Sunday, February 8, 2009

Welding-In The Seat Platform

After grinding down the umpteen million welds of the floor up to this point there were some imperfections and pinholes in the welds that needed to be filled. I went down to my local NAPA and bought a selection of items. Dupli-Color red oxide primer filler, 3M body filler and NAPA house brand red oxide glazing putty. I tried a little of each on test areas on the inside bottom of the tunnel to test their filling, convenience, color, and durability. I found the easiest to work with was the glazing putty because it could be squeezed out of a tube, spread with a putty knife, dries rapidly, and sands easily. If I were filling large voids or what have you, I would go with the 3M since it's a more durable 2-part concoction.

I filled the few pinholes around the various welds that I had made in the toe boards with the glazing putty and also evened out the seam welds a bit and then sanded the excess putty away.

I then re-applied primer to all of the exposed metal and putty and then attempted to blend the new shinier primer with the old floor primer by roughing it a little with some steel wool. As you can see, the blending attempt didn't go too well but that's okay, primer is primer.

Re-priming the floor was an important step because any exposed metal would be forever exposed between the soon-to-be-installed seat pedestal and the floor where moisture could become trapped and rust through any unprepared areas.

Having completed that step, I could now focus on preparing the new seat pedestal for installation. I laid out the plug weld hole pattern based on my 1968 Mustang Weld & Sealant Assembly Manual and spent another hour or so center-punching and drilling holes in the flanges.

I then fit the seat platform such that the seat rail holes in the seat platform lined up with the access holes on the floor/lower reinforcements. I then gently "massaged" the flanges of the platform flush with the floor using the surgical precision tool: the dead-blow hammer. I marked the seat platform flange locations on the floor so I could remove and reposition the platform. I then used the markings to determine the locations of the various seam welds over which I ran my grinder to expose metal to weld to.

I repositioned the seat platform, and then used a flat-end spot weld bit through each of the holes to expose bare metal to weld to and drilled 1/8" holes anywhere I felt the need to pull the flange tight against the floor for the insertion of clecos. Note the use of clamps at the front and long bolts through the seat rail holes to initially hold the platform in position before inserting the clecos.

I was finally able to begin welding the 46 plug welds that affix the seat platform to the floor. These welds went really well and came out flush with the seat platform flanges such that I have very little weld grinding to do to finish and the seam welds turned out nice too if I may say so myself. It's too bad I'm finally getting a handle on this welding thing right towards the end of the project. ;-)

Here's an image up through one of the seat rail bolt access holes. This shot also exposes a shameful secret; a skeleton in my Mustang chamber of horrors, an evil misdeed that surely will have repurcusions through the generations. I' m speaking, of course, about the undersides of the welds you see in the photo. They are NOT on the flanges of lower seat reinforcements where they belong. The flanges should align between the seat platform and the lower seat reinforcement panels and my reinforcements are too far back. This error was conceived way back when I was welding in the front floor supports (frame rail extensions) OR I may have welded in the new floor 1/4" too far forward. I think the latter since I positioned the front floor supports based on the position of the original lower seat reinforcements. Either way, I'm thinking that the front floor supports could actually be welded in after the floor and lower seat reinforcements. I can't think of any welds you wouldn't be able to get to if you were to weld them in last.

Whew... now that I've confessed that, I feel like a huge weight is off my shoulders. In fact, I'm in a confessin' mood now. So check out the picture below. If you can't spot the error, please leave the room and forget I said anything. What the rest of you saw was that the flange on the lower left side of the picture is tweaked way in towards the inner rocker to allow it to be welded. Why? I'm not entirely sure but I figure it's one of the following:

  • The seat platform is at an angle, which I don't really believe this because all of the other ends flanges meet the inner rocker correctly and they wouldn't if the entire platform were crooked.
  • The entire floor is crooked causing the seat platform to misalign which I also don't believe because of the reason above and the fact that the floor settled onto the front and rear tunnels without a problem.
  • The left rocker is 1/4" angled outward. Maybe. This could have happened when I was forcing the front torque box/inner rocker into position.
  • The seat platform itself is made wrong. Maybe, but I'm sure I wouldn't be the only one who this has happened to.

Despite the errors above, I'm pretty sure the car will still drive in a straight line. If not, please let me know now so I can have it crushed. Thanks.


  1. Alex what welder did you use for your restoration? Sorry for all the questions but I am really enjoying reading your blog. I started from the beginning and am up to the engine rebuild!

    1. I have a Millermatic 140. Glad you're enjoying the blog!