This article will step you through the rebuild of a badly damaged Bach Stradiarius C Trumpet.
1. Disassemble the Instrument
After checking the valve slide alignment, we strip down the instrument and put aside all the small parts for later, once the horn is rebuilt. Next we un-solder the bell and lead pipe from the valve block.
Depending on the severity and location of the damage, dent work is preformed either before or after this step.
It is crucial to keep in mind the reversal of the damage sustained. This will govern the steps taken and the order they are carried out.
We now carry out any remaining dent work and prep the solder points for reassembly. This image represents the instrument close to this point.
2. Begin Rebuild
We now can begin rebuilding the instrument. If we have reversed the damage correctly all sections should be shaped properly and line up perfectly with all other sections.
It is very important that we do not just get 'close' to a proper fit and then rely on applying pressure at the point of soldering, as this will put unnatural tension on the instrument and restrict it's playing vibration.
When soldering, it is very important to get a solid bead of solder all the way around the seam of the join. This gives an indication that the solder has flowed completely and the two sections are joined solidly by solder.
We now use lead-free solder. This solder operates just like the old leaded solder, but it's healthier and it doesn't oxidise like lead solder, which gives a cosmetic advantage. Yamaha now use this solder exclusivly on their instruments.
3. Clean and Reassemble
Once the bell, lead pipe, and valve block are properly rebuilt, we then wash the entire instrument like it had just come in for an annual service. This is very important, as every trace of the flux we used for soldering needs to be removed from the trumpet, both inside and out.
We then check that the valve alignment, valve tuning slide alignment, waterkeys and all parts are lubed correctly and replaced if needed.
Depending on the extent of the damage we've repaired on the bell, the customer would have the option of having the bell annealed to release the tension gathered as the dents are first put in and then worked out. This has the effect of 'work hardening' the brass. Annealing the bell has cosmetic trade-off, as lacquer does not survive the heat.
The result is a rebuilt trumpet, free of any added tension and as close as possible to the composition and alignment it had when first produced.
