Advice on undercoating & rust proofing.

[Harry01]

Hi,

Super excited to say that I just got my first 71' bay! I'm in the process of cosmetically restoring, and rust-proofing it and wanted to get some advice on protecting the underside.

It's a california import, so the underside is in really good condition, however the seal that is currently on it is starting to chip away and expose rust-prone metal. The undercoat that's currently on can't be wayoyl as absolutely nothing I have tried will dissolve it (kerosene, thinners, WD40). I think its some sort of bitumen based sealant as I have to scrape it off with some force.
My question is that, as it's extremely tough stuff to get off, could it be worth keeping it on and only re-sealing parts that are exposed?

I've attached some photos below, and would greatly appreciate any advice on what would be the best way to go about keeping my van rust-free (ish).

Cheers,
Harry

EDIT: Embedded photos are too large I think, here's a link to the album on dropbox: https://www.dropbox.com/photos/album/KVLVKAp8xavSYog" onclick="window.open(this.href);return false;

Load floor, comparison between undercoat on and undercoat off:

Load floor with majority of sealant off:

Main chassis (sealant off most):

Sealant has begun to chip away:

Beginning to rust:

 

[trebor]

Wish I could give you advise chap, I'm in the same boat really only I could not face laying on the floor scraping it. I might get a roll over jig so I can lay the bus on its side to do mine. Trouble is you wont know how good the body is till all that stuff is off. As for rust proofing :? Best to get rid of rust first. For bare metal I've tried a load of crap rust converters and the only one I would recommend is Ferrol Betol. I think 5 ltr was about £30, has very thin consistency so it runs into panels and cracks and could cover lots. Haven't got as far as stone chip though :?

 

[magoo]

I'm not an expert on the subject, but you need to just scrape it all off and treat any bad spots first. It's not a nice job and it is very time consuming, some jobs are worth paying for! There is some info in my restoration thread about the products we used, I am really pleased with the results.

 

[marco]

Mine is covered in the same stuff, I've just soaked every inch of the underside in Dinitrol and regularly check to see if any chips apppear in the old bitumen underseal.

 

[72baywesty]

Ours was the same. 4 months of media blasting got it back to bare metal then por 15 d the lot. Looks great, been done 4 years and still looks good. No chips or rust. Wouldn't want to do it again though

 

[trebor]

4 months :shock: now that's dedication !!