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alfadriver
alfadriver MegaDork
1/10/23 3:23 p.m.

And welded it 

alfadriver
alfadriver MegaDork
1/10/23 3:24 p.m.

Primed 

alfadriver
alfadriver MegaDork
1/10/23 3:25 p.m.

And I had some time to take a first cut at the body patch. 

alfadriver
alfadriver MegaDork
1/10/23 3:28 p.m.

It's curious that this side patch is too big- too long front to back. Although there's a real minor crease in the patch that is right where it should be cut. 
 

But it should be easy to fit for that. The trick will be to trim it back to my cut line. 

Carl Heideman
Carl Heideman
1/11/23 11:20 a.m.

Glad to see you're working on this again. I've put hundreds of doglegs in cars, mainly British. I have a Miata that I have to make similar repairs to. I ordered the commonly available patch panels that repair the dogleg and wheel arch and am not very impressed with them. So it doesn't surprise me that the patch is too long. I don't know if I'm going to use the patch panels or make my own (I've got some tools).

There are a lot of pictures on the Eclectic Motorworks website showing how we weld doglegs in MGBs and MGAs that may give you some ideas.

Good luck and keep going! You've owned that car so long and it will be cool to see it back on the road.

alfadriver
alfadriver MegaDork
1/12/23 1:28 p.m.

In reply to Carl Heideman :

The amount wrong seems straightforward to deal with, especially since it's a small part of the patch. 

I do have a question you may help with in terms of tucking the patch under the original- I'll take a picture next time I'm with it. 

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
1/12/23 1:37 p.m.

Dodgy aftermarket patch panels are part of the British sports car experience, no? ;)

alfadriver
alfadriver MegaDork
1/12/23 3:03 p.m.

In reply to Keith Tanner :

The passenger side fit perfectly, just the drivers is not quite right. 

alfadriver
alfadriver MegaDork
1/17/23 12:59 p.m.

So here is the question. Is it ok to flange the patch panel to go under the original panel, making a water trap?

alfadriver
alfadriver MegaDork
1/17/23 1:00 p.m.

And a close up

alfadriver
alfadriver MegaDork
1/17/23 1:06 p.m.

Ignore that it's far from level- it also needs some finesse to fit right... But I have a flanging tool for that crease.

What I'm concerned about is that it will result in a panel that can trap water.  This is pretty high up, and wasn't damaged, even with so little coverage, so in theory it's going to see very little water.

Carl- you've had to have patched a panel like this- is this ok?  By far, it's the easiest welding- as the butt welding will be pretty small.

For sure, the back side of everything will have some good primer- some weld through primer on the back side, too (not the welded part, just the back.  

This isn't for investment, but as a good looking Miata to be a 2nd main car, anyway.  

classicJackets (FS)
classicJackets (FS) SuperDork
1/17/23 1:26 p.m.

I replaced that same section on the Miata I had, ~2 years ago. First, I agonized over the interior patch, so nice job on knocking that out!

 

I cut /filed a slight gap into the fit you are showing - and just butt welded. The folks who seem to know better/do this often ( and a lot of whom I've read on here) seemed to suggest a slight gap (like 1 mm? did I make that up?) to allow the wire to feed in between the panels vs just building on top. I didn't fully finish grinding mine down after before priming, but it came out pretty solid - and I am far from an experienced body-worker. I'll see if I have pictures..

 

alfadriver
alfadriver MegaDork
1/17/23 1:30 p.m.

In reply to classicJackets (FS) :

I'm really good at blowing through some sections of the weld- and I know the flange weld is easier to pull off.   Some if it will still be butt welded, though.

classicJackets (FS)
classicJackets (FS) SuperDork
1/17/23 1:34 p.m.

Definitely fair enough. I also realized I patched mine much higher up the panel, too. 

I would imagine it wouldn't be terribke for the joint. You would fill most of the flange with weld/new metal, and only have a little space where filler would smooth it out. I would imagine that should keep you nicely covered for another ~20 years.. 

I sold mine for a Camaro. You definitely made the right call keeping this one!

Carl Heideman
Carl Heideman
1/17/23 9:27 p.m.

In reply to alfadriver :

Your self-knowledge is a good thing, and if you're not comfortable butt welding, the lap weld will be fine. A well done lap joint will last a lot longer than an iffy butt joint.  However, I'd flange the Miata side, not the patch panel. Lay the patch panel on top of the Miata side instead of tucking it behind. Then the water can't get in from the top and any water that condenses can drain from the back.  I've cut apart a lot of cars that were previously flanged both ways, and the water trap way is always in way worse shape. I've also seen people seam seal the flanges and sooner or later water gets in and then the seam sealer doesn't let it back out. So my opinion is no seam sealer.

If your flange tool won't fit in the space, I would just lay the patch panel on top of the Miata side and accept that it will be .040" thicker. Filler should be able to hide that. Or you can gently hammer the Miata part down a little before welding.

The most important thing is that you cut the Miata high enough that there is good, clean metal at the joint. If there is pitting on the backside, cut it higher. Three problems there: 1. Where it's pitted, it's thinner and you're more likely to blow a hole. 2. Where it's pitted, it's dirty, and the dirt will creep into and contaminate the weld assuming you've got good penetration. 2. And worst of all, where it's pitted, the welding will actually accelerate the rusting process (at higher temperatures, chemical reactions like oxidation (or "rusting") occur much more quickly) and you may have pinholes or bubbles sooner than you'd imagine.

At Eclectic, we've had other shops send us cars they welded/painted and then had bubbles literally weeks after the paint job because of problem #3. Every time when we rectified the issue for them, it was because the pitted metal right next to the weld seam started to get pinholes, let water in, and bubbles in the filler follow.  We make a new patch, move the weld seam to clean metal, and the cars never come back.

Keep going. You need to enjoy this car again!

alfadriver
alfadriver MegaDork
1/17/23 9:48 p.m.

In reply to Carl Heideman :

Thanks- with my patch panel not being quite perfect, the butt weld will be along the door- which isn't a bad thing.  And I can fit in the flange tool over that span of original body.  

So what I will do is perfect the patch panel I have, and then use that to define a line to flange.  I've got it cut to a pretty sharp length- with a nice clean vertical line next to the body crease in the rocker.   Now I'll clean up the curved section along the door and then do the horizontal line.  

alfadriver
alfadriver MegaDork
1/18/23 6:08 p.m.

Did some work today, but no pictures.  More about fitting and whatnot.  And prepping all of the surfaces to never see the light of day again (hopefully).  Still need to paint it, inside.

But the flanging of the body worked out nicely- although if I had cut the panel 1-2" higher. the tool would have fit a lot neater.  Oh, well.  It's going to be interesting to weld it in- that's for sure.  But it will be good enough to keep.

And looking at the underside some more- solid, but  messy.  I'll take full advantage of changing the shocks and springs to clean up the sub chassis better- get the scale rust off, clean it, cover it, and move on.  Once I get the body to a point I can paint it, I'll give FM a call and order some parts.

Ain't going to be a perfect car, but considering how it drove with all of that mess in it, it will still be a fun car to have and drive.  And that's all that counts for me.

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
1/18/23 6:12 p.m.

Consider some new bushings when you do suspension. After my recent experience on Miata 338, I won't shut up about it. Ask anyone within earshot :)

alfadriver
alfadriver MegaDork
1/18/23 6:40 p.m.

In reply to Keith Tanner :

I should do that, yea...  BTW, where is the worn bushing that you can hear when reversing?  Is that straight forward to change?

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
1/18/23 8:16 p.m.

I'm not sure what you're referring to. You mean inside the trans, or something big moving? If it's the latter, it's gotta be the two diff bushings. Easy enough to change. 

alfadriver
alfadriver MegaDork
1/18/23 8:20 p.m.

In reply to Keith Tanner :

It's a clunk in the back, so the diff for sure.

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
1/18/23 10:23 p.m.

I suppose it could be something like a rear upper control arm bushing. The diff bushings are almost a separate job, so you could do the suspension ones first and then see. Bad diff bushings can exaggerate the 2-5 shift, though. 

alfadriver
alfadriver MegaDork
1/30/23 1:42 p.m.

So some work today

alfadriver
alfadriver MegaDork
1/30/23 1:43 p.m.

Did a lot to clean everything as best I could. Which was good. 
Then welded it in

alfadriver
alfadriver MegaDork
1/30/23 1:46 p.m.

And that was kind of a pain, as the body is quite a bit thinner than the patch. The overlap part was good, but I naturally blew through a lot of the butt welds. Ugh. All but one I was able to just carefully clean up. But a section under the door will need some more than that. Too cold to continue today through. 

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