Unterbodenschutz PQ35 | Posts 16+

"Bitumen-free" is not explicitly mentioned, but the reference to a wax base suggests that it is."

I completely coated my A4 8K and my father's T5 with Mike Sanders anti-corrosion grease. It's supposed to remain creep-resistant for 15 years and, as a result, seal small stone chips. It's not the easiest to apply, as it needs to be heated to 80-100°C before spraying, and I ended up with grease all over my clothes after spraying, but I hope it lives up to its promises.

Hello!

Well, we "Ossis" (people from East Germany) have quite a bit of experience in that area.
The Trabant was designed to last for about 20 years, because it wasn't easy to get a new one quickly.

My method, which I have tested and refined over the years, is as follows:

Wash the undercarriage and let it dry thoroughly.

Then, a mixture of 70% hydraulic oil, 30% heating oil, and graphite solution is thinly sprayed onto the areas to be protected, ensuring that it covers the surfaces without dripping.
Let it sit for a couple of hours; it will penetrate into all the cracks.
Be careful not to let it come into contact with the brake discs or rubber mounts.
Then there's the UBS 2 underbody protection from Elaskon, which is sprayed thinly over the surface. It bonds with the oil and creates a surface protection layer.
This stuff stays sticky permanently, doesn't drip, will become soft again next summer, and it heals wounds.

The problem is that when you spray the underbody coating at high temperatures (using a common airless sprayer for liter bottles), it tends to create a lot of mist, which covers the entire car, even up to the roof.