diff --git a/code/modules/mining/equipment_locker.dm b/code/modules/mining/equipment_locker.dm
index c6749528908..11bafb24e26 100644
--- a/code/modules/mining/equipment_locker.dm
+++ b/code/modules/mining/equipment_locker.dm
@@ -335,6 +335,8 @@
 		var/datum/design/alloy = files.FindDesignByID(alloy_id)
 		if((check_access(inserted_id) || allowed(usr)) && alloy)
 			var/desired = input("How many sheets?", "How many sheets would you like to smelt?", 1) as null|num
+			if(desired < 1) // Stops an exploit that lets you build negative alloys and get free materials
+				return
 			var/smelt_amount = can_smelt_alloy(alloy)
 			var/amount = round(min(desired,50,smelt_amount))
 			materials.use_amount(alloy.materials, amount)