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Using Dry Ice to remove undercoating

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#1 toolman


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Posted 26 February 2017 - 02:32 AM

Dry Ice for underseal removal
   Removing undercoating is usually one of most labor intense jobs when restoring a vehicle.   So when I heard about using
dry ice to remove undercoating, I decided to try it.   Dry Ice is usually found at industrial welding stores.  The price runs from
$2.00 to $3.00 per pound.   When using dry ice,  gloves and safety glasses worn to prevent frostbite.   First, I tried using dry
ice right from the package and just laid the block on the undercoating.  The undercoating got to 15 degrees but didn't really
remove large chunks of undercoating.   So I tried the next method- put the dry ice in a 5 gallon plastic bucket and smash it till
it resembles snow.   Then I poured alcohol-92% (bought from CVS) into the bucket and mixed it till it was mud like. I checked
the temperature and it was minus 15 degrees.  I packed the mixture on to the undercoating( packing snow).  After couple of
minutes, undercoating made a cracking sound.  The undercoating was so frozen, it cracked.  Now all you have to do is to hit the
undercoating with a hammer.   The undercoating came off in small to large chucks.  Inspecting the area shoes that there was
hardly any undercoating remaining( came off very cleanly).   I worked a small area 12" x12" at a time to get the most of the dry
ice-kept moving the ice around slowly.  I used about 15 pounds of dry ice and two bottle of alcohol to do the interior floor of
the car.  Haven't tried this procedure on the undercoating on the bottom of the car yet.  Building the rotisserie now.


#2 Namor


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Posted 26 February 2017 - 05:28 AM

I used the same method when I removed my undercoating, except I got dry ice in pellet form (little cylinders about 1" long and 1/2" diameter) so I didn't have to crush it up.


I got mine through a connection at a shipping company which specializes in temperature sensitive deliveries.  

#3 Greeko


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Posted 26 February 2017 - 09:48 AM

NICE! I used a heat gun and putty knife..12 hours later lol...

#4 Richard Oben

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Posted 26 February 2017 - 11:40 AM

Have been using the dry ice for years.  We get it at the grocery store, two 5 pound chunk does it, one one each side.  We crush it in the bag (gloves etc) and then spread it out on the floor boards and the whole thing scrapes away in minutes.  Getting the tunnel and sides is harder but a plastic bag shaped to the side of the tunnel does that job.  


There is a short window for this to work.  Have the car ready to go.  Get the ice in the good cooler go straight to the car and get the job done fast or all that is left is a bunch of cold CO2.  HTH, Richard. 

#5 toolman


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Posted 27 February 2017 - 03:28 PM

dry ice-4
Last Updated Feb 27 2017 03:18 PM

 Another video of the results of using dry ice to remove undercoating.  Anybody has a good method of removing the paint on
the interior of the car?   I was planning to using the 4 1/2 grinder with a wire wheel to do the exposed areas.   The confinded
area would be sandblasted outdoors.

#6 seattlejester


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Posted 27 February 2017 - 11:20 PM

Or if you live some where cold you can do this with just the hammer lol. I used an air chisel and freezing weather. Took maybe an hour or two to get most of it off.

#7 socorob


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Posted 01 March 2017 - 06:33 AM

I used an air chisel and dry ice after trying a few other things. Definitely worked way better than any of the other ways. I got it at the grocery store in blocks.

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#8 260DET


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Posted 02 March 2017 - 10:53 PM

Get dry ice at your grocery store? I had to drive to a specialist gas supplier to get it and damn, I bet it was way more expensive than yours. It's the gun thing to use to remove interior tar sheet off the floor, comes off in sheets, amazing.

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