Update on Englebert Schmid Horns + Marcus Bonna Cases

A relatively short post today, about an issue that is causing grief among owners of Englebert Schmid horn and Marcus Bonna horn cases.

According to a report posted on Schmid’s website, the adhesive used in Bonna cases can react with the metal in Schmid horns. This lab test – which used Beilstein test and a silver nitrate test – was performed in March of 2020.

This isn’t a new discovery – there’s a post in Facebook’s Horn People group about this issue from 2016. That post was started by Englebert Schmid himself, seeking responses from members of the group that may have experienced the issue. His original post:

Hello dear friends! I remember a heavy discussion years ago about Bonna Cases and their eventual influence on the brass metal at lacquered and unlacquered horns. The “tone” between Marcus Bonna and Kendal Betts got a little rough in that time. I don´t want anything bad for Marcus Bonna, but the damages at horns are going on and of course the players are concerned, whether its the case or the metal. In my experience I can say, that all damaged horns first for years, when the case was opened regularly at using the instrument, had no problems. All damages appeared when the horn later for whatever reason (retirement, used as a second instrument …) stayed in the case for months. It seems that then an aggressive chemical environment is developing, which colors the metal red and even can go through the lacquer.

Please tell me your experience!

Lacquering the instrument will not stop this reaction from happening, although it can slow it down. Keeping the horn in the case for long periods of time seems to be a common thread among most of the reports. For an instrument that is played (or taken out of the case) regularly, there seem to be fewer issues.

It also is worth noting that this is more likely to happen as the case gets older – from one of Herr Schmid’s posts in the Facebook thread:

As the expanded foam deteriorates, the Chlorine content of its manufacture is released, it’s the Chlorine that attacks the Zinc content of the Yellow Brass, So with time the chemical components seem to deteriorate and put free more chlorine.

It seems like the solution is relatively simple – if you have a Schmid horn and a Bonna case (especially an older case) make sure that you don’t store the horn in the case for long periods of time.