Shot some weld-through zinc primer on the panel:
Attachment 747021
Attachment 747022

And then on the repair area:
Attachment 747023

Especially inside:
Attachment 747024

That area is the end of the A-pillar, and is pretty much inaccessible when that giant hole isn't there, except for the little round hole in there, and the holes where the drain tube for the sunroof go through.
Attachment 747025

All the junk that fell down to the ground:
Attachment 747026

I went through two Dremel reinforced cutting wheels, and several rol-lok Scothbrite pads. Their sacrifice was worthy, though.

Next, I need to cut a couple patches and weld them in. I'm debating on how exactly I will do the patches. The rust seems to have been largely because two bits come together there, and create a mostly-sealed area that traps moisture. The inner piece needs to be sealed from outside, because it's the inside of the car, but I think I may leave/create some breathing holes in the outer piece. That location is covered by the inner fender, so there should be no direct splashing. I'm also going to coat the inner area with POR-15 after the first patch is in place, before I weld in the outer bit.
Some of that might get done this week if I'm not wiped out after work, but definitely will NOT get done next weekend - I'm working the video room at a local sci-fi con Fri-Sun.
http://www.fencon.org/, for those that are local enough to Dallas (Irving, actually) and of a science fiction bent.

While ordering some other stuff on Amazon, I decided to pick this up:
Attachment 746952

I'd made one out of wood that was serviceable, but this one was :tenbux: and adds the ring stand for the filter.

Seems to work well enough, though I either need to raise it, or have it at the edge of the table, due to my attached at-gun regulator.
Attachment 746953

I may attach a larger base to both raise it and make it more stable. It's fairly stable as-is, but it's clearly designed to be screwed down to a table or wall.

I finally made time to move on with rust repair.

Step one, find some replacement steel:
Attachment 746954
Chunks from a Harbor Freight blasting cabinet that I cut out on top to add a light.

CAD work:
Attachment 746955
Attachment 746956
Attachment 746957
Attachment 746958
Attachment 746959

Check fit, sand/grind, repeat, until:
Attachment 746960
Attachment 746961

Ready to weld:
Attachment 746945

Just got gas and changed out to .024 wire, so a couple test welds:
Attachment 746946

That looked OK, so off I go.

Jiminy fragging Christmas, the actual weld didn't go near that well.
Attachment 746947
I think maybe I should have wire-brushed the weld-through primer off.

Fine. "Grinder and paint..."
Attachment 746948
This will be behind another later, so, meh.

Speaking of, more CAD for that filler:
Attachment 746949

And said filler:
Attachment 746950

But first, that upper hole, while I can get to the back side for templating and such. More CAD (not shown,) and a little shaping:
Attachment 746951

I figure I could fill those pinholes above it with weld. Not only was I wrong about that, the weld on the filler didn't go well. You don't get a "before" because man, it looked *terrible*, and I was getting pissed off by that point - a sure sign that I should have stopped sooner.
I ground that mess down.. and opened more holes, as well as wrecking the edge of the larger hole below.
Attachment 746934
Attachment 746935
Attachment 746936
Attachment 746937

I stopped there. It was dark by this time, and I'm outside in the driveway. Not only did that go badly, somewhere along the way, I let the grinder get away from me and zapped the edge of my door:
Attachment 746938

Now I have to fix that, too. Argh.

Sunday, after several hours of killin' fools in Battlefield V the night before, I was in a much better mood.
Started out addressing how the hole in the outer layer had opened up, and my patch no longer fit. First, trim the ragged edge to something smoother than can actually be fabricated:
Attachment 746939

Not CAD, byt TAD (Tape-Aided Design):
Attachment 746940

Cut new additional patch:
Attachment 746941

Weld, grind, and adjust fit:
Attachment 746942
(The weld on that went a lot better - I neglected to take a picture before grinding, though.)

With that fitted, I need to patch the upper hole while I can still reach the back side for templeting and fitment purposes. Again, trim the ragged edges, then a little more CAD:
Attachment 746943
Attachment 746944

File and sand to fit:
Attachment 746930
(lower part will be tapped down after the vertical bit is tacked.)

Weld:
Attachment 746931
UGH.

Welder did not like welding here. Settings should have been spot-on for the metal, wire, and gas. It welded fine putting the two other patch pieces together. I *think* it's because I had to hold the gun a little further out than it wanted due to the tight space, and the gas wasn't shielding quite as much as needed. I should have probably upped the flow a bit.

Grinding down revealed some pinholes and a chunk that didn't penetrate properly:
Attachment 746932

I went through several iterations of weld, grind, find a hole, repeat. Finally, I got it down to no holes, and just lightly ground it, then primered:
Attachment 746933

It's ugly as heck, but it's solid. Fortunately, it can't be seen with the fender on.
This is where I stopped. It was 7 PM, and would be getting dark, and dinner was ready. I'll get to the other patch shortly. God willing, that should go a bit better. It's much more accessible. Then I will need to do some seam sealing, and paint, then replacing the brace that was spot-welded over all that. That should be the last of the rust up front - I'm dreading the entirely missing lower right rear quarter panel.

After the patch is complete, I can go back to more sanding and surface rust removal in the engine bay, then 2K epoxy primer, then red. Will have to remove the suspension and steering gear again, though.

Good Lord I hate rust.

More actual work - more rust repair! Still not done, of course.

Taped up the edges of the hole, since I did not want to be grinding cured POR-15 so I could weld later:
Attachment 746879

Applied POR-15, tried to get it all the way back in there:
Attachment 746880
Attachment 746881
Attachment 746882

Had some left over, so did the area where the battery tray goes, and some hard-to sand spots in the bumper mount areas:
Attachment 746883
Attachment 746884

While that was curing for the second coat (2 hours+) I thought about the driver's side, and decided maybe I should take a closer look there, as well, since I'd done a little repair there already with epoxy.

Attachment 746885
Attachment 746886
Attachment 746887

Not as bad, but glad I checked:
Attachment 746888
Attachment 746889

Trimmed the ragged crap:
Attachment 746870

I still need to trim the hole out to square for ease of filling.
So on this one, I think I may just weld the outer layer to the inner layer there at the cut. The inner layer curves back rearward at that point. I don't thein the outer skin above that point adds much strength, if any, though I may add still add a piece back in to help support the top of the fender/cowl right there, just in case. Probably just a corner, to prevent forming a catch basin like OEM.

Surface rust and seam sealer wire-brushed back:
Attachment 746871
Attachment 746872

This needs to be fixed:
Attachment 746873

The hose from the sunroof drain isn't long enough, and drips into the kick panel. This pic after primer show better what I mean:
Attachment 746874

I tried to pull the hose through more, but its brittle and just... broke.

Leftover grit from blasting still hiding out in the upper chassis member:
Attachment 746875

I blew that out, along with all the sanding dust and such from removing the rust and seam sealer.
I forgot something when I did that:
Attachment 746876
POR-15 is sticky and takes a long time to not be. So the grit and dirt got semi-permanently embedded in that particular bit of POR-15. I'll have to sand that down, if not remove entirely, when it dries. :(

Applied second coat, then headed out the the local RX-7 club meet, where my AE86 soiled itself and refused to start for an hour or so. Still don't know what that was about. Seemed like the mechanical fuel pump quit, but after letting it sit, it started up without too much fuss, and drove home perfectly. I'm glad Mazda went with electric fuel pumps way back.

Sunday, back at it.
POR-15 crept under the tape a bit, but still much less of a pain to clean up:
Attachment 746877
Attachment 746878

Patch in place.
Attachment 746863

I tacked what was lined up, then body-hammered the bits that were out closer in. It actually went pretty well for a change:
Attachment 746864

Still kind of ugly welds, but better. Didn't blow through anywhere. I did have to fill a couple small spots I missed, after I ground it down (which was the reason I ground it down, really,) but nothing major. Ground flat(ter):
Attachment 746865

Zinc primer:
Attachment 746866

And just to be sure, and to replace the old seam sealer that dried up and fell out of the factory seams, fresh seam sealer:
Attachment 746867

I'm letting that cure and will hit it all with some regular primer. I should probably mix up a small batch of the catalyzed epoxy primer, but, eh.
Also got after the grit in the POR-15 over at the battery tray location:
Attachment 746868

I'll have to re-do that application when I coat the driver's side repair.

While I had the welder and such out, I filled a hole in the engine compartment area where I removed a bracket, but got too zealous with the spot-weld cutter and went through. It went terribly. Poor penetration/adhesion, sputtering, crappy looking welds, pinholes. Took a bunch of tried, grinding it down and welding again, to get it somewhat presentable.
Can you guess what the problem was, beyond my lack of skill? The result was this reminder label:
Attachment 746869

...yeah. I turned the bottle off when I went to the store briefly. And forgot to turn it back on.
At least I remembered to check all my *other* settings before I started to weld then and at the beginning of the day. Good thing, too, because my wire speed dial has almost no resistance to turning, and will spin to some new, exciting value at the drop of a hat.
Hopefully that particular error won't happen again. I was surprised that it welded as well as it did, now.

Next update: more of the same, but on the driver's side! #wow

Great work on the metal repair!

Thanks! I'm hoping I can make enough mistakes here where it doesn't matter, cosmetically, so I can do a decent job on the right rear lower quarter where some previous owner let the antenna leak. I'm basically missing the lower 3" or so of body back there!

Still winter, and still working on the garage remodel/re-org, which is going well. I don't know if I'll actually be able to get a car in there completely, but I will at least be able to nose one in to work on it when I'm done, which will be nice.

While rearranging and putting up stuff in the garage, I found these:
Attachment 746372
The SE badge I found in a wrecking yard - it's broken between the "S" and "E", but I repaired it and repainted the black. No pins on the back, either, so it would have to use trim tape to mount it.
The black "Mazda" is an original part. The two silver ones are aluminum I cut on a waterjet years ago. One is polished, and the other is brush finished. Both are exactly the same size as the original part. I also cut two in stainless steel. Those two are on the '79. Well, one is, on the rear. The other is in the parts tubs at the moment, since the front of the car is disassembled.

Also this:
Attachment 746373

This is a spare of the wide gas pedal cover I made - the flared out part lines up with the brake pedal for easier heel-and-toe action (not that I can make my big ol' feet do that in this car...) This was my first attempt at the pedal cover, and I used the wrong setting to do the etching, I think. It came out a little rough. I also have no idea why I went with three "MAZDAs" instead of modeling the "RX-7" logo as well. I wish I still had access to that waterjet. I could make so many things with it...

Not dead.
Finally not cold, but was still renovating/organizing garage. Now COVID-19 sort of slowing things down. You'd think WFH might allow some time for that, but I'm actually *working* from home, since I'm in IT. Kind of saps the will, honestly. I'm at home, but can't do home stuff.
Will get back on it, though. Really want to drive my baby again.

Now if I can get someone to buy the AE86, I'll have some dosh to buy goodies, too. COVID-19 not making that easier, either.

I actually did something!
So, I had actually forgotten that I had removed the brace on the driver's side to assess the rust over there, but I found it when I organized all the parts from the project into something slightly more organized than "a pile".

Parts on the shelves, shelves are straddling the trans that was in the car.
Attachment 745667

I had made some mods to my media blaster (foot pedal operation, better vacuum attachment port, and more lighting) and was itching to use it, so I grabbed that brace and went to town on it.

Start:
Attachment 745668
Attachment 745669

Just some minor surface rust where it was sandwiched against the other panels.
The blaster worked fine. I was concerned that the pedal wouldn't flow enough air, but it seemed to be sufficient, and *way* easier on the hands.

Attachment 745670
Attachment 745671

And after some zinc weld-through:
Attachment 745672
Attachment 745673

I love making clean metal like that. Messy as heck, especially if you don't have a cabinet, but the end result is so satisfying.

Hopefully I can keep momentum and at least do some smaller stuff consistently on the '7.

Did some stuff, but first, while picking up a prescription for my sick wife, I found these at Walgreens:
Attachment 745613

1967 Toyota 2000GT, and a pair of 1974 Mazda RX-3s with their race pants on, all from Jada Toys. Nicely detailed, with opening doors, about 1/43 scale. All are RHD, BTW.
Walgreens also had the 2000GT in white with orange striping, all black with plain tires, and all red with plain tires. They also had modified NA Miatas in 2 colors, as well. Nice!

A week or so ago:
OK, so, frigging rust on the driver's side.
Here's what I got:
Attachment 745614
Attachment 745615

That entire area should be covered by another layer. For comparison, this is the repaired passenger side:
Attachment 745616

I cut the hole
square, for easier fitment, then cut and shaped a patch:
Attachment 745617

The lumpy sh*t above and to the right of the patch is JB weld I used to patch the pinholes I was able to see before removing the brace that was media blasted in the last episode. For reference, this is what the area should look like with said brace (passenger side shown):
Attachment 745618

I did the epoxy quite some time ago, before I had a welder. At any rate, some of it had to be ground back to clean metal in order to weld in the patch.

And then I did my usual stellar job of welding in the patch. Man, I need more practice.
Attachment 745619

Grinder and paint...
Attachment 745620
Attachment 745621

At least penetration was adequate. I did have to re-weld a couple spots where it wasn't, but not too bad. Also had to weld up a pinhole I found to the right of the patch while smoothing everything down. I didn't get it perfect because this is not only under the fender, but will be under another layer. Mainly ground down to make sure it's actually welded to the surrounding steel.

Next up was the broken sunroof drain hose. The end completely snapped off, and it was basically draining into the kick-panel (which has a drain itself, but I don't care to depend on that.)
Attachment 745622

Getting in the car, I note another thing I'll need to fix:
Attachment 745623

Drain hose, as noted above, goes through the kick panel area, passing above and forward of the speaker that mounts there from the factory:
Attachment 745602
Attachment 745603
Attachment 745604
(the thing with the grey stripe. That's excess primer from me spraying the inside of the rust repair that followed the hose.)

Drain hose going up, speaker, power mirror, and power lock wiring going to the door on the left:
Attachment 745605

The drain connects up to the sunroof in the headliner, of course. Up in this area:
Attachment 745606

Vinyl headliner, so it's all glued around the edges, and attached to the sunroof weatherstripping. I started to remove that corner, thinking I would replace the entire hose, then decided I didn't want to tangle with that headliner just now, plus the sunroof was actually stuck to the weatherstripping (pop-up sunroof, not sliding) and I couldn't open it easily, so I decided to punt and only replace the bottom bit.
I cut off the broken end, both to square it up, and to give me something to size a barb union with. It turned out to be 3/8" ID, or near enough. I just happened to have a couple of short lengths of 3/8" hose that came with a fuel pump or something in my stash of hose and tube, and hit up Home Depot for a union:
Attachment 745607

Fits!:
Attachment 745608

Shoved into the car end:
Attachment 745609

And poked through (with a bit of wiggling. It was a close fit, which is fine, and the remaining original hose is stiff, making it difficult to line up with the hole):
Attachment 745610

Excellent!

Now back to that rust.
CAD (cardboard aided design):
Attachment 745611
Attachment 745612

That corner bit folds, and will require a filler piece to make it work, I think. Will be able to tell more with the actual metal in there. The cardboard is a bit too floppy.
That's as far as I got on that, but I got a couple other things done as well. I do intend to POR-15 that area before welding the next layer on. I really don't want to have to ever deal with this again.

I did note that I'll need a new windshield before I can re-register it. There's a new crack right across the driver's view. That wasn't there when I parked it
Previously, it was only the crack at the bottom, and up the passenger side, which were fine per the law. I mean, I was still going to replace it, but now it's a "have to."
Attachment 745599
Attachment 745600
Pictures of cracks in glass are difficult to capture...

As it sat then:
Attachment 745601
(I do throw the fenders and hood back on, just hanging there, and put a car cover on it.)

Saturday, the Fourth of July, I did approximately jack. So Sunday, I made myself go out and work on the RX-7 a bit.

Last episode, we had a template:
Attachment 745587

Now we have it marked out on actual steel:
Attachment 745588
(This was the casing for a VCR, as I recall. This is the drop from when I made new glove mounting rings - well, ovals, actually - to replace the melted plastic ones on my blasting cabinet that survived a fire. It's a little light, at about 22 ga., when the car is mostly 20 ga., but it'll do here.)

I still haven't made a mount for my vice on the workbench, so I attached it temporarily to my welding table to bend up the patch.
Attachment 745589
I probably should have used my smaller one. It's got sharper corners on the jaws. This one is pretty beat up. I really should build a small bending brake to clamp in it instead.

Test fit #437, before bending the corner bit, as that doesn't affect fitment, but fitment will affect it.
Attachment 745590

This is after the vertical corner at the top (behind the cardboard) was welded to set the position, so I could then trim the angled corner to fit:
Attachment 745591
The cardboard is to make a pattern to fill the gap at the top that I completely failed to measure properly.

Said gap filler in place (overhanging end will be trimmed after welding):
Attachment 745592
And you can see the corner weld I was talking about.

Welded inside:
Attachment 745593
and out:
Attachment 745594

Outside welds are marginally better. For one thing, I wasn't worried too much about penetration on the outside welds, as that's mainly for appearance.
A couple rounds with the flap-wheel got me to here:
Attachment 745595
FWIW, none of the welds flaked off or broke, so I guess they were adequate. I didn't try to dress the inside welds. Out of sight, out of mind. Actually, all of this will be out of sight... but I think of it as practice for stuff that *will* be visible.

Another hour or so of fettling, trimming, careful disc- and belt-sander work, and the fit is acceptable to me. I'm not ecstatic about the gaps, but they are manageable, I think. I *probably* should have made this two or three separate pieces, welded together in place. Ah, well. I'm not up to the Binky level yet, obviously.

Since I had the upper hinge loose to get it out of the way (the weld will be right at the angled edge of the hinge,) I took that opportunity to de-crustify it.
Before:
Attachment 745596

After,
Attachment 745597
Attachment 745598
Sooooo satisfying.

I threw the patch in just to guarantee a good surface for painting.
Somehow, I didn't take pictures, but the hinge bolts also went in the cabinet. They cleaned up beautifully as well.

I got out the POR-15 to coat the area that will end up behind the patch, and, while I was at it, I cleaned up the hinge mounting point (no pic), and the rusty area outside of where the dead-pedal mounts:
Attachment 745583

And then put POR-15 on all of it (once you get POR-15 out of the can, you have to use it or lose it, and there's only just so little you can pour out):
Attachment 745584
Oh, hey, hand shielding the camera from the setting sun!

Slapped some galvanizing weld-thru on the hinge and patch:
Attachment 745585

and the bolts:
Attachment 745586

I could plate these bolts, but I think I'll paint them for this location. Or not. I reserve the right to change my mind when I start plating stuff in batches.

In between dealing with sick wife and hospital, and, honestly *to deal with sick wife and hospital*, I did some things in the garage.
Over the weekend I found the energy to get out and
weld in the patch on the RX-7.
Used a couple hard drive magnets to hold it flush and in place:
Attachment 745517

And then made a travesty:
Attachment 745518

Seriously, I am so glad this is going to be out of site. I'm not sure if it's my technique, settings, or the welder not feeding consistently or something. Penetration seems to be OK, and I didn't burn through until I went to re-weld some spots after grinding, so, functionally, it's fine. Just ugly.

Speaking of grinding:
Attachment 745519
The stuff on the upper, and the left side of the photo was difficult to reach, and, as noted, will not be visible, so I just hit it enough to knock it down and stress test it a bit.
The bit that's ground flatter is marginally visible from inside when the door is open, but realistically not much.

Primer coat. Not worried about the possible pinholes in the welds, there - it;s mostly double-walled there, and I'll be hitting it all with seam sealer.
Speaking of which:
Attachment 745520
Attachment 745521

This was messy without disposable gloves...

And, the door hinge reinstalled:
Attachment 745522

Next session, I might pull the lower hinge and clean and paint it.
At this point, I can weld both of the braces back in. I may tape off the spot/plug weld areas, and hit the rest of what will be hidden with POR-15 to seal it up, though I can probably just roll with the cold galvanizing. After all, those areas were only primered originally, and weren't rusty.

added oddity: I got seam sealer on the screwdriver I used to open the caulk tube of seam sealer. It dried, so I used my wire wheel to get it off of the screwdriver, and discovered just how pathetic the chrome plating on HDX screwdrivers was:
Attachment 745523
Attachment 745524

Went right through the "chrome" and nickel layers. If there even was a chrome layer.
At least the copper plating seems up to the task.

Decided to attack replacing the braces today, starting with the driver's side.

I hit the spot weld areas with a scotch-brite wheel, on the theory that the weld-through zinc primer might have been causing some of the welding issues, then clamped the brace in place. the drilled spot welds make it easy to line everything up.
Attachment 745511

And then laid into welding:
Attachment 745512
Attachment 745513

I finally figured out the welding issue about here:
Attachment 745514
Definitely looking better.


It felt like a feed issue, so I turned off the gas, and just started pulling the trigger, looking at the wire coming out, and had the door open to observer the spool. Sure enough, the feed would stall fairly often. The motor was actually stalling. I could grab the wire at the tip and pull it, but the feed couldn't push it. I took the tip off, and it fed just fine, so it's not a liner/feed tube issue. Checking the fit of the tip over the wire, it was tight. Too tight, obviously, even though the tip and the wire are supposedly both 0.025" (0.6mm) spec. I ran a 0.6mm drill through it to make sure, and that helped a little, but not enough for my liking, so I drilled it about 3/4 the way through with the next size up I had, 0.8mm, leaving about 1/4" at 0.6mm. that seems to have done the trick. Feed was consistent after that. Made things much nicer.

Primered:
Attachment 745515
Attachment 745516
(the primer is still drying in the pictures, hence the mottled appearance in places)

I ground the welds on the top back to prevent interference with the fender, but left all the other ones alone.

I need to do the passenger side, and probably go ahead and clean up the other 3 hinges, then I can get to sanding everything in and around the engine bay smooth-ish, so I can lay down the epoxy primer everywhere.

Nice to be putting parts back on the car!

You're really doing a nice job and going the distance on the car! Nice job thus far! What ever happened to that light blue FB you were robbing parts off of?

I like how you put everything out there. Welding is tough! I've only ever done enough with an arc welder to be just awful at it. So much harder than it looks.
And I hope everything goes well with your wife.

It's in the backyard, still serving as a parts source, and storage for other spares.

Thanks. Welding is just a matter of a little knowledge, and a lot of practice. Of course, it also helps if your equipment operates properly! thin gauge metals make it a bit harder, but again, practice - which I don't have a lot of. Most of my previous experience was with heavier stuff, and that's fairly easy. Honestly, if everything is set correctly, and clean, it *is* fairly easy, with a little technique and the aforementioned practice.
Thank you for the well-wishes. She's home and much better, now that the colitis infection has been dealt with.

Sunday, I made myself get back on the RX-7, and I'm glad of it. Felt better once I got going. Fighting the lazy/apathy.

Started by removing the lower driver's door hinge and the passenger upper.
Of course, there was a bolt I couldn't get to with the door closed on the lower, that I couldn't see until I removed the door-holder spring:
Attachment 745445

So i had to put all the bolts back and remove that one with the door open:
Attachment 745446

Hinges before:
Attachment 745447

Bolts and upper hinge after blasting. Driver's lower is still in the blaster.
Attachment 745448

Mounting area is a little crusty on the passenger side.
Attachment 745449

...poop. I didn't even look at the driver's side lower. I'll do that before I reinstall.
Got those painted with the zinc paint (no pics - looks just like the after, only a different grey :),) then got started on reinstalling that brace on the passenger side. Procedure was the same as the driver's side, though I had to clearance one of my welds a bit for fitment:
Attachment 745450
and clean the seam sealer off of a weld point at the top (which happens to be just around the corner from the weld that was clearanced):
Attachment 745451

All welded up. The MIG behaved much better now that it feeds properly.
Attachment 745452

Ground the top ones down:
Attachment 745453