As others have said I use a brush to get between the rails, but it does need some help in settling, ballast should "lock" together when tamped down to form a fairly solid bed, in order to achieve this in the model world I tap the rails lightly with the brush handle, this takes time but really does settle the ballst.

In the past I have used PVA in a 50/50 mix with a dash or washing up liquid, I pray this onto the ballast from a couple of feet, pre-wetting does help it to flow quicker.

On my 00 layout it could take me about 1/2 hour to do a metre and get the ballast right, forming the cess etc, use a steel rule to get neat edges and stop the sprayer from disturbing the edges to much.

Quote from: Graham Walters on May 19, 2015, 10:20:19 PM
I pray this onto the ballast from a couple of feet

That's an unusual application method. Does it work?

I suspect that the speed of ballast application is mostly determined by the size of the ballast grain. I have found that without pre wetting, my ballast goes all over the place when droplets of glue are applied. Even brushing the ballast between the sleepers is not a simple operation. I estimate that the major time required is getting the ballast into place before any wetting agent or glue is applied. My ballasting rate is no better than  0.5 m of ballast per 1.5-2 hours.

Webbo

I use a hypodermic syringe from a printer ink cartridge refilling kit to drop at a time of my wetted 50/50 mix between each sleeper individually and vary rarely get any movement of the ballast.   

Hypodermic needles and syringes are fairly cheap to buy through EBay. Before I knew what I really needed, I bought some 1 ml and 3 ml syringes as well as #18 (0.8 mm I.D.) and #22 (0.4 mm I.D.) needles. The combination of the 3 ml syringe with a #18 needle works for me for wetting agent and glue application. I'll keep the 1 ml syringes and the #22 needles for loco lubrication purposes.

Provided they are well flushed with water after each session the needles and syringes can be used over and over. After a while, the plunger becomes a bit stiff in the syringe, so I pull the plunger out and lubricate the seal with some silicon grease, then we are back in business. Having a smoothly sliding plunger minimises the likelihood of sudden squirts of liquid coming out of the needle.

Webbo