Floor Pans

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plrgpr
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Floor Pans

Post by plrgpr »

I have some weak ones in my 66 convert. Ordered floor pans from Clark’s. I plan on welding them in overlapping the solid floor after I cut out the weak area, rather than trying to precisely fit the pan to the hole and butt welding. Should actually be stronger and the seams will not be visible once the new carpet is in (moulded, from Clarks), and as the car was under coated, I will be reapplying the undercoating, the seams will not be visible from the top or bottom. Anyone see a problem with this method?
Gary Roberson
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Re: Floor Pans

Post by terribleted »

Yes. It leaves the areas between the overlaps to collect moisture and become rust sinks. You need to weld the floor panels in continuously around all edges anyway for best strength so why not butt weld. You certainly do not want large areas of new steel overlapping old rusty steel. Very often I do not use the entire supplied patch panels. I retain as much original floor as I can (good sections) and trim my patches to fit what I had to remove (of course I will cut out some good floor between badly rusty areas if it is efficient and easier than trying to leave it). The fitting is not that bad. Make a plan on what you will replace. Cut out what needs to go away. Lay the Clark's pan in place, align it with where it needs to be and trace your holes and braces onto the underside with a sharpie marker. Trim your replacement steel down leaving it larger than it needs to be by around 3/4" on all edges. lay the new piece back in place and carefully trim it down until it pretty much fits (a hair large is good). At this point I trim one edge to fit perfect with a 1/32" or so gap and I tack weld a few spots. I then using a 1/16" cutoff wheel cut along the edge of my patch trimming the floor beneath until the patch now fits flush all the way around. Tack all around and then complete the welds using stitch welds. (weld little 1/4" welds a few inches apart from each other all the way around and let cool, repeat until weld is continuous...helps avoid warpage). Do not forget about the spot welds needed to attach to subframes and tunnel braces/.
Corvair guy since 1982. I have personally restored at least 20 Vairs, many of them restored ground up.
Currently working full time repairing Corvairs and restoring old cars.
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Located in Snellville, Georgia

plrgpr
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Re: Floor Pans

Post by plrgpr »

Ted, I think I understand your instructions. When you say trace the holes and braces. I think you say to trace the braces so you know where to drill the holes for the spot welds, but what “holes” are you talking about? I have attached a pic of the pass side front which is the worst of the damage. It’s about a 10” x 13” area and I am pretty sure I won’t get anywhere near the center tunnel. The info in the Clarks catalogue says the floor panel fits over the seat floor for a better fit. Not sure I understand that (I haven’t received the panels yet (should be here this Thursday) as my seat floors are perfect.....not gonna cut into that!
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Gary Roberson
66 Vert 140 4-sp Corsa “clone”

plrgpr
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Re: Floor Pans

Post by plrgpr »

Ted, I should also mention that the big reason I thought about overlapping joints is that to say that i am an inexprieced welder is an understatement. I tend to burn through light gauge material when I butt weld😏
Gary
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Re: Floor Pans

Post by terribleted »

Look under the floor. There are some braces and also a subframe on each side in the front. The floor sheet metal is spot welded on top of these braces. Tracing from under is so you know what part of the new panel you are going to use. You trace braces and the edge of where you cut out the rusty floor. The key is to make your patch exactly fit what you are removing. I always fit a side or corner exactly with the rest of the patch edges a little too big, and then I tack the exactly fit are into place and trim or grind the rest of my edges with the patch in place for a precise fit. As far as the burning thru....if you are burning thru your welder is set too hot or you are moving too slowly or both. When you make your patches you want just a very little gap at the butt welds. No gap can be hard to get good penetration so a very small gap is best (business card thickness is super). Are you using flux core wire? If you are you really should convert or replace your welder for inert gas use. Flux core is not so great for thin steels as they often will not allow the lower heats needed for thin stuff.

I suggest you practice butt welding some similar gauge steel before you do it in the car. Develop your skills a little play with the welder setting etc., then weld in the car
Corvair guy since 1982. I have personally restored at least 20 Vairs, many of them restored ground up.
Currently working full time repairing Corvairs and restoring old cars.
https://www.facebook.com/tedsautorestoration/

Located in Snellville, Georgia

plrgpr
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Re: Floor Pans

Post by plrgpr »

Thanks Ted, you’ve convinced me to butt weld 😬. I will follow your technique. I have a good gas shielded welder (Miller, purchased new a couple of years ago). It’s the one that is supposed to take the guesswork out, you set the wire size and thickness of the metal and it sets the heat and feed. I am getting a little better as I had to weld a 1 1/2” x 13” patch (14 ga., a little thicker) on the outside of the rocker panel. Had to butt weld that as it’s plainly visible. Burnt through a few places and had to fill those with weld. Thank goodness for a good grinder and I had to do a powerful lot of grinding, but it’s done and it looks good. I just think how long it took me to weld the small rocker patch in....it will take me a week each floor panel and I’ve got three of’em to do!
Gary Roberson
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doug6423
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Re: Floor Pans

Post by doug6423 »

Gary,
Have you ever tried structural adhesive? Works as good and without heat distortion and corrosion.



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65 Monza
Cincinnati, OH

plrgpr
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Re: Floor Pans

Post by plrgpr »

Ted, nope, never heard of it. I’ll read up on it.
Gary Roberson
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Re: Floor Pans

Post by terribleted »

doug6423 wrote:
Wed Jun 12, 2019 9:06 am
Gary,
Have you ever tried structural adhesive? Works as good and without heat distortion and corrosion.



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Not a particularly good choice in structural floors. Such adhesives are fine for structural panels designed to be mated that way, not so much for patching panels that are supposed to be continuous. The strongest repair will be from solid welding. The rusted floor and the well shaped but not perfectly shaped replacement steel panels will not provide the nice tight flat overlap seam that structural adhesives really want either. If you wanted to eliminate an antenna hole or bullet hole without welding adhesives and epoxies can work well as these type repairs are not subjected to any stresses like people stepping on the repair or road debris hitting the back of the repair.
Corvair guy since 1982. I have personally restored at least 20 Vairs, many of them restored ground up.
Currently working full time repairing Corvairs and restoring old cars.
https://www.facebook.com/tedsautorestoration/

Located in Snellville, Georgia

plrgpr
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Re: Floor Pans

Post by plrgpr »

I have been reading up on these adhesives. 3M specifically recommends using their 8115 for quarter panels, door skins, roof skins AND floor pans. In one video a body shop said they use the 3M product and one of the quarter panel replacements that they had done using the adhesive cane back to them with much damage from rear end collision and the adhesive seam held as well as the welded ones. The was also a write up and pics on an experiment where gauge material was welded one one end and then structural adhesive was used in the other end. The strip was placed in some kid of hydraulic machine and stretched until it broke. The welds failed and the adhesive held. As far as the floor pan not fitting flat......3M recognizes this and recommends using self tapping screws to hold it down until it cures. I am thinking seriously of usin this product to do my floor pans. BTW, is the an easy way to get the accelerator pedal off of the linkage shaft?
Gary Roberson
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Re: Floor Pans

Post by terribleted »

I have worked professionally in the collision industry where use of adhesives like these are part of the manufacture of the vehicle and must be replaced exactly per the manufacturers instruction for crash worthiness and corrosion integrity to be assured. If it was designed with structural adhesives it is repaired that way if that area of the car was not designed that way adhesives are not to be used as it may compromise vehicle integrity. There have been a number of examples where shops have repaired cars with adhesives that were originally welded (or combination weld and adhesive) and the repairs failed in a subsequent crash. These might work fine in our floors, maybe not. I like butt welded steel because if done well it is very easy to do a very little bodywork on the underside of the floor to attain a like new appearance. If you bond the patches there will be a metal thickness seam to bury all the way around under the floor which means wiping filler in much larger areas to make the seams disappear.

If you are talking about removing the pedal from its's rod, remove the pedal retaining nut and then remove the pedal assembly from the car. Find a small socket or similar to support between the 2 brackets on the back of the pedal. Chuck the rod in a vice and tap the pedal off the rod while making sure not to bend the brackets out of alignment. If you are reusing the same rod and pedal the pro tip is to mark the exact relationship between the pedal and the rod so you can put it back in the exact same spot on the splines on the rod. It will save some fiddling around later. To remove the pedal assembly from inside the tunnel take off the little E clip that holds the big rod to the little pedal rod and then remove the 2 bolts that hold the pedal to the floor from inside the car.
Corvair guy since 1982. I have personally restored at least 20 Vairs, many of them restored ground up.
Currently working full time repairing Corvairs and restoring old cars.
https://www.facebook.com/tedsautorestoration/

Located in Snellville, Georgia

plrgpr
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Re: Floor Pans

Post by plrgpr »

Ted, thanks for the tip on accelerator pedal removal. I don’t have the center tunnel pan yet off and it didn’t appear that it would come out as an assembly. I would like nothing more than to butt weld my pans, but I know my limitations and i know if I burn through too much, or screw up and trim too much off the new pans.....well you can’t add material and it’s ruined. But having said that, I still may have a go at the buttt welds. Which brings up a couple of questions for you. You mentioned with the structural adhesive, it would be tough to get the pan and old floor flat together. How much more difficult, then, would it be to get the pan and old floor to line precisely enough for a butt weld? Do you plug weld the new pan to the floor support? If so how do you prevent moisture and rust from building between those two components?
Thanks for all your help,
Gary
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Re: Floor Pans

Post by doug6423 »

I've worked professionally in the collision industry also. I'm Master ASE Certified in Collision Repair and trained and certified by Mercedes Benz of North America in welding and collision repair. Also provide expert witness services to anyone suing a repair shop.

I don't dispute anything Ted has in his response, but... if your Corvair is ever in that serious of a crash, that the small section you put in by welding, structural adhesive, duct tape, pop rivets, etc... has anything to do with whether you live or die in the crash, chances are everyone in the car will be dead regardless.

As for the metal overlap difference, use the adhesive that squeezes out as a seam sealer and smooth the edges out. Plus if your spraying undercoat it will most likely completely hide it. I do recommend testing and practicing before doing your floor. Like welding, you'll have one shot. At the end of the day, it's your choice and wish you the best of luck whichever way you choose.
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Re: Floor Pans

Post by terribleted »

If you are burning thru either your rusty metal is not clean enough, or is too thin from rust, or your welder is set too hot. or you are holding the arc too long. When welding in sections I trim and fit a corner or side so I can make it sit flush with existing for welding. I then tack a few spots in the corner or along that side. I then will clamp or screw down and weld and spot welds to bracing (use some weld-thru primer beforehand for the best corrosion protection). I then proceed to carefully trim the rest of the edges of my patch starting where I am already tacked in. I trim a little make it lay flat and tack weld, trim a little more along the edge, make it lay flat and tack weld etc. until the entire panel is tacked in all the way around about every 2". Next I start welding the rest of the unwelded seam about 1/4" at a time, welding a spot over here and then a spot over there and then one on the third side, never stitching in the same area 2x until the area has had time to cool. Continue until all the stitches are a continuous weld. I use a small flat tip screwdriver or putty knife in the gap to move the metal edges into better alignment before welding as needed. You can also push with a prybar or other tool to do this. A second person holding things in place with a 3" prybar can be a blessing, but , is not generally necessary. You can hammer and dolly a little along the way if areas need to be flattened or aligned as you go.

Are you using gas mig or flux core mig? I have found flux core mig setups to be not so great for lighter gauge steels (like body gauge). To me they are more prone to burn thru I think because you need to make more heat for the flux to work than the surface really wants. If you are using flux core I highly suggest changing your welder over to gas and regular non flux wire. Your welding will be much more controllable and much cleaner regardless of what thickness you are welding.

Here are a couple photos of a patch on an early fender top rear
IMG_0309.JPG
IMG_0310.JPG
IMG_0311.JPG
Corvair guy since 1982. I have personally restored at least 20 Vairs, many of them restored ground up.
Currently working full time repairing Corvairs and restoring old cars.
https://www.facebook.com/tedsautorestoration/

Located in Snellville, Georgia

plrgpr
Posts: 214
Joined: Sun Oct 14, 2018 7:51 pm

Re: Floor Pans

Post by plrgpr »

Welp, the new floor pans have arrived from Clarks. Going to cut out the old ones today or tomorrow and I still don’t know whether I am going to attempt butt welding or glue. thanks for all the tips and input. One minute I say to myself I am going to butt weld, then I envision myself cutting the pan too short trying to get that perfect 1/32” gap and ruining a $100+ pan, then it’s no, better play it safe with the glue. Decision time is rapidly approaching. Ted, if I do butt weld , I will follow your instructions, and I do have a great gas shielded welder, it’s an auto feed to boot. It’s the idiot running it I am afraid of.
Gary Roberson
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doug6423
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Re: Floor Pans

Post by doug6423 »

If you don’t have scrap metal to practice welding on go to a local body shop and see if they have a junk panel they can give you. Practice welding, cutting or whatever on it first. I like to ‘warm up’ before doing something on a customers car.


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