I'm a fairly new owner of a '77 spider and am just starting to try and restore the interior. I have removed the carpet and old padding. I have read a lot on the forum about what insulation to use and how to do the carpets. But I am curious about the tar like substance on the floor. Is it worth it to remove it and do I need to reapply something else? Or can I leave it there and install insulation and carpet over it?

I used Dremel's version of a multi-tool with the flexible scraper blade; worked very quickly, and very well. I also used a "Spider" scraper blade, which fits in a recip saw; worked well for the larger flat areas, but kicked like a mule when fitting any sort of variance from dead flat. Cleaned up the misses with a sharpened cold chisel powered by hand (no hammer). "POR"'d the exposed metal, Rustoleum antirust primer on top of that, followed by Rustoleum Marine blue enamel.

Here's the URL to my original post series, with pix of the interor clean up:

http://www.fiatspider.com/f08/viewtopic ... 30&t=23101

Apply patience (external application), and a beer or two (internal application), if so inclined.

It's worth the effort.

Neil

This might help (page 5)

http://fiatspider.com/f08/viewtopic.php ... hilit=cool

It's worth it to remove it just to see if there is rust under it. It can hide rust and since you have everything out, now is the time to find out and address it. Once removed I just painted it with rust inhibitor (e.g. POR15) and then put sound deadener over it (e.g. Dynamat).

The thread 4uall listed is a good one for info on how to remove it and what to put down for sound deadener.

Awful stuff, awful job to remove

You will be glad you did

Thanks for the advice. I read through more of the info. and decided to scrape up an area that seemed fairly soft. I managed to easily remove a section on the passenger side in the back (the rest will clearly not be so easy). I am including a picture if I can because it looks to me like something has already been done to this floor? I think I see patched up holes and I don't recall any of the pictures on the forum of a white floor pan. Is that another layer that needs removal? Or has someone else already tried to seal it and put their own layer of tar on top? Any opinions are greatly appreciated!
https://flic.kr/p/rnLHq5

What you are looking at is the original factory paint before the sound deadener was applied. It all looks pretty pristine to me. The perfectly circular spots are not rusted out spots. What I see at the top part of the picture between the door rail and the seat rail looks very suspicious. The deadener does a very good job of rust protection. Most floorboard rust was created from salt water attacking the underside and rusting through. The big exposure is around the edges of the floorboard where there is no deadener. particularly on the PS where you get rust from the heater valve leaking. I have found the deadener is best removed when it is cold and brittle and can be chipped off with a chisel.

I'm in the middle of removing the tar from my 1981. I used one of those vibrating multi-purpose tools on the passenger side; it worked, but the heat from the vibrating blade softened the tar and made it gooey. For the drivers side, I'm using a stiff 1" putty knife and a heavy hammer to chisle it up. This method is working a whole lot better, as there is virtually no leftover goo to clean up.

i have also heard of people using dry ice then just hitting the floor pans with a hammer. may cause more damage though

I used a couple techniques. Where the tar was dried and cracked the BFH took care of things. Bang away and it cracks and breaks into pieces. Where the tar still has some substance the electric scrapper and hammer and chisel did the trick, but with much more effort. Its important to be through as you'll find hidden rust underneith. I was going to leave the rear floor pans alone but I'm glad I didn't. Rust was evident in the area where the trailing arms attach to the body. Mine wasn't serious so cleaned and treated with POR but I'm glad I found it when I did. It would only have gotten worse.

I hear ya

I used a propane torch and a putty knife, came off like butter.

I have been down this road, I used a propane torch from plumbing section of Lowes to heat the stuff up and scraped it with a putty knife. Saved countless hours. Work's on the undercoating also. Sand blasting has virtually no effect on it. I yes it will eventually remove the under coat and floor pan stuff but it will take weeks. The coleman propane tanks are a better deal then the benz o matic refills. Yes they fit the benz o matic. Get the one with the built in igniter. Have fun.

If you want to use the heat method a heat gun will be safer than the torch or you can use an old steam iron over a wet cloth to soften the tar so you can scrape it up. The steam iron over a wet cloth can also be used to ease remove sheet flooring in a home or to re-adhere a bubbled section back down to the glue that let go.