18 replies to this topic

[hhhh]

Well that's the theory, LOL.

[ings]

There are a lot of Metallsheets welded together. capillary forces drag water between this sheets and keep the water trapped.

When the innerside of your metall begins to oxydise you get a huge poruos surface and more water will get trapped there.

 

You can apply a lot of paint and stuff on the outside, the frame will still rust from the inside. cavity sealer is very important to reduce this problem.

[bluedragon]

 

If what you say is true then the rust patch I have in the centre of my bonnet only needs repainting and a nice thick layer of 2k laquer and it will never rust again.

I don't think so somehow.

 

 

 

Automotive paint - even 2K - is not moisture-proof, believe it or not. Moisture can penetrate topcoats if left exposed to it long enough. This is why we are warned not to use plastic or non-breathable car covers outdoors in wet areas. Prolonged exposure to moisture (with no chance to dry off) eventually bubbles the paint.

 

A good epoxy primer is relative proof against moisture, so if that bonnet were completely sealed in epoxy, it wouldn't rust.

 

But epoxy doesn't adhere to rust very well, so you end up grinding off all the rust anyway to provide a good surface for the primer to grip.

 

The main issues with using rust sealing products are

 

1) as written, many people forget (or choose to ignore) the backside of the metal, where the rust keeps going, rotting out the seal from behind and

 

2) users don't grind away the paint around the rust spot to clean metal, often just sealing over the visible rust spot. As all who deal with rust know, the rust you see usually is just a fraction of the actual rust spreading beneath still-shiny paint. If not uncovered, it will keep on spreading and again undermine the seal. 

 

 

Dave

[Richie83]

Has anyone used Bilt Hambers epoxy? Can you overpaint it or spray stonechip over it?