Extract CleanRip and put it in your apps folder on your SD card or USB drive
The root of your SD Card should now look like this
(root)
apps
CleanRip
boot.dol
icon.png
meta.xml
Insert your SD card or USB drive into your Wii and launch CleanRip from the Homebrew Channel.
Usage
Select the device you want to dump your game to
Select Yes to download the redump.org DAT files if prompted
This is required to ensure that the resulting dumps are clean/accurate
You may get an exception error if you do this. If so, simply skip and verify your dump on Dolphin Emulator if needed.
Insert the disk you want to dump
Select the settings as shown below
If you are dumping one of the 13 games on this list, set Dual Layer to Yes.
Press A to start dumping the disk, once it's done, go to joining PART files
Joining PART files
If you dumped the disc (regardless if it was to a PC or Wii) on a FAT32 formatted device, you should have gotten at least two files that end with .partX.iso. They need to be joined.
Copy the files with the same name and end with .partX.iso into a new folder on your computer
In this folder, click the address bar in Windows Explorer and type cmd
Type copy /b *.part?.iso game.iso, then press enter
Wait until the merging process finishes, It should end with it outputting 1 file(s) copied
Copy the files with the same name and end with .partX.iso into a new folder on your computer
Open the terminal
Run cd [PATH], replacing [PATH] with the folder path to your .partX.iso files
Use the following command as is: cat \*.part?.iso > game.iso
Wait until the merging process finishes.
You have successfully dumped your Wii/GameCube disk!