Pinhole (thin slot) exposures

20 Second exposure at portencross

For few days now I've been thinking of ways to get long exposures from my digital cameras. One of them gives up to 15 seconds the other up to 60 seconds but because they only go down to F8 in bright daylight even with an 9X neutral filter the exposures are too short for that lovely ghostly wave thing that I'd like to do.
I tried pseudo pinhole (pinhole in front of the lens), its fine if zoomed in but for wide angle its no good.
I then thought what about a thin slot moved in front of the lens with the 9X filter added. I think I struck gold it worked a treat until I went out in the sun and all the light leakage made a nonsense of it.
Wasn't beat though, got an old black tee shirt from my son and stapled it to the slot thingy then went down to Portencross to check it out. It was a SUCCESS! except that I was nearly blown to Fairlie trying to cope with the wind and tee shirt over the camera (like and old time photographer).
I was so chuffed with the result view the two end photos here.

I have another perhaps better idea that I'm working on now but if anyone needs more info just ask in the comments.