Let me preface this by saying don’t try this unless you’re over the age of 18. Caustic chemicals will be used. Get an adult to help you and use proper PPE.
Now that that’s out of the way, I’ve been toying with the idea of acid etching and stonewashing a titanium or steel yoyo for quite some time now. The opportunity finally presented itself when I was able to get my hands on a raw Anomaly Yoyos Euphonious. Here it is in its original state.
First thing I did was gather the necessary materials. In this case I’d be using FERRIC CHLORIDE (often marketed as PCB Etchant). This is a strong acid and SHOULD NOT be used on aluminum! Protective eyewear and gloves should be used as well as something to neutralize the acid (baking soda or windex work well). You’ll also need a vessel for your etchant and one for your stones. Plastic works well enough. Finally some denatured alcohol or acetone to clean the yoyo thoroughly before etching, as well as silicone or nail polish to mask sensitive areas of the yoyo. Any oils left on the surface will negatively effect the etching process. Get some stones and pebbles (varying shapes and sizes) for your stonewash and you’re ready to start.
After disassembling the yoyo I masked off the bearing seat and response area, then inserted an M4 screw into the axle and masked that as well. The screw will give you a good hold on the yoyo without having to actually handle it. This will reduce the risk of introducing debris to the surface prior to the etch. Wipe down the yoyo with a paper towel soaked in acetone or alcohol to clean the surface. Make sure you’re wearing gloves throughout this process. Below you’ll see the masked area of the yoyo (the axle hole was accidentally covered. I redid this mask but you get the idea)
How time for the etch. I used “MG Chemicals Ferric Chloride” (https://www.amazon.com/gp/aw/d/B008O9XMYA?psc=1&ref=ppx_pop_mob_b_asin_title)
I used it undiluted and did a 10 minute bath. Make sure you’re getting good coverage with the surface of the yoyo free of air pockets. After the etchant bath neutralize the acid with baking soda or windex and rinse with water. Remove all surface oxides with a paper towel and rinse again. These were the results.
This gives an appearance and feeling similar to a heavy blast. I honestly loved the look and feel so much I almost stopped here. I wanted to see the effects of the stonewash though so I continued.
Rinse your stones so they’re free of dirt and debris (it’ll just make this even dirtier than it is already). Toss half your yoyo into the vessel with all your stones, spray with WD40 or soapy water, and get to shaking.
Make sure you run a timer so you get even finishes on both halves. Remove from the stonewash, rinse it off, and you’re just about done. This is the finish i got after 5 minutes in coarse gravel and pea sized river gravel.
Now it’s time to remove all your masking using acetone or alcohol, reinstall your favorite response system, and enjoy your newly finished yoyo. Make sure to give a light coat of thin lube, especially to the axle threads, to reduce the risk of rusting. Here are final before and after shots. No vibe was introduced in the process, and the finish feels great. I feel like it adds a lot of character as well.
I know this wasn’t the best laid out, so if anyone has any questions or would like to try this themselves and needs further instructions please comment below or message me directly.