Refinishing Vintage Instruments

When dealing with vintage instruments it is usually in the best interest of the owner to preserve it's originality as much as possible, monetarily speaking. Not only does stripping a vintage instrument hurt it's value, but on instruments with rare colors, it destroys it's uniqueness.

Generally speaking, the only time I would recommend a vintage instrument be completely refinished is when it has already been refinished and done so poorly. Severe damage may also necessitate complete refinishing.

Overspray, Touch-Up, Refinish...what's the difference?

On occasion you may hear the term overspray or touch-up or amalgamating. Though all deal with repairing finishes they are quite different from "refinishing".  I'll clarify...

Touch-Up When I use the term touch up I am usually referring to a relatively small area that can be repaired by brush work (drop filling finish into a chip or valley) or air brushing a small area.

Lacquer which is applied by brush must be wet sanded and polished in order to render the smooth, glass like surface one expects to see.

Of course the most difficult part of "touching up" chips or scratches is not necessarily the application of the lacquer but the blending of new with old. It is truly an art form in many respects and one must aptly judge the thickness of the finish they are dealing with in order to avoid sanding or buffing thru the finish.

Lacquer "Melting" Flaking, brittle lacquer finish that is easily removed by simple contact can often be stopped by amalgamating (re-melting) the finish. Finish that has separated from the wood can sometimes be "reattached" by this method. Top coats are normally diluted with a retarder and thinners that soften the original coat and allow the new coat of finish to melt into the existing finish.

Overspray When I use the term "overspray" I am referring to a technique whereby I apply a new lacquer top coat over the existing lacquer finish without removing the original finish completely.

Overspray and Aging

It is not uncommon to run across instruments who's binding has begun to crumble and literally fall off. With this type of deterioration it is necessary to replace the binding and of course when we do so the new binding stands out like a brand new penny. Solution...we age it. We can age binding by applying a top coat of tinted lacquer to render the yellow hue we normally see on vintage instruments. On most instruments the yellow tint you see on the binding and other areas is simply the result of yellowing lacquer. Once the lacquer is removed you are likely to find white binding (assuming it was white when new). That's why worn areas often differ in color. Other repairs may also necessitate this synthetic aging technique.

Overspray and Non-lacquer finishes

When applying overspray one of the most crucial elements to success is adhesion and melt in. It is absolutely essential that our new top coat "bite" into the existing finish. That "bite" is one obstacle we often run into when trying to overspray finishes other than lacquer. Many of today's newer finishes are so hard and impervious to chemicals that overspraying them with lacquer or other finish may not be an option. The factory can advise you of your finishes repair techniques.

Finish Checking (Crazing)

This is an extremely common, somewhat expected condition in older instruments with lacquer finishes, though it will vary according to the extremes the instrument has been through. An instruments wood is continually expanding and contracting based on it's environment and the moisture level in the wood.  The lacquer itself is put thru allot of stress as this takes place and the finish may develop checking/crazing is a result of this movement. Checking looks like very fine finish cracks running in all directions.
Extreme and sudden temperature changes can also cause finish checking, regardless of the instruments age.
 

How do I stop finish checking?
If you travel with your instrument and it is subject to severe temperature changes, you should make it a common practice to allow it to acclimate to room temperature before opening the case. When instruments are shipped to me they are left unopened until I am sure the contents have had the opportunity to warm to room temperature. You should follow the same procedure when traveling with your instruments.
Since complete refinishing is the only remedy to repair it and because the majority of your instruments with lacquer finishes suffer the same fate, refinishing is not advised.
Below you can see an example of finish checking. Click to enlarge.

Checking/Crazing

Yellowing Lacquer

Instruments finished in nitrocellulose lacquer not only tend to craze with greater ease than the newest catalyzed finishes but they also yellow with age. Instruments normally consist of a color coat and clear coat, with the exception of a natural finish which is just clear coated. This top clear coat will yellow with age. This can turn a white guitar yellow and, since blue and yellow make green...older blue instruments can eventually take on a much more green appearance. This phenomenon is a simple fact of life. While it's true that UV rays may accelerate the process (just peak under a pickguard), nothing can be done to stop nitrocellulose from yellowing. In fact, like crazing, it is a common and expected occurrence.

Finish Clouding

The above photo shows finish clouding, a milky white coloring that quite literally "clouds" the finish. Due to the nature of these finishes (extremely difficult to remove and refinish) and the fact that it is most often seen on inexpensive/import instruments it's a problem that most will simply have to live with.

Lacquer Repair Challenges

Lacquer is very high in solvents and it's shrink rate is incredible. (It keeps going and going...) For this reason small chips, sink marks, dings and cracks can reappear after a flawless repair weeks or even days after being repaired. I try and educate my customers to the nature of  lacquer so they know what to expect...shrinkage!
 

Non-Lacquer Finish Repair

Polyester, catalyzed, cross-linked and other finishes present different challenges when trying to repair them (in comparison with lacquer that is). As manufacturers seek more efficient and durable finishes many have begun using finishes other than lacquer. In fact there are so many different finishes being used that it's easy to get confused. It is often best to call the factory with the instruments build date or serial number to determine exactly what finish was used and what repair options are available.