The most common and most likely answer to this crossword clue is the 5 plus 3 letter word SPRAY GUN
I've seen this crossword clue in Financial Times
S
P
R
A
Y
G
U
N
More clues leading to the result SPRAY GUN
- Mister Angry’s up for a scrap
- Special sci-fi device that’s used by Banksy
- Request good breaks in weather for painter?
- Newspaper includes petition, good device that can make a splash
- Drops much unpleasant material, graffiti artist’s recourse?
- Yet it’s not used for shooting the rapids
- 29 Special light — good one — that is an aid in painting work
- Ask girl in brown to get painter’s equipment
- Special sci-fi device that's used by Banksy
Buddy explains!
The straight part
We know that "device that can make a splash" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case device that can make a splash = spray gun.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.