Tech/maintenance challenging soldering project

[syevad]

The best advice is free. Contact your local supplier specialist. A source in person other than here.
Cheap is not necessarily bad. Expensive is not necessarily good. Two ways to be educated. One by learning correctly and associated costs. The other by paying to have mistakes corrected and the costs of making them.
Overheating parts gets expensive really quick.

I've set to spend no more than £30 for the gun - the local shop sells 400ml cans for £14, that's it for me. That neck connector is detached from the sax body - the high temperature is limited to that connector...
Then if it works ok if it doesn't I'll use the torch for the odd car body repair. I have other saxes to mend and none require silver soldering. De-soldering those 2 bits was an odd mistake (never again)....then on second thought, if I managed to desolder silver soldered bits with a butane torch I might just use the same and do the job without any mapp gun - but then, I guess it's a useful tool to have.

 

[Colin the Bear]

Don't over think it and don't buy tools you're reluctant to use. Most of all, don't be in a rush.

 

[syevad]

Today I tried to silver solder the screw eyelets - first ever attempt at silver soldering....I've practiced on 2 bits of steel and it was ok...but when I tried to solder the eyelet (I tried with only one of the 2) the soldering failed miserably.
As you can see from the pictures, the silver solder moved away from the centre and it's mostly on one side, what's the reason? Wrong flux? (it worked fine with the steel bits maybe for brass I need a different type of flux?).
The protrusion along the perimeter of the area where the eyelet is supposed to sit is also a suspect...I didn't removed it because it helps in keeping the 2 eyelets in the original position but maybe the old soldering has corrupted the new solder? In that case I'd rather remove it...also, probably I should clean the whole lot - but that would remove the patina and look odd with the rest of the sax.
Any suggestion?

What's wrong here...why the solder moved away from the centre? Why didn't stick in place?

solder didn't stick at all in the collect - only in the eyelet - also notice the "perimetral ridge" of the old solder (probably it's better remove it?).

 

[PigSquealer]

Dirty or contaminated surfaces.
Too much heat. Or flame directly on solder / bonding surfaces.
Tin the part & surface first. Flux then assemble in position.
Work the heat around the part. On & off in short bursts.
Solder flows to the heat not away.
If you overheat brass it will go soft. No fix for this. The parts are ruined.

 

[Colin the Bear]

At the right temperatures silver/hard solder will flow everywhere there is flux. You need to use the appropriate flux. Soft solder flux doesn't work. Use minimal amounts of solder. Heat the object not the solder. Hard/silver solder jobs need to be very hot. You may need a more powerful heat source.

Steel reacts differently to brass. Practice with scrap brass.

 

[ghostler]

If you overheat brass it will go soft. No fix for this. The parts are ruined.

Thanks for the inputs, gives me a bit of reconnoitering to do.

When I repair the separated bell brace from the body on my 1952'ish Beaugnier Vito 37 low-Bb bari, I think I will skip attempting silver solder. Appears the original was lead-tin solder. It is a lot easier to handle.

I received the sax as tech special back in 2010 for $315 total case included, a well battered, well used, well maligned high school instrument withdrawn from service. (Looked like it fell off the gymnasium bleachers a couple times.) It was a blast to get it back into playing shape, learned a lot from it, my first project sax.

It will also allow me to realign the distance to bell pads. Whoever resoldered it previously, let the pads be aligned off center, and the sax needs repadding anyway. Just got other priorities so it is a back burner project.

 

[syevad]

I've used a map-x gas torch - plenty of heat...in fact, for such a tiny bit seems overpowering. I don't think I've damaged the brass but you all might have a point in the fact I was targeting the soldering not the surround (and there's the problem...it's so small there's very little to choose).
I've used the "right" white flux (borax?) which came with the silver solder as a package - and worked very well when tested on 2 bits of steel.
The main problem is the area where I work isn't proper for soldering - I have to improvise with stuff I find around...I might spend more time building a soldering enclosure with a proper clamping system and place the lot is a safe area (or I risk to burn the house down). Cynder blocks or Breeze blocks are very good for this sort of jobs as can be shaped/sculpted and hold any shape and won't burn...that's a starting point for my soldering enclosure.

 

[syevad]

Then, there is a clever shortcut too....cut the top of a conventional ligature which includes one pair of eyelets + 1 screw and solder that with normal solder around the collect (the eyelets are silver soldered already). I mean, this project is also about learning to silver solder so I keep this idea as an option....and the Conn seems close to the original (no mods as far as I can tell) and this shortcut wouldn't look good but useful a and practical solution unless I decide to sell the horn.

 

[PigSquealer]

Wrong or too large of tip.
Too much heat, reduce oxygen feed.
Wrong flux.
Dirty parts or oxidized from technique or materials ( flux) used.

 

[syevad]

Wrong or too large of tip.
Too much heat, reduce oxygen feed.
Wrong flux.
Dirty parts or oxidized from technique or materials ( flux) used.

The white flux I've used worked fine with these 2 piece of steel (the bond seems unbreakable) - maybe for brass there is a better type of flux?

 

[cappers]

The white flux I've used worked fine with these 2 piece of steel (the bond seems unbreakable) - maybe for brass there is a better type of flux?

Steel reacts differently to brass. Practice with scrap brass.

I admit I have little experience of soldering, mainly electronics and also some welding for my Land Rover. A clean surface is vital, bare metal ideal, plus of course the correct flux, temperature etc.
I was told to always practise on the materials involved before doing the real thing.

 

[syevad]

I admit I have little experience of soldering, mainly electronics and also some welding for my Land Rover. A clean surface is vital, bare metal ideal, plus of course the correct flux, temperature etc.
I was told to always practise on the materials involved before doing the real thing.

From what I've found online...this flux I'm using (borax) is ok with brass.
I stick to the fact the brass area should be cleaned properly not just the soldering area (some impurities might have played their part in this failure)....and not pointing the flame directly to the solder - this I believe is the main difference between the 2 jobs above.

 

[cappers]

@syevad Good luck, I'm sure you'll get there.
I wouldn't dare try myself, off to a tech for me!

 

[turf3]

Borax by itself isn't probably good enough - get a proper flux (I use Harris Stay-Silv).

You heat the workpieces, and let the hot workpieces melt the brazing filler. But if you overheat things it'll scorch the flux, or it'll oxidize the brass under the flux, and then you have to take the whole thing back to bare metal.

Meticulous cleanliness is key.

 

[PigSquealer]

The Harris Stay-Silv or muriatic acid.
When you cook food with a flame, it’s usually not directly on the food product. That as you know will burn it long before done.
Where you place the heat to what you’re cooking matters.
Pan with oil, food on top. Heat under pan. Not much can go wrong 😑….6” pan 10” burner one egg.

Clean & Tin the parts
Flux the surfaces
Assemble position secured.
Heat from inside, gently. Add flux or metal only if needed. Clue is flow and joint fill.
:30 with a tip for 1/2” copper pipe and Mapp gas = burnt parts.