I tend to agree - undercoating can hide a whole lot of trouble. The damage you show in this picture

http://i1230.photobucket.com/albums/...psa5a1c7ef.jpg

was probably caused by a leak from above rather than a problem from below.

I've been using old fashioned - not so great when it burns - bitumastic undercoating that doesn't trap water for lengths and lengths of the car. Better still would probably be that POR15 chassis top coat (on solid metal)

Can you weld?

190D dilemma- what do I do?
 

Because that technology has improved a lot since your car was built.

I haven't got into it yet so I don't know what to use.

In Hawaii we used something that was meant for boat trailers that were backed into the ocean constantly. Worked great.

On the farm I used a brush on enamel. Also worked great.

They make a lot of spray on bed liner materials. Haven't checked them out.

But as stretch said, the rust usually comes from the top. Keep the windows sealed and problems won't start.

I'm in the same boat. I was riding a motorcycle before, so I feel pretty safe with the rust. I'm getting another chassis, and I'll slowly pick away at getting it prepped. Sandblast and paint every surface. Well, probably primer, and pay someone to paint. But if you bring something in ready to go into the booth, it's not bad.

Bummer man, seems odd usually everything else goes first (brake lines, fenders, etc.) before you have to worry about structural rust, maybe that's just with the salt induced variety.