I am installing floor pans now. The original pans were installed with spot welds. What is the correct method for a restoration? Tack welds every couple of inches or welding the entire perimeter?. Also I have read posts regarding Seam Sealer, Who makes this product and should it be applied to both sides of the Pan before painting with POR 15?
Thanks for your replies.
John

On seam sealers....

I have successfuly used construction adhesive in between sheets of metal before joining them. It helps bind them tight, keeps water out and helps stop squeaks. I run a bead along the edges as well. Much cheaper too!

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Joe G.
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John, I just finished the installation of floor pans on the drivers side of my 69 convertible. I stitch welded the pans, weld every inch or so, Then POR15 in and out, then seam sealer in and out, then final coat of paint in and out.
Were you are in Canada, you have the same climate as I do in upstate NY. Rust is a major problem. Thats why I coat and paint everything.

I completely welded my seams on my floor and trunk pans. I am just as nervous about rust and I was also worried about strength.. Don't know if it was worth it or not. But I sure do feel more comfortable having done it!

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My 72 is in the shop now. I am having just the front halves of both driver's and passenger's floor replaced. I was there last week and they already cut out the drivers side. They are talking about glueing in the new panels with a new bonding process. I have heard a few manufacturers are doing this on new cars but have not seen it doen on a resto. Has anyone else used this method? What are the pro's and cons?

I can think of a couple pros. Less heat (welding process) and distortion and less potential for rust at the welds.

Also, I am planning to paint the floors, inside and out and the frame with Por-15 and chasis coat black. I have only used their exhaust manifold paint before and it worked great.

Any idea how much of this stuff I should buy to cover both the floor and frame? I also understand that you have to be real careful about keeping the can seeled while painting.

I'm replacing them too on my '69 ... on the same subject, are there any good methods to getting the pans to line up & fit before welding? I'd like to butt weld the entire perimeter, but am afraid of not getting the same alignment each time I pull them in/out. Any good techniques out there?
Thanks,
Neal

I would fully weld the seams shut. You just tack weld them and moisture will find its way in there and you will be right back where you started-FULLY WELD the seem shut.

The only way to replace a floor or any type of metal is one piece at a time, sometimes it cant be done that way. On floors and trunk I do the braces first get them to fit to the old floor first. Fully weld them on the sides of the inner rocker. I use sheet metal screws to hold them to the floor, and a tack weld or two. Then ONLY remove one half of the floor. DONT remove the entire floor at once. If you remove the entire floor it will be a pain in the rear to algin the new floor up. Fit the new floor half to the braces and the old remaining half of the floor. Once you have that in place where you like tack weld that to hold its position. Now remove the remaining half of the old floor and fit to the braces and the new floor half.

If you want to butt weld the two together you can just use a cutoff wheel and cut a splice down the floor. That will give you the gap needed to butt weld, just use the very thin wheels from 3M. If you use screws to hold the panel in place you can remove the floor halves all you want and still get the same fit. Just algin the holes and srcew it down. Plus the screws will hold the panel flat and tight agaist the braces and the surrounding floor. Once the floor is in just weld shut those holes...Eric

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1949 and 1972 chevy trucks
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An air saw works well too,it leaves a thinner gap than even a thin cut off wheel.

You say that an air saw will work? ... How well would my sawzall work then?

I'm really getting interested here ... I assume that you are rough cutting the old floor out first, then laying the replacement panel over top.

Do you just then sheet metal screw every 1ft (or so), and cut in between?

I had thought about this method, but wasn't for sure how the fit would be since the panels were cut while overlapping each other.

Neal if you get the panels tight you wont need to worry about the overlap it wont affect it. Just use enough srcews to hold the panel tight you wont need one every foot. Get the panels in place then cut your gap for the butt weld the entire length no need to go inbetween screws, it wont shift.

As for the sawzall cant say never used one, Ive always used my cutoff wheel or air saw. Some times I prefer the wheel others I like the saw.

If you are replacing the entire floor yes you rough cut it out and trim out the excess. Get that half to fit to the new braces and the remaining old floor. Once you like the fit screw it down to the braces in a few spots and a few along the cowl. Then remove the other half...Eric

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1970 chevelle
1970 chevelle SS455 not a typo its a buick baby
1949 and 1972 chevy trucks
http://briefcase.yahoo.com/bc/sevt_chevelles

The sawzall is good for rough cuts put i have found it to hard to handle for precision cuts.It has a tendency to 'walk away' when trying to cut a perfect line.Its great for big stuff though,like rough cutting off an old quarter.It saves a lot of those precious cut-off wheels

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Where do you get this construction adhesive and who makes it?

As you noticed, originally the car was spot welded together and seam sealed. I agree that a seal weld is best to close everything up however you should use the stitch method, a little weld at a time to avoid distortion, seal welding is excessive, however if your are a good enough welder go for it.
I also contemplated using some high strength adhesive (Loctite brand) designed for sheet metal bonding, see thier web site for application. But opted to weld instead, as you get instant bonding with the welds.
Use a few sheet metal screws to hold your position and take extra care fitting up the panels. 1/2 inch overlap looks good when done, fitting the pans exact enough to but weld would be extremely difficult.