Underseal

I was going to underseal the v70.
As it shows some fly rust on the back end mainly where the Towbar is sitting on the chassis I been thinking of underselling the whole car.

Where the question is?
Underseal pur?
Underseal mixed with machine paint colour ?
- had good result and long lasting on other cars before, and makes it clean looking!
Althought I have a 10 liter tin underseal and 5 x 10 liter tins maschine paintpaint.
Plasti coat?

Thinking of the second choice because it sticks and you need a hammer to get it off. Good for mot too.

Anobody is doing underseal on his cars?


Not sure using a paintbrush and the spray gun for the complicated corners or just use the gun all the way along.
The rover and audi had a flat pan with no deep ends, where the volvo has a lot edges where you can't reach with the brush.
Brush gives a thicker coat.

Use quality wax oil and spray into all the holes and cavities etc.Do this once a year and you shouldn't have any rust problems unless you do offroading .
You should also do this to a new vehicle as that is something that is not done as it used to be.
Do not use underseal because if water gets underneath it will start rusting and you wont know untill it is to late.