I am an N scaler, but have done all my ballasting on a friends layout, which is HO. I do not consider I am giving you the best technique, but I do know I am giving you the cheapest one that works. Like many of you, I've had problems when ballasting. And, I've read lots of threads from folks who have had trouble ballasting. I ballast with a chap who is the "master"; he ballasts most people's layouts in our group of model railroading friends. He is also the best modeller, layout builder, etc of all of us. So last week we ballasted a new area on the Kettle Valley HO layout we were working on, so with all the problems I have read about and experienced, I watch him like a hawk. So I am going to give you - step by step - what we did. First, you have to saturate the ballast. The level of "wetness" of the ballast is actually critical. You will notice I did not say wet it, but saturate it. So lets looks at the difference. Its summer and some one jokingly turns a hose on you and your jeans become wet. The water spreads out over the jean and you aren't dripping. Now the party continues and another friend throws you in the lake, now your jeans when you walk out will be saturated, can't hold any more water; and you are dripping. I will explain why this is important in a minute. Now when spraying, don't spray directly onto the ballast, nor too closely to it or it will move and holes might form. You are trying to create a heavy rain with the sprayer, but that's it. So spray on the horizontal to the ballast, or slightly down towards it, but maintain your distance with the sprayer. The object is to wet it and saturate it. What is in your sprayer is plain water. Now I know half the planet advocates "wet water" (water with a couple of drops of detergent in it), or an alcohol water mixture, or pure alcohol. So there I am spraying and I ask Mike how much detergent to put in the water. His response: "Rick, I stopped putting detergent in the water because I couldn't tell the difference when I added it and when I didn't. Since I couldn't tell the difference, I stopped adding it." You will only want to spray three or four feet only, then move on after the glue/water mixture is eye dropper into the ballast. The mixture of white glue to water is 50/50. Again others will tell you to use matte medium, but the white glue water mixture has worked since the beginning of time. It is possible the earth is held together by white glue and water mixed together. Since this is the cheapest technique and it works, why muck with success. This next part is important. You must establish a pattern of laying the glue down; its easy to miss a part. So I watched the master. First pass is the white glue/water between the ties, next pass is on the outside of the rail ties, next pass on the ballast beyound the rail ties, then lastly repeating this same procedure on the other side; so 5 passes in all - one in the middle, two on either side of the track. We used kids eye droppers. What I recommend, if you've never done this before is try an experiment on the first six inches you do. After you have done this experiment, it will be as though the scales fell from your eyes. For the first 6 inches, don't wet or saturate the ballast for the white glue/water mixture. Put on liberally some glue/water without any wetting agent. What you will discover is that the glue/water sits on top of the ballast without sinking in, also some ballast may float to the top of the glue/water bubble. Now with the glue sitting on top of the ballast, grab your sprayer and start spraying. You will find it takes a bit of spraying, but once the ballast really gets soaking wet, the glue/water will be sucked into the ballast. When glue sits on top and won't go into the ballast, the ballast isn't wet enough. Finally after the glue has dried, a day or two or three, go back and run your finger over all of it. You should discover that about 98 % of it is rock solid. You will probably run into a part that isn't securely glued and easily moves. So then you re-soak the ballast with water, then add your glue/water mixture again. And voilà your ballast will be glued solid.