Prep For Undercoating

joe buckle · 01-29-2003, 10:52 PM

What is the best way to prep the undercarriage for undercoating? Do you have to completly strip it? Or just get most of the loose crap off. Thanks

Joe

korijo · 01-29-2003, 11:10 PM

Are you worried about any rust underneath? If not, Clean and scrub all areas to be recoated with Simple Green, rinse w/ water. Spray a couple new coats on...

Thats what Im doin'

DSPTurtle · 01-31-2003, 02:51 PM

For the love of Pete... throw the can of undercoat in the trash!!! Today I spent three hours going from this:

to this:

Actually, it was all there to begin with but I did not take a pic before I started. Uncoat SU(KS!!! Either paint it or POR-15 it... I am willing to bet that you are never ever ever ever going to drive it on a salty road. But maybe I am wrong

cshogen · 01-31-2003, 03:29 PM

Geez JB you've been working hard lately! Looks great! You POR-15'ing that area or painting it? I need to do that myself. I have a '75 with very old undercoating I want to strip off. I think I might do both... POR-15 then paint over it. The guy at POR-15 said if you rattle-can it while the second coat of POR-15 is still tacky you can do without the top coat POR stuff.

DSPTurtle · 01-31-2003, 04:38 PM

I am planning on POR-15. I have a quart or the tie coat primer so I just might paint it body color if the mood strikes me.

korijo · 01-31-2003, 06:38 PM

I did the same thing on my bug. Took me almost 40 hours (over 2 weeks) I would again, if I could.

campbellcj · 01-31-2003, 07:07 PM

Undercoat is evil! I too am trying to rid my car of that demon...I am trying to avoid the wire brush approach though, so as to save the original paint in the wheel wells. A putty knife and brake cleaner works, but is slow going.

Zeke · 01-31-2003, 09:18 PM

Quote:

Originally posted by campbellcj
Undercoat is evil! I too am trying to rid my car of that demon...I am trying to avoid the wire brush approach though, so as to save the original paint in the wheel wells. A putty knife and brake cleaner works, but is slow going.

Heat gun maybe?

On low setting.

campbellcj · 02-01-2003, 08:32 AM

I have a heat gun and may try that. I'm worried that it might just lead to a gummy, tarry mess though? Without heat, the stuff is brittle and "chips" off.

DSPTurtle · 02-01-2003, 05:36 PM

Here is what happens when some idiot (I will never admit to it) pays someone the spray undercoat in the front trunk. Actually, this is the said idiot way of starting the stripping process. It always ends with a hand grinder though...

74914 · 02-03-2003, 08:27 AM

I used a putty knife and mineral spirits to clean off the residual stuff. As long as you don't get too aggressive with the putty knife you can do it without gouging through the paint.
Ed

74914 · 02-03-2003, 08:34 AM

Oh, FYI; I tried a heat gun and it softened it too much. I found that the undercoating chiped off well in my 50-60 degree garage. Heat gun did help though with the white stuff (seam sealer? ) that's under the undercoating in some places.

Griznant · Griznant's Garage

I spent a few hours stripping the inner wells of my 912 not too long ago. I typically go at it with a propane torch and a putty knife. Sit back in a lawnchair and heat the area with the torch, then scrape. Works great, and if you are careful with the torch you won't screw up the paint.

Funny thing about the 912 though, is that when I got the undercoating off, there was a white primer-ish paint under it, which is not the color of the car (original car, in red). Well, then some stripper to take off the paint, and some lacquer thinner to clean it all up. I'm going to hit it all with Metal Ready, POR-15, some rocker shutz, and then paint. The rocker shutz helps to keep the rock dents down (from inside out), and adds to some sound deadening. This is a street car, not a race car.

I have done this on some VW floor pans, and it comes out absolutely fantastic. Almost impossible to chip or flake, and rust resistant for as much as these cars will ever see rain/snow again.

Later,

G