You don't need to max your weapon to +35 to change the appearance.

If you go to 'Customize' (which is in the first option on your hotbar) there should be an option where you can select a weapon camo you currently have in your inventory. So for example, if you pick a sword weapon camo, then all your swords will change appearance to that camo when equipped.

Weapon transmutation though, which is done at the item scientist, changes the appearance of that 1 weapon and you will need a lot of resources for that.

I just figured this out and thought other people might have thought the same thing at first. Hope this helps.