Rust perforations on the car are easy to fix: On a weekend and with around 30 Euro investment you get the repair point back – almost like new.
It was actually just a small scratch on the fender of Ulli Kaast's VW Passat, but that "actually" was already a year ago. In the meantime the rust had lodged in the scratch and attacked the surrounding areas. But it was still not too late for repairs: The damage settled in a weekend and with around 50 Mark use to fix it again. There are fiberglass mats in the accessories trade, spatula, Harder and almost any color from the spray can. The seller even has complete sets ready for quick help with minute damage, which for just under 20 Mark includes everything you need except primer and varnish. But since Kaast had waited a long time before the repairs were due, he had to put in a little more work. The preparatory work is crucial for all work on the look of the car: Only when the rust has been completely removed, the thing lasts longer than half a year. Otherwise, all the work is in vain – and the money gone. By the way, a half-hearted repair only makes the damage worse.
Do not trust the effect of rust converters or fine sandpaper. Only the use of an angle grinder can help against rust, but at least one grinding attachment on the drill – Rust is a tough opponent. After combating rust, the sheet must be smooth and without any dark indentations – A single small rust spot soon develops into a major rust perforation. After the preparatory work has been completed, close the crack or hole with fiberglass mat and fleece. The cut piece of the mat must overlap the hole by about two centimeters. Brush off the repair resin (it gives the mat stability and sticks it to the fender) first right around the hole. At this point (and only here) gilt: a lot helps a lot. Has the mat achieved the necessary stability around the hole, soak the rest of the mat with the repair resin. You can repeat this process several times: The more layers of mat you put on, the more stable the repair point will be.
Although the surface of the mat layers after about 30 Minutes (in the example prestolith special) is still sticky, you can now start filling. Mix the putty knife and hardener for the first coats, but only so much each time, as they need for a shift. With the first filler, it is better to apply several thinner layers than one thick one, that would get cracks. According to the manufacturer, the ideal processing temperature for the glass fiber filler prestolith extra is between 15 and 25 City.