Making the jump from short story to novel

Many ubergroupers I know and love are afraid they will never finish their novel. Earlier today, @Eliseliu confessed:

I definitely write more than half an hour a day! - but not on the novel. Huge writer's block right now in terms of plot. I've always been a 'pantser' and so the practice of writing into the unknown of an entire book (as opposed to a short story) confounds me.

I think this is a feeling many writers share, and so I wanted to repeat here what I found myself telling her:

FWIW - I pantsed, in the biggest sense of the word, the universe of my novel for 4 years. I'm a long-form improv actor, so I developed the shit out of every character and aspect of the world as if it were environmental theatre, and THEN I picked a plot I wanted to focus on out of it last summer.

The problem I see here is a misplaced expectation that everything you write when pantsing will go into the final product, and discouragement when that's not the case.
With clothing, cloth is woven in a big square before you cut out the shapes that make the final piece, and there are scraps left over. With cooking, you make the sauce in a pan before some of it goes on the plate. (Baking is easier to visualise - you make a big sheet cake and then cut out the circles you stack for the cake, or you roll out the dough and the cut out shapes with a cookie cutter.) There are also scraps. With construction, someone fells the tree and rips the lumber down to manageable pieces before you cut off the bits you need to go into the house.

There are ALWAYS scraps and THAT IS OKAY.

I think people who feel like you do, Elise, can't bear to see that scrap bit of wood/cookiedough/fabric get thrown away,  because dammit, you MADE that. You made ALL the dough / wove all the fabric, etc. But you don't get haute couture by lumping ALL THE FABRIC ON THE BOLT together on the model and throwing a tantrum when someone says "that looks like a cross between a toga and a potato sack, you might have to use less there." If you re-use the bits of dough by kneading them together again, you'll overwork the gluten and it will be hard as a rock. And lets not even get into how much a house won't stand or a boat won't float if you refuse to cut the lumber to size.

Pants your happy little ass off with your novel idea, going into it with the recognition that you are just creating a stock of raw materials. Then plot - as in, draw a blue print/calculate a recipie/design a pattern for your house/cookies/dress.  Then use what you need, which may not be all the wood in the truck / flour in the bin / buttons in the box.

You can always save the rest for another project. 

I've never believed "pantsing vs plotting" to be a binary thing.  Both have their uses, and they work particularly well together.