How to choose specific Abyssalite to insulate walls or pipes?
You can't choose the temperature of the materials you are using to build.
What you can do is:
- Mine the desired Abyssalite and store it in a designated Compactor (use sweep only, choose only Abyssalite to be stored and isolate the place with a mechanized airlock and proper access control)
- Move the Abyssalite to the place you want to use it with the same techniques as above
- Build your pipes, again with proper control : lock up the area to ensure that no Abyssalite goes in except the one you choose.
but if you only want insulate pipes, why not using some insulated pipes ?