Soldering multiple copper bits needs multiple arms???

[BritishChemist]

(With Thanks to MooseMan for guidance on where to post this!)

Some aspects of soldering together multiple bits of copper when still-building can become a serious headache because all of the bits have to end up in the correct place, in three dimensions. Even though we might get away with it and have no leaks, the result can look and feel pretty amateur!!!

Building a jig which holds each and every jig part correctly even when heated (with the copper bits themselves in place) in fraught with issues. Particularly time and cost.
So I'm gearing-up for experimenting with "micro spot welding" the bits in place with small, heat-proof retaining welds, prior to hard soldering (and potentially even soft soldering).
Anyone tried this idea and got some feedback to share?

[NormandieStill]

Not tried spot welding stuff, but depending on what you're trying to solder, and where, the simplest jig can be a bolt with two pieces of metal plate. I've used this technique to fix ferrules to the outside of kegs. You drill a hole where you want to fit your ferrule, then put a bolt through the hole with a length of metal plate on the inside. Fit your ferrule, the second plate, and clamp down with a nut. Once it's nearly locked down, you can still adjust the position with some gentle taps, and then a last little turn will stop it from moving when you solder.

For copper pipe, I find that working out which pieces can be soldered up independently before hand helps. Otherwise, having at least the start and end points fixed will often stop the whole lot from wandering. Mechanically fixing them (slightly crimp the joint to reduce movement might help.

From my bike building past, I've used sacrificial wooden jigs to support frame parts while brazing. They'll often smoulder and even burn, but they'll usually hold long enough to sweat a joint.

[MooseMan]

(With Thanks to MooseMan for guidance on where to post this!)

Some aspects of soldering together multiple bits of copper when still-building can become a serious headache because all of the bits have to end up in the correct place, in three dimensions. Even though we might get away with it and have no leaks, the result can look and feel pretty amateur!!!

Building a jig which holds each and every jig part correctly even when heated (with the copper bits themselves in place) in fraught with issues. Particularly time and cost.
So I'm gearing-up for experimenting with "micro spot welding" the bits in place with small, heat-proof retaining welds, prior to hard soldering (and potentially even soft soldering).
Anyone tried this idea and got some feedback to share?

You're welcome BC, we were all new here once.

Hard without seeing the specific job, but I think I'd look at brazing each section together with the very minimal amount of brazing rod, then once all sections are held in place soft solder it all.

As for jigs etc. Like Norm, I've used bits of wood, homemade clamps and jigs, and quite often soft alloy wire, which can provide a good secure hold when twisted up tight onto the parts.
I do remember seeing on here that someone used a type of clay as a temporary, high temp adhesive when soldering up a complex part. That worked well I think, so worth searching out and trying?

As regards welding, if you are a fairly accomplished tig welder, you could do that I'm sure.

[Reefer1]

A couple of tricks i use are, wet cloths, and silver soldering, i recently built a shotgun condenser, there where several part that needed soldering in close proximity, so i decided to silver soldered the main parts and then soldered the other parts, makes it easier, use wet rags wrapped around or close to points you dont wanna come un soldered,
But i have used wire, home made jigs nuts bolts, you gotta get creative,
Its all about temperature, so working with the hottest work first like brazing, or silver solder and move to the lower heat soft solder last.
If your doing one joint at a time it will be easier that 2 or 3 at once.

[Steve Broady]

Another useful technique is to make some kind of mechanical connection between the parts first. Small screws, rivets, interlocking tabs, bits of wire, etc. Anything that holds the parts together prior to soldering will work. One thing I’ve learned is that trying to solder loose parts is almost always an exercise in frustration.

[OtisT]

On a few occasions I have tacked pieces together with the TIG before soldering. It works, but is not needed in most cases. As others have said, there are multiple ways to hold parts tight while working on them. It’s nice to have the TIG as an option.

Probably the most import skill to learn for soldering is heat management. Once you learn how to properly heat all the various parts and materials you will have greater success and less issues/rework to deal with. This skill becomes more critical when joining big parts with small ones, joining parts of different materials, and joining new parts to sections already soldered up.

Multiple posts in build threads discuss applying heat for soldering. If there is a special section you want to ask about, post a pic of the dri fit section and we can discuss further.

Good luck.

[NZChris]

Your drawing looks simple on paper but would be a nightmare to solder. There may already be easier to build designs that do what you want, but you don't hint at what it is for.

[quadra]

A spot welder capable of working on copper that size might be bigger than you expect and not required.
You can almost always dry fit and mark alignment lines on your parts, and a gentle crimp with a set of channel locks ( slip joint pliers ) or a couple taps with a light hammer and center punch will easily lock a fluxed joint before soldering. If you have little experience soldering take time to practice a bit before you commit to your still. There are lots of good tutorials online and members here that can walk you through the tricks needed for larger joints and complex assemblies, but most people just need to learn how much heat is enough and how much is too much... prepping, fluxing,assembling and disassembling, cleaning and resoldering a few elbows and t joints on some 1/2" copper pipe scraps can be a real confidence builder.

[quadra]

... also, is there a reason for the design you have posted? Have you considered alternatives like a coil or worm condenser?

[Saltbush Bill]

and potentially even soft soldering).

You seem to think soft solder inferiour for still building.
In 99% of cases it is more than adequate for the job.
Alternating the use of soft and hard can be a usefull method at times when soldering two joins close together.
The majority of stills I've seen built are soft soldered.

[BritishChemist]

(With Thanks to MooseMan for guidance on where to post this!)

Some aspects of soldering together multiple bits of copper when still-building can become a serious headache because all of the bits have to end up in the correct place, in three dimensions. Even though we might get away with it and have no leaks, the result can look and feel pretty amateur!!!

Building a jig which holds each and every jig part correctly even when heated (with the copper bits themselves in place) in fraught with issues. Particularly time and cost.
So I'm gearing-up for experimenting with "micro spot welding" the bits in place with small, heat-proof retaining welds, prior to hard soldering (and potentially even soft soldering).
Anyone tried this idea and got some feedback to share?

You're welcome BC, we were all new here once.

Hard without seeing the specific job, but I think I'd look at brazing each section together with the very minimal amount of brazing rod, then once all sections are held in place soft solder it all.

As for jigs etc. Like Norm, I've used bits of wood, homemade clamps and jigs, and quite often soft alloy wire, which can provide a good secure hold when twisted up tight onto the parts.
I do remember seeing on here that someone used a type of clay as a temporary, high temp adhesive when soldering up a complex part. That worked well I think, so worth searching out and trying?

As regards welding, if you are a fairly accomplished tig welder, you could do that I'm sure.

Hi again MooseMan.
I do like the idea of trying clay as a heat-proof self-moulding fixative! I will have a little play around with that just to investigate the practicalities.
I also agree that a TIG welder just might do the job too, if the power can be turned down enough, though I don't have one and they don't come cheap? My son does a bit of welding with his own kit so I'll ask him for advice on the practicalities/expense of it.

A key element, I feel, is the need to hold together the parts precisely and (other than maybe using clay!) But that is easier said than done if the whole part is heated to red heat (for brazing or silver soldering). A millimeter of movement when joining 10cm parts might not look too bad, but a millimeter error on a 15mm part?
The idea is to use a cheap spot welder of the type used to weld connectors on small lithium batteries. That is a routine thing nowadays and the welders (see photo) are very cheap. I suspect (TBD) that with power set to maximum, I'll be able to tack weld 15mm copper tube joints etc. NB: it's likely that the welder tips (usually copper!) will need to be changed to something more inert at the temperatures involved. Graphite, tungsten or maybe even titanium (I have such things available for experimentation!!!)

Perhaps the key attraction of the idea is that as shown in battery tab welding, you can have your finger-hold extremely close to the welding spot because the heat is closely confined and cools quickly via the surrounding metal (following the inverse square Law on distance to the finger too!!!)

And here is a very simple joint using just two parts (15mm diameter copper pipe):

If it transpires that maybe double the power is needed to get the desired result, I can quite easily adapt the device circuitry to employ more Power FET's to do that (I have stock of such things in connection with my ESP32 projects).
I'll report back here when experimentations are completed in a week or two!
Hope you and onlookers are having fun and like the "suck it and see" value of something new!
PS: All be very much aware that I'm very much SAFETY AWARE!!!! Doing new things doesn't mean that unacceptable risks can be taken.......

[quadra]

Looks like fun! keep in mind that soldered plumbing joints generally use fitted lap joints to create the surface area for a structural solder joint, a butted end connection like the above diagram would not be ideal.

[Salt Must Flow]

BritishChemist, this is the image you originally posted in the Welcome Center.

To me the drawing resembles a product condenser similar to a Worm, but rectangular, not round. This can be very very easily soldered by laying it flat on a concrete surface (or a steel bench) while using copper 90 elbows instead of the more complicated cuts & open ends needing capped like it is drawn. IF this is a condenser, you would not want the copper pipe to be completely horizontal. You would want at least a slight downward slope on each leg. When soldering copper elbows, there is enough slop/play within the elbows to create this slope very easily.

I really don't see the need for anything out of the ordinary like spot welding or even spot soldering. Just cut the pieces, prep the ends (abrade them), flux them and assemble it. Solder it one joint at a time from top top the bottom and this can be completed very quickly.

[NZChris]

I'm not guessing because it doesn't make sense for a condenser or a riser.

[Yummyrum]

I’m also not sure if you are asking a generic question and that diagram is merely an example you have created or whether the whole purpose of this question is to be able to make the article in that diagram .

I have no idea what you might want yo use that for how ever , if it was me I would wrap wire around the parallel pipes and twitch them up tight with a block (spacer) at the other end to keep them spaced (parallel ) . Then you should be able to stand it up to access 360° brazing on each joint . (By brazing , I mean using brazing rods that have about 5-15% silver in them and using an Oxy torch )

Your spot welder might work but I have my doubts . Copper pipe sucks heat as those that TIG weld it can attest to . You might need a very powerful unit .

I’d also wonder about twisting as it cools , throwing the tacked piece out of alignment :

[shadylane]

"Copper alloys have low resistivity and high thermal conductivity, so it is difficult to generate heat even with a high welding current, and heat will quickly transfer away. They are rather difficult to weld with resistance spot welding. Instead, copper and copper alloy are excellent materials for electrodes."

https://www.swantec.com/technology/spot-welding/

On a side note.
Spot welding butt joints on copper tubing would be almost impossible.
It's something I wouldn't even try.

[BritishChemist]

BritishChemist........
To me the drawing resembles a product condenser similar to a Worm, but rectangular, not round.

Thanks for your response.
It's not a condenser - it's a part of a new and as yet undisclosed prototype component I'm working on.

The key element of my question is that when many copper components are involved, small and close together, it can be the Devil's Own job to keep them in place to precisely solder them together - hard or soft solder.
With small components heat applied travels all over most of each component and can be difficult to control, so the joints are at risk of being poor quality. My "welding idea" - which I am in the process of pursuing when the kit arrives - is to make tiny, same-metal bridges between items using a highly-focussed heat source so that I can hold either side of each required joint without frying my fingers.

I do get it that those who don't get involved with such relatively tiny, multi-part work may not see it as a problem they have encountered and perhaps never will.
So far, no-one has volunteered any experience in taking my suggested approach, so it may be that once I've defeated the problem (or not and it remains a problem!) it can go into the Group's Memory Banks under "Seen that, know how to beat that one"?

For now, probably best to see what I come back with when my experimentation is completed? I will report and I do think that it will be of use whenever small copper parts need to be joined with precision.

For those following the discussions - even if only with passing interest - I have a supplementary question for further thought:
Anyone had success using "Phosphorus Copper" brazing rods instead of silver solder?

[Copperhead road]

Thanks for your response.
It's not a condenser - it's a part of a new and as yet undisclosed prototype component I'm working on.


What exactly is it, anything to do with distilling?
Kinda confusing

[NZChris]

Some of my stuff has been built using it, but I didn't do it myself.

[NormandieStill]

For those following the discussions - even if only with passing interest - I have a supplementary question for further thought:
Anyone had success using "Phosphorus Copper" brazing rods instead of silver solder?

I've brazed steel bike frames with phosphor bronze. A quick look suggests that the rods include some of zinc, magnanese and or nickel. Not sure how these metals fare in terms of food safety. The manufacturer of the rods I used to use specifically recommends that silver solder with high silver levels (55%) be used for food-safe brazing.

You can wrap already soldered parts in wet rags to prevent them from reflowing. For the shape in your diagram (which is 2D) I would consider using little wooden standoffs attached to a board to fasten to hold the basic structure and then wrap single core copper wire around each pair of tubes where there's a bridge to pull them tight for soldering. Of course it depends on the diameter of the tubes. For 16mm tubes, heat will wick the solder around the entire joint. For 50mm tube you might need to get the torch and rod to the back to work from the other side.

The problem with playing your cards close to your chest is that it can make it difficult to help when you ask questions. If we knew what you were trying to achieve, it's possible that people might be better able to help. And if you don't like the advice offered, nothing will stop you from building it anyway. Unless your concerned about trade secrets and marketability, in which case it's a bit rough to ask people to volunteer help to make you money!

[Saltbush Bill]

Not sure how these metals fare in terms of food safety.

The manufacturer of the rods I used to use specifically recommends that silver solder with high silver levels (55%) be used for food-safe brazing.

I might be being a little pedantic here Normandy, your post is good, but I'd point out that we are dealing with solvents here rather than food.

[NormandieStill]

Not sure how these metals fare in terms of food safety.

The manufacturer of the rods I used to use specifically recommends that silver solder with high silver levels (55%) be used for food-safe brazing.

I might be being a little pedantic here Normandy, your post is good, but I'd point out that we are dealing with solvents here rather than food.

No pedantry noticed! You're right that food-safe doesn't cut it, and I was even thinking about that when writing but didn't put it into words.

To the OP: Certain metals can be dissolved out by the solvents present during distilling. While solders containing those metals in the boiler might not pose a risk (as the solvents will not make it out as vapour, so they'll be "locked" into the boiler), the same is not true of (for example) a condenser. Bearing this in mind, and the risk of contamination should you ever decide to use backset as a post-distillation addition (BB's Rum does this), you might want to avoid them altogether. From memory, zinc is generally regarded as To Be Avoided although that might be a durability thing.

[Saltbush Bill]

Its probably more relevant to seals ,gaskets and other boiler/ sealing materials, than metals IMO, but all the same worth mentioning.

[BritishChemist]

For those following the discussions - even if only with passing interest - I have a supplementary question for further thought:
Anyone had success using "Phosphorus Copper" brazing rods instead of silver solder?

The problem with playing your cards close to your chest is that it can make it difficult to help when you ask questions. If we knew what you were trying to achieve, it's possible that people might be better able to help. And if you don't like the advice offered, nothing will stop you from building it anyway. Unless your concerned about trade secrets and marketability, in which case it's a bit rough to ask people to volunteer help to make you money!

in response to the last few posts....

The melting point of a phosphorus-copper brazing rod is typically between 645–815°C, while the melting point of hard silver-based solder is typically between 741–788°C, both well below that of copper; so provided it flows well enough into the joint, Cu-P may provide a much cheaper alternative to Ag-based at very similar soldering temperatures......
Cu-P solder rods contain only copper and phosphorus, so even if not food safe accredited, I would have no concerns about it's appropriateness for this component. Others may think otherwise in consideration of the use of it for their own work, but that's their prerogative.



It's way too early to discuss "what might be" with respect to a potential use of the joints which I can't make, precisely enough, yet. There's all sorts of kinks in the research road before I get to usage.
I'm about prioritising removal of roadblocks to my progress, if that's possible.

As can be seen, I've already shared the idea of using such micro spot copper welds for copper workpiece support. It seems, so far, that no-one here in "the land of experienced copper still-building" has tried the idea for themselves, so it is novel! Even if the need, herein, is rare or even non-existent. Yet.......
Everything postulated is vulnerable to dismissal by those experienced enough to feel sure in their own minds that it's a Blind Alley?
I have no problem with that.

BTW, MooseMan's response included an idea that, for me, has strong initial merit in the thought process of such "out of the box" solution thinking, when he suggested maybe using clay as a workpiece support.
That just might be at least the start of a new ideological pathway to achieve the same goal....... With a little creativity and flair along the way?
I think my micro spot welder kit will arrive this week. I'll keep my findings flowing!

[GrumbleStill]

G’day British,

Good luck with the build. I hope it goes well for you, but to be honest, those joins look like a tough ask.

As for the spot welder, well I haven’t used one, so can’t be sure, but struggle to visualise how the tack would work without obscuring the join and making the final job harder.

A couple of thoughts that may or may not be of any value depending on your end goal.

• You could modify a couple of copper capillary tee pieces and solder them together to create the vertical transition a bit like this:

  

  That would create a transition with good structural integrity, and would hold pressure pretty well.
  
  Another option would be to break out the mill (I seem to recall you mentioning you had access to a machine shop) and machine a transition piece out of some hollow bar, which would have a lot more material to work with and get a solid join

Whatever you decide to do - have fun & stay safe.

[quadra]

BC, nobody is saying you can not spot weld these parts, but you will not be doing it with a unit like the one linked above.
The materials you are talking about "soldering" with are brazing rods- expensive and will require an oxygen acetylene torch. The silver bearing solder typically used by many of us is available in most hardware stores can be used with a propane or MAPP torch and flows at almost half the temperature of those brazing rods:
https://www.rona.ca/en/product/oatey-si ... lsrc=aw.ds

If you are looking for even more complicated ways to build your project, have a Google for " plumbers T-drill" a tool that let's you pull a swaged saddle joint for soldering.

[Steve Broady]

If you are looking for even more complicated ways to build your project, have a Google for " plumbers T-drill" a tool that let's you pull a swaged saddle joint for soldering.

Ooof! I had to go look that thing up. The price is notably absent from every company I can find that sells one. I did find an article from 2007 saying it was $4k, and i imagine it's only gone up since then. Very neat tool, but I can buy a lot of premade parts for that kind of money. If there's a cheaper way of forming a similar opening, i'd be curious to hear about it. Hydraulic pipe spreader, perhaps?

[BritishChemist]

BC, nobody is saying you can not spot weld these parts, but you will not be doing it with a unit like the one linked above.
The materials you are talking about "soldering" with are brazing rods- expensive and will require an oxygen acetylene torch. The silver bearing solder typically used by many of us is available in most hardware stores can be used with a propane or MAPP torch and flows at almost half the temperature of those brazing rods:
https://www.rona.ca/en/product/oatey-si ... lsrc=aw.ds

If you are looking for even more complicated ways to build your project, have a Google for " plumbers T-drill" a tool that let's you pull a swaged saddle joint for soldering.

There may be a terminology issue between our countries there.....

When I say "Silver Solder" I don't mean "lead-free solder that contains silver".
Convention, at least here in UK, is that low temperature solders (lead-bearing or not) are called "soft solder". They are based on eutectic alloys of tin and lead, or if "lead free", tin and silver.

Those which have much higher M.P. based on silver are traditionally called "Silver Solder" or sometimes, "Hard Solder".
Silver solder is made of silver, copper, and zinc, with the proportions of each metal varying by type.
For example, a typical silver solder is made of 65% silver, 20% copper, and 15% zinc. The most common general purpose silver solder is 40% silver.
- not too long ago, silver solder used to also contain some Cadmium, but that has now largely been discontinued on the grounds of it's health impact.

None of the above should be confused with "brazing rods" which usually consist mostly of Copper (Cu) and Zinc (Zn) and only sometimes, a small amount of silver (Ag).
Hope that helps prevent confusion.

[zach]

Here is a link to homemade tool to pull a branch connection

tee hook going in to the pipe_small.jpeg (14.21 KiB) Viewed 2061 times

https://www.builditsolar.com/Projects/S ... Puller.htm

[BritishChemist]

Here is a link to homemade tool to pull a branch connection
flaring tool_small.jpeg
tee hook going in to the pipe_small.jpeg
https://www.builditsolar.com/Projects/S ... Puller.htm

Along the path to where I am right now, I'd played around with similar tools. Big issue is that with just a single tang they are unbalanced and apply force that is unbalanced too.
I saw with interest the (very expensive) tool video shown by "quadra" which addresses a lot of the problem, at a price, using retractable, twin tangs. Lots of scope for a bit of hobby-engineer creativity to duplicate the function with a simple work-around to making the tangs engage WITHOUT removing the tool from the hole it's in...... Quite a brain teaser, especially for work on a 15mm tube. But it's set the grey matter pondering!

Update for the thread followers:
I got my hands on a micro spot welder today and did a very quick attempt at a copper/copper "bridge" weld.
Even at the highest setting (300Amps for a few milliseconds) it is compromised by both the high heat and high electrical conductivities of copper, both compared to nickel (the usual workpiece material).
A lot of the energy applied transferred remarkably quickly - and over quite a distance - in the form of heat.

These machines are designed to weld very thin nickel foil, so I'm not in Disasterville, yet!
But maybe I'm a lot closer than I'd like to be!
It might just be that there's a need to apply much higher currents in a much shorter time to increase the energy density, to overcome the energy leakage away from the intended weld spot?
Such are the peaks and troughs of experimentation!!!!!