2001 SE Miata Rust Correction

More of an art than a science - discuss metalworking and welding here.



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PostPosted: Sun Feb 11, 2018 6:38 pm
Hi,

First, I wanted to say that this forum has been an amazing resource for me. It taught me the skills required to successfully do the repair and repaint on my racecar linked below.

viewtopic.php?f=12&t=24761&hilit=duncan

But, now I have a different type of challenge. I have a 2001 Miata SE that I use as a street car that has some rust on the lower rockers. This is a pretty common issue with these cars, but the rest of the car is in good condition and I'd like to fix it.

First, some pictures. The passenger side is worse than the front.

Passenger Side.
IMG_20180211_135036.jpg


IMG_20180211_135030.jpg


IMG_20180211_135030.jpg


IMG_20180211_135046.jpg
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PostPosted: Sun Feb 11, 2018 6:48 pm
Driver's Side

IMG_20180211_135020.jpg


IMG_20180211_135015.jpg


I've found replacement quarters and rocker's on Ebay.

https://www.ebay.com/itm/Rocker-Panel-S ... 4d&vxp=mtr

https://www.ebay.com/itm/Wheel-Arch-rea ... LD&vxp=mtr

But I've never attempted a panel replacement of this kind before so I don't really know where to start. My biggest concern, and I think one of the most important things is how much of the original quarter to cut back? Should I use the replacement panel as a template and put the entire panel in? Some other misc questions.

1. The car has been repainted at least once, in the factory color. Should I just paint the entire rocker and quarter. With red non metallic is this likely to leave an obviously different color panel?

2. I know that once the outer panels are removed, I'll have inner structure rust to deal with. I have a both a handheld spot sandblaster and a larger pressure pop blaster. Should I blast the rusted interior metal clean. What is the right product for the interior structure. Epoxy primer? Something else.

3. Not sure how to tackle the welding back on of new panels.

I have access to a large assortment of tools, including 15 CFM compressor, MIG welder, sand-blaster, 2-post lift. I'm not in a hurry to get this completed as the car is not a daily driver so I can pause as I go to take pictures, ask questions, get feedback, etc...

Lastly, a picture of the entire car.
IMG_20180211_134756.jpg


IMG_20180211_135115.jpg


Thanks in advance.

Duncan

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PostPosted: Tue Feb 13, 2018 3:09 pm
I usually only cut out the rusted metal in quarter panels. However if the quarter panel seams are all easily accessible then it might be better to replace the entire quarter.

Coat clean metal with two coats of epoxy primer, it will last a long, long time if not exposed to direct sunlight.

You will need a spot weld drill to separate the panels. Use the old panels to lay out the spot weld locations on the new panels. Also, measure and mark reference points to ensure proper panel alignment.
1968 Coronet R/T


ACTS 16:31



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PostPosted: Tue Feb 13, 2018 6:32 pm
The quarter panels I ordered aren't full panels. Is it okay to make a horizontal cut above the rusted area between the wheel well and the door when patching in my new panel?

Would you do a partial patch of the rocker as well? That replacement panel is a complete replacement.

Also the panels are EDM coated. Is that sufficient for the backside, or should I paint them with epoxy as well?

thanks,

Duncan

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PostPosted: Tue Feb 13, 2018 8:56 pm
Try to make your welded seams in an area that is easy to finish. Not too close to body lines or curves but not in a really flexible area either.

I am thinking the rocker panel rust is a lot worse than it appears. You may want to replace the whole thing just to ensure there is no structural damage from the rust where you can't see it.

Not all panels come with true EDM coating or with it applied correctly. You can try a lacquer thinner soaked rag and see if you can get any of the coating to come off. If not you should be okay.

I normally scrub with soapy water and a maroon scotchbrite pad to dull the finish, rinse, wipe with W&G remover, let flash and then apply epoxy primer.

Here's a couple of pics of a quarter panel patch I have done. This one was almost a complete quarter but being a convertible I didn't want to jeopardize the structural integrity by removing the entire quarter panel. It will give you an idea of what to do.

Quarter Left Removed.JPG

Wheel House in epoxy.JPG

Quarter Install Welding 1.JPG

Quarter Welds 2.JPG

LH Quarter - Poly Primer.JPG

P1010001.JPG
1968 Coronet R/T


ACTS 16:31



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PostPosted: Tue Feb 20, 2018 9:22 am
I am not a fan of aftermarket panels or Replacing Quarter panels.
I go to great lengths to save and salvage as much of any original panel as I can because a Panel is only original once!

Just my opinion but I would repair your panels Not replace them.
Dennis B.
A&P Mechanic, FCC General radio Telephone Operator
Line Maintenance A&P Mechanic and MOC Tech specialist.



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PostPosted: Wed Feb 21, 2018 11:53 am
The answer to question about a partial or full rocker, or any panel, will not be known until you strip off the paint to see what you have to work with.

Without that knowledge you are simply guessing what is the best approach.



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PostPosted: Wed Feb 21, 2018 2:19 pm
Marq wrote:The answer to question about a partial or full rocker, or any panel, will not be known until you strip off the paint to see what you have to work with.

Without that knowledge you are simply guessing what is the best approach.


This is true
Dennis B.
A&P Mechanic, FCC General radio Telephone Operator
Line Maintenance A&P Mechanic and MOC Tech specialist.



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PostPosted: Sat Jun 23, 2018 5:44 pm
Started work on this today, cutting off the lower part of the quarter panel skin (driver's side).

You can see that the rust extends to some of the inner structure where it wraps around the front of the wheel well. Since you can't buy this part I was thinking about carefully separating it, sandblasting it clean, and then welding it back into place. Thoughts?

Also you can see that the inner structure rust extends past the quarter panel seam onto the adjacent rocker panel. I was planning on cutting this back in sections to see how far it extends. The quarter panel is just wrapped around the sill and spot welded on this car. It's no wonder this is a common rust area.

Any tips on cleaning up the remainder of the rust on the inside of the panel. Wire brush? Spot sandblaster?

Also, as you can see there are three pieces of metal that come together at the front of the wheel well and then are spot welded together. When I'm welding this back together, what should I use to seal this area as good as possible so water doesn't get back in. I plan on using weld through primer.

Any advice is appreciated. This is my first rust repair.
Attachments
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PostPosted: Sun Jun 24, 2018 5:06 pm
A few more pictures from today.

The passenger side was worse than the driver's side, but I have a replacement rocker for that side so I won't need to save the inner structure.
Attachments
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