Brazing/silver soldering brass and steel

[twr7cx]

I’m looking to add a hose connection onto the TD5 turbo oil drain tube in order to drain my Provent back into the sump similair to how isuzurover describes in https://www.aulro.com/afvb/projects-and-tutorials/57154-fitting-mann-hummel-provent-td5-110-a.html

Called a plumber mate to ask about borrowing or getting help with silver soldering/brazing the fitting into the tube and he queried about what flux or solder we would need to combine the brass and steel. He hadn’t combined with steel before and had only worked on copper and brass before it seems.

anyone able to advise please?

[trout1105]

I’m looking to add a hose connection onto the TD5 turbo oil drain tube in order to drain my Provent back into the sump similair to how isuzurover describes in Fitting MANN+HUMMEL Provent to a TD5 110 (https://www.aulro.com/afvb/projects-and-tutorials/57154-fitting-mann-hummel-provent-td5-110-a.html)

Called a plumber mate to ask about borrowing or getting help with silver soldering/brazing the fitting into the tube and he queried about what flux or solder we would need to combine the brass and steel. He hadn’t combined with steel before and had only worked on copper and brass before it seems.

anyone able to advise please?

I would go with Bronzing the brass and steel together as it will be easier and will produce a stronger weld [thumbsupbig]

[weeds]

Why wouldn’t you use the same material for the drain rather than having two different materials.

I didn’t bother and just ran a piece of clear tube down to the bottom of the fire wall and put a valve on the end. Over 10k kms the amount of oil is only small.

[twr7cx]

Why wouldn’t you use the same material for the drain rather than having two different materials.

Ive only been able to find the hose barb is stainless steel, bronze or plastic. All three being different to the tube. The instructions from isuzurover used the brass one hence I assumed it would be achievable...

[incisor]

Ive only been able to find the hose barb is stainless steel, bronze or plastic. All three being different to the tube. The instructions from isuzurover used the brass one hence I assumed it would be achievable...

is very achievable, dissimilar metals isnt 100% ideal but it will work and last if done properly

just braze it with the blue fluxed rods

make sure you have it clean as you can get it and "tin" each surface before you do the brazing together, makes life much easier.

[scarry]

Blue tip silver solder as Inc said,but make sure the steel and brass is extremely clean.
Must use correct flux,or fluxed rods.


Bronze rod will also do and is cheaper but also must be clean and use flux coated rods or separate correct flux powder.

Watch the heat as the steel will heat up differently to the brass,don’t overheat,particularly with the silver solder.If the steel gets red hot it won’t take.

[Toxic_Avenger]

For soldering, I'd be gunning for 45% silver solder, and flux to suit.

For brazing, I'd recommend Tobin Bronze (AKA Comcoat T).

[Rick1970]

Silver solder. As said, everything must be clean (brake cleaner). I personally prefer a plain rod and seperate flux.
If you can get the tail in stainless, why not use that? Stainless silver solders beautifully.

[uninformed]

Silver solder. As said, everything must be clean (brake cleaner). I personally prefer a plain rod and seperate flux.
If you can get the tail in stainless, why not use that? Stainless silver solders beautifully.

Dont ever use brake cleaner for cleaning welded surfaces. The gases it can release under the extreme heat can be literally deadly!

[Rick1970]

Dont ever use brake cleaner for cleaning welded surfaces. The gases it can release under the extreme heat can be literally deadly!

You let it flash off and/or dry off with compressed air obviously. But yes, had the odd unexpected flame up when got sidetracked, usually talking when should have been concentrating .

[twr7cx]

Thanks for the responses. I was ignorant and had previously assumed that brazing and silver soldering where two terms for the same process.

So if silver soldering then best to use the stainless steel barn, blue tipped fluxed rods or blue tipped non fluxed rods with seperate suitable flux. How do I know which flux is suitable?

If brazing then use Tobin Bronze (AKA Comcoat T). Is it preferable with stainless steel Or bronze barb for this?

[Rick1970]

Silver solder only for stainless...
I would silver solder only the brass as well, but that’s just me

[Toxic_Avenger]

Thanks for the responses. I was ignorant and had previously assumed that brazing and silver soldering where two terms for the same process.


Soldering, as a process, wets the metals, but does not key into the parent metals.
Brazing has keying at the metal surfaces, hence the filler and the parent metal alloy at this joint.
Real world, most people get the idea whichever term you use.

As for the fluxes, choose one as per filler material manufacturer's recommendations. Unlike filler materials, there is little in the way of specifications for fluxes (that I'm aware of), but you'll need to know what active ingredients they use (eg flouride), and the flux should remain active at the temperature at which the filler material melts.
FWIW, people often refer to coated fillers by their flux colour. Realistically, there is no convention here, and a white fluxed rod, a blue fluxed rod, and one with pink and blue polka-dots may all have the same metallurgy... But try telling an old boily/engineer that the comcoat rods with the pink flux are the same as the same spec rods with a white flux, and you'll be in for a bit of an argument.

[uninformed]

You let it flash off and/or dry off with compressed air obviously. But yes, had the odd unexpected flame up when got sidetracked, usually talking when should have been concentrating .

I said gases , not flame or flame/flare up.

google it. Can be fatal

[Toxic_Avenger]

Chlorinated brake cleaner makes phosgene IIRC.

[rick130]

Stainless silver solders beautifully.

It's really easy to stuff it up, you can oxidise the joint badly as the stainless dosen't dissipate heat well.

If using stainless use 'pickling paste' and at a minimum 45% silver brazing rod and flux.
The flux I've been using for the last couple of years actually turns from green to white when the temps roughly correct.

Using 15% and 45% silver solder is technically brazing, not soldering even though that's what we all call it.

Just remember that 45% silver doesn't fill voids near as well as 15% that is used on copper/copper joints, but it capillaries really well if you get your heat right and makes for a very strong joint if the parts have a good fit.

[Rick1970]

It's really easy to stuff it up, you can oxidise the joint badly as the stainless dosen't dissipate heat well.

If using stainless use 'pickling paste' and at a minimum 45% silver brazing rod and flux.
The flux I've been using for the last couple of years actually turns from green to white when the temps roughly correct.

Using 15% and 45% silver solder is technically brazing, not soldering even though that's what we all call it.

Just remember that 45% silver doesn't fill voids near as well as 15% that is used on copper/copper joints, but it capillaries really well if you get your heat right and makes for a very strong joint if the parts have a good fit.

Yeah, 45% is what we use. 99% of the time we are just joining steel/steel (hydraulic fittings)

[Rick1970]

I said gases , not flame or flame/flare up.

google it. Can be fatal

Interesting.
Think I will be checking the label on the parts cleaner we use......

Years ago it was always cut down 20L drums with Petrol in them that we used, tho that’s kinda frowned apon these days.

[rick130]

Yeah, 45% is what we use. 99% of the time we are just joining steel/steel (hydraulic fittings)

I used to do a lot of work on industrial ice machines a long time ago.
The tubes the ice forms on are over 1m long and about 150mm in diameter with stainless tails out the top going onto copper.
I had some higher % silver rod once (60%??) and god it was good to use.

[Toxic_Avenger]

I had some higher % silver rod once (60%??) and god it was good to use.

There is a 56% silver alloy rod. Packed out with copper, zinc and tin in decreasing percentages.

[scarry]

And there is another trick as well,if the 45% doesn't seem to take well,which happens with some steels,run some 15% over the top of the soldered joint.

[uninformed]

Interesting.
Think I will be checking the label on the parts cleaner we use......

Years ago it was always cut down 20L drums with Petrol in them that we used, tho that’s kinda frowned apon these days.

I use petrol to clean all mechanical things.

For prepping for welding I do wire wheel,sanding, grinding which ever I can and need, and use acetone as the cleaner.

i have never used oxy to weld or braze, just use it for cutting or heating.

Id bet my lunches you’d know more about this stuff than me.

[Rick1970]

Id bet my lunches you’d know more about this stuff than me.

Na, I’m just a dumb unqualified hydraulic fitter who picked up what I know out of necessity 🤪