You can iso wash an 1/8th of weed and if you really want o be dangerous and smoke your product quickly you can simmer the iso post wash on a double boiler and get it purged much more quickly. Granted it's much more dangerous to cook it quickly but if you want a quick dab it's not a bad route, but it's much healthier than butane.
I didnt actually make any of those concentrates myself, i just grew the weed they were made from. I leave that stuff up to the professionals haha my buddy "The Shaman" is semi-famouse here in California he's got all of the proper equipment to purge that shit good for me. I know butains not the safest, but bubble hash isnt dabbable and CO2 hash is too damn expensive, iso always seems to be lower quality...