I've gone for an old red carriage. Weapon variants can follow.

1. Base - Airbrush Dark Sea Grey
2. Base - Airbrush (lower opacity) Plate Mail Metal
3. Base Glaze Khorne Red
4. Heavy Dry Khorne Red
5. Dry (50/50 mix) Khorne Red Wazdakka Red
6. Dry Wazdakka Red
7. Dry (50/50 mix) Wazdakka Red Evil Sunz Scarlet
8. Light Dry Evil Sunz Scarlet
9. Edge Highlight (50/50 mix) Evil Sunz Scarlet Ulthuan Grey
10. Base Gorthor Brown
11. Layer Karak Stone
12. Dry Brush Highlight Ionrach Skin
13. Wash Strong Tone
14. Base Abaddon Black
15. Layer - Dry Brush Mechanicus Standard Grey
16. Layer - Drybrush (50/50 mix) Mechanicus Standard Grey Ulthuan Grey
17. Light layer - Drybrush Ulthuan Grey
18. Base Ulthuan Grey
19. Full coverage Dark Tone
20. Re-highlight with Plate Mail Metal followed by Stormhost Silver
21. Add grime drips with Ratling Grime as well as highlighting edges with Stormhost Silver
22. Apply to all metallic parts Rust
23. Add Fresh Rust
24. Finish with adding final touches. I added Moot Green and Disgusting Slime to add the light source
25. Add your chosen weapon source and Base. Highlight if you want less of a Grim dark finish