Best way to remove undercoating-DIY
 

I would like to remove the undercoating from my 85 911 track project. I've heard all types of ways:

strippers (too weak-doesn't really break down the undercoating)
sand blasting (may not remove all undercoating-can damage galvanize-messy)
soda, plastic, walnut blasting (too weak)
heat gun (time consuming-scratches metal)

I would like to save the galvanize coating, any suggestions? Thanks

The heat gun is really the best way.
How about scraping the softened undercoat with something made of wood rather than metal.
It may not damage the finish underneath as much.

-Ernie

i used peel away easy strip. it is available at sherwin willams stores. it does not smell and really softens the undercoating making it easy to scrape off with a razor. some areas take a couple coats but it really is painless. getting into the tight areas is the problem. i would get most of it off and then usea media blasting company get it to bare metal. i think i read somewhere that galvanizing has a lifespan and it may not be worth worring about at this point.

This is what I did this weekend, I have tried numerous ways and this is by far the best.

Propane torch and large metal blade scraper. Heat it up until is starts bubbling. then scrap away you can get one entire well cleaned up in a little over an hour. Fumes are nasty, so wear a mask.

After that you will have a bunch of residue left over and seriously Aircraft stripper the brand cuts it off in seconds. Leaves you nice and shiny metal once your done. It really does work but you have to get that top layer off first.

This is what I have just done and im telling you it is the best way to do it!

JW

I, too, have gone thru this and there is no one solution that is good for all areas. For relatively flat area (i.e. under the hood) use a flat razor blade mounted in a scraper. You don't need to use heat or anything - it will just lift it right off. This will even work in the fender wells where there is not too much curvature. As soon as you get into areas where there is a lot of curvature or lots of nooks and cranys, you need to start using a heat gun and scraper (I use a 1" paint scraper). But believe me, the razor blade will take off 80% of it, but the rest will take 80% of the time. Remember to keep changing blades in the razor - once they get dull it won't work nearly as well.

Good luck.

Geoff

Anyone taken off the entire undercoating of the belly pan without the use of a rotisserie? Seems like it would be a hassle without rotating the car.

Im removing it now, I have the car very very high and have a nice full head cover with a clear lens kinda like a welding mask and I use a creeper . Its a little rough but not impossible, very rewarding!

JW

I removed the undercoating of my '68 without the use of a rotisserie. Used a 3" spackle knife and a face mask- found the belly was much easier than the wheel wells due to the flat surface. Took a few hours; it was suspended about 3' off the ground. And it still is!!

dry ice blasting
 

Anyone used dry ice blasting to strip the car? Inherent benefits - no powder residue to contend with, no stripper chemicals, only residue is material blasted off. Cost may be an issue, but may rent machines. I am concerned re any possible metallurgical effects with significant surface cooling.... Any experience/input greatly appreciated

:)

There is a great post on this very subject.....

http://forums.pelicanparts.com/porsche-911-technical-forum/551021-undercoating-removal-fastest-method-yet.html

A real breakthru on removing the factory semi-hard Undercoat.

However, I am trying to remove the soft Black goop used by American car dealers to cover defects in the floorpan, etc without removing the good factory stuff.

Anyone used a gasoline soaked rag to "wash" it off or some similar method???

Len

:)

Lacquer thinner?

My car's PO had someone do a crappy respray. The fender I'm stripping at the moment has that black crud sprayed inside the fender. It gummed up sandpaper and stripper didn't really cut it. I grabbed a can of lacquer thinner to wipe down the metal and the thinner cut that black crud with ease...wiped it off in a few strokes of the rag. Be sure to use in well ventilated area or wear a respirator or both.

By the way, I bought one of those multitools for when I tackle the floor pan. It cuts right through the factory rock guard as advertised.

Hello everybody!

This thread is a bit older now but I thought this would be interesting for you. I removed much undercoatings in my activity as dryice blaster. I have a dryice blasting service in germany. Undercoatings which are based on tar (we call it "Bitumen") are no problem to remove. Porsche and also Mercedes have undercoatings which are made of a flexible material not based on a nature product.
This is the border for dryice. It can be only removed where it has no holding to the sheet because of rust or something else.
Cable isolations are handable. For those parts I use a special nozzle which blast fragmented ice.

You can watch many pictures of my work at my website: Fahrzeugreinigung Motorrad bis LKW | Mangold Trockeneisreinigung - Just click on the pictures to see them in full size.

And please excuse my english.... ;-)

+1 only I use a big wire hand held brush instead of a scraper.