Metal finishing Q&As since 1989

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Stainless steel ring toy needs a safe finish so kids don't get poisoned

March 10, 2010

Okay, so I am one of the few people in the world that plays a game called Sling Ring.

It is a super clever little device made of five thick metal beads that are stung onto a larger metal ring.


It is a really fun game but the company that makes them has really cut down on their manufacturing quality to the point in which the toy can barely function.

I have tried for the past two years to convince the company to make rings like they use to, but all they care about are margins.

At this time, hardly anyone knows about the game's existence, and I want to change that fact. That said, I am in no position to spread awareness until people have quality rings at their disposal.

I have totally given up on the original manufacturer, and have taken the task of making the rings into my own hands. I have commissioned a local machine and fabrication shop to provide me with beads cut with computer precision, and rods bent and welded with seamless perfection... but the final product must have some degree of color contrast between the beads and the ring they're strung upon.

The ring must be stainless and the beads must be stainless. I want to give the beads a gold color finish. I want to have the finish be very resilient and very safe. There is a lot of friction in play and I don't want toddlers to get poisoned if they come across a discarded ring.

I want to avoid using paint in fear of ware and tear chipping, but also because paint will take away from the ascetic value of the metal.

I am wondering if there is a a technique that would be analogous to staining that wouldn't kill someone if they sucked on the finished metal.

In the future I may utilize black oxide technique because I hear that it is a hearty yet non toxic finish. That would clearly resolve my color contrast issue just fine, but for now I would like to replicate the style and appearance of the rings as they have been made traditionally.

I am going to send in images for reference. I am looking to make a safe toy, and I'm not sure if plating or staining will provide that end. Thank you so much for your time and energy.

If you want to see the game in motion visit- vimeo.com/7993528

Kurt Alford
Product Designer - Eugene, Oregon, USA

Oil blackening is old and simple process(and non toxic)-oil your objects very very slightly with linseed oil(any other edible oil or fat can be used,expensive substitute is 20% shellac solution),and then heat it to 300-400 C(slowly).Hot air gun can be used as heat source,or electric kiln.Repeat if needs.Hope it helps and good luck!

Goran Budija
- Cerovski vrh Croatia
March 16, 2010

Gold, silver and tin are safe metals for contact with food and mouth but are soft. Perhaps TiN and similar IVD species are also safe and they are hard.

Guillermo Marrufo
Monterrey, NL, Mexico
March 19, 2010