Hey, I have some minor experience with designing yo-yos made from high density materials, namely brass which is about half the density of materials you are working with but considerably higher than normal yoyo materials.
My designs are currently in the prototype stage and am planning v2 prototypes at the moment after some help from some wonderful people in the community.
Here’s some pictures of the brass ones.
You can see that they are micros and much smaller than normal yo-yos. This is because the ideal weight for a yoyo generally falls under 60 grams, which will be a bit of a challenge with those high density materials if you plan to make them solid precious metal.
The larger of the two is called the Pocket Watch and uses a bearing and silicone self adhesive pads to enhance its spin and response (its ability to go back up the string). Including a bearing can be a great way to improve performance but has a drawback that it requires high precision (about +/- 0.05 mm or better tolerance). I can share more information about bearing types, bearing design principles, the silicone pads I had custom made etc if you are interested.
The smaller is called RIP and is a fixed axle (one piece design) at the time of writing this I believe it’s the only high density fixed axle yo-yo made. At least as far as I know. The holes are part of the response system that lets it go up the string. This one was sand blasted to give it better response but the blasting was too aggressive and it tends to break strings rather quickly.
I’m planning to remake both, the RIP will get a less aggressive sand blasting and the Pocket Watch l will get a high polished surface to better reflect its name and fine jewelry idea.
Yo-yos this small require specialty string that is thinner than normal and I work with someone in the community who is custom making string. I’ll tag them @rkalajian
Eventually I’ll be having a machine shop produce a run of about 50 of each to sell, which is about standard run size for a small new yoyo brand.
If you don’t want to produce micros another option is precious metal plating. This has been done before with some solid success. One company At Design Lab has some gold and I believe silver plating on top of aluminum yo-yos. Copper plating has been done before too. The plating process can introduce some vibration and affect the yoyo and if not done correctly can introduce so much that it becomes unusable.
Another solid idea is bi-material. You mentioned you are a maker, not sure if that includes wood work but an inlay of precious metal ring around the outside of a wood yoyo would add density to the outer rim which would increase its spin time.
I’m happy to help, answer questions, or chat about yoyo design. I’m early into “branded design” as the idea of selling stuff isn’t really my vibe so these are my first metal yo-yos. My main yoyo hobby is designing and releasing open source 3d printable yo-yos as well as printing them myself and giving them away.
