Since I can't do an off the frame restoration I am hoping to at least clean up the underside. So far I am planning on just using a wire brush attachment/grinder to clean things up. Any advice on this or what type of undercoating would be best? This next question may seem strange but its coming from a guy who painted the family car with a brush. Are all undercoatings spray on or do some brush on? Thanks so much.

 

You can probably get brush on undercoating but the spray is so easy and looks better.

One tip my father-in-law showed me (he owned a body shop for many years) is to use a putty knife to remove some of the old undercoating even before wire brushing or grinding it. It surprised me how much of the old undercoating will just scrape off. This won't work for all undercoated areas but is a real time saver prior to grinding or wire brushing.

 

The best way to remove old undercoating in my opinion is with a needle scalier. (Cheap tool Harbor freight) Great results. Just need some air ( air compressor).

 

They make an electric powered "scraper" if you will, it's got a few attachments for different applications.

 

I agree with therobski- Needle scalier is a very good tool to use

 

using a wire brush on a drill and lots of "hand scrubbing", then coat with Rustoleum rust Reformer, then a coat of Rustoleum primer and then black paint. Almost all was done "brush on", some spray but it is a hassel prepping for the overspray, fumes etc.....I was lucky with this car as there was only undercoating in the rear wheel wells. It has been my experience that it works well and does hold up. I don't drive my car in the rain at all so I suppose that helps it longevity. My grandson and I just finished the chassis this weekend....on to the motor!

 

BOESE1978 you have alot more patience than I do. The needle scalier works best on a cool surface, not in direct sun light that heats the metal and undercoat. It actually chips and vibrates the undercoat and rust off. Then just sweep up the mess. Its dry, no fumes.
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