Thanks to  Terrapin Z (David), He supplied me with a spare lower radiator support for the rearward panel for my crunchy one that will need to be replaced.

2 minutes ago, Patcon said:

I don't understand.

Where were you blowing through??

I dont have pics of it. It was the area where the frame rail was attached on the opposite side that must have a little rust in it. The firewall (footwell) thickness seems a lot lighter than the floor thickness. Maybe old, thin, slightly rusty metal didnt want to cooperate. Maybe of I were a better welder it would work.

I try the following when I have blow through issues:

Turn the welder down (I have 12 settings on mine and have had to use #1 on certain areas of the car)

Really short trigger burst

Feed out more wire from the tip

Put a piece of copper behind is to help distribute heat

Is the gas too high

24 minutes ago, Patcon said:

I try the following when I have blow through issues:

Turn the welder down (I have 12 settings on mine and have had to use #1 on certain areas of the car)

Really short trigger burst

Feed out more wire from the tip

Put a piece of copper behind is to help distribute heat

Is the gas too high

Gotten used to these techniques with this old Datsun metal. It was getting to the point of being such a cold weld that it was causing more problems. Decided to cut a bunch out and patch it. I was just the area that was under the original floor pan up front where its seam sealed.

Finished patch panel on forward attach panel for right floor pan, and welded up holes where I drilled spot welds on the rear attach area.

Next, weld in floor pan.

Copper backing to weld in holes.

Edited December 7, 20213 yr by DC871F

Final fitting of passenger floor pan. 

Had to go to work before welding in, hopefully before Christmas it will be in.

Have some weld through primer on the joining seems, but I'm wondering what to use after its installed on the area that will be plug welded on the rocker. Just something like epoxy primer to get it up there in the seem thats on the bottom of the car?

I would use seam sealer on the joint from the floor pan to the rocker panel. If it already has weld thru primer on it, it'll be fine.

8 minutes ago, Patcon said:

I would use seam sealer on the joint from the floor pan to the rocker panel. If it already has weld thru primer on it, it'll be fine.

When you look at the factory installation, down on the bottom side of that joint it seems they left it bare. On the inside there was all kinds of sealer that had to be ground out, seemed pointless unless it was just to make it air tight, but did nothing from below to keep water and debris out.

I like the idea of seam sealer, but before I was thinking pf packing as much epoxy or rust pain as possible in there before had.

 

7 hours ago, DC871F said:

When you look at the factory installation, down on the bottom side of that joint it seems they left it bare. On the inside there was all kinds of sealer that had to be ground out, seemed pointless unless it was just to make it air tight, but did nothing from below to keep water and debris out.

I like the idea of seam sealer, but before I was thinking pf packing as much epoxy or rust pain as possible in there before had.

 

Anything you do will be way more than the factory did and the cars lasted 50 years, many of which were probably neglected due to being a relatively cheap car. That won't be the case going forward. Should last just fine another 50-60.

It may be all (or most) the seam sealer was done from top side for ease of manufacturing. I suspect the seams were sealed to keep the interior dry, not necessarily for longevity

Passenger floor pan installed, touch up areas still need to be welded up and then seat mounts.

Passenger front seat mount.

Classic Fab.

Just ordered these.

It had been a while since I've been on their site, they have added some nice panels to their list.