Adhesives for jewelry and gemstone bonding and coating
Compared to bonding automotive or aircraft components, you would think a jewelry bonding application would be a walk in the park – surprisingly this isn’t always the case. Think about the wear and tear a ring would have – in and out of hot soapy washing up water or a set of earrings getting a regular shampooing. Bond areas are tiny – with the glue line exposed to water, soap, hand cream, cleaning fluid, detergent etc. It is really important the jewelry maker uses the right adhesive for the job – otherwise they will have dissatisfied customers, returns and repairs to deal with.
Commonly used adhesives for crystal / rhinestone bonding for jewelry.
You will find precious gemstones such as rubies, diamonds, sapphires etc. are held in place firmly by claw settings formed in gold, lasting hundreds of years with minimal upkeep. This manufacturing method is highly skilled and carried out by expert jewelers. For high volume costume jewelry, quick low-cost solutions are required, often using basic adhesives such as solvent-based craft glue or hotmelt adhesive. Cyanoacrylate adhesives also give a fast and accurate method of attaching crystals or rhinestones. These types of adhesives will not stand the test of time like the claw setting on a gold ring. Possibly the lifespan is long enough for the wearer to lose interest in the jewelry item and move onto the next fashionable piece. However, some of these semi-precious crystal jewelry items can be several hundred dollars and the loss of several stones or the discolouration of the adhesive attaching them is very disappointing. Larger stones or decorations may fair a bit better as they would have a larger bonding area and a smaller ratio of exposed glueline.
Are there any better types of adhesive that can be used instead?
Yes, epoxy adhesives have much better environmental resistance and can withstand hot soapy water without degradation. Permabond offers clear / colourless two-part ET500 and single part heat cure epoxy ES560 which can be used for jewelry applications. These are ideal for use in thin gluelines for bonding glass, stone, most plastics and of course metals. It should be noted that they are probably not the best choice of product aesthetically if you need to produce a thick dome coating.
UV adhesives offer the best aesthetic appearance as well as excellent environmental resistance and a very quick manufacturing process. For clear crystal bonding, a regular UV-curable clear adhesive such as Permabond UV670 can be used – but often rhinestone crystals have a foil backing in which case the UV light may not be able to penetrate for adequate curing. Dual cure Permabond UV7141 offers a sophisticated bonding solution for bonding gems to metal where shadow areas could be a problem. The product can be cured immediately by flashing with UV light (which will cure around the edges, hold the crystal in place) and then the adhesive underneath the gem will cure anaerobically (the surface of the metal and the absence of oxygen will cause the adhesive to cure).
The UV option sounds good for a proper production line, but what about for a hobbyist jewellery maker?
Equipment for curing UV adhesive can be very expensive – particularly for production line conveyors and high intensity lamps, shielding etc. But there are some really easy and low-cost “home” alternatives. We have seen customers using sunbeds for curing adhesive for window bevels. Of course, jewelry is tiny by comparison but a nail polish curing lamp (which you can purchase from eBay for less than $50) is the ideal size for small jewelry items.
For more help and advice about adhesive selection, please contact Permabond.