Disassembly: materials, junk and research tiers

Disassembling an item destroys it and gives Invention materials and experience. Each item rolls a fixed number of materials, each roll picks a material by its share, and some rolls turn into junk instead. Junk is the part you can change.

What one item gives

A rune platebody rolls 20 materials. Of the rolls that are not junk, 35% are cover parts, 30% plated parts, 30% deflecting parts, 3% strong components and 2% protective components. The shares are the same for every platebody. What varies from roll to roll is which material comes out, so the counts the tool gives are averages over many items.

How the item level sets the junk chance

The junk chance follows the level of the item. Below level 75 it is 100% minus 1.1% per level, so a level 50 platebody turns 45% of its rolls into junk. From 75 to 89 the chance falls along a short table, from 4.2% at 75 down to 0.3% at 89; magic logs at level 75 lose 4.2%. From level 90 an item gives no junk at all. High-level items lose fewer of their rolls for this reason.

What junk reduction research changes

Each of the nine junk reduction research tiers multiplies the junk chance by a smaller factor, down to 0.8 at tier 9. A platebody's 45% becomes 44.55% at tier 1 and 36% at tier 9. The gain is largest on low-level items, where most of the rolls are junk; on a level 89 item there is almost nothing left to remove.

For ten platebodies, 200 rolls give on average 90 junk and 38.5 cover parts with no research, and 72 junk and 44.8 cover parts at tier 9. Open the rune platebody in the disassembly tool, set the item count to 10 and change the research tier to see each material move.

Find the cheapest source of a material

Choose a material instead of an item and the tool lists every item that gives it, with how many of that material one item gives at your research tier and what the item costs at its Grand Exchange guide price. Dividing the price by the expected count gives coins per material, and the list is ranked by it. Guide prices move, so the ranking is worth checking before a large buy.

From materials to perks

Materials go into gizmos, and which materials you choose decides which perks you can get. The gizmo perk calculator shows the chance of every perk result for a set of materials, so you can decide which materials are worth collecting before you take anything apart.