The hazy days of summer aren’t too soon to begin thinking of designs for the holidays—and how to best cast them. During these hot summer days, the last thing you want to think about is the cold winter that’s just a few months away.
But as you’re sitting on the beach working on your tan or catching up on the latest bestseller, you’re probably already thinking about the designs you want to sell during the upcoming holiday season. You’ve done your research on what’s trending, and you’ve got some great ideas for designs that you suspect will be big hits with this year’s shoppers. And although it seems like you have plenty of time to get back into the shop to produce those designs, you really don’t, especially if you plan to send them out to have them cast.
Like many folks in the jewelry industry, casters get swamped before the holiday season. The more time you can give them to turn your designs into reality, the better. In addition, you can take steps to make sure your designs don’t cause delays and waste time. This month, experienced industry casters share tips to help make sure the casting process is as smooth as molten metal, and your holiday orders are ready for the earliest of shoppers.
If you’re looking to hire a caster for the first time, or you need to outsource a job to a new caster, do your research. In addition to seeking recommendations from fellow jewelers, it’s important to make sure the caster you hire is properly equipped to cast your designs. You should show potential casters the type of designs you’d be asking them to cast, specify the material out of which the models will be made, and review the types of metals they would be cast in. “ You want to make sure a caster has the correct array of equipment and investment materials to successfully cast your designs,” says Dennis Busby, casting director of Stuller Inc. in Lafayette, Louisiana. This is especially true if you’re creating your designs in CAD and having them printed on a 3-D printer using photopolymer resins, as not all casters are equipped to cast these materials.
Additionally, consultant Paul Finelt recommends splitting up your contract work. “ Send 80 percent of the work to one caster, and 20 percent to someone else,” says Finelt, the principal of PF Associates LLC in the Greater New York City area. “ It’s important not to get too committed to one vendor in case something ever happened and you can’t get your castings in time. It’s just good supply chain management not to put all your eggs in one basket.”
Before sending off a new design for casting, it’s always a good idea to have your caster review the model first because pieces often require some tweaking to best translate into a casting. “ The more time you can give your caster to review your models, the better results you’ll get,” says Finelt. “ If you send them your model and say that you need the casting in a few days, you’re not giving them a good opportunity for a good casting.” Sending the model in advance will allow your caster to review it and point out potential problem areas.
You can also help the process along by inspecting your models before sending them in. “ Inspect your waxes or models under magnification,” recommends Teresa Fryé of TechForm Advanced Casting in Portland, Oregon. “ This will give you the chance to repair any holes, open seals, or defects before the model is cast.” In addition, “ clean your waxes before sending them to your caster,” says Fryé. “ For wax, you can use a standard citrus cleaner, but for 3-D printed models only use the type of cleaner recommended by the machine’s manufacturer. And don’t use anything on them that could contaminate the metal, such as super glue or paint.”
Although designers often mean well, casters generally recommend that you leave the spruing to them. On a ring, for example, “ designers have a tendency to want to put the sprue at the bottom of the shank,” says Busby. “ A lot of times, that’s not the best location if you want to avoid different kinds of surface porosity.”
From a casting perspective, the best place for a sprue is usually where the ring is the heaviest, and generally that tends to be at the top of the ring. For a ring with stone settings on top, Fryé recommends using a halo to feed the prongs directly during casting. “ Use a halo that attaches to the top of the prongs,” says Fryé. “ This will feed the most critical area, and then the halo can be cut off for an easy cleanup.”
It’s also important to keep in mind that “ there can’t be design elements completely covering the piece,” says Busby: If you have too many elements, at least one or more “ will be destroyed when a sprue is attached.”
If you’re determined to designate a spot for a sprue, discuss things with your caster first. “ If you’re going to do [it], collaborate with your caster to make sure [the location is] good for the caster and easy for you to clean up at the bench,” says Fryé. And Finelt recommends that, before attaching a sprue, you “ be the metal.”
“ If you want to place the sprue, think about where the metal will flow when it enters the design,” he says. “ When you understand that, you’ll know where to put the sprues.”
As designers turn more to CAD to create their designs, it’s important to remember that just because you can design something, that doesn’t mean it can be cast—at least as it was originally designed.
“Textures on CAD models don’t tend to survive the casting process well,” says Finelt. “ Generally speaking, no primary feature should be smaller than 0.25 mm, and preferably 0.5 mm.”
If you’re printing your CAD designs on 3-D printers using photopolymer resins, there are a few additional things to consider. Because these materials don’t melt away during the casting process like wax does, they’re liable to expand and could potentially damage the investment mold. This is important to remember when creating fine details such as lettering. Tall, skinny lettering is more likely to be damaged during the casting process, so you should make lettering no more than 0.6 mm tall, says J. Tyler Teague of JETT Research in Fairview, Tennessee. In addition, adding a draft angle to the tops of the letter—making the top of the letters as wide as needed but tapering the width toward the base—will also help produce a better cast.
There’s no sense in spending hours crafting a delicate model if it winds up being dropped loose into a box and shipped off to the caster. “ Take care when shipping your models,” says Busby. Ideally you want to make sure your model is packed securely so it isn’t jostled around during shipping. Individual plastic bags will keep the models from snagging on packing material or colliding with other models. “ Cotton makes for a good packing material, and peanuts also work well,” he says. “ Whatever you use, use a lot of it to keep your models safe during shipping.”