Melt the butter in a medium pot over medium-high heat. Add the bacon, onion, celery and thyme, season with salt, pepper and hot sauce and cook 5 minutes. Add the flour and cook a minute more.
Add the half-and-half and stock, bring to a bubble and stir in the potatoes. Return to a boil, then simmer 15 minutes, until the potatoes are cooked and the soup coats a spoon.
Add the clams. Remove the thyme stems (the leaves will have fallen off), stir and adjust the seasoning.