POR 15 is your friend. If I were living in an environemtn like that, I would strip everything I could and POR as much as possible.

The entire car is going to be media blasted in a couple weeks.The rust repaired,then POR15.It appears I'm going to have trouble getting the factory undercoating off the underside of car.Anyone have any input as to how remove this stuff? I don't think the blaster will do it.Seems like the media will just bounce of that tar.Possibly burn it off? It doesn't scrape off to easily.

Roger. Great father/son project. With your experience the rust issues shouldn't pose any real problems. As for removing the undercoarting, one of the best, and easiest ways I've found is dry ice. Once frozen, the undercoating will chip off cleanly using a putty knife and hammer. Conversely, if you don't mind waiting, do the work in winter (that's how I discovered this method, in an unheated garage in Ottawa in January, at minus 20, .)

I read in another thread that freezing by rubbing it with dry ice makes it brittle enough to just knock it off with a hammer.

Complete media blasting' date='then rust repair.[/quote']

From personal experience I can tell you that there are downsides to media blasting an entire car. Not the least of which is having residual media blowing round when you spray primer or final paint. Past that point it can be blowing round for years - as it comes out of every crack and cranny that you had no idea existed.

By and large, most body/paint guys hate dealing with it. They will prefer to chemically strip and sand the surfaces.

You may not have a facility near you - but I would consider having that body dipped, to chemically or electrically remove/convert hidden rust. This too has its downsides, but given the fact that these cars rust from the inside out - dipping them is about the only way to stop the rust.

If you have long spry wands - and a good micro camera - you can spray POR15 inside the nooks and crannys, then inspect for full coverage with the camera.

Are you talking about "undercoating" that is under the car - - or are you asking about removing the sound/heat insulation that is on the floorboards and rear deck area inside the car? The dry ice method that some have mentioned is usually recommended for the heat/sound insulation {tar mats} inside the car. For undercoating under the car - Kerosene works, after you use a heat gun to soften the bulk of the material and scrape it off with a putty knife.

FWIW,

Carl B.