Deterioration of Grenadilla* Instruments - Part 4: Immersion Processing of Deteriorated Grenadilla Instruments

Written by Larry R. Naylor

Part 4: Immersion Processing of Deteriorated Grenadilla Instruments

Rewinding the Video

If the manufacturer uses the best wood available, seasons it appropriately, and manufactures it accurately, the instrument will be in its best condition when it initially leaves the factory. Perhaps, we cannot keep instruments in this pristine condition, but, with reasonable care and maintenance, we should expect that instrument to last the player’s lifetime and more. In this context, reasonable care means:

• Upon purchase, we should “set-up” the instrument for your climate and your playing environment
• We should religiously adhere to and perform appropriate, sensible care and maintenance routines
• Our repairman should render appropriate periodic, preventive maintenance
• We should develop good playing habits including preventing foreign materials from entering the bore, mitigat­ing saliva impact, playing only after warm-up, etc.

Still, even with reasonable care the wood of your instrument may eventually deteriorate due to the myriad factors of constant usage. So, you have a deteriorating or already deteriorated instrument. It is blown out. We are now left with the question: what should one do? Can it be restored?

Restoration: Goals & Objectives

While playing an instrument is a craft and art, the acoustics of why your instrument plays well involves physics and chemis­try. Doing nothing to a deteriorated instrument will only hasten its further deterioration. Repadding the instrument would be illogical, irrelevant and a waste of money. The problem is the wood. We need to solve the problem with deteriorated wood!

Restoring Wood: How to Approach the Problem

Restoration would have to bear some connection to how the wood was seasoned in the first place. When manufacturers season the wood, they set their “ideal” moisture content. And in so doing, they try to promote equilibrium in internal stress.

Saturating the deteriorated wood in water is not the answer. Applying a petroleum distillate like mineral oil is not the answer. Painting or staining the wood is not the answer. One needs to impact the wood at the molecular level to realign and re-hydrate the fibers to gain greater resiliency. The solution? Carefully staged immersion in organic oils.

Immersion Rebuild: the Process

Immersion processing can repair damaged wood in about eight weeks. Immersion processing stress-relieves wood, while generating greater fiber resilience. It begins the healing of rough, deteriorated bore, and can correct loose tenon to socket fit. After immersion processing in my shop, there is a three to four week break-in period in your environment where the instrument becomes stable in dimension and moisture balance. This stability allows the player to travel to different climate zones without suffering the typical performance problems that result from dimensional change. Typically, clients state the scales of their instruments “lock in” during this post-immersion, break-in period. In addition, most players report a noticeable increase in resonance — as well as a better scale and evenness, register to register.

Immersion processing involves preparing the wood, first by removing petroleum products from the instrument body, as well as any key oil and petroleum based cork grease. We then immerse the instrument in a tank containing a specific blend of organic oils at a controlled temperature. Depending on the condition of the wood, actual immer­sion lasts five to eight days. After immersion, we drip-dry the instrument and monitor the wood for three weeks. Once the wood is ready, we then mechanically rebuild the instrument: cleaning & refitting all keys, and installing new pads and tenon corks. Total time in shop: about five weeks.

Immersion Rebuild: Evaluation Post Facto

I usually enjoy long-term relationships with my clients, thus allowing me to receive feedback from them over the years. I also work on their instruments annually and have the opportunity to monitor instrument durability. I have found that if my clients take good care of their instruments and correctly perform periodic hand oiling, cracking is rare to non-existent. Their instruments are typically quite stable, whether in their normal environment or moving between environments.

Must we relegate that deteriorated instrument to the back of the closet or discard it? I hope I have shown you that there is a viable alternative: the immersion rebuild.

Interested in restoring that deteriorated grenadilla instrument? To determine if your instrument is a good candidate for an immersion rebuild, I invite you to contact me.

Thank you for visiting my website. I hope you found your visit useful and informative.

By Larry R. Naylor

Ed. Tait L. Solberg & N.E. Gilbert