Seam sealer

One of the most important things to do when you're preparing your car for painting is sealing the seams. Most rust problems will start in seams if not sealed properly.
There're a lot of different types and brands of sealants on the market,
Never, never use a sealant with silicone in it for the simple reason you cannot paint over it.

I tried two brands; Sikaflex 227 and HB Body 115. I put a bead of both of them on an old sunroof and after letting it cure for a day I put it in the scorching sun for a couple of days. They both survived, but in my opinion the HB Body 115 has a better adhesion.

Sealants

Seams sealed in engine bay

Seam sealing bonnet

 Within 30 seconds after applying the sealant I dipped my finger in thinner and went over the sealant to smooth it. After all the seams were sealed I let the sealant dry for a couple of days and then brushed over it with epoxy primer.

Epoxy primer

I intended to use an etch primer and on top of that a HS primer. But as the Volvo was only bare metal on the outside I've heard you can get problems with etch primer going underneath the paint at the edges and it will probably lift the existing paint. Hmm.. what about epoxy primer.. it can be used on as well as bare metal and painted surfaces, doesn't absorb water and it will seal the body too.
I started looking for a epoxy primer which could also be rolled or brushed on. And I found one: 408 Epotec primer surfacer from Protec . It's a polyamide cured Epoxy primer surfacer. On top of the epoxy primer I'll use Carmaster Acrylic Primer filler, also from Protec.

Protec 2K Epoxy primer

I painted one panel with a mohair roller and brush and sprayed another to see the difference. I used ca. 10% thinner for the rolled-on epoxy mix and ca 20% with the spray epoxy primer. The panel that has been sprayed looks smoother but the rolled-on primer looks pretty good too, there's a little bit orange peel. Next time I'll use more thinner for the rolled-on mix.

Before I could spray the body and all the panels I had to build a spray booth in the shed. I used a couple of cheap plastic dropsheets as walls, masking tape and masking paper on the floor. To get rid of the water in the air I used a water trap ca. 10 m from the compressor. If you put it to close to the compressor it wouldn´t work as all the water is still steam.

Spray booth

Spray booth made of plastic drop sheets with fan

As flash rust started within minutes after cleaning  I had to sand back every panel. After sanding the roof I applied the first epoxy coat with a roller so I had more time to sand the rest of the body.

Flash rust 15 minutes after cleaning

I hang the doors with octopus straps so I was able to spray all the sides in one go. The protec epoxy primer has a flash time of ca. 10 minutes. That will give you the time to mix some new paint for the second coat. After mixing the epoxy with the hardener and the 202 reducer you have to wait for 10 minutes before you can use it.

Door with two coats epoxy primer

Bonnet in epoxy primer

Body Amazon in 2K epoxy primer

Body Amazon in 2K epoxy primer

Next thing to do is filling all the dents with bondo. I used U-Pol 0712 Dolphin body filler. It's unbelievable how many little dents showed up when the surface is glossy... especially the bonnet...

Filling, the supervisor is watching..

Half way filling the dents in the bonnet...