I prolly already know the answer but do you weld your floor

[Roothawg]

I prolly already know the answer but do you weld your floor panels solid or just tack em every half inch or so?

I have mine tacked all the way around and they seem pretty solid. I thought about just seam sealing it and moving on.
I had cut the rust out so I would have a nice uniform hole and then overlapped the panels about 2 inches...then welded in.

[porknbeaner]

Yes. http://www.jalopyjournal.com/ubbthreads/images/graemlins/crazy.gif
Done it both ways, and both worked. I welded the F-Truck up solid except the hump I skip welded it (got lazy at that point).

[spudshaft]

I am at the same point on my f-1, and I have been considering just sealing mine up too. I kinda feel guilty about doing it that way though. What are you going to use to seal it up?

[Paul]

p'n beaner

I did the opposite, I welded the hump and tunnel solid, the pieces butted,

and the perimeter skip welded where it lapped.

Paul

[Tman]

Tack and seam seal. Thats how we do all the floors at the shop. Use the 2 part seam seal though. Tinbender told me that little tip.

[Mr 42]

All new cars are spotwelded, and are seamsealed.
So i guess it will work OK,

[Roothawg]

I am going to use a sealer that we use on aircraft fuel cells. Shhhhh....don't tell on me.

[Tinbender]

On lap joints, I like to plug weld. 1&1/2" to 2" pitch. Skip welding is fine, but plugs look better.

[Roothawg]

It's sealed!
Now if it would hurry up and dry I would spray some good ole undercoating on it and move on..... http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif

[colorado51]

This is the first time Ive done this, so Im not sure if its the right way to do it or not, but this is what I did:

The new outer floor piece is welded to the original floor with a 2-inch long bead every few inches. The new rocker is attached to the new floor piece using a plug weld about every inch. I used seam sealer on the rest of the gaps

http://photo.starblvd.net/colorado51/3-2-1.jpg

[HOTRODPRIMER]

Guess I'm the only guy that welds them solid...HRP

[MercMan1951]

I was wondering the same thing, right about when I ran out of mig wire tonight. Here's what I'm gonna do:

Anywhere there is force pushing on the floor regularly, it's getting a perimeter weld (like a driver's footwell.) This includes the entire door opening area. Anywhere that is just a patch welded to repair rust is getting the inch long bead, followed up with liberal amounts of seam sealer on both sides. The underside will be undercoated, so I don't care what it looks like after it's welded (top and bottom) and seam sealed. Oughtta be plenty strong.

Now you must realize, patching my floor is secondary, I am attaching the body to the floor the ENTIRE PERIMETER of the flooring, so obviously that is all getting welded solid...but we're talking floor pans here. The welded area will be stronger (theorhetically) than the actual metal itself, so skip welding should be sufficient. I have the door jamb areas already welded solid, using 3" 16 GA filler to join the Lincoln flooring to the Mercury body. It's solid.

NOW-- here is MY question: do you grind down your welds so they look pretty, right before you cover them up with seam sealer and carpet, or do you leave 'em raw? I say leave 'em, cause I want to drive my damn thing!!!!!!!!!! http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif

[kustumizer]

i didnt weld mine. I pop riveted them then put some silicone around the edge. I will eventually get new metal and weld it in! Nate

[kustumizer]

after it was fixed!

[briggs&strattonChev]

whats the advantage of stitch welding it? I did mine solid and it seems fine. Do you still skip weld when you are butting the pieces, as opposed to skip welding on a lap joint which I can understand.

[porknbeaner]

[ QUOTE ]
I am going to use a sealer that we use on aircraft fuel cells. Shhhhh....don't tell on me.

[/ QUOTE ]
I wish you hadn't told me now ya gotta kill me. http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif
Of course I could be bought off.
I used to have a friend that worked for TWA, if you use the same stuff, that stuff is killer.

[porknbeaner]

B&S Chevelle,
I probably wouldn't skip weld a butt joint.
The biggest advantage of skip welding is saving time and wire. BUT when you're doing structural welding (IE bridges, skyscrapers, etc) you don't weld solid to allow (sp?) for expansion and contraction, and something to do with vibration. I'm not a structural engineer, but that's what the engineers always told me when I asked.
My tunnel on the F-truck is lap welded so I can get away with the skip weld, I stiched it up solid everwhere it wasn't lapped or had to be ground out for cosmetic reasone (IE the Door Jams).

[briggs&strattonChev]

hey, thanks alot porknbeaner http://www.jalopyjournal.com/ubbthreads/images/graemlins/cool.gif

[JimC]

Over here, the floor gets held in place with self tapping serews about 4 or 6 inches apart.
Then, tacked in place with the tacks about 4 inches or so apart.
The next step is to move around 2 inches from the tacks, and tack agin, moving around the perimeter in 2 inch increments until there appears to be a continous weld.During this series of tack welding, the screws get removed and the holes welded.
The floor tkes a beating if it is a driven car, both from the foot pressure, weight, and under car turbulence.
Seam sealer is a must.

Jim

[Roothawg]

I got her all undercoated and looking like a new dime. I'll post pics after it dries. Looks a little splotchy until dry.

[ESnacky6]

I'm getting ready to this very thing next Monday...

so if you are putting a patch panel in the driver's foot area, let's say,
do you cut it to fit the patch perfectly, or should you overlap it a bit..?
with the patch on top, what should you do on the bottom exposed edge..?
just seam seal, then paint it..??

Is there really a right or wrong here..??
It seems(seams..?) to me that all option could work just fine....

Opinions..??

[hatch]

It is fine to spotweld...the factory does it. I noticed that nobody is using weldthru primer...why not???...It's a great product.

[Roothawg]

I cut my hole say 20"(just for funnies) the panel may be 22". I lay the panel over the top , then I welded it about 1/2" apart all the way around. Then I sealed it on top, undercoated it. Maybe later this weekend I'll seam seal the bottom. I'll have enough sealant on it to hold it in place without even welding it. http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif

Then I'll undercoat that as well. Liquid asphalt cures all.

[TP]

After seeing ya'll floors mine in the new merc aren't that bad. I'm getting started on the floors sunday.

[MercMan1951]

Overlap, Overlap, Overlap...and...weld-thru primer is an extra step that won't get you anywhere...unless you're so anal you think you need it. Skip it. Why use it? I guarantee if you patch your floors, use seam sealer AND undercoat it, it's WAY more than the factory ever did, anywhere - even on newer cars- and is a good, solid repair that will last AT LEAST 10 years...how long do you plan to keep your car?! Forever? HA! Call me in 10 years and tell me you still have it! http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif As far as pop rivets go...well...they're pop rivets!...Seal the shit out of them. They'll last...for a while...nothing replaces a welder, but I say work with what you got. Nothing wrong with that. I just hope I don't buy a car that ends up having pop-riveted floorboards in it, unless I plan to do a CHASSIS SWAP! http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif

[Sam F.]

i weld them all the way up...only because i have nothing better to do.

[hatch]

Do what ever you want....YOU are the one who will be standing by it when the questions start....

[manyolcars]

When metal is overlapped, it often rots. Seal it good. I'm glad no one suggested screwing new metal over rot. Thats guaranteed to rot more and poke you when you're under the car. I bet everyone has gotten a car like that.

[Tinbender]

[ QUOTE ]
weld-thru primer is an extra step that won't get you anywhere...unless you're so anal you think you need it. Skip it. Why use it? I guarantee if you patch your floors, use seam sealer AND undercoat it, it's WAY more than the factory ever did, anywhere - even on newer cars

[/ QUOTE ]

New cars use galvaneal(sp) steel(both sides)This is a zinc coating That prevents rust by a galvanic corrosion. Most are then electrostacticly coated, seam sealed and painted. Many manufactures are going to weld bonding the seams, not to mention various other coatings. They take corrosion seriously.
The idea behind weld thru primer is to protect the steel from the traces of moisture and oxygen left in between the lapped metal, by applying zinc. Foolish not to use it. It's cheap, easy to apply. If you didn't use it in the last shop I worked in you'd be lookin for work. If your a DRF with most insurance companies, your required to use it by contract. Use it lightly, but use it. BTW, undercoat over bare metal is just about useless.

[hatch]

When I took the ICAR course, the instructor sprayed undercoat on a piece of plexiglas....probably left a million pinholes per square foot. Interesting course...learned how just about EVERYTHING I was doing was wrong!!!

[fordnutz]

If I am just dropping in a patch I will butt weld it solid. If you can go from one side of the floor to the tunnel and make it look like a factory seam, overlap and spot weld it. I have left a 2 inch lip on the side at the rockers and the front of the rear seat riser and dropped a complete used floorpan in and overlapped it and spot welded it and it looked original. Same for the trunk pan. All old cars were spot welded, but their floor pans generally went from the rocker on one side to the rocker on the other side. Nothing looks tackier underneath than a patch with ragged edges that you rip your skin on. Plan ahead so your patch weld in over top of a body support or something that will hide it and overlapping is fine. That spray weldthru stuff T-man is talking about works great.

[Roothawg]

Here's a pic of mine. I need to spray another coat of undercoating to even it out a bit.

[Boones]

Two questions, WHere do you get weld thru primer as I am getting ready like several others to start my patches and what thickness do you recommend for front floor (seat bracing area is great) and I have to rebuild the rear door opening rear fender well. (area between door and rear tire that is about 5 inches wide). Should I use 18, 20 or 22 gage..(18 would probably be best but I am not sure what cars of the 50's had stock

thanks

[hatch]

Weld thru primer is available at welding supplies or body shop supply houses...you can get spray bomb or brush on application.


As far as metal thickness...use what the factory did....heavier rather than lighter if you want.