but might be the best way to get a permanent repair. I have not tried metal spraying yet but it comes highly recommended for repairing rust.
Good luck
08-30-2011, 10:14 AM
#18
Rennlist Member
08-30-2011, 10:22 AM
#19
Racer
Thread Starter
Join Date: Aug 2011
Location: Fayetteville AR
Posts: 324
Likes: 0
Received 0 Likes
on
0 Posts
I have done complete quarter replacement / floors / trunk pans and frame rails on a 69 Roadrunner. I have also installed a power brake booster in an early 911. The booster was way harder that the quarters, in one piece you had to a portion of the floors, bulkhead and front truck area. It was a real PITA. I am a long ways from doing the paint and body on the 928. Just looking for input. Thanks guys!
08-30-2011, 10:36 AM
#22
Rennlist Member
Were you just the spray guy or did you prep it as well? It is unusual to leave the bumper covers and headlights in place for a respray. Looks like you know how to use a spray gun though! 
As for the rust on your car, that is surface rust. If the metal is still good and solid I would sand blast it, treat it and put a thin coat of filler on it like Jhowell said. Cutting out and adding metal can bring new problems, like rust forming on the weld and cut lines because the underside with the factory coating gets compromised.
As for the rust on your car, that is surface rust. If the metal is still good and solid I would sand blast it, treat it and put a thin coat of filler on it like Jhowell said. Cutting out and adding metal can bring new problems, like rust forming on the weld and cut lines because the underside with the factory coating gets compromised.
08-30-2011, 10:51 AM
#23
Racer
Thread Starter
Join Date: Aug 2011
Location: Fayetteville AR
Posts: 324
Likes: 0
Received 0 Likes
on
0 Posts
Thanks Ted. I did the prep and the spray both. The bumper covers and headlight were sprayed separately, I took this picture as I was putting it back together.
08-30-2011, 04:29 PM
#26
Rennlist Member
The trick is getting someone who is good enough to butt weld in the patches (overlapping is for amateurs) and metal finish the area so all it needs is a very thin swipe of filler. All of which takes time and skill. As noted you wish to minimize the amount of metal replaced. Porsche used to sell portions of the 1/4 panel for just that reason. The bit around the gas filler might be easier to use a chunk of a 1/4 for the shape that should be easy to find and a small piece is pretty cheap to ship.....full 1/4s get expensive to ship.
08-30-2011, 04:52 PM
#27
Racer
Thread Starter
Join Date: Aug 2011
Location: Fayetteville AR
Posts: 324
Likes: 0
Received 0 Likes
on
0 Posts
Cut a piece out of a wreck somewhere at a salvage yard. Beats self made panels by a wide margin. A small overlap is not hurting if you make a small step on the edges of the new panel. The results will barely be visible. The hard part will be along the joint at the rear quarter windows. You may need to replace a part of the inner panel as well. No big deal really with a good MIG welding machine. First tack weld it into place. Than complete the welding.
08-30-2011, 05:53 PM
#28
Addict
Lifetime Rennlist
Member
Lifetime Rennlist
Member
You need to determine how large a piece you will need.....And "A small overlap is not hurting if you make a small step on the edges of the new panel. The results will barely be visible." The problem with an overlap even with a step is rust forming between the two layers of sheet metal if any mosture gets in.....
08-30-2011, 06:06 PM
#29
Rest in Peace
Rennlist Member
Rennlist Member
Join Date: May 2006
Location: Bird lover in Sharpsburg
Posts: 9,903
Likes: 0
Received 2 Likes
on
2 Posts
You need to determine how large a piece you will need.....And "A small overlap is not hurting if you make a small step on the edges of the new panel. The results will barely be visible." The problem with an overlap even with a step is rust forming between the two layers of sheet metal if any mosture gets in.....
08-30-2011, 07:23 PM
#30
Rennlist Member
I am accused in another thread of always thinking the worst. Here, however, I am thinking that just about every suggestion is worse than mine.
What you are going to find when you scrape the blistered paint off of this area is that the holes of rust are really not too much more than pin holes. A little more but not much. Then you will see that just small pieces of sheet metal will be needed to fill the holes once you have cut the rusted material away in the rust holes.
The welding can be done readily with a torch (oxy/acetelene) and even without the usual need to hammer weld the seams. Do butt welds. Then the total area(s) involved with patches will be very small and not so succeptable to rust in the future. You can cover the backs of the welds with primer and undercoating and they will likely last the life of the rest of the car, even with the zinc burned off.
The bigger you make the panel repair the bigger will be the area covered by burned off zinc, so keep them small. With the zinc coating on the car already it is likely that the rust holes are very small and isolated, so that the patches will not need to be very big. Since they are so small and in such a tightly curved area you will not need to do the hammer welding as stated above.
Bring it over here and I will show you how to do it.
Jerry Feather
What you are going to find when you scrape the blistered paint off of this area is that the holes of rust are really not too much more than pin holes. A little more but not much. Then you will see that just small pieces of sheet metal will be needed to fill the holes once you have cut the rusted material away in the rust holes.
The welding can be done readily with a torch (oxy/acetelene) and even without the usual need to hammer weld the seams. Do butt welds. Then the total area(s) involved with patches will be very small and not so succeptable to rust in the future. You can cover the backs of the welds with primer and undercoating and they will likely last the life of the rest of the car, even with the zinc burned off.
The bigger you make the panel repair the bigger will be the area covered by burned off zinc, so keep them small. With the zinc coating on the car already it is likely that the rust holes are very small and isolated, so that the patches will not need to be very big. Since they are so small and in such a tightly curved area you will not need to do the hammer welding as stated above.
Bring it over here and I will show you how to do it.
Jerry Feather