Mix 2 cups warm water, yeast, and sugar in a large mixing bowl. Set in a warm place 15-20 minutes until yeast bubbles.
Add salt and melted butter and stir just enough to mix.
Add 4 cups of flour one cup at a time and mix in until incorporated. Knead dough until smooth and elastic about 6-8 minutes.
Cover with a towel and let sit undisturbed in a warm place until doubled in size about 1 hour.
Preheat oven to 350 degrees.
Punch dough down and let sit 15 more minutes.
Divide dough into 12-14 pieces and form pretzels.
Bring 6 cups of water to a boil and add baking soda.
Dip pretzels in boiling water two at a time for 20 seconds. Place on baking sheet covered with parchment paper. Salt pretzels with margarita salt or other large salt and bake for 30 minutes.
Remove from the oven and brush with more melted butter.