Undercoating removal

[64studeavanti]

Any suggestions on a good way to remove undercoating? I am doing body off and would like to get this done. Some of it is very dry and scrapes easily. Most of it l, not so easy. I don't want to use anything too aggressive for fear of damaging the fiberglass. 

[silverstude]

You can try a heat gun to soften it, a putty knife to scrape it, but there's a risk of gouging the glass

[64studeavanti]

Saw that on Corvette forum. They suggested plastic scraper. Also suggested several petroleum distillates such as kerosene.

 

Has anybody had any success with a method?

[Avanti83]

Kerosene or other solvent needs to soften or dissolve the undercoating so it will take a fair bit. A total mess in my mind. I've used it to get the last of the undercoating when it's just a film and it kinda OK for that.

Try the heat method with a less than sharp scraper and only use as much heat as necessary before you get all jiggy with solvents. Plastic might work but most are made from olefins that soften at fairly low temps.

[Wasjunk]

I have had luck with an air powered gasket scraper. They vibrate more than work like a air chisel. A regulator on the air line helps with not being to aggressive.

[Stacey]

When I owned a paint/rust removal company in the Detroit area we used low pressure blasting with plastic, glass bead and walnut shells. Depending on what it was we were trying to remove. Plastic or walnuts were for paint, bondo, undercoating, caulking and other non rusty things. Either the plastic or walnut would remove undercoating very easy. Low pressure in the 15 to 25psi range and using a 1/2 nozzel to get the jkob done. We did many older Corvettes and lots of steel bodied cars this way. Problem was the materials we shot for that job got tossed after the car was done as the oily undercoat mess ruined the materials. We shot low pressure but lots of volumn, we had a 800 cfm conmpressor to get the job done. Don't know how the Avanti body underside would take to that blasting, but Corvettes did great.

[64studeavanti]

Tried a heat gun today. Need surprisingly little heat to soften it up. Kept a fire extinguisher handy just in case.  Was able to clean some undercoating from the torque boxes and floor pan. It is thicker in the fender areas so may require more effort.