See last post. Welding and rubber sealant removal coming to the end. Thanks.

Haven't been very active for a couple of years. Partly because the 911 has taken up my time. So I am finally getting around to rust repair on my '76. The floors have rusted through so I have been working on the layer cake that makes up the right side longitudinal, focused on the hell region. The rust has affected both the inner pieces as well as the outer ones, and it is concentrated where all of the pieces come together.
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I have cut away the pitted and perforated metal. My question is as follows. I am addressing the problem by restoring each piece to produce a longitudinal as it came from the factory. For example.
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In this case I made a piece to restore the tab of the forward inner layer of the outside long.

Then I added a piece to restore the rear inner layer piece the overlaps:
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Then I have made a patch for the outer wheel house piece to produce the outer layer. The patches are butt welded to good metal on the original pieces and shaped to reproduce the originals.

Here is the question. Is this really best practice? For example, instead of making a bunch of pieces that join together to match the original I could use a single sheet that replaces them all at once. With fewer butt welds and seams. My method so far has been heavily influenced by threads from people I admire here on the world. You folks make nice welds.

That is no light project! I have digging into mine to do and hoping it's not bad. You've already done most of the hard work, remove and prep for new metal. Keep the pics coming!

Personally, i like to weld as little as possible. No matter how much care you take to prime the new metal, the welds will leave exposed spots that are starting points for new rust.

RD has a lot of replacement metal for your needs:
https://www.restoration-design.com/

In my experience, fitting a patch takes about the same amount of time regardless of the size of the patch. So three small patches might take three times as long as one big patch that covers the whole area.

I also like the idea of minimizing welds, which is what you get from a larger patch. And in these layered areas, avoiding having a weld in one layer lined up with a weld in another layer. Of course I picked up all this from the more experienced guys on this forum.

Use Cold Galvi weld thru primer instead of red - red burns off more than the Galvi when welding close by

I've learned from others over the years replacing larger pre-made sections can be less work than patching a number of smaller areas. Plus, it just looks cleaner in the end.

Grinding.....grinding, ugh.

FWIW -- RD panels are Galvaneal. The Zinc that is annealed into the top surface of the panel sheet metal will actually serve as a sacrificial cathode for nearby sheet metal and welds. Not perfect, and protection diminishes with distance from the Galvaneal panel, but, the Zinc in Galvaneal goes a long way toward holding off surface corrosion at the weld sites.

Thanks to all who replied. The way the rust worm turns it seems that all of the rust ends up at the overlap pieces that made up the original. Both inside and outside longitudinal pieces were in turn made up of inner and outer sections. The spot welds produce a wonderfully strong unit. In my case each and every piece has the last couple of inches rusted off. That is why I have started down the road of restoring each end one at a time.

Just spent a day in a frozen garage trying to avoid setting my car harts on fire. Making progress. My big problem now is dealing with the moat of metal on either side of the weld beam. Pictures tomorrow but the basic problem comes when trying to grind the welds flat. Bright middle, with dark edges, and then bright surroundings. The area around the weld has shrunk. Any solutions?
Thanks folks!

I have several orders in from RD. One problem is that the rust generally is affecting ends of panels such that I would have to replace 90-95% good metal to get rid of the 5% that is really rotten.

I think it was BBrock who suggested the Cu UPol primer. And it does seem to weld nicer than the Zn. I have sets of wire brushes welded to 3 foot quarter in rods to clean the old out of the longs. Cut where there are pits, use a rust converter to turn the rust to ferrite covered with vinyl sealler. That gets a coat of marine epoxy and that gets a coat of 3M cavity treatment wax. But between the layers there are places of clean metal plug welded to clean metal, and that is what is looking like copper.

The shop is pretty comfortable: about 50 degrees F when it warms up, but I still have problems with fogging the welding helmet. And I have an extra reading glass lens to fog. So, have to route the warm air away:

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The wheel house sheet metal right behind the battery was perforated, and the RD pressing doesn't seem to reach that far up.

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Here is the beginning pretty crude repair, but I will be able to get it from the other side. You can also see the reinforcing piece that lies inside the inner long. That is covered with epoxy. The wax material from three M will be sprayed in as the last step to reduce fire.
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A bit better. The worst part is the slight furrow on either side of the weld in the HAZ. Any suggestions? It is a new to me Hobart 135. I also have a Lincoln I can use, and a TIG.
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My childhood summers were spent in a 34 foot wooden boat anywheres from Puget Sound to Uclulet. Dad had zincs on the hull tied into everything metal. I figure I oughta just trail anodes from the bumper. This time of year you can encounter either blowing clouds of snow, or salt up here in the north. Turns everything white either way.

Of course the worst parts are inside. The inner long has a U-section on its side made out of heavier metal with corrugation. The lower part has rusted, but the upper two planes are solid. Made a piece out of 14 gauge for that. Welding upside down on my back adds to the fun. Thankfully Harbor Freight has improved their welding blankets. One spark ate through the Carhart, the sweatshirt, the other sweatshirt, the T-shirt, and then rolled along my side to end up underneath me.

On the upside we have this.
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and I quit yesterday with it partway put in.
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I could have approached things by replacing both inside and outside longs, along with their internal reinforcements, but that would mean removing both inner and outer suspension consoles. I did remove the right side motor mount, but that alignment is a good deal more forgiving in my mind than the suspension parts.

As seen in some photos the top of the inner longitudinal member was cut out because of pitting. There are reinforcing pieces inside, and fortunately they were shielded on top by the outermost layer.


Thanks for any and all suggestions. I have the RD rear floor, the crossmember and the firewalls yet to install as well as more welding on this onion. It is amazing how monocoque layering creates a sturdy shell

Your repair is great! Nice work so far. Keep updating us.

Lots of great advice in here. My only advice, I covered this exact same repair. I used a few new panels (outer long, floors) the rest I made myself.

It really went by much faster than I anticipated. I enjoyed it.

Made some progress this week. Got the wheel house panel in completely. Am experimenting with new techniques to reduce undercutting in the surrounding metal.
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The inner long has a heavy reinforcement section inside. Restoration designs makes it, but it rusted badly only along the lower flange where it flattens out to collect water and sulfuric acid and what ever else causes rust Here it is
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I fabricated a repair piece from 14 gauge steel because this piece was thicker than other body parts. Did my best to add the corrugations. This is all welding on my back covered with a welding blanket. Hardly enough room to get my helmet angled to see the weld. But persistence pays off.

I did more welding after this but since the longitudinal provides an out layer I left some ugliness be rather than grind everything off.
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Then of course there are floors to deal with.
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The floor carries many items for use on the new floor. I like the idea of reproducing the holes used during manufacture, and I need to pull out the plugs.
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and make new holes for them
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In order to remember where everything goes I have to save the pieces for awhile. Never throw them out till you have finished the project.
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The upside down welding involved solid metal that has been hit with rust converter to deal with surface rust followed by epoxy primer. This is inside the longitudinal. The best I can do is scour it with a wire brush welded on the end of a long shaft and spun with a drill. It won't readily return to its evil oxidizing ways and I will make sure to cover the parts burned off in welding by spraying with a narrow tube. That is what it is. Which means that I am welding my patches onto metal that isn't quite clean. And of course, that isn't pleasant even if the results are OK. You get flares and spatter. I was covered by a welding blanket, but I didn't put a welding sleeve on my left hand and my elbow caught fire. How do I know? I saw smoke rising from the left.

After spending a few hours on my back on the frozen floor (thank you Carhart) I decided to switch to the new floor. Welded on my seat reinforcements. Suddenly I was the god of welding. Clean galvaneal!
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And for those who think I have been slighting Restoration Design by making patch panels I have this to say.
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This is about half of the items from my first order. My second order came yesterday and today I ordered more new stuff from RD. They are really nice to work with. While I am at it I want to say nice words about Millennium Technologies. I am having a 911 cylinder over bored and replated, and they have been very nice to work with.

I have been measuring the door gap after every patch. Found that it was widening and installed the typical brace with a turnbuckle.
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Given the obvious strength of the longitudinal pieces I was surprised that I could move the door gap open and shut by twisting the turnbuckle. I should have known but was surprised to see this:

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Note how the patch panel is flexing. All of the butressing pieces have been removed. The door latch pillar, the outer fender and the inner and outer firewall pieces normally come together so this thin piece of metal can prevent flexing of the B-pillar and roll bar. Nice to know.

The inner reinforcement of the longitudinal has been patched and covered with a patch for the covering inner long piece. All of the layers are also stitched together with plug welds. Rust converter sealer followed by epoxy primer and I am ready to weld in a patch for the top of the inner long. Just under the battery tray. The inner reinforcement was in great shape here, probably shielded by the outer shell.

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This shot shows something amazing. The air and electric angle grinder tools cost about $10 a piece at Harbor Freight. So I bought enough of them so I don't have to wait to swap wire brushes and abrasive wheels: I have a tool for each. Great but also frightening. Before I close everything up, I spray what I can with this.
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And after some welding and grinding.
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The area under the engine mount is pitted, but I cut off a small square of this piece and it was very solid as the pits though ugly are not very deep. The same was the true for the back of the engine mount.
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This has been sanded rust converted for the pits and then coated with epoxy primer. Epoxy primer is a miracle for restoration projects. It bonds very well and unlike many other paints is actually waterproof.

Typically the right side of the car has less rust on the long. An unfortunate surprise is not this time. The car was originally purchased by a Baltimore Colts player, reportedly for his wife. You would think such a person would be able to park the car in a garage, but the rust shows that the car was parked slightly nose upwards in the rain. And of course by 2008 when I bought it, it was just a used car.
Starting the patch from the inside. Cutting away the bad like a layer cake. This shows the inside strengthening piece with the congregation. The diagonal edge is the original end of the piece. I have cut away the captive nut for the seat belt.
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The strengthening piece is thicker than the outside layer of the long. I am using 14 gauge for the inner and 18 gauge for the outer. Both just slightly thicker than the original.
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This is mostly done with a hammer and a vise, but I had to cheat a bit at the curved ends and cut and welded to get the deep shape. I maybe could make the thin outer pice by hammer forming, but with the 14 gauge I wouldn't have a chance. They have to nest in order to get the plug welds to be strong. I still have a ways to go to get them right. Then they go back in like a layer cake.

The inner strengthening piece holds the seat belt point. The metal around the nut had deteriorated so a new strap was fabricated to hold the nut.
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And welded in.
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And then the 14 gauge piece goes on with seam welds to the existing inner piece of the inner long. The seam is part way up, and I was glad to get the corrugations to line up.
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The outer shell of the inner long is thinner: 18 gauge is what I am using to match what I think corresponds fairly closely to the original 19 gauge.
Here it is being shoved into place.
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And welding has started to complete this side of the long
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The two parts are supposed to nest together with spot welds joining them. This produces a lot of strength. I used the inner piece as a strong anvil to completely form the outer shell to the inner. This works well, but leaves some small hammer marks.

I found perforation in the driver side engine shelf, so I cut half of it away. I am tempted to try to duplicate it with a hammer, but the easier move would be to dial Canada. Also, smarter move even though I find metal forming the most fun of the whole project. Along with welding. The grinding and the dirt and the working upside down: not so fun. Welding upside down in leather and gloves and hood and swathed in a welding blanket is kind of surreal; sort of like sensory deprivation with sparks flying.

Nice looking work and it appears your project was not tooo bad. Some of these hulks will never be close to original. Keep posting you work and thank you

Thanks. When you get rust on the left side there are fewer options. Not as many replacement panels for sale. You can buy the outer long, but in my case only the rear part of the panel is damaged at maybe the rearmost two inches. I think I can see the waterline from being parked in the rain. Rust from the inside out shows a slight nose up slant. Didn’t find any debris inside, but the rust was there in specific areas along the undersides.

Nice work.

Great repair job!

You are on a roll now.

John

Yep. Moving to the outside layer cake. I really hoped that the left side would be better, but it is slightly worse. Looks like the Counting Crows hit the nail squarely on the head. It was probably Raining in Baltimore much of this car's life.

At any rate this shows three layers of metal.
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There is the front outer long: rusted at the last two inches. This panel is made by RD, but that is a lot of cutting to patch that little part. In the rear there is the outer layer that goes on to make the wheel house and then a strengthening layer (with the punched large holes. This is made out of stronger steel. Fortunately I have a punch set. Not sure how close a match they are yet. Farther in the hole are the weld back sides of the repair of the inside long. Screws poking in are temporary: have to get them out and finish those plug welds.

Question for anyone who might know. Is it possible to replace the jack point without cutting out the fender and sill? I don't see how, but still wonder.

Been awhile but in the mean time I have been remodeling some rooms, rebuilding the 911 engine, and getting gifts made for x-mas (shaping and grinding Damascus steel kitchen knives).

Returning to the left side:
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like the right side I worked from inside out. Replacing the rear end of one piece.

This inner piece to the rear is overlapping the first patch. As before, I am replacing ends or bottom areas of a large piece. Matching the holes originally there was a PITA and perhaps I should have just them out, but here they are a bit of the ugly.
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The hole towards the front is behind a depression in the next piece that overlaps. The depression is for the jack point.
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The jack point has to be located such that it lines up with the hole in the outer rocker.
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Then yet another layer goes on
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Then a nice pressing from RD. Glad the DeJonges are here for us.
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So the left side is seeing some progress. All in an afternoon (at the computer)

Back to the right side. Spent some time fiddling with bits I didn't like and then welded on the jack point. And fabricated the next layer.
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On it goes
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And another perfect pressing
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Speaking of RD wonders, here is the rear part of the box beam that connects the longs from side to side.
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Note the cuts needed to get past the heater tubes.

For the parking brake and heater control tubes I took them out and will be brazing them back in.
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That was a killer on mine. Bled through in a few spots and had to get very creative to get the cables through

I just found this thread. Is this Creamsicle on the Can Am Registry?...and if so what is the VIN?

Sorry Jeff, it isn’t a real Creamsicle. Originally owned by a Baltimore Colt who bought it in his college colors of silver and white. Sold to a man who quickly sprayed it white and orange. It is a ‘76.
Warren

I know. I now use silver brazing rod. It comes covered with bright orange flux. Flows really nice. A bit pricey, but so is all of the irritation of fighting uphill.

Why do we punish ourselves with this crap??

Great looking work and soon she will be back on the road.

Thanks for the updates

As the Brits would say, I offered up the floor to see what I need to do to get that piece welded in. Looks good , except there is a bit that sticks out towards the middle of the outside firewall.
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I know that I usually have to do some work on the pressings in order to get them to fit right. Or do I need to unbraze some tubes and pull the firewall out?

Answer was - Yes.
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Then I could weld in the floor patch
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I have some advice to those who try this sort of thing. It has probably been mentioned by others: if you are going to paint the car after rust repair, strip the paint first. You never know what you might find underneath. Second piece of advice: Think about ways to get the project up and off the ground higher than jack stands. You can probably get a lot of the cost back on a rotisserie if you sell it afterwards, and in the meantime you get the full benefit.
In my case I found rust underneath the paint that made me get out the welder again. And I also waited too long to get the vehicle up on the lift, although for awhile the lift was occupied by the 911.

Here goes the paint.
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The wire brush will take away seam sealer - and move it all over the place.
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I knew about the trunk floor, and in front I am replacing part of the floor altered by long gone AC. But I didn't know about the sails. Shown with fabricated patches.
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and the driver side.
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Nor the area around the vents on both sides.
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You're not the only one who got started, found more trouble, and had to back up and go deeper.

And I strongly endorse a rotisserie for any serious body work. Even stuff "on top" is easier when the car can be rolled on its side.

The trunk floor supplied by RD is made for the earlier cars. 75-76 models had spring loaded bumpers to withstand small impacts without damage. That means at each side the floor of the trunk steps up. If I just install the new piece as is I will loose considerable trunk space. The reshaping requires that I first flatten out the little ribs pressed into the floor at the sides and then reshape to match the old.

Here is the frame that ties the bumper to the floor and other structures.
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And here is what it looks like outside with the spot welds drilled out
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I want to get different parts against the anvil so I had to get a bit funkifized with the string.

Here is what it looks like
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This is the trunk floor after some welding.
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I made several patches out of material left over from trimming the trunk floor, but to use them I had to hammer the ribs flat. I got tired of that and also ran out of scraps so I bought some galvaneal sheet from online metals. Same stuff that Restoration Design uses. Here is the transmission mount reinforcement cut from my new sheet of steel.
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I found that rust often lurks behind the rubber seam sealer. So, you don't know until you take it all out.
Guess what these are.
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Dedication

Wow! Nice work.

Charlie

Great job!!

Thanks folks! The piece of foam is from the very tip of the rear fender, just above the lights. I used a piece of cable and a piece of brake line to make a mini wire brush. In an electric drill you can spin it in either direction, winding or unwinding the cable. Crude, but gets into tight spots. I also discovered that the rubber sealer fears fire. A quick run with the torch and it softens. But it sure will make you dirty in a hurry! More to come.

Wow, way to go Warren. That was a task. Well done.

Kept hitting my head while backing out of the engine bay. My solution.
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I finished up the rear with a couple patches where metal was in layers surrounded by failed sealant. My favorite was this one, which spans two pressings - the rear fender overlaps the piece that covers the rear of the trunk.
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The two pieces were made separately and plug welded together before welding to the car. I flattened some of the left overs from the trunk floor piece and then reshaped. The seam is crooked, but I am not going to fix it.
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Another hole found. I had to buy the B-pillar pressings twice because I originally thought the rust didn't go all of the way to the top and fixed only the bottom. Had to carefully try to remove the plug welds, which is harder than drilling out spot welds.
This shows the new excavation with earlier fix still present.
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You can buy the B-pillar, but not the piece of the upper inner wheel housing. This goes from the engine bay all of the way through into the cabin. Again I hadn't bought my galvaneal sheet, so I flattened out a piece of trunk scrap.
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You can buy the tube that lets air move in and out of the cabin, but by the time I was done I had carved most of it away. The piece that holds the tube also holds the door latch plate.
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You can buy the piece that holds the door latch along with the nut plate. But, you can't buy the little box that houses the nut plate. I have seen some cars where the factory just used a strapp across the middle of the nut plate. This is a '76 and the box and nut plate were liberally covered in sealer...thus the need for repair
I used silver bearing brazing rod to attach the tube, but epoxy wold probably be just as good.
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Into the big hole.
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Not shown is the welding the patch inside where it meets that inner fender piece.

Why should the driver's side be any different?
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The sail rusted where failed sealer met overlapping metal and rain and road spray. Same on both sides. Patched.
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