I just thought this was another thing that might be better suited being on steam somewhere. This info should help with some of the endgame challenges and amuse people who just appreciate having busted equipment. I'll keep experimenting with crafting and updating with what I can find.

Visit Kirbye's Gamefaqs forum post as this is where I got most of this information.

Material rarity point list included for my own personal convenience, though hopefully some people get a use out of it.

Scrap+ is useful for 2/10 Fold Steel farming steels from Mineral Chipsqueeks. Sets base damage to 1 as an effect. As a bonus to how to use this, works great with range extenders (Glitta Augite/Raccoon Leaf) when farming steels. After testing, the Scrap+ effect will not be inherited through overridding. Though it might hurt your rarity points.

This mechanic will only unlock once you hit level 50 Forging for weapons or level 50 Crafting for armor

When you create an item, it has a slightly hidden stat which is its total material level. Creating an item with high level materials will give it special tiered bonuses depending on the combined total level value of all materials you use in its creation. You can have up to 15 items in the creation of a piece of level 10 equipment: 6 creation items and 9 upgrade items.

There's 5 total tiers of total level bonuses, getting much higher with each tier. The maximum total level bonus you can get on a single item is 150 with 15 level 10 materials. Here is a list of the tiers and their respective bonuses.

Weapon Buff | Armor Buff

T1 : LV30 - +10 Atk, +5 M. Atk | +6 Def, +6 M. Def
T2 : LV60 - +25 Atk, +10 M. Atk | +15 Def, +12 M. Def
T3 : LV90 - +70 Atk, +40 M. Atk | +36 Def, +28 M. Def
T4 : LV120 - +200 Atk, +180 M. Atk | +180 Def, +170 M. Def
T5 : LV150 - +700 Atk, +650 M. Atk | +350 Def, +350 M. Def

I am unsure if you need to be level 50 to activate this system, though it won't do you much good early game if you do use it. Late game it can be worthwhile.

The second tier system that grants bonuses, and raises far more exponentially than the total level bonuses. Every material in the game has a rarity bonus which can be applied up a total maximum score of 225 with 15 level 15 rarity materials being used in creation.

The tiers go as follows :

Weapons | Armor

T1 : 25TRP - 10 Atk | 3 Def
T2 : 50TRP - 30 Atk | 10 Def
T3 : 75TRP - 80 Atk | 20 Def
T4 : 100TRP - 150 Atk | 50 Def
T5 : 125TRP - 300 Atk | 90 Def
T6 : 150TRP - 500 Atk | 150 Def
T7 : 175TRP - 1000 Atk | 400 Def
T8 : 200TRP - 2000 Atk | 800 Def

Generally the later in the game you get, the higher rarity materials you'll have access to. Though some for certain categories can be obscenely difficult to attain, let alone at level 10. Some item categories don't even hit the maximum 15 rarity, making getting both the TRP and total level bonuses maxed difficult.

I briefly described this in the first draft of the guide, but figured it was important enough to have its own segment.

If you have a strong weapon you like but are unable to get it to level 150 easily due to a certain material being too hard to get, this trick will save you.

Craft your piece of equipment you want the stats of first and raise it to level 10 using any junk materials. The materials don't matter, it just has to be level 10 so use cheap materials such as low level iron.

Once its level 10, create the most basic weapon you have available in a category. Every weapon has a one mineral requirement recipe that's usually the base one you get when starting the game. (Except for Battleaxes and Gloves. Sorry!)

Now you treat it like you're creating a level 150 item, make sure your mineral you're using is level 10 and put the desired item you wish to have the basic item take the effects of in the second slot. In the creation process, fill the remaining slots with level 10 materials. Proceed to upgrade with more level 10 materials, and you'll now have a basic weapon with the stats of a level 150 total material level weapon.

The only exceptions to this are the Gloves and Battle Axe. The gloves require a level 10 cloth to create the basic recipe, and the axe requires a level 10 claw or fang.

You will not get any additive stats you put onto the higher item. You will only get the base stats of the original high level weapon recipe. This is why you should use iron and such when upgrading the weapon level itself to 10.

TL;DR: Step by step, do this

Craft high stat weapon
Upgrade high stat item to LV10 with low quality materials
Create level 1 recipe of the weapon in the same category using the weapon in the first free slot
Fill the rest of the slots with LV10 materials
Upgrade the new basic item to LV10 with LV10 materials

This also works with armor, though you need a way to easily get LV10 strings and fur. I'd suggest a max friendship Wooly and Spider.

In the case of maximum Rarity Points, you need to replace EVERY LV10 item with a LV10 Great Emery Flower, Dragonic Stone, or something of similar rarity value. You have 10 Rarity Points of leeway to use lower quality materials.

Minerals are by far the easiest thing to get bulk level 10s of, however some base requirement items for overriding require items of different categories. These can be gotten most easily with the most basic producers of the items in your monster barn. These likely wont be good for rarity points, but it should help you easily upgrade your gear to LV150 when you need to swap. (Especially in the final area)

Get these monsters to friendship level 9 for a level 10 material per day in their categories. Brush them and gift them every day to raise their friendship up fast.

Weagle - Feathers

Wooly - Fur

Ant - Cloths and Skins

Sillver Wolf (Story one starts at high friendship) - Claws and Fangs

Spider - Strings

Buffaloo - Sticks and Stems

Tricky Muck - Powders and Spores

This is assuming you want a pure item with no added inherited effects, if you want multiple inherited effects, it might not be possible to attain the maximum rarity bonus as I'm unsure if the equipment itself has rarity.

If you wish to only maximize both of these stats with little regard for your effects and bonuses, the best way to do so is to use Great Emery Flowers (+15) and Dragonic Stones (+15) in your crafting. Both of these are relatively easy to attain at level 10, and upgrading with 9 of either of them will put you at an automatic 135 rarity points. Craft and forge during the creation process with the Dragonic Stones as your extra minerals for the extra push you need to hopefully break the next tier.

If you use equipment overriding, even if the equipment inheritance has no rarity value, you will be able to get 210 TRP for most of your weapons doing this. May mercy be on your soul if you're a glove user, as the only options for cloths and skins are ones with 5+ rarity.

Get to farming level 10 Great Emery Flowers.

Also you might be able to inherit weapon additive effects through overriding (Glitta, Raccoon Leaf, Rare Can, etc) but I haven't confirmed this. You will always replace the base stats of an overridden item with the base stats of the one you're using to replace it, not the fully upgraded version.

NAME - RARITY POINTS

Remember that 225 is the max rarity point value and the final rarity tier is 200 points

Iron - 1

Scrap Metal+ - 2 (Don't use this lmao it lowers your damage to 1)

Bronze - 4

Silver - 7

Gold - 9

Platinum - 12

Orichalcum - 13

Dragonic Stone - 15

Amethyst - 0

Aquamarine - 2

Emerald - 5

Ruby - 7

Sapphire - 8

Diamond - 11

Colored Cores - 13

Crystal Skull - 15

Dark Crystal - 3

Magic Crystal - 4

Fire Crystal - 7

Earth Crystal - 8

Love Crystal - 9

Wind Crystal - 10

Water Crystal - 11

Light Crystal - 12

Small Crystal - 13

Big Crystal - 13

Rune Crystal - 14

Electro Crystal - 15

Stick - 0

Insect Horn - 1

Plant Stem - 3

Bull's Horn - 7

Moving Branch - 9

Rigid Horn - 10

Thick Stick - 12

Devil Horn - 13

Glue - 5

Devil Blood - 9

Paralysis Poison - 10

Poison King - 14

Bird's Feather - 2

Yellow Feather - 5

Black Bird's Feater - 10

Thunderbird Feather - 12

Dragon Fin - 15

Turtle Shell - 2

Fish Fossil - 3

Dragon Bones - 8

Skull - 9

Blk. Tortoise Shell - 12

Ammonite - 15

Round Stone - 4

Tiny Golem Stone - 9

Golem Stone - 12

Golem Tablet - 13

Golem Spirit Stone - 14

Tablet of Truth - 15

Yarn - 1

Old Bandage - 2

Ambrosia's Thorns - 2

Spider's Thread - 4

Puppetry Strings - 6

Vine - 6

Scorpion Tail - 7

Strong Vine - 10

Pretty Thread - 12

Chimera Tail - 15

Arrowhead - 0

Blade Shard - 2

Broken Hilt - 5

Broken Box - 8

Hammer Piece - 9

Shoulder Piece - 11

Rusty Screw - 11

Shiny Screw - 12

Glistening Blade - 12

Great Hammer Shard - 12

Left Rock Shard - 14

Right Rock Shard - 14

MTGU Plate - 14

Pirate's Armor - 14

Broken Ice Wall - 15

Fur (S) - 0

Fur - 1

Yellow Down - 3

Quality Fur - 4

Lightning Mane - 5

Quality Puffy Fur - 6

Fur (M) - 7

Wooly Furball - 9

Fur (L) - 10

Penguin Down - 11

Red Lion Fur - 15

Blue Lion Fur - 15

Chest Hair - 15

Spore - 1

Fairy Dust - 3

Gunpowder - 5

Poison Powder - 6

Holy Spore - 7

Root - 8

Magic Powder - 9

Mysterious Powder - 10

Earth Dragon Ash - 11

Magic - 11

Fire Dragon Ash - 12

Fairy Elixir - 12

Water Dragon Ash - 13

Turnip's Miracle - 14

Melody Bottle - 15

Cheap Cloth - 0

Insect Carapace - 1

Ghost Hood - 4

Pretty Carapace - 6

Quality Cloth - 7

Quality Worn Cloth - 8

Silk Cloth - 9

Giant's Glove - 10

Blue Giant's Glove - 11

Ancient Orc Cloth - 14

Insect Jaw - 0

Panther Claw - 4

Wolf Fang - 5

Palm Claw - 6

Giant's Nail - 7

Chimera's Claw - 7

Ivory Tusk - 8

Big Giant's Nail - 9

Unbroken Ivory Tusk - 10

Scorpion Pincer - 11

Cheap Propellor - 12

Gold Wolf Fang - 11

Quality Propellor - 12

Magic - 12

Dragon Fang -13

Malm Claw - 14

Queen's Jaw - 14

Dangerous Scissors - 14

Wind Dragon Tooth - 15

Wet Scale - 11

Dragon Scale - 14

Blue Scale - 14

Glitter Scale - 14

Love Scale - 14

Black Scale - 14

Grimoire Scale - 15

Firewyrm Scale - 15

Earthwyrm Scale - 15

Legendary Scale - 15

Double Steel - 5

Invisible Stone - 5

Shade Stone - 6

Cursed Doll - 6

Glitta Augite - 8

Rafflesia Petal - 9

10-Fold Steel - 10

Raccoon Leaf - 10

Big Bird's Comb - 10

Light Ore - 13

Warrior's Proof - 13

Proof of Rank - 13

White Stone - 13

Throne of the Empire - 14

Icy Nose - 15

Rune Sphere Shard - 15

(+4 for giant versions where applicable)

Bamboo Sprout - 0

Turnip - 0

Spinach - 1

Potato - 1

Radish - 2

Pink Turnip - 3

Pumpkin - 3

Cucumber - 3

Yam - 3

Corn - 4

Carrot - 4

Eggplant - 5

Green Pepper - 5

Leek - 5

Hot-Hot Fruit - 5

Cabbage - 6

Onion - 6

Bok Choy - 6

Pink Melon - 7

Tomato - 7

Golden Veggies (except turnip) - 9

Golden Turnip - 10

(+4 for giant versions where applicable except Emery Flower)

Toyherb - 0

Blue Grass - 0

Green Grass - 0

Weeds - 0

Withered Grass - 0

Moondrop - 1

Purple Grass - 1

Pink Cat - 2

Charm Blue - 3

Cherry Grass - 3

Lamp Grass - 4

Ironleaf - 4

4-Leaf Clover - 4

Pom-Pom Grass - 4

Indigo Grass - 4

Autumn Grass - 5

Yellow Grass - 5

Fireflower - 6

Noel Grass - 6

Red Grass - 6

Orange Grass - 7

All Flower Crystals - 8

White Grass - 8

Elli Leaves - 10

Emery Flower - 10

Great Emery Flower - 15

Fodder - 0 - Collectible

Scrap Metal - 0 - Collectible

Boot - 0 - Trash

Can - 0 - Trash

Branch - 0 - Other (Can be used as a stick)

Rock - 0 - Other (Can be used as a stone)

Material Stone - 0 - Other (Can be used as a stone)

Lumber - 0 - Other (Can be used as a stick)

Mushroom - 0 - Mushroom

Strawberry - 4 - Fruit (Can be giant)

Rare Can - 5 - Trash

Grape - 5 - Fruit

Apple - 5 - Fruit

Orange - 5 - Fruit

Pineapple - 8 - Fruit (Can be giant)