Can you mix satin paint and semi gloss paint and if you do will it give a dusty finish?

you can mix paint of different sheen levels provided they are of the same vehicle or base (i.e.. water based, oil based. Mixing a satin with a semi-gloss will still be reasonably close to an "eggshell" finish. The best way to know is to use the chart below and add the 2 sheen level percentages together and divide by 2.

For example a low sheen (satin) is 20% sheen + Semi-Gloss which is lets say 50%

20+50=70 divided by 2 = average sheen of 35% giving you an eggshell finish.

• Flat (1-9% gloss)
• Low Sheen (10-25% gloss)
• Eggshell (26-40% gloss)
• Semi Gloss (41-69% gloss)
• Gloss (70-89% gloss)