How many hours did it take you to scrape off the undercoating?

[bull]

I like undercoating but my original stuff is pretty beat up. Plus it's got a lot of dirt in it and from what I've read about what it takes to scrape off the loose coating, clean the dirt and grime off what remains and blend in the new coating it might be just as quick and easy to scrape it all off and start over. Therefore, I'm just curious how much time I'm looking at killing to remove it? Can you guys give me an estimate?

[green69rt]

Many, many, many hours.  My personal opinion is that undercoating actually holds the water against the metal as much as it protects.  Everytime I took old undercoating off I found rust.  Take it off and never put more on!!!!

[thatildo68]

are we talking about underseal that thick tar type coating? its good stopping stone chips
and providing sum noise insulation but you cant see if rust is starting to form underneath
i know that wasnt the answer you were looking for   

[lilwendal]

Bull....Lot depends on the stage the car is in.  Shell on a rotisserie is allot easier than all the driveline in and working off jack stands. Its slow monotonous work. I usually do it for a couple hours then break off to something else.
Propane tourch and a putty knife are my tools of choice.  Followed by solvent and scotchbrite.  Then media blasting.
Followed by epoxy primer then body color.  After that I replace the undercoating in a more organized than factory application. I like to mask off all the frams rails and torsion mount.
You will not have rust issues beneath the undercoating if its epoxy primed and painted first.
But to answer your original question...Just to remove all  original undercoating applied to a bare shell.  8 to 12 hours
Wheel wells are the worst.

[69*F5*SE]

Bull....Lot depends on the stage the car is in.  Shell on a rotisserie is allot easier than all the driveline in and working off jack stands. Its slow monotonous work. I usually do it for a couple hours then break off to something else.
Propane tourch and a putty knife are my tools of choice.  Followed by solvent and scotchbrite.  Then media blasting.
Followed by epoxy primer then body color.  After that I replace the undercoating in a more organized than factory application. I like to mask off all the frams rails and torsion mount.
You will not have rust issues beneath the undercoating if its epoxy primed and painted first.
But to answer your original question...Just to remove all  original undercoating applied to a bare shell.  8 to 12 hours
Wheel wells are the worst.

  with every word. 

[Fitz73Chrgr]

Our car was completely undercoated.  Propane torch & putty knife, followed by media blasting.  The scraping I'd say took upwards of 15 hours of hard work & I'm probably underestimating.  Of course the car was on jackstands, no drivetrain.  Good luck, it's a PITA!

[defiance]

with the entire driveline and gas tank out, on jack stands, I spent about 8 hours total with a soda blaster.  That SUCKS too, let me tell ya - soda blasting under a car on jack stands, the dust gets so thick you can't see your hand 2 inches in front of your face shield.  You pretty much have to pick out the area you want to blast, then do it blind by memory   And of course soda's quite a bit slower than sand.  But sand is too harsh for possibly rusted sheet metal, and builds up a lot of heat.  I tried more manual methods first, and after about 2 hours I'd made almost NO progress, so I switched to blasting.  Having said that, if you don't have a pretty large capacity blaster and at least 5hp air compressor with a large tank, you'll spend more time refilling the blaster or waiting for the air to build up than you will working

After that mess (it was honestly torturous!), taking <1hr to apply a full covering of raptor liner felt like MAGIC!   That stuff is awesome!

[Charger-Bodie]

I have always sand blasted the underside.....just work an area for a while then another,after a while come back and clean it up some more.....keep moving around until youve got it,and then blow it off and go back over what you missed.

[Rolling_Thunder]

propane and a putty knife...        I used an oxy-aceteline at the shop once and WE (I manned the torch and two others with scrapers) scraped all the undercoating off a 69 road runner in 4 hours...       go us   

[defiance]

I have always sand blasted the underside.....just work an area for a while then another,after a while come back and clean it up some more.....keep moving around until youve got it,and then blow it off and go back over what you missed.

Really?  I'd always heard it was too harsh and could push through if there was any rust or could warp the metal.  Of course I've never seen that myself. 

[bull]

Well, sounds like I'm going to be cleaning it instead of removing it.

[6d9 charger]

REMOVE IT , IT LOOKS GREAT WHEN FINISHED , I USED A SPRAY BOTTLE WITH SOME DIESEL FUEL , LET IT SIT FOE ABOUT 30 MIN. THAN SCRAPED IT OFF , ALSO USED A PROPANE TORCH  TO WARM UP . IT CAME OFF LIKE BUTTER , AND I DIDNT SET ANYTHING ON FIRE . THAN SAND BLASTED  WHILE ON A LIFT .  IT IS NOT A QUICK JOB , BUT LOOKS AWSOME WHEN COMPLETE

[bull]

REMOVE IT , IT LOOKS GREAT WHEN FINISHED , I USED A SPRAY BOTTLE WITH SOME DIESEL FUEL , LET IT SIT FOE ABOUT 30 MIN. THAN SCRAPED IT OFF , ALSO USED A PROPANE TORCH  TO WARM UP . IT CAME OFF LIKE BUTTER , AND I DIDNT SET ANYTHING ON FIRE . THAN SAND BLASTED  WHILE ON A LIFT .  IT IS NOT A QUICK JOB , BUT LOOKS AWSOME WHEN COMPLETE

Funny you mention diesel because there was one spot where the coating came off real easy. It was the spot where the rear trans. seal had leaked and flung oil onto the driveline hump turning it dark black. So if you let it soak for oh, say 30 years in oil it will come right off.

[69*F5*SE]

Propane torch and a scraper is very easy to do but completing the whole underside will take a while.  Join the club.

[moparguy01]

if your careful with your blasting you wont have problems, put a steep angle on the nozzle of the gun so its not direct, and keep moving, dont stay in one spot too long or you will have problems. I've sandblasted many a cars underneath without so much as a hint or trouble. for the real hard stuff sometimes I've used a needle scaler too, and it'll help to vibrate it loose abit and make sandblasting easier.

[bull]

I won't be sandblasting it. I don't have the space and the means to do it that way.

Anyone ever tried the dry ice method?

[Fitz73Chrgr]

I won't be sandblasting it. I don't have the space and the means to do it that way.
Anyone ever tried the dry ice method?

The only space you need is underneath the car.  Sandblasters can be relatively affordable.  I'd get a water separator though.
Dry ice is a great idea, I just don't know where to find it readily available in grains small enough to blast with?

[defiance]

Yeah, I paid around $90 (I think) for my blaster from harbor freight.  Came with a separator ... but the one that came with it blew apart first time I put air to it, so another $15 for a replacement puts the total at $105   Having said that, if you don't have an air compressor that will run it, there's where it gets expensive...
since having it here, though, I'm CONSTANTLY finding things to clean up with it, though.  It's one of the most useful tools in my shop

[mopar73]

propane torch and scraper.  It took probably 10hrs with the car on a rotisserie, that includes the fenders. PITA!!!!!!!!!!