As we said back in our Payables Accounting column -- "Inventory (products bought for resale, materials bought to manufacture products to be sold, etc., can't be expensed until sold --- and in the meantime are accounted in an inventory asset-account, e.g., payable/amt- inventory/amt+". So we got materials into the inventory account through payables. How do we get them out? That's the job of inventory accounting.
If you're doing just custom jobs, where you're buying materials strictly for that job -- like a residential custom builder -- you could use a "percent completion" method. You buy the materials to a job-number and account your labor to the job-number -- accumulating them in an inventory account -- and then periodically expense them according to the percent the job is complete, inventory/amt- cost-of-sales/amt+. When the job is 100% complete, all of your costs for that job have been expensed, and no more sits in inventory.
