[Metric]

I need to replace the front driver toeboard and front driver portion of the floorpan, the rest is alright.

I've read that the floorpans on these cars are very important for rigidity, but I was wondering if it's alright if I rivet and seam seal these parts on. I know this method has a higher chance of rusting in the future, but I'm okay with that as at the moment I don't have a means to weld them on.

My plan would be to take the new pieces of sheet metal that I have, trace it on the current floorpan, and then cut about 1in inside the trace. So I'd have a 1 inch perimeter for seam sealer and rivets.

This would be a "temporary" solution, as in something I just want to last for a few years.

 

[Woodchuck]

Negative. That entire assembly around the cowl/firewall/toeboard is structurally significant.

 

[swooshdave]

Has it been done? Sadly yes, too many times. Is it the right way to do it? No. If you have no other choice then it's up to you.

 

[LeeFred]

Nope...don't do it. One day you could be driving down the road, then this:

 

[66coupe289]

I just did a similar replacement on my car.

The only place a rivet will have as good, if not better holding power is where the floor pan up turns to meet the rocker. A 3/16" steel rivet has pull out strength of 800+ lbs. While I have not calculated the strength of the factory spot welds, certainly the sheetmetal would tear along the spot weld edge well before a rivet would fail. Yes, the sheetmetal might tear around the rivet head, but it does have some metal captured underneath the head which helps distribute the stress riser vs a spot weld.

The toe board to floor pan was also factory spot welded, but those work in shear vs pull out. Granted, both methods distribute loads to points so not a huge difference there.

Where there is no comparison is where it was once one piece of metal and is now two. Those basically need to be continuously welded to achieve the same structural value.

 

[kenash]

I need to replace the front driver toeboard and front driver portion of the floorpan, the rest is alright.

I've read that the floorpans on these cars are very important for rigidity, but I was wondering if it's alright if I rivet and seam seal these parts on. I know this method has a higher chance of rusting in the future, but I'm okay with that as at the moment I don't have a means to weld them on.

My plan would be to take the new pieces of sheet metal that I have, trace it on the current floorpan, and then cut about 1in inside the trace. So I'd have a 1 inch perimeter for seam sealer and rivets.

This would be a "temporary" solution, as in something I just want to last for a few years.

Just learn to weld. Besides, you don't want to be the PO that we talk about after a few years when your car is sold and the new owner comes here seeking advice on how to fix your work properly.
I know this is easier said than done. But, it's better to put this off until you can afford a welder and the tools to support it, than waste your time making a repair that you are not proud to endorse. The toe board is an integral part of the entire inner box section and must be treated accordingly.

 

[swooshdave]

I need to replace the front driver toeboard and front driver portion of the floorpan, the rest is alright.

I've read that the floorpans on these cars are very important for rigidity, but I was wondering if it's alright if I rivet and seam seal these parts on. I know this method has a higher chance of rusting in the future, but I'm okay with that as at the moment I don't have a means to weld them on.

My plan would be to take the new pieces of sheet metal that I have, trace it on the current floorpan, and then cut about 1in inside the trace. So I'd have a 1 inch perimeter for seam sealer and rivets.

This would be a "temporary" solution, as in something I just want to last for a few years.

There are welders who will come to you with portable units. And they are usually very reasonably priced. If you get it cut and in place (I believe about a 1/16" gap, I'm not a welder so some will correct me) then they can just stitch it right up.

 

[somethingclever]

it would for sure be worthwhile to look for a mobile welding outfit....I would guess for $500 or so, you can have them welded in, if you do the prep in advance.

Or buy a welder and accessories for $500 and get after it yourself.

 

[BlackSabbath70]

The guy we contracted to do the floors in our car riveted the pans in instead of welding them. We had them cut out and re-done by someone else. We were under the impression the first guy would use a welder but I guess in this day you actually have to tell people what should be done instead of assuming someone is going to weld a floor into a subframe car. The pictures of both are in my build thread. He also just beat the floor pans into place instead of making everything level and he never did cut out all of the old floor with the rust in it.

TLR - weld them in.

 

[swooshdave]

it would for sure be worthwhile to look for a mobile welding outfit....I would guess for $500 or so, you can have them welded in, if you do the prep in advance.

Or buy a welder and accessories for $500 and get after it yourself.

If you prep it shouldn't take more than an hour to weld it up. I just looked on the local Craigslist under services and one guy said $150 for the first hour. Most others say they will quote. Maybe give that a try? If you can drive the car to a shop it might be even less.

 

[BlakeTX]

When I was young and dumb and didn’t have a welder or much money, I pop riveted in some patches in a couple of spots and fiberglassed over the patch top and bottom. They were small (less than 4”).

They’ve held up almost 20 years with no issues. Now that I have a welder and a bigger budget, I’m sure I’ll do that work right some day, but for now it just runs good and looks shiny, so I’ve had a hard time justifying the disassembly and time. I’ve got other old Mustangs to work on, lol.

 

[maverick_tlc]

I used a 110v arc welder for floors my first round of repairs to those areas when I was a 20 yr old kid and learning. Those are cheap and easy to find to buy or borrow. (Practice outside the car!) I riveted it in with best steel rivets I could find then welded it up. Later, I got a 220 mig and did a much better job replacing full floors.
I guess I advise to , in all cases, weld it up best you can. That buys you time. Which in this hobby a decade or more can fly by!

 

[Brian66]

Let’s put it this way, I’ve seen cars with huge holes in the floor driving around and the front end hasn’t fallen off. I’ve seen people patch the floors with rivets and old road signs and license plates. Is it the best…nope…will it last a few years…sure. Riveting them would be better than nothing. Structural automotive panel adhesive (the stuff they use on new cars) would probably be stronger yet and comparable to welding in certain applications and can be had for less than $50. Even less if you go for Eastwood’s brand. https://www.amazon.com/3M-08115-Pan...ocphy=9031493&hvtargid=pla-442628174137&psc=1

 

[supershifter2]

Nope...don't do it. One day you could be driving down the road, then this:

View attachment 847868

 

[Magnus]

I had my passenger floor pan riveted in for years. Was it the right way? No, obviously. But I figure that Kenmoore dryer sheet metal was slightly more structural than the hole it was covering so it wasn't making anything any worse than it already was.

It's fixed now, but the rivets and silicone got me by for quite a few years. As long as you keep it in mind that you're going to need to fix it properly one day I don't think you'll have any problems patching your toeboard with riveted in metal for a few years.

IMO this, even riveted in:

Has got to be stronger than this:

 

[kenash]

I had my passenger floor pan riveted in for years. Was it the right way? No, obviously. But I figure that Kenmoore dryer sheet metal was slightly more structural than the hole it was covering so it wasn't making anything any worse than it already was.

It's fixed now, but the rivets and silicone got me by for quite a few years. As long as you keep it in mind that you're going to need to fix it properly one day I don't think you'll have any problems patching your toeboard with riveted in metal for a few years.

IMO this, even riveted in:
View attachment 847987

Has got to be stronger than this:
View attachment 847988

Is the ceramic side face down? Better chip resistant against road debris. LOL!😂

 

[supershifter2]

airplanes are riveted together and stay together just fine until ..........,......,.....,.........,..... !!!.

↓ Some things leak out in airplanes. ↓

 

[Koltar]

Nope...don't do it. One day you could be driving down the road, then this:

View attachment 847868

That is ridiculous, There is no way you will be driving down the road and all the sudden your car is on jack stands just because you used rivits.

 

[Russstang]

Yeah Lee! Are those Habah Frate jackstands???

 

[zray]

This is the kind of topic that is more appropriately read on April 1st.

Millions of dollars are spent every year by people wanting to improve the rigidity of the early Mustangs unibody construction. And for good reason, as there is unwanted chassis movement in every place imaginable.

I’ve yet to find anyone anywhere that says (with a straight face) that making the unibody less rigid is a good idea.

Z