Undercoating. Ugh.

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It is an asphalt product, even smells like roofing tar. If it were super frozen with dry ice, it might work. But at room temperature it will just put a bunch of dimples in it.

Use a plumber's torch, heat small areas about 4x4 inches, keep the torch about 6-8 inches away so it doesn't catch fire and only until soft, about 5 seconds, then scrape with a putty knife. You want it soft like clay and it comes off nice and clean (mostly). If it is too hot it will melt. It will still come off but will be messy. A few seconds to cool and you're back in good shape.


I don't know. Looks like they scuffed it with 80 grit on a DA. A bunch of factory paint came up with the liner. They did do a lot of short cuts, however. Like lining over rust. The bed has dozens of holes from self drilling screws, and they just put masking tape over them and sprayed. Didn't remove any dents on the floor, either.

Listening to this sounds like any thin paint would be never found. As expected. I suppose my biggest thought is Toyota never sending out bare metal on production of these machines.
 
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It is an asphalt product, even smells like roofing tar. If it were super frozen with dry ice, it might work. But at room temperature it will just put a bunch of dimples in it.

Use a plumber's torch, heat small areas about 4x4 inches, keep the torch about 6-8 inches away so it doesn't catch fire and only until soft, about 5 seconds, then scrape with a putty knife. You want it soft like clay and it comes off nice and clean (mostly). If it is too hot it will melt. It will still come off but will be messy. A few seconds to cool and you're back in good shape.


I don't know. Looks like they scuffed it with 80 grit on a DA. A bunch of factory paint came up with the liner. They did do a lot of short cuts, however. Like lining over rust. The bed has dozens of holes from self drilling screws, and they just put masking tape over them and sprayed. Didn't remove any dents on the floor, either.I just remembered
I just remembered one of the 80 guys saying he uses a bag of dry ice to remove the pasted-on sound deadener pads on the floorboards, before applying DynaMat. It didn't occur to me until just now that the pads are probably very similar material. He had really good luck using this method. He lays the bag on the pad, waits a couple of minutes, removes teh bag of dry ice, then smacks the pad with a dead blow hammer. It shatters and he sweeps it up.
 
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Listening to this sounds like any thin paint would be never found. As expected. I suppose my biggest thought is Toyota never sending out bare metal on production of these machines.
If the paint is so thin it is invisible, is it protecting anything or even really there?
 
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If the paint is so thin it is invisible, is it protecting anything or even really there?

I will try to grab an image of 50 year old undercoating, over paint, and find a spot where I removed the undercoating and in removal process went to metal. I suppose there is some chemical to remove just the undercoating but I did not go that route. Also, I have never heard of any vehicle sold with bare metal except a delorean. One would expect rust to appear even in the trip coming here if Toyota did that.
 
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I will try to grab an image of 50 year old undercoating, over paint, and find a spot where I removed the undercoating and in removal process went to metal. I suppose there is some chemical to remove just the undercoating but I did not go that route. Also, I have never heard of any vehicle sold with bare metal except a delorean. One would expect rust to appear even in the trip coming here if Toyota did that.
Thanks, I am truly not trying to argue with you. What I am saying is, mine has no paint under the undercoating. That said, I am still interested in seeing what yours looks like.

A film of undercoating is still there but is so thin it is transparent. Bare steel can be seen through the film. Also, I have done the entire underside of the bed, and the lack of paint is even and consistent throughout. I don't believe I could have gone through paint that evenly if I tried. Nor is there any evidence of paint on the tar I have removed.

I agree with you that it never should have left the factory bare. To me, a more plausible theory is the undercoating was applied at the factory when they discovered the error. This is not my first restoration, been doing this for almost 40 years. I just thought it was odd. I do appreciate your experience and contribution to this quandary.

Edit: I can admit when I am wrong. Where I was sure paint existed in the wheel wells, I was super careful to try and find paint underneath. I managed to get the tar off and leave paint behind, in a tiny spot. Wasn't easy as it is just as soft as the undercoating and has no bond left to the metal. It doesn't appear to have primer under it, same as under the cowl, just color to bare metal. The paint is not good, which explains wherever they missed undercoating it's just rusty.
 
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Thanks, I am truly not trying to argue with you. What I am saying is, mine has no paint under the undercoating. That said, I am still interested in seeing what yours looks like.

A film of undercoating is still there but is so thin it is transparent. Bare steel can be seen through the film. Also, I have done the entire underside of the bed, and the lack of paint is even and consistent throughout. I don't believe I could have gone through paint that evenly if I tried. Nor is there any evidence of paint on the tar I have removed.

I agree with you that it never should have left the factory bare. To me, a more plausible theory is the undercoating was applied at the factory when they discovered the error. This is not my first restoration, been doing this for almost 40 years. I just thought it was odd. I do appreciate your experience and contribution to this quandary.

Edit: I can admit when I am wrong. Where I was sure paint existed in the wheel wells, I was super careful to try and find paint underneath. I managed to get the tar off and leave paint behind, in a tiny spot. Wasn't easy as it is just as soft as the undercoating and has no bond left to the metal. It doesn't appear to have primer under it, same as under the cowl, just color to bare metal. The paint is not good, which explains wherever they missed undercoating it's just rusty.


I hope I did not come across as argumentative, I am wondering just as you are. There is another possibility. Maybe the owner took the paint off when new believing that would be better and undercoated the bare steel. Sometimes trying to track down history is almost impossible. Actually , if there were many owners , who knows when/where it happened. Looking at the metal, it looks pretty nice to work with. Another interesting item with the FJ40.
 
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My apologies to everyone. Yesterday I was mindlessly scraping and made a hastey assumption of what I saw. Today I took care to assess what I was looking at while scraping some more.

That brown stuff, while coincidentally the same color as the tar film looks to be a coating. It is transparent but appears to be protective. Working on the passenger floor today, as much as I tried, I could not avoid scraping down to that coating. I did not find any body colored paint. I did, however, find a couple spots of paint still having some integrity. The paint is black. And, there is a spot where I inadvertently scraped through it.

Anyhow, Toyota did put something on the underside metal. It kind of looks like cosmoline but more durable. I did scratch it while scraping off the undercoating.

That's what I think. Now I want to just get back to mindless scraping while streaming Pandora.

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Not to contradict anyone but I sandblasted the undercoating off of some areas under the tub on my 40. The vehicle was supposedly from a "dry" climate but there was a lot of rust. I used a bucket of aquarium sand and a home blast kit. I only did the problem areas along seams and around brackets from the big mid-body channel back so not the whole underbed area. I did along the back/underside of the sills as well. The undercoating was so dry that it just flaked off fairly easily but the paint went with it. It was kind of a pain because the body was still on the frame at that point. After that I used a metal wash to get things clean. It took me an afternoon and I started painting the next day.
 
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Not to contradict anyone but I sandblasted the undercoating off of some areas under the tub on my 40. The vehicle was supposedly from a "dry" climate but there was a lot of rust. I used a bucket of aquarium sand and a home blast kit. I only did the problem areas along seams and around brackets from the big mid-body channel back so not the whole underbed area. I did along the back/underside of the sills as well. The undercoating was so dry that it just flaked off fairly easily but the paint went with it. It was kind of a pain because the body was still on the frame at that point. After that I used a metal wash to get things clean. It took me an afternoon and I started painting the next day.
I removed the sill already and tried to sandblast the area to prep for the new sill, but the media had no effect on the undercoating except maybe clean the dirt off of it. I wish. I am about 8 hours in and 3/4 done with the floor area. Then will start on the wheel wells. There is still residue left behind from the scraping and I'm hoping it will come off fairly easily with mineral spirits. The undercoating that got on the chassis just came off quickly with a putty knife, like 10 minutes.
 

WarDamnEagle

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I had good luck removing the factory sound deadener off the floor pans of my FZJ75 using a scraper and a heat gun. I know a plumbers torch has been suggested but the heat gun will soften it up as well without having an open flame. By using this method none of the paint was removed. Of course that's not applicable if there isn't any paint under the coating.

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I had good luck removing the factory sound deadener off the floor pans of my FZJ75 using a scraper and a heat gun. I know a plumbers torch has been suggested but the heat gun will soften it up as well without having an open flame. By using this method none of the paint was removed. Of course that's not applicable if there isn't any paint under the coating.

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Nice work. Did you use plastic scrapers to avoid scratching the paint? As some have said, there is paint on the underside, but it was more like over spray than actual paint. Anything that resembled body color paint was softened, I believe, by the solvents in the undercoating.
 

WarDamnEagle

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Nice work. Did you use plastic scrapers to avoid scratching the paint? As some have said, there is paint on the underside, but it was more like over spray than actual paint. Anything that resembled body color paint was softened, I believe, by the solvents in the undercoating.
I tried 3 or 4 different plastic scrapers and they all got too soft with the hot sound deadening material. In desperation I "borrowed" one of my wife's Pampered Chef scrapers. It was perfect; thankfully she was out of the country at the time. :D

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While scraping the softened undercoating with the putty knife, surface looked very even and "coated" with a brown, transparent material. It did not come off scraping any more but I could scratch it with the corner of the putty knife. Today I went over it with mineral spirits and it cut right through it. It looks like it was a stain on the metal from the undercoating. Progress.

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