W&N floor plan fitment/welding advice needed

[floatinghead]

I'm working on getting the new replacement W&N drivers side floor pan fitted, careful not to take off too much off at one time, but making a slow project of it for sure. ( first time disclaimer) The thing thats throwing me off is the original pan had the spot weld flanges facing up, whereas the new pan has them pointing down and almost non existent on the front edge. It wasn't a big deal along the door sill as I could just cut out the floor and it now sits even and i'm good in the front corner which will require a few plug welds.

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I'm just not sure how to manage the front edge really. The flange thats on there looks like it fits below, but is too narrow to allow for a 5/16" spot weld. Or maybe its really meant to be trimmed off adn seam welded along the front. My other issue is that the metal i'd be welding too is awfully pitted up. Its reasonably solid ( a pin hole or two) but the stiffener bead isn't in great and worries me.

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1. Should I just trim to best fit and seam weld across the front instead of spot welds? I wanted to butt weld, but should i lap weld this section to increase strength and just make sure its welded solid from both sides?
2. Do you think the metal I'm welding to is good or should I cut out and replace with new?

thanks!

Baron

[floatinghead]

After looking at the area a bit, if the pitted area is solid enough, i could weld on a strip to the end of the new pan so that i have adequate material for spot welding. This actually would be pretty straighforward and then make the panel more similar to the original. just a thought.

[okieflats]

So the new metal should go under the old? But along the front edge it is too short?

A rosette or plug weld is when you drill a hole in the top layer, pinch the two panels together, and fill the hole; joining the two panels together. ... These days most areas where a spot weld would be needed hobbyists are rosette or plug welding the panels together.



https://garage.eastwood.com/eastwood...-or-spot-welds

[okieflats]

Oh, yes I see what you mean now. The new metal is supposed to go on top of the old, but it is bent wrong. But it's also too short, doesn't even reach.

I would say re-bend it, there is some crimping tool to do that. But that wouldn't fix the too short, doesn't even reach problem.

[floatinghead]

It's hard to tell from the photo, but the flange on the end is pressed in toward the ground, as if it was meant to go underneath, but its also too narrow to even drill at 5/16" hole for a rosette or plug weld as you mentioned. I wonder if the pan and this feature is more of one of alignment and not a true "weld in as is " part. I just happen to need more on that end as that section of my floor was toast. My recent thought was to cut the depression off and weld on an appropriate tab along that top edge so I can then plug weld as was the old panel.

Do you think the metal on the receiving end ( with pitting) is sufficient? I might do a trial on a scrap piece from an area similar on the section i cut out.

[floatinghead]

Yeah, I used a wire wheel. I’ll try the grinding wheel and see how much I have left!

[floatinghead]

well i did a test weld on a portion of a pitted scrap section. Some blew through super quick, others not too bad. I'm having more issues fitting the panel than anything else, so hopefully I'll get to welding sooner than later.

and Okieflats, i did a test plug weld on that same panel and it seemed to hold up ok, so feel like it could work.

[okieflats]

I'd say hammer that leading edge of the new grey panel flat. Take the crimp out of it. Then add a strip of new sheet metal to it, along the whole length of that edge, using spot or "plug" welds, to extend it. Then trim that added strip so it just overlaps the old pitted sheet metal still in the car by just the right amount.

[floatinghead]

I didn't think of flattening out that section and I think adding on and extending up is the way to go. I think I've been looking at this replacement panel as the "correct " piece, when its really just a "close but not that close" a part. Right now i'm having issues with it sitting tight against the frame rail ( which i had to straighten out), so need to trim some metal away from the W&N panel to then determine how much to add.

[floatinghead]

update: decided to patch in a section below the pedals as it had some pin holes and was pretty thin and pitted up. Plus I figured its some more practice fitting and welding. The hardest part is getting my head in there to see things to weld, but i think it's coming together. Hope to have this section wrapped up this weekend and will cut out the accelerator stop and replace that section as well....

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[320iAman]

Looks like a good butt joint weld. Are you going to completely weld the sheet metal together or use seam sealer ? What did you use for the spot welds Mig with C25 ? and what size Mig Wire solid 023,024 or 025 ? A piece of metal with very low specific heat abutted to the area of welding pulls heat away to help prevent burn thru's and warp-age .

I have been using a flux-core welder and tried 035 and 030 in spot and filet tests on 18 Gauge Sheet metal , 030 is better for sheet metal 18 Gauge then 035 at minimum settings--max setting caused war-page ,,these cars use a lot of 18 and 20 Gauge sheet metal. I have a feeling the welding wire makers discontinued 025 flux core wire under pressure as it would dent into Mig with Gas...

At present Flux Core is best with thicker metal and Mig with Gas better for thinner sheet metal like 18 and 20 Gauge.

Randy

[floatinghead]

Thanks Randy. I'm running MIG with C25 and .025 wire and starting to stitch in sections to fully weld it up. Will hit the back side as well depending on the penetration. Metal is 20ga and will certainly be a lot stronger than the metal that was there. I'm getting a bit of burn thru but did my best to get a tight fit. Practicing on a welding table vs on the car is much different, but I'm glad I got a number of practice runs in before this.

[okieflats]

What do you think the gage of the original floor metal was? New as it left the factory?

[floatinghead]

20ga was close to the metal around the area I filled. my floor pan from W&N is between the 20ga and 18ga sheets I have

[autox320]

Thanks Randy. I'm running MIG with C25 and .025 wire and starting to stitch in sections to fully weld it up. Will hit the back side as well depending on the penetration. Metal is 20ga and will certainly be a lot stronger than the metal that was there. I'm getting a bit of burn thru but did my best to get a tight fit. Practicing on a welding table vs on the car is much different, but I'm glad I got a number of practice runs in before this.

I found a handy tip from an old timer welding sheet metal since I hate it so much. Keep an air hose nozzle from a compressor with you. Each few stiches blow the cool air at the work piece. Not so fast air pressure you blow through a hot weld, but quickly cool to keep from excess heat build up. This let me stitch sheet metal much faster once have a rhythm. Beers made it even more bearable.

.025 wire is a must. I use .030 in my welder at all times but yup .024/25 for sheet makes it even easier.

Clean bright metal sheet welds easy. But with an old car that's not what your doing. What some don't realize is how dirty factory metal is. After years of road grime even cleaning to weld it will still have impurities in it. Can burn with a torch helps but still crappy 30/40yr old sheet metal surrounded by undercoating and sealers. Cleaning both sides sufficiently still can yield frustrating results. Some metal is just too "worn" even if it doesn't look bad has rust specks or spots in it keeping you from welding it reliably.

Frustrating job so bravo on tackling this. Just thought I'd point out to some this ain't easy as it looks.

[floatinghead]

I had heard of folks using an air compressor as they welded along. I might try that with the next panel.

and I agree, the old metal isn’t as clean. I had to balance getting it down to bare metal and not thinning it out too much. Also Wiped it down with acetone which helped a bit.

[320iAman]

Yes... Air is good to cool down the weld area also patience , let each weld cool down before doing the next so that you can bare hand touch it and its cool also alternate the spot welds where you can so that your welding on the opposite side going back and forth, completely welding the sheet metal by spot welds takes time yet that's just part of the job.

Randy

[floatinghead]

autox320 and Randy, I used air on my last patch and i think thats the way to go. My first panel went in ok (without air) but warped in a few spots, but nothing that can't be hammered into shape! This smaller one went a lot faster and stayed true. need to get on the back side a bit, but should be wrapped up with this one tonight. My pancake compressor is probably the only one not liking it....

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and smaller patch where gas pedal stop mounts:
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(plug welds aren't pretty, so need to work on my technique before getting my floor pan fully in)

[320iAman]

Looks good,, pretty welds is more like Tig welding( many different rods as well) which is a slower process and use lower amperage and thus better heat control, Mig is faster. Its definately coming along. Functional is more important than pretty looking, your not going to see it anyway...

Rule of thumb 1 amp per 0.001 " metal thickness,, so 18 Ga Sheet metal ~50 Amps,, 20 Ga sheet metal 37.5 Amps, also set the voltage up as High as it gets or high(15-18 Volts),, the higher the voltage the easier the amperage flows, the lower the voltage the harder it is to flow amperage--what this means is the other half of ohm's law which is missing from most people posts the higher the voltage the less heat is generated at a given amperage... Both parts of Ohms law is necessary for cogent welding, electrical work , ect.


Randy

[floatinghead]

Well, after a some family visits and vacations this summer, I finally was able to get the floor fitted and welded in! I still have a fair amount of grinding ( and some rewelding), but its in there all the way around and 10x more solid than before! Feeling good for a change.

Here's before, during and after:
e21-floor-BEFORE.jpge21-floor-DURING.jpge21-floor-AFTER.jpg

still have to weld the trans mount and pedal stuff in place and then on to the frame rail in the engine bay before painting it all up.

[gsumzzz]

nice. man i hate rust.

[320iAman]

Indeed, very nice, way to go.

On a side note I picked up another new welder. The welder has Tig/Arc Functions it came with WP-9 Tig Torch, I bought a WP-17 to go with it, I tried out the Arc function with 1/16 in rods on 20 Gauge Sheet metal pieces doing a butt weld, nice little bead very little to no distortion, I have wp-9 and 17 accessories kit with gas lenses ect and Argon regulator, I also got one each of tungsten-2% Ceriated tig electrodes in 20,40,and 60 thousandths of inch dia. common for sheet metal , the only item I have to get now is the Argon tank, I worked in a the Oxygen Reduction Plant years ago and filled Oxygen lines and Argon Lines ect, also checked the valves and tank threads for leaks so this will be no problem to get a daily deal with the price is right here..

Randy

[floatinghead]

October update: got the trans bracket welded in and painted up!

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Then it was on to re-supporting the car for the front frame rail repair. Cut off the outer layer a bit larger than the inner (rear section ) of frame rail. Once I cut the rear section out, i made a paper template and cut it out in steel, folded the sides with a desktop break and then shaped the curve of the piece. It came together relatively quick and required less welding/ grinding than if I made it from 3 individual pieces. Fit up still took a bit, but I got it to line up well and it welded in pretty easily, though maybe cause it was 16 ga

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[floatinghead]

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and a few more photos of it welded in. Now grind back a few sections for the 2nd layer to to welded and plug welded in...

[mjweimer]

Well done! That frame repair is coming along nicely. Are you planning to fog the inside with cavity wax when complete?