No spray, please. Sooner or later, and probably sooner, you are going to glue your turnouts. It will not be pretty.
I have found the following to be a good method;
1. Lay the ballast (stay away from the turnout points) and brush out so there is nothing sticking up above the ties.
2. Use either alcohol or dishwashing detergent to break the surface tension. Otherwise, the ballast is going to float up towards the ceiling. You may spray this or use an eyedropper. If dishwasher stuff- one or two drops per quart is enough. Shake before using, blow away bubbles.
3. Elmer's white glue- NOT the school glue which will dry with a shine- You can dilute to half and half or thereabouts. There is no exact formula but the more water you use, the longer to dry. The less water, the more likely it will neither spread properly nor be absorbed downward into the ballast. Let it dry thoroughly, like a day or more.
4. THEN- go over your work inch by inch with a magnifying glass after you have wiped the tops of the rails down with a rag with alcohol to get rid of glue that hit the tops of the rails. Remove any ambient pieces of ballast that have migrated away from where they belong and will interfere with operations.
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