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I have recently bought a B&S F-tuba - 4 valve military style, 17 mm small bore, 380 mm bell.
The 2. valve slide had probably not been moved for decades, and is badly stuck.

I have tried this:

- filled the valve slide with citric acid, waited some hours and tried again - no luck
- applied creeping oil several times over a couple of days, and tried again - no luck
- tapped lightly with a plastic mallet on the ferrules to break the deposits - no luck
- more creeping oil and warmed gently with torch, tried to pull with a cloth - no luck
- use moderate hand force to twist the slide from side to side in the hope to break it free - no luck

This worked for all other slides, but not the 2nd.

My next step would be to solder the slide bow off, re-solder it one leg only and try to twist with moderate force

Do you have any suggestions to try before I do anything involving soldering ( the advice: bring it to a repair tech does not count ..) ?

Are you applying the penetrating oil on the inside of the slide tube? Do you have PB Blaster in the EU? Take the rotor out and apply liberally inside the tube. Use heat until the oil is just boiling off. Use a rag and then twist it a bit. You're wanting to break away corrosion and I've found just yanking doesn't do a whole lot. The method I've described works 99% of the time on badly stuck slides I've encountered.

For one hopelessly stuck set of ancient alto horn valves, I soaked the valves in penetrant for about a week. Just don't use pliers!

I haven't tried this yet but want to... I've seen some Instagram/YouTube people be successful with it (but I tend to take all that with a big grain of salt).

Use a low temperature moldable plastic.. like this that get soft when put in warm water.

https://pollyplastics.com/collections/moldable-plastics

mold to the inner crook. Then use a wooden dowel and a hammer to bang the slide out.

The idea is the hard plastic is contour fitting the to crook and will distribute the force of the hammering over the whole area to prevent denting.

Again this is a YouTube/Instagram "Hack" not a "tested by someone I trust" recommendation.

gocsick wrote: Fri Oct 23, 2026 1:55 pm I haven't tried this yet but want to... I've seen some Instagram/YouTube people be successful with it (but I tend to take all that with a big grain of salt).

Use a low temperature moldable plastic.. like this that get soft when put in warm water.

https://pollyplastics.com/collections/moldable-plastics

mold to the inner crook. Then use a wooden dowel and a hammer to bang the slide out.

The idea is the hard plastic is contour fitting the to crook and will distribute the force of the hammering over the whole area to prevent denting.

Again this is a YouTube/Instagram "Hack" not a "tested by someone I trust" recommendation.

Something like this would be good for those dumb Yamaha trumpet slides where the ferrules are press-fit and not soldered. Screwed up a couple of those when I was first starting out and learned the hard way.

Nope, I have not seen PB blaster here in DK, but we have other brands of penetration oil.

I did apply it from the outside, bur will tomorrow try to fill the valve circuit from inside for a day or two, warm and try again.

Good idea.

While I see the point of using some form of mold, plastic or other, to protect the crook from damage when hammering with a dowel, I have my doubts.

Can it be removed without traces from silver plated surfaces?

Probably I also risk to damage other parts of the tubing by applying to much force.

I prefer to wait and see what the penetration oil and gentle twisting force applied with hands and towel can do.

Patience is king ...

Second slides are more difficult to twist because the space between the two pairs of tubes is typically quite narrow.
It's usually the only slide that I would (possibly) consider doing something like beating on (in the crotch of the slide bow) with something like a quarter inch round Phillips screwdriver inserted and tapping on the screwdriver with something (though I actually have a tool with an inertia slider for that specific type of use).
With any wider slide bow, that would immediately do devastating damage.