Brush Electroplating Techniques

Introduction

An essential part of the surface finishing process is polishing. The electroplated surface takes on the appearance of the underlying substrate and hence, if the surface to be plated is scratched, then the final plated surface will also contain scratches. The phrase "The job is only as good as the work you put into it" holds true with the electroplating trade. A well polished surface is an essential prerequisite for perfect plating. Sometimes an article will be delivered for plating already in the polished condition and thus no polishing will be required. If an article is already chrome plated and the chrome plate is in good condition, again, no polishing will be required.

Buffing

A surface can be prepared for plating by polishing on a buffing machine. The buffing machine consists of a polishing mop attached to an electric motor via a shaft on which is a tapered spindle. The main types of mops used are sisal mops, stitched mops and loose-leaf mops.

• Sisal mops:
  Used for deeply scored and scratched articles. Care should be taken not to distort the shape of the article.
• Stitched mops:
  Used after abrasive mopping for articles in a medium scratched condition and for first stage polishing of hard metals e.g., stainless steel. The operator can apply large pressures to get the maximum cutting speed. Again, care should be taken not to distort the shape of the work.
• Loose-leaf mops:
  Used for the final polishing stage. In many cases, where there are only minor scratches on the article, this polishing stage is the only one necessary.

Polishing Waxes

These are supplied in bars and are applied to different mops; each wax contains different abrasive size particles. There are many different types of polishing waxes available and the choice can seem daunting for the beginner. The three polishing waxes we recommend are:

• Grey bar - course wax for use on a sisal mop.
• Green bar - medium wax for use on a stitched mop.
• Blue bar - fine wax for use on a loose-leaf mop.

Warning! Do not cross-contaminate mops. That is, for the final polishing stage on a loose leaf mop, don't apply a medium wax (Green Bar) as this will render the mop useless for final polishing.

Polishing by hand

The three main types of recommended are brass polish, silver polish and resin polish (used for waxing cars). These three polishes have proved extremely useful. With experience you may find your own preferred polishes from the many brands available.
The following list should only serve as a guide:

Brass polish (we recommend Brasso wadding polish) should only be used for pre-plate polishing or for polishing back thick copper plate when doing renovation work.

Silver polish (we recommend Goddard's silver polish) is used mainly for polishing silver to bring up the final lustre and to impart anti-tarnishing properties to the plated surface. We advise that you do not use it for pre-plate polishing as the anti-tarnish layer it leaves can hinder the plating process.

MetaSeal is non-abrasive and gives your plating (especially gold) its final lustre. MetaSeal is available from our online shop.

Cleaning after polishing

The article has to be in a clean state before it is electroplated. That means that all dirt, especially oils and water insoluble dirt, such as polishing waxes left over from the buffing stage,  have to be removed. The best way to remove these is to use our MetaPrep surface conditioner which is available on our online shop.

Health and Safety.

Great care must be taken when using a buffer wheel. If work catches on the wheel it can snatch causing injuries to the operator's hands.  The operator should take all measures to stop clothing and hair getting tangled up in the machine. When using a buffing wheel the operator should wear all the recommended protective clothing: gloves, face shield and a dust mask.

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