Glue? Depends... If the "old glue" is not too old and the "foundation" was nice and "plump" and even a bit sticky then 1 thin layer to the rim and a thin layer to the basetape is sufficient. If its not sticky and not too thick-- after many years of adding glue it can get THICK--- you can, if it makes you feel better, add 2 very thin coats.. A good bed of glue is around 0.5 mm (0.2" for the Imperial minded) thick. The important bit is that its at the edges of the rim bed to firmly attach the tyre and lessen squirm.
When to remove old glue? When its getting THICK and LuMpY.. How much to remove? Depends on how big the A is in anal.
Glue? Depends... If the "old glue" is not too old and the "foundation" was nice and "plump" and even a bit sticky then 1 thin layer to the rim and a thin layer to the basetape is sufficient. If its not sticky and not too thick-- after many years of adding glue it can get THICK--- you can, if it makes you feel better, add 2 very thin coats.. A good bed of glue is around 0.5 mm (0.2" for the Imperial minded) thick. The important bit is that its at the edges of the rim bed to firmly attach the tyre and lessen squirm.
When to remove old glue? When its getting THICK and LuMpY.. How much to remove? Depends on how big the A is in anal.