Surface rust...bottom of car. (Question)

[SUBARU3]

   Posting this here, due to higher volume of people.

 

       I have multiple Generation 1 Subys, but the one I'm restoring now has a light surface rust all over the bottom surfaces. This car is NOT a northern car and it has never, never been in salt, there is no rust through anywhere....solid. It only had the light factory undercoating, (mostly wheel wells), that came with the car, so the bottom of the car was just painted.

 

 What does one do it this? Again, it's very light, surface only, but widespread. The car is a 1978.

 

   Spray it with a treatment, prime and paint? Undercoat over it? I don't want to have to strip the car, rotisserie it and sandblast.

 

 Thoughts?

 

  Thanks!  Todd 

[Crazyeights]

I would probably start with a rust conversion product like POR-15 on the affected areas.

[gbhrps]

subaru3,

 

At the restoration shop I work at infrequently, we often have to replace rocker panels and the bottom of doors with new sheet metal. Some lower sections don't need new metal, but require the rust to be removed before it is epoxy primed and then finished (filler to smooth out shallow dents and pits) and finally painted.

 

We simply lightly sand blast the entire lower section (from the doors down) to remove the rust and keep the blaster pointed down and moving quickly to minimize heat buildup and warping of the metal. The fact that most rocker panels are curved to begin with, they have the strength to prevent warping that would happen in the middle of say a door panel where its flat.

 

We've never had any issues doing it this way

[Datsunrides]

I sounds like you are not looking to do a full on resto. If you were, I would recommend media blasting, epoxy primer, then undercoat (the good stuff, not the stuff on a spray bomb). The good bodyshop grade stuff can be topcoated if you wish. Depending on what end product you want to achieve, you could just leave it alone (it only took 35 years to get where it is) or the next level would be to wire brush it to remove the rust, prime any spots showing bare metal and undercoat (once again use the good stuff). I plan to do the wire brush treatment on my coupe when I get to that point. IMHO, don't use POR type products. Here is the full boat job I did on a Datsun PU I just finished.

 

 

 

Mark

[Leeroy]

I am just about to cover my '74 sedan's underside in Ankor Wax. While I have been doing a rear disc brake conversion I have noted there is quite a bit of surface rust so I will give it a good cover of Ankor Wax. It does need to be recovered every couple of years but is simple enough. I must say I love this stuff! You can paint it on with a brush or spray if needed and in my experience it stops further rusting completely. Only downside is that It does take a few days to dry completely if the weather is hot.

 

I don't suppose Ankor Wax is available in the US but it is used a lot by the VW crowd for their Patina Beetles to keep the rust at bay. Perhaps there are similar products?

 

This is certainly easier than striping and repainting the underside of the car, far less time consuming and cost effective in my opinion. Especially when it is surface rust that you want to contain not rust through.

Edited October 20, 2014 by Leeroy

[SUBARU3]

 Thanks for all the information....super appreciated. I'm thinking along the lines of a spray rust converter.

 

Todd

[lmdew]

Rust converter and then paint it.