planeur.net

Prior to your first flight with water ballast, there are a few things that you should do. If your glider has removable bags pull them out, place them on a sloping surface and fill them with water - looking for leaks. Patch any leaks that you find and make sure that the valve system is working ok. Patching methods depend upon the construction of your bags, but usually a life raft, inflatable boat, or swimming pool liner repair kit will do the job.  Some bags are reinserted into the wing by use of a string at the wing tip (used to pull the bag in) while some can be inserted with a long length of PVC water pipe. Patting down the empty bags with talc or baby powder can help them slide back in easier. If your glider has integral wing tanks, fill the tanks with the wings on sawhorses to check for leaks. I use plumber's silicone grease for small leaks because it does not attack rubber.

>>> https://wingsandwheels.com/blog/post/your-first-ballasted-flight