Mystery coating

[jeff1]

I removed the seats and carpet on my spider and there is a thick black coating underneath, presumably some kind of sealant. Does anyone have any idea what this might be, and (more importantly), how one might remove it?

[18Fiatsandcounting]

It's exactly what you guessed: a sealant. Perhaps also a sound deadening material. Unfortunately, it wasn't very good, and it tended to trap water against the metal as much as it repelled the water.

There's no easy way to remove it. You either have to go at it with a putty knife or scraper to remove the larger chunks, followed by some sort of wire brush to remove the rest. It may loosen up with acetone or kerosene or the like, but that would be one nasty job and possibly even dangerous, so I would be hesitant to go that route.

Could you just leave it as is? Perhaps clean up the areas where the sealant has worn off, clean up the metal underneath, and seal these bare patches with new sealer? Unless you have floorboard issues or really are trying to restore to originality, maybe just let it be?

-Bryan

[jeff1]

I like your idea.

I saw some spots of rust poking through, so I was thinking of removing it to see what was underneath, but perhaps some things are best left unknown...

Thanks!

[lanciahf]

Dry ice is your friend. Spread it out on the floor. Listen to the lovely cracking noises. Wait 10 minutes, hit the floor with a hammer and it all comes up. Nice and neat.

[jeff1]

Thanks! that worked pretty well. I used a putty knife and screwdriver to help peel up the frozen chunks (there also seemed to be a lot of JB weld and fiberglass patches under there). There's still some to clean up to do, but the condition of the metal underneath doesn't seem too bad.

[TX82FIAT]

Next time, (if there ever is) a vibrating cutting too used the same way a putty knife is used removes the factory insulation quickly. Now after cleaning real good, patch if/where needed, put a coat of POR15 down, re-insulate. Depending on what you want for insulation, you can use dynomat. The rolls of tar backed roofing foil you can get at Home Depot work well, look good. at a fraction of the cost.

[Anbele]

I second TX82FIAT on the Home Depot suggestion. I used the AC wrap they sell. Self stick. About 1/4” in thickness with aluminum foil facing. A fraction of the cost. I did prime the surfaces with Rustoleum rust primer followed by a rubberized truck bed paint. From what it was to what is now, Night&Day!

[jeff1]

Thanks! Those are helpful suggestions. If anyone else is doing something like this, the vibrating tool idea seems well worth taking. Getting the last remaining chunks of insulation took a fair amount of effort, using a hammer and screwdriver to chip and scrape them up, and I felt pretty beat up all over the next day (my elbow is still sore).

A few more questions:
1. As I understand, the triangular shaped holes with the piece of metal underneath are drains and should be left open, but I also see a number of round holes drilled in the bottom. Should I find some rubber plugs for those?
2. I did find some rusted through areas. I guess I have a few options for repair: weld in patches, or use fiberglass/epoxy. My welding skills are still... a growth area, but perhaps I need to face my demons and get some more practice. Any thoughts/suggestions on what would work best?
3. There is still a lot of glue/adhesive around the sides that was used to stick down the carpet. I used a heat gun/putty knife to try to scrape it up, with mixed success. I live in a solvent-challenged state (it's not legal to sell isopropyl/denatured alcohol or mineral spirits in CA ). Any other suggestions for removing this gunk?

Here's what it looks like now:

[18Fiatsandcounting]

A few more questions:
1. As I understand, the triangular shaped holes with the piece of metal underneath are drains and should be left open, but I also see a number of round holes drilled in the bottom. Should I find some rubber plugs for those?

Yes, triangular cutouts are drains, and there should be rubber plugs for the round holes.

2. I did find some rusted through areas. I guess I have a few options for repair: weld in patches, or use fiberglass/epoxy. My welding skills are still... a growth area, but perhaps I need to face my demons and get some more practice. Any thoughts/suggestions on what would work best?

Another option is some sheet metal with rivets, followed by undercoating/panel sealer/whatever works best for you. I've done this numerous times, and it works fine. Welding in new metal is ideal, but as you say, it can require facing demons.

3. There is still a lot of glue/adhesive around the sides that was used to stick down the carpet. I used a heat gun/putty knife to try to scrape it up, with mixed success. I live in a solvent-challenged state (it's not legal to sell isopropyl/denatured alcohol or mineral spirits in CA ). Any other suggestions for removing this gunk?

Acetone? Last time I checked in CA, you can still buy it by the gallon at hardware stores.

-Bryan

[jeff1]

Acetone? Last time I checked in CA, you can still buy it by the gallon at hardware stores.

Thanks, yeah. Should I start stockpiling this?

[18Fiatsandcounting]

Should I start stockpiling this?

I am.

But seriously, you can always buy nail polish remover, although it's diluted with water and sometimes has an annoying fragrance that smells worse than acetone. More expensive than acetone, but I find it useful around certain plastics where full-strength acetone might haze the plastic surface.

-Bryan

[DieselSpider]

Should I start stockpiling this?

I am.

But seriously, you can always buy nail polish remover, although it's diluted with water and sometimes has an annoying fragrance that smells worse than acetone. More expensive than acetone, but I find it useful around certain plastics where full-strength acetone might haze the plastic surface.

-Bryan

Watch out for the nail polish remover that has oil in it. My bigger problem though is that my daughters have started refilling their nail polish remover from my shop supplies and are adding their own water and then use my extra virgin olive oil in it.

Much cheaper for them but...

I was wondering how I was going through so much more of it lately.

[jeff1]

In case anyone is interested, here's a progress update.

I finished scraping off the rest of the gunk on the floor pan, which seemed to be a mixture of asphalt, bondo, jb weld & fiberglass cloth, seam sealer, and adhesive (used to stick down the carpet).



It was pretty miserable work at times, but a friend came over the weekend and helped finish it off. For posterity, here are all the things I tried:

1. Dry ice: as recommended earlier, this worked pretty well on the big areas, but I wasn't able to use it in tight corners or vertical surfaces, and it didn't work as well on the other non-asphalt coatings.
2. Heat gun + putty knife: Required a bit of elbow grease, but cut through the seam sealer/adhesive pretty well and left a relative clean finish. I mostly focused the heat on the putty knife to heat it up.
3. Mineral spirits: You can find the low-odor variant in California, which seems to work fine. This was okay for dissolving the asphalt film when it was already mostly scraped away, but not well on the thick stuff, and not so much on non-asphalt.
4. Acetone: I didn't have much success with this, as it evaporated too quickly to dissolve stuff.
5. Denatured Alcohol: I thought this wasn't available (https://www.timesheraldonline.com/2019/ ... -nonsense/), but I did manage to find some at the paint store. . The guy at the store said they had some way of getting around it. As far as I can tell, it's the real deal (it tasted the same j/k). Either that or I'm now a rum runner. This didn't work to dissolve stuff, but I used it before painting to clean up the dirt and residue.
6. Oscillating multi-tool: I found one of these at Harbor Freight for $20. How have I not known about these until now! This is a handy tool, great at getting into tight spaces. I used a few scraper attachments, which cut through the coating pretty well.
7. Wire wheel/drill: When the coating was thicker, it just kind of smeared it around, but once I had it thinned out, it was good at removing the rest. Also, we used to to clean up pitted rusty spots.

I welded in a patch panel in the floor where a hole was rusted away. My wife and daughter helped cut out the old rusted section. I made an improvised welding spoon out of a copper pipe that I smashed with a hammer, and also used a hunk of aluminum I had around as an additional heatsink. It was a bit tricky to keep burning through, but I kept the current low and took my time:



Here is the whole thing prepped:



There are many strong opinions on the Internet how paint metal. I ended up using Rust Destroyer (https://rust007.com/destroyer.html), as it seemed like a pretty good all-in-one solution, and I've used it before. Here is the bottom all primed:



After giving this a few days to cure, I'm planning to top coat with an oil-based paint, then perhaps fill in some of the smaller pinholes with epoxy.

[18Fiatsandcounting]

In case anyone is interested, here's a progress update.

Yep, definitely interested, thanks for the pictures! Nice work. And I was very relieved that you were "just kidding" on the taste test of the denatured alcohol. The ethanol (booze) is usually denatured with methanol, which is extremely toxic. Causes blindness and possible death. Nasty stuff.

-Bryan

[dinghyguy]

Are you planning to reinstall the little triangle drains?

cheers
Dinghyguy