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TR4/4A The Horror--Floorboards

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KVH

KVH

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Jeepers. I pulled up the carpet in my "new" '66 TR4A and found that the prior owner did, in fact, glue a thin sheet of foam to the entire floor and firewall area. We're talking "glued" every square millimeter with the only removal means being my finger tips and a plastic scraper. Hours and hours.

And just as Geo and others over the years warned, the foam did a great job of holding moisture in and causing some rust that likely never would've been there otherwise. A real bad choice by any calculation.

So here are my questions.

I'm going to sand away the rust areas, but how thin is too thin, and can I strengthen the floor and repair the rusted areas using fiberglass mesh sheeting? The rusted areas are spotty and small, like on the passenger side maybe 7 areas 1/2 inch by 3/4 inch. Some spot rust areas, too.
 
!). If you can see light through them, that's too thin.
2). If you fiberglass over metal, someone, sometime, somewhere, will be cursing as much as you are about the foam.

Rough it, vacuum it, and rustoleum it. It'll be awrite.
 
CJD said:
!). If you can see light through them, that's too thin.
2). If you fiberglass over metal, someone, sometime, somewhere, will be cursing as much as you are about the foam.

Rough it, vacuum it, and rustoleum it. It'll be awrite.
Click to expand...

I don't know. Here's a pic. Six holes. I put a light under the car to illustrate better--so you can actually see the holes in at least two cases. Biggest is about 1/8th by 1/4 inch, after I chipped it out with that awl. Then I punched the awl all over the floor, and no more holes opened up.

Note the floor looks entirely rusted, but it isn't. Using a buffer, I can expose the white paint beneath that ridiculous bed of red/brownish glue that remained after I tore out all the foam. See second pic.

Well, so what do I do? I feel that I need to rust treat the entire floor, but also patch and reinforce where those little holes are, and I'd think any kind of filler makes sense, but what alternatives do I have? Bondo and glazing putty? I can see why not fiberglass, but the mesh fabric does really seal the area up, and the overlap could help strengthen the surrounding area. But I'd like to hear any more thoughts. thx

Holes in Floor Board.jpgFullSizeRender (2).jpg
 
I had exactly the same "pin holes" in the floors of my TR3. To me, pin holes indicate the entire area is weakened by corrosion: pin holes don't appear in otherwise strong steel.

So I wire brushed and sanded the entire area, then sprayed with phosphoric acid (top and bottom). I couldn't afford to buy new floors and have someone weld them in, so I repaired with the "POR15 -> fiberglass material -> POR15" method that I learned here on BCF about ten years ago.

Phosphoric ended the rusting, POR15 sealed the area, and the fiberglass topped with POR15 reinforced the pan.

Another possibility - if the entire area is "flexible" due to corrosion, you could do the above phophoric/POR15 treatment, but pop rivet an aluminum plate over the area, then paint.

Tom M.
 
There's a chopped fiberglass hair product that is basically chopped strands of fiberglass in resin called Tiger Hair. It worked well for me with similar pin holes. I cleaned the area to metal then treated the area with phosphoric acid (got a gallon from HD). After a soap and water wash and dry for a couple of days, applied the Tiger Hair. It's sticky gooey but can be put on flat with a little practice. Anyway, the hair filled the void, the resin ran through and left small drips under the pinholes. You can spread out the hair similar to a mat by pressing down with a putty knife after the sticky stop a little. Makes a nice patch and after a little paint is nearly undetectable. Most front pinholes on my car have been from wet feet and weatherstrip leaks. Unless you see large areas that spread, this worked great and the resin totally seals out oxygen. That's what I'd do anyway. If it comes back, then consider metal patching. My two cents.

edit: Just need a tiny amount of TH to fill the holes. Also to apply the Phosphoric, I use a small brush and soak the area, repeating it every so often but let it soak for a few hours. The result will look whiteish so wash to residue well. Don't forget to treat the floor under the pin holes as well.
 
That's pretty minor as repairs go. Not bad enough to replace the floors yet. If you have a mig welder, you can plug them all up in a few minutes. If you don't then just dabs of glass filler, like Peter says, before repainting.
 
I cannot speak to the reinforcement issue; but for paint, I recommend Hammerite Rust Cap. I have sanded rust to get it relatively clean and then painted with Rust cap on 3 cars I have had in the past. It even comes in different colors. It "encapsolates" the rust. And i have never had an issue subsequently
Good luck
 
If there aren't too many holes and they are small you can also use JB Weld. I used it on my '40 Buick and it worked well. I thought I might have have been committing some sort of apostasy by doing that but I have spoken with other more "professional" restorers that indicated that it is acceptable to do this, especially for a driver. Let the goo settle for about 30 mins after you mix and then you can apply using a plastic trowel. Once it sets and hardens fully (give it a few days) you can sand and paint.
 
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