Welding floor onto rocker

[Vinnie]

Hey folks,

Soon I'll be starting to weld in my floors. I'm thinking about first welding the floor pans to the rocker. To do this I'd like to put a clamp on the lip of the floor before I put in the plug welds but the rocker is round... Anybody have a bright idea on how to put a clamp on this?

Cheers,
Vincent.

 

[71ProjectJunk]

What I did when doing a front drivers side floor pan was weld the rocker area last. Since the rocker is flat and the panel is flat, it is not difficult to have them mate well. After I had everything else welded, I went in with a hammer, and in the areas where the pan was a little separated from the rocker, I just wacked the floor pan to get it flush with the rocker, and then welded it on. My first welds were from the floor pan to the frame rails, before I did those I made sure that the pan was as close to the rocker as possible.

 

[tony-muscle]

What I did when doing a front drivers side floor pan was weld the rocker area last. Since the rocker is flat and the panel is flat, it is not difficult to have them mate well. After I had everything else welded, I went in with a hammer, and in the areas where the pan was a little separated from the rocker, I just wacked the floor pan to get it flush with the rocker, and then welded it on. My first welds were from the floor pan to the frame rails, before I did those I made sure that the pan was as close to the rocker as possible.

Like he said

 

[mjlan]

I screwed the floor pan to the inner rocker with self-tapping sheet metal screws to keep it flush. I think I popped holes every 2" or so in the floor pan flange and put a screw in every other hole, then welded up the holes as I pulled the screws out.

 

[Vinnie]

Thanks for the tips guys! So start with the frame rails, rockers last, might use screws too.

Cheers!

 

[turtle5353]

Self tapping screws are a must!!

 

[Vinnie]

Self tapping screws are a must!!

I have used rivets on my quarter panel but I'll entertain the thought of using selftapers ok? ;-)

 

[71ProjectJunk]

I did use self taping screws on the floor pan, I screwed it on to the frame rails. To make it easier to tap the screws in, I drilled a small pilot hole before I put the self tapping screw in. Frame rails, and if you do it on the rockers are quite thick, or at least thicker than the floor.

 

[Steve McMahan]

Just because I’m getting close, like next spring, to replacing both floor sides, is there a 71-73 Mustang specific video out there of replacing either side? Don’t mean to hijack thread.

 

[tpj71mach]

I have used rivets on my quarter panel but I'll entertain the thought of using selftapers ok? ;-)

Self tappers are best IMO because you can remove them when done welding the plug welds and weld up the holes left behind.

 

[69 Rustang]

Sheet metal screws for sure. I use a lot of them—i actually switched to 1/4” hex head sheet metal screws as they are easier to remove than the old school Phillips Head. For butt seams I bought Cleco pliers and Cleco’s to hold the panels flush together.

 

[4sp72mach]

Sorry if I'm hijacking this thread. But since we're discussing welding in floors...
What's you no1 tip for getting the floor to line up perfectly against the trans tunnel?
I wanna do butt not lap.

 

[71ProjectJunk]

Just because I’m getting close, like next spring, to replacing both floor sides, is there a 71-73 Mustang specific video out there of replacing either side? Don’t mean to hijack thread.

Before I did my front floor pan, I probably saw every video on replacing Mustang floor pans on YouTube. IMHO these 2 are the best:

 

[71ProjectJunk]

Sorry if I'm hijacking this thread. But since we're discussing welding in floors...
What's you no1 tip for getting the floor to line up perfectly against the trans tunnel?
I wanna do butt not lap.

I kind of figured this out the hard way while doing butt welds on quite a few patch panels on my Mustang. First thing I would say is that doing lap welds is much easier, and the end result is probably stronger as you are not doing a ton of grinding on your new welds and metal, which will weaken the weld and the metal. All my first patches were butt welded and the last ones were a combination of lap and butt welds. As to your question, what I found out was the best way to get a panel to fit perfectly was to cut it too big. After I have my too big panel, if I could go to the back of it and trace the opening with a sharpie on the back of the panel, using the hole in the sheet metal I had, I would do that, and then get the a hand held high speed metal air saw and start cutting close to the sharpie mark (maybe a 1/4" to 1/8" from where the sharpie mark is. If you cannot get a sharpie in the back of it, then it will just take you longer. I would then get an angle grinder with an 80 grit flap disc for the final cutting, it works fast and great on a patch panel. Do not get to the sharpie mark as you may just grind off too much metal. You want to get it close but still end up with a too big panel. No matter how hard you try to trace an accurate mark with your sharpie, it will be a little off. Now, you put your panel on and start doing your final grinding with the angle grinder and an 80 grit flap disc a tiny bit at a time, and inch at a time, putting the panel in place, grinding a bit off a small edge of it, and then testing the fit, removing it again, grinding a bit off, and then testing the fit again. You keep removing the panel, grinding a bit on the edges, and putting it back on, as many times as you need to, till you have a panel that fits perfectly in that hole. It may take you 1-4 hours of grinding to get a panel to fit perfectly, but it is time well spent. If your panels are basically touching or almost touching each other, welding them will be easy. As soon as you have gaps that are a little too big you invariably end up blowing through your welds, especially on thin sheet metal, and then having to fill the holes you blew into the panels. Trust me on this one, get the panels as close as possible to each other, if not touching each other, it will be much much easier to weld and you will have much less issues with blow through and then chasing the holes you made with weld.