Pewter Polishing & Finishing

When the word pewter comes to mind, most people think of the classic brushed look that was a hallmark of the metal during the height of its popularity as tableware. The standard brushed finish was originally used to hide the scuffs left by daily use, but as pewter has transitioned into trophies, giftware, jewelry, and figurines, the sophistication of the final finish has developed with it.

Bright Finish

Pewter trophies and gifts are most often polished with a bright, mirror finish that looks almost identical to sterling silver. A bright finish is reflective like a mirror and is perfect for centerpieces that are supposed to stand out which is why it is so common for trophies.

Satin Finish

A satin finish is done by hand and leaves a soft, non-reflective matte color that is known as the classic pewter look. Satin is typically the finish of choice for items that get daily use. Countertops, sinks, tableware, and jewelry are very often finished in satin.

Oxidized Finish

An oxidized finish, also known as an antique or patinated finish, is a darkened variation of satin that creates contrast to make designs stand out more prominently. It is a variation that can be applied to either the bright or the satin finish in jewelry and figurines. The purpose is to make details stand out, so smooth, flat surfaces will not be oxidized and relieved.

To oxidize pewter, use Mi-Tique 1795 from Hubbard Hall.

The Polishing Process

There are two main ways to form pewter, casting and spinning. Spun pieces are cylindrical or round pieces that are made on a spinning lathe. Trophies, bowls, cups, etc are all made via spinning. These pieces are either ready for pre-polishing or soldered together for polishing on a buffing wheel.

Cast items come out raw from a rubber spin-casting mold. Before they are pre-polished, the sprues and gates need to be cut off, and the parting line along with any flashing should be addressed. The coarsest operations come first, so usually this is done with flush cutters, a dremel, or a sanding belt.

Sand Buffing

Sand buffing uses a leather wheel and pumice powder (Grade FF) to remove solder drips and any major defects from the raw piece. Sand buffing wheels are shaped and sized to fit the pieces you’re working with. Don’t be afraid to cut down a wheel and shape it to the piece you’re working on. The leather wheel will last a long time. It’s not something that needs replacing often.

Pre-Polishing

The raw casting then undergoes pre-polishing to remove any surface porosity and uncover any defects that were not caught previously. Defects can be difficult to see when the piece is still raw. The pre-polishing operation uses a coarse abrasive to remove metal faster than the finishing operation similar to how sandpaper comes in different grit sizes. Compounds are colored based on their abrasiveness for easy sorting during work. For pewter, we recommend 751EZ Brown Tripoli from Osborn.

When pre-polishing cast pieces, sometimes you will find a hole and try to remove it, but the hole will keep getting larger. Deep porosity is much more likely in castings than spun pewter. Good casting will make for easy polishing.

Final Polish

Once the piece has been pre-polished, it can either be finished in satin or bright depending on preference. When finishing by hand on a wheel, as opposed to a tumbled finish, there are two compounds that we use.

1. Bright Finish - KC-11 White from Kocour
2. Satin Finish - 220 Grit Greaseless from Kocour

For more information on choosing a compound you can look at Kocour’s guide.

Vibratory Finishing

Machine finishing is done using a vibratory tumbler containing various types of abrasive media depending on the desired result. Before tumbling the raw castings need to be degated and deburred. Any parting line should be removed as well. Media comes in different sizes, shapes, and materials. There are many many types of media, but in general for pewter, ceramic material cuts whereas stainless media polishes. Regular steel media is also an option, and it is cheaper than stainless, but steel will rust and discolor your pewter if not cleaned and maintained properly. It is usually better to pay extra up front for stainless steel.

A variety of shapes within a media batch allows the media to polish down into cracks and crevices as well as flat surfaces, leaving an even polish. Media size is especially important when there are hollows within your pieces that can catch media. Media should be sized so that 1 piece is either too large to fit in any holes or small enough that 3 pieces fit easily. Otherwise, when the tumbling is finished, there will be media stuck up inside.

Impingement is what happens when pieces within a vibratory machine hit against each other and leave dents or nicks in the surface. Having large pieces or too many pieces in a tumbling batch can cause this. Using softer casting alloys, like ROK or RO5, that contain silver also increases the risk of surface impingement.

In case you do not have vibratory equipment yourself, you can send pieces to be vibratory finished professionally. Prices for large-batch pewter are quite competitive and are based on the weight and the time required in the vibratory machine.

Pewter is an easy metal to work with, but it can take some time and experimentation to achieve the look you’re after. Learn more about the uses of pewter and how to work with it.

Email: sales@oldanibrothers.com

Phone: 203-630-6565

This post was written by Peter Oldani. Find out more about the author.