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Firewall to floor pans and but welding connections etc..?

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Firewall to floor pans and but welding connections etc..?

Old 10-02-2010, 11:01 AM
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Coupe
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Default Firewall to floor pans and but welding connections etc..?

OK, so I am going to do my drivers side firewall to floor, and also the drivers side long floor if it looks like it needs it. I am also going to change out the frame extensions.

My question is about the welds and the connection points, to do it right should I but weld the seams? I want it to look good underneath the car and I think any overlap would leave a place for rust to hide again.

And when I buy the new pieces will they have a folded lip on the side that welds to the inner rocker panel and the kick panel area?

I would really like to see some pics of this being done, so if you have any can I see?
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Old 10-02-2010, 02:37 PM
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LynnBob Mustang
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Right or wrong I over lap welded my pans. On the underneath with what gap I had I hammered it tight to the section it was welded to and I then put roofing stop leak sealer on the joints to keep any moister out. I then painted all that over with the truck bed coating.

Some people me balk at the idea of using roofing stop leak sealer on a car, but it has lasted years on my house roof around the chimney and pipes with no problems. Besides, a gallon of roof sealer was $13 and it is ton cheaper then using auto seam sealer at $5-6 for a small tube of the stuff. I also used it on all seams inside and it was paintable a well.

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Old 10-02-2010, 02:44 PM
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Originally Posted by Coupe View Post

And when I buy the new pieces will they have a folded lip on the side that welds to the inner rocker panel and the kick panel area?
The stock floor pan on a '65 has the rocker lip is folded upwards, my new front pan had it folded downwards. I still haven't fully welded that area as I still don't know if I'm keeping that rocker yet.
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Old 10-02-2010, 02:46 PM
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Here is my left floor welded and done with the roofing stop leak sealer. I just used the sealer on all the welded joints inside and underneath.

Right side patch as I wanted to keep as much original metal as possible

The underneath is done similar.
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Old 10-02-2010, 02:48 PM
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I am a fan of butt welding panels together, but imo it is totally not needed for floor pans. It will take far more time than is worth it for the results butt welding (here) generates.

If you seal the seams with a good grade seam sealer rust will not be an issue worth mention.

Ooops, posted this on wrong account!!!!

I was trippin, Jim posted the same thing I did.... (duh)...

JMD
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Old 10-02-2010, 04:56 PM
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Well, I want to try to restore the underside of the car over time, if I touch anything it must end up looking professional and correct. I really want to end up with a car that is worthy of crawling under.

What do the restoration shops do? Do they just go ahead and replace with a one piece floorpan? And if so, how do they connect to the firewall to floorpan steel?
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Old 10-02-2010, 05:08 PM
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Originally Posted by LynnBob Mustang View Post
The stock floor pan on a '65 has the rocker lip is folded upwards, my new front pan had it folded downwards.
A down fold is a convertible floor.
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Old 10-02-2010, 05:13 PM
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Originally Posted by Coupe View Post
What do the restoration shops do? Do they just go ahead and replace with a one piece floorpan? And if so, how do they connect to the firewall to floorpan steel?
Given the choice, a pro shop will replace the whole floor. The results are better, and at lower cost, than piecing it together.

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Old 10-02-2010, 05:45 PM
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Originally Posted by 2+2GT View Post
Given the choice, a pro shop will replace the whole floor. The results are better, and at lower cost, than piecing it together.

So in reality they overlapped and rosette & stitch welded that pan in place?
I wonder how they handled the underside air space between the panels? Do they weld those on the underside also to make it tight or just seam seal it?


I have often thought of attempting a one piece pan, but I will not know until I get the goo off of the underside to make the determination. My big concern is the firewall to floor pan piece, it would show up in the front wheel well and I dont want to see it every time I am looking at the car with the wheels turned, in reality the overlap may be stronger and less brittle than a but weld....
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Old 10-02-2010, 06:05 PM
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Originally Posted by Coupe View Post
So in reality they overlapped and rosette & stitch welded that pan in place?
I wonder how they handled the underside air space between the panels? Do they weld those on the underside also to make it tight or just seam seal it?
There was no air space, other that the typical mis-match often seen between the parts. Ford welded these panels (the floor and firewall) together with really big spot welders, but rosette welds work out just as well. Then a little Seam Sealer does the rest. The seam itself is a lap seam, with nearly two inches of overlap.

Originally Posted by Coupe View Post
I have often thought of attempting a one piece pan, but I will not know until I get the goo off of the underside to make the determination. My big concern is the firewall to floor pan piece, it would show up in the front wheel well and I dont want to see it every time I am looking at the car with the wheels turned, in reality the overlap may be stronger and less brittle than a but weld....
No, it won't, it's impossible to see the floor through the wheel well, unless you are laying on your back on the ground.
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