Big dent in a trombone inner slide. Inner slides are (usually) nickel, which makes them way harder to work than the brass outer slides, so the usual -- or only, if the damage is severe enough -- way to deal with this is to replace the entire tube.
I didn’t have the correct diameter of replacement inner slide tubes in stock, so on a slow day I gave dent removal a go, because the slide already didn’t work anyway and it was no big deal if I failed to fix since it would just bring us right back to the original “replace tube” plan.
I fixed it. Truth be told I was expecting it to be much more difficult than it turned out to be.
There is still the very faintest bit of catching near the damaged section if you move the slide real slow. Not acceptable if this was a pro instrument from one of the philharmonic trombonists, but it belongs to a middle school and works well enough for them, plus they’re glad to not have to shell out $$ for a new tube.
FUN FACT: the manufacturer (Ferree’s Tools Inc.) shortened the handles on the slide dent rollers two or three times because it used to be TOO POWERFUL and had so much leverage that it could easily crush tubing with no mandrel inside it even if you were being careful. It can still crush tubing if you’re not careful, but it takes more grip strength to do it now.
