I've not used the bug-zapper version of the static grass applicator.  I've had a Grassmaster for many years (7 or 8) now so there has been no need to build one.  Not knowing the details of what 'grass' you are using, my guess would be that it is not true static grass and hence the results you are experiencing.  Static grass was not being used 25 years ago or had not been 'invented' 25 years ago.  Go out and get some new Nock or Silflor static grass.  I've tried the WS product and don't care for it.

I would start with new static grass. The other thing you might want to experiment with is humidity. Since I am in  the desert South West where the humidity is low, I use a mist bottle to mist the air above where I am going to apply the static grass. The static grass seems to work better with a little humidity in the air.

-- Bill.

Given the age, more than likely the Kibri grass material won't give you the best results. Also double check that you have the ground wire properly secured to the layout surface to insure a good static field.

I have used both Woodland Scenics static grass and Silflor. My opinion, Woodland Scenics gives "OK" results for shorter grass in HO scale. Silflor gave me great results. I also like the length and color options you have with Silflor.

Try another practice patch with  really wet glue.  The ground charge might not be strong enough.

Thanks for all the advice. I mail ordered static grass material and waited until the humidity was below 60% to try again. I used WS glue on foam instead of carpenters yellow glue on a piece of cardboard and now the application is working well. I think it was a combination of everything before that was my problem with getting the grass to stand up.