I hope this not considered hijacking the original posters thread but they are related.
The vehicle I am repairing has extensive rusting. It has not been waxed at all so ironically that makes the work a little more straight forward.
I have listed the approach I will take on this repair.
It is messy and time consuming but look on it as an investment in peace of mind.
Prep.
Strip out the interior as far as is practical to allow access to all areas to treat.
Using a hose pipe wash out the box sections with water including all the interior ones like the roof sub assy and the pillars. I said it was messy.
Allow a few hours to drain.
Dilute the Fertan with 10% ish warm water.
While still wet/damp spray the Fertan into the cavities. Give particular attention to the seams and spot welded joints. If using the gun you will see the Fertan leaching between these joints.
Leave it 24/48hrs.
Using a hose pipe wash out all treated areas with water.
Chase out the remaining water with an airline blower if/where possible and leave a few days to dry out.
In my case I will repeat this process in stages later.
The Fertan will leave a coating on the rusted areas that can be painted over directly.
Paint over any rusted and repaired areas, I use Davids zinc paint for this.
Thin the first coat with cellulose thinner so it is a little thicker than water.
Preferably spray this on a point setting or with a lance into the seams and over the repairs , the thinner added will flash off quite quickly so you can second coat shortly afterwards with a full thickness of zinc. Keep a thinners soaked rag to wipe off any excess paint.
Immediately after clean out the gun if you are using one.
The idea of the thinned coat is to allow penetration of the seams and between the spot welded surfaces.
Now re-coat with zinc using it from the pot if brushing diluted if spraying. I try to leave seams and flanges with a thinner coat and I dont try to seal them with the paint, I want the wax to penetrate at these points.
Immediately after clean out the gun if you are using one.
Allow a day at least for the zinc to cure through.
Wipe off the panel you are fixing to with thinners on a cloth, keep turning the cloth.
Once the thinner has flashed off apply a generous amount of hi temp spray adhesive to the metal work and stick the shaped foil to that.
Bubble foil. The type I use has raised bubbles and will allow any moisture to track down between the bubbles that is why I leave it a bit short at the bottom.
Now wax the work with warmed/thinned wax ,use white spirit,paying particular attention to the seams.
Then carry on with the insulation fill as per my previous post.
Here is a link to my other thread covering this vans refurb. The last post covers the equipment I use. The gun, about 60 ukp, comes with probes and lances and can be used for all of the materials stated above. It has a spray gun nozzle fitting too. Just remember to thoroughly clean it after using it for the zinc.
http://igmaynard.co.uk/bongo/forum/view ... =3&t=72827
Any Q`s just ask.
Good Luck.