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Wednesday, June 7, 2017

Triumph Spitfire Body Repair #1 - LH Floor Pan Replacement Prep

As promised, on to the body repair work. For the most part, I will use the British terms for various body parts (here's a "translator" just in case). Additionally, by convention, I will refer to the sides of the car as if you were sitting in it and I will either use passenger's / right hand (RH) or driver's / left hand (LH) side.

Essentially, the lower four inches of the car is rusted out and here's what I know I have to repair:

Replacement panels on hand: floor pans (both sides), floor crossmembers (both sides), inner, middle (strengthener) and outer sills (both sides), sill filler panels (both), RH lower "A" post.

Fabrication work (unless I buy panels): LH lower bulkhead, RH upper to lower "A" post transition, rear wing front lower (probably both), rear wing rear lower (probably both), inner rear wing rear lower sections (from inside the boot) and the lower rear outer valance.

Of course, that's all I've found so far. I'm sure there will be more repairs to do. I haven't look over the bonnet closely, but I am happy to say that one area that I know tends to rust out, the D-shaped bonnet strengthener panels, are both good. Also, I still have the body of the black car sitting in my back yard. Of course, it is slowly rotting away back there, but several of the panels, namely the boot area, are in better shape on that then they are on Dorothy, so I'm sure a lot of donating will happen.

The victim awaits my hacking.

Before I get started with what I've done, I want to recommend a book that I picked up from Amazon that I initially heard about on my favorite forum, titled How to restore Classic Car Bodywork, by Martin Thaddeus. The physical copy of the book is pricey at about $45 while the Kindle version is only about $24. For reference books like this, however, I like to have a hard copy so I shelled out the money.

Worth every penny! It is a British title, so it is a larger format than a typical book of its type over here. The author covers the basics (tools and equipment), metal fabrication, and repairs. The repair portions not only cover repair methods but also the approach, or order of operations, in which the typical repairs should be performed. For example, for the floor and sill repairs (which he replaces in a Triumph Spitfire!) he explains why it's best to replace the floor and then the sills in an inside to outside order. This was a nice touch for someone like me who has never done this sort of work.

Additionally, it is absolutely full of photographs, most, if not all, of which are in color. It's only 128 pages, but the text is very small and in two or three columns, so there's a lot of information packed in there. Being British, there are some different terms used from what us Americans use (other than the typical boot and bonnet), but it is easy to figure it out in context. Take a look and, if you have a Kindle, you can download a sample of the book to get a feel for it.

Armed with the knowledge provided in the book, I wanted to tackle the floors and sills first, one side at a time. The new floor will be attached on three sides until the new sills are installed, so I decided to start with the driver's side since one floor attachment point, the front bulkhead, would need to be repaired first.

LH Lower bulkhead showing cancer.

Same area but from inside the passenger compartment. Note the fiberglass repairs (yuck!).

Before I got too far I decided to poke around inside the sill area and found about three pounds of Bondo as well as oiled paper. I thought it might be a mouse nest or something but learned that oiled paper was used as a repair trick to provide something for the Bondo to hold on to while trying to prevent water collection. Awesome.

A peak inside showing the "mouse nest" repair.

What I dug out of the hole. This wasn't all of it.

Enough of that mess. I turned my attention back to the bulkhead repair. The cancer extended behind the body mounting bracket so, in addition to splitting what remained of the front of the floor from the bulkhead, I had to remove the bracket for a proper repair.

Showing the cancer moving behind the body mounting bracket.

Armed with a few 1/4" drill bits and a pneumatic drill, I got to work. Not too bad, though a sloppy factory spot weld resulted in me tearing some metal before I realized I missed some of the weld. I take care of that in a bit.

Bracket removed showing cancer damage behind it.

I cut back some of the front sill to get an idea of how the bottom of the bulkhead curved.

Sill filler panel cut away. Actually doesn't look too bad in there. Must be more Bondo repairs!

I cleaned the entire area up, including inside the footwell, with an angled die grinder and a Harbor Freight 2-inch Medium Grade Fiber Surface Conditioning Disk to make sure I was going to cut away all of the rusted metal, but no more. These things work pretty well and seem to hold up okay as long as the surface is relatively smooth. If you run in over ragged metal (like at the edge of damage) they get shredded pretty quickly, as you would expect.

Area cleaned and marked for removal. I circled the two holes and put an outline of where the body mounting bracket attached.

Then, I cut a template using a manila folder. Sorry I didn't take any pictures of that, but this wasn't a very complicated fabrication. I provided extra metal for the bottom lip of the bulkhead and also, since I was doing a lap weld, the top to make the lap joint. Using the manila template, I cut another piece of metal from my old boot lid and formed it to the rough shape.

Cut per pattern and the lip formed. I'm bending here to account for the inward slope towards the sill.

I went back to the car and set the new piece in place to check dimensions.

Rough trace of the new piece, outlined on the existing bulkhead.

Using a Harbor Freight Air Punch and Flange Tool, I pressed a flange into the new piece to make the lap joint. 

Initial run of the flange tool. Got a bit sloppy with it towards the right edge.

I used a ruler and measured the width of the flange that the tool makes, and transferred this to the bulkhead to make sure I wouldn't cut too much metal away. I needed to ensure that I cut the metal at a point the thickness of the flange smaller than the initial trace of the new piece.

The flange cut identified. The bottom horizontal-ish line is the cut line.

I followed my outline to cut away the damaged metal and, using the Air Punch tool, popped several holes, about every 1/2" or so, into the bulkhead. I left the right side of the bulkhead alone since I'm not positive how that all sandwiches together quite yet.

Holes punched and initial fit up. I was able to correct most of the large gap on the left side.

To take care of the larger of the holes that I put in the bulkhead removing the body mounting bracket, I used my step drill bit to cut a smooth, 1/2" circle to make it easier to weld.

Nice round circle.

A small metal disk to fill the hole. Tin snips work great on fingers, too <ouch>.

With that, I sprayed both sides of the area with Dupli-Color Weld Through Primer that I picked up at Amazon for about $12 a can. I had previously used the SEM stuff, but it didn't go on very smoothly, coming out...chunky. Hard to explain, but the Dupli-Color stuff went on very nicely and I gave it about 30 minutes to dry before welding. I'm not sure if that's enough, but I could only find times for "dry to the touch" (12 minutes) and recoating. Seemed to work okay.

Area prepped and primed, ready for some action.

I got right down to welding. Some of the welds were pretty nasty, but I had only one spot where I blew through and everything cleaned up nicely. After each weld, I blasted it with several seconds of compressed air to keep the area cool to prevent warping.

The first weld. Not pretty.

Done. Meh. The left most joint was a butt joint vice a lap joint. Note the left gap is closed up as well.

I then tacked in the metal disk. I was pretty happy with this result.

The little metal disk held by a magnet...

...welded in.

I ground down the welds using a 80-grit flap disk. Some spots needed a few more shots of the MIG, but all in all not a bad showing.

Welds ground down.

Most of weld area from the footwell side. Pretty good penetration all around.

I then shot the area with some more weld through primer in preparation for putting the body mounting bracket back on. However, before I can do that, I wanted to fill the seam left by the lap weld. Hopefully as I gain more experience, the seams will be come smaller, but I don't know that I can ever really eliminate them in lap welds. Butt welds, of course, won't have this problem.

I cleaned the seam area of primer with the fabric disk and applied a thin coat of Bondo. My intention with the Bondo is to sand all of it away except that which fills the seam itself, so i don't expect there to be much of it at all. The only other alternative that I could see was filling the seam with weld metal, but I thought that was simply unnecessary and risked damage and warping.

Bondo applied in excess which will be heavily sanded.

That's as far as I got. I'll sand down the Bondo and probably have to do another skim coat (you can still see the seam in the shot above) and then be ready to put the body mounting bracket on. Once that's in, I'm building a rotisserie!

1 comment:

  1. Very nice. I suspect I will doing lots of that in the days to come.