How To: Use Dry Ice to Remove Tar Insulation

[MikeW]

I used Xylene to clean up the remaining residue. I also tried Acetone but Xylene works much better. It's the main ingredient in those goo remover products but is much cheaper and you can buy it buy the quart or gallon at places like Home Depot or Lowes, etc. It is toxic so wear proper breathing protection.

[SuperDave]

I used Xylene to clean up the remaining residue. I also tried Acetone but Xylene works much better. It's the main ingredient in those goo remover products but is much cheaper and you can buy it buy the quart or gallon at places like Home Depot or Lowes, etc. It is toxic so wear proper breathing protection.

I got a xylene product and it worked very well. Only took moderate elbow grease and now all the remaining bits of tar are gone and the bare metal looks nice an clean. Well...at least the parts that aren't all rusted look nice and clean.

[AChev]

I was thinking about using the dry ice technique, for I am having one hell of a time with the transmission tunnel. I did the floors, and they weren't too bad, the tunnel is worse for me.

Although I had some thoughts and concerns with the day ice maybe somebody can help clear this up. Is it possible to damage the metal by exposing it to such cold temperatures, maybe even crack it? We have all seen objects such as tennis balls surrounded in dry ice, and then they shatter like glass. I just need some re-assurance

[CrashNBurn]

I'm not a chemist, but I believe the shattering tennis balls of which you are thinking were dipped in liquid nitrogen. Thanks for the write-up by the way. I've been having some difficulty getting all that tar mat off the interior.

[EScanlon]

There is a big difference in the temperatures involved. I don't have my Chem book handy, but LIQUID Nitrogen is (if memory serves) MUCH colder than SOLID Carbon Dioxide.

That is because Carbon Dioxide (CO2) does not pass through a liquid state at normal pressures. You have to have an ungodly amount of pressure to keep C02 liquid. It sublimates from a solid to a gas while gaining thermal energy and taking it away from the metal it comes in contact with.

Yes it hardens the metal but you'd have to strike it just right at the exact spot that the metal has begun to crystalize (and that takes time) for it to crack it. I'm not saying it can NOT happen, just that it takes very special conditions for the famous shatter the metal with a hammer strike experiment.

Enrique

[Bambikiller240]

Yes, a Large difference in temps.

A block of dry ice has a surface temperature of -109.3 degrees F (-78.5 degrees C)

Nitrogen changes from a gas to a liquid at a temperature of -320 ºF

[Mr Camouflage]

Petrol disolves the leftover tarmat pretty well.

[new_2_z]

wow that would of saved me a 2 day process of hell

[AChev]

Superdave, thanks for the write up. I took your advice and gave it a whirl on my hatch bed. It worked excellent! After doing the entire transmission tunnel and floor boards by hand, the dry ice was a gift from heaven.

The clean up with the dry ice is minimal! If the dry ice technique is done when it is fairly chilly outside no water condenses on the ice. So therefore there is no clean up other than the pieces of tar paper that are removed, and they get as large as 6" x 12". Because the pieces of tar mat are removed so easily, there is barely any residue left behind, so the need for xylene and scrubbing will be minimal

Although I did have one problem. I did not purchase enough dry ice. When I got to the dry ice place, about 20 min. from my house, it turns out I only had $5 so I could only get 3 lbs. It just barely covered it, but the sections that had more dry ice on them came up significantly easier. Even 3 lbs. was enough to make the job only take about 20 min. of labor after the dry ice sets in. Sorry I could not post my pictures yet

All in all, a perfect thumbs up. I recommend it to all who need to remove tar paper

[marximus]

this is a stupid question i realize, but why remove the tar mat? i am restoring my 280z, and i was going to just leave mine alone since there is no rust. it doesnt look pretty, but it reduces noise compared to no tar mat and it is covered by carpet anywho, so why remove it? is there any reason besides to remove rust? thanks for putting up with my stupidity

mark-

[MikeW]

this is a stupid question i realize, but why remove the tar mat? i am restoring my 280z, and i was going to just leave mine alone since there is no rust.

There is almost always rust under the tar mat. If you really don't have rust please post some pictures of your floor pans.

[AChev]

Under the majorty of the tar mats there was no rust, except for the floor boards. Transmission tunnel, and hatch bed were good!

Many guys remove floormats if they are doing full restorations, they want to get rid of the old, gross, problemful mats. Eventually the mats will trap moisture and cause problems, so for a full resoration guys normally remove them so the entire car can be painted, then new sound deadening or thermal insulation can be installed