Soldering multiple copper bits needs multiple arms???

[OtisT]

Just my 2 cents worth…..

IMHO, a spot welder is the wrong tool for the job. The material you want to join is too thick, is the wrong material (copper), and you are trying to make a butt joint which is not what spot welders are typically used for. Keep thinking outside the box, but if you are just looking to hold pieces in place for soldering try a few tack welds with a TIG. This also eliminates any concern with adding other metals that may be undesirable.

If it’s just for holding things in place for soldering, a single joint jig could easily be made.

That branch tool is slick and could be great for your application. I made one like zack’s and they work well. A little practice and some manual cleanup was needed to make it work and look good.

If your lacking the tool skills or just want to get the project done, use standard fittings. It will be much heavier and more expensive for the parts, but you could be done in a day. The extra costs for parts would likely be cheaper than all the tools and time you would need for an alternative.

I you shared what the application for this item was, it may help get you better feedback.

[shadylane]

I'd give up on trying to spot weld copper.

[Yummyrum]

I'd give up on trying to spot weld copper.

Them's sound like fight’n words Shady but I tend to agree .

Was thinking about the spot welder my uncle had in his plumbers shop . It had a transformer in it the size of 4 Besser bricks .
It had big solid copper arms and was for doing sheet metal .

Got me thinking what electrodes you’d need if it was to spot weld copper . I’m guessing Tungsten or similar to TIG .

But if a tranny that size was needed for sheet metal , how much power would you need to deal with copper .

[shadylane]

But if a tranny that size was needed for sheet metal , how much power would you need to deal with copper .

Enough to heat the copper and turn into a molten glob that suddenly runs away.
Kinda like when I try welding aluminum with a torch.

On a side note.
A spot welder would have a very low duty cycle of use so it can be smaller than a traditional step down transformer.
It's wired to grunt for a couple seconds and gets to rest while the part is unclamped and moved.

All of which brings into question the OP wanting to find a way to temporarily hold copper fittings in place before soldering /brazing them. Spot welding by it's nature requires the part to be clamped in place.

[NZChris]

Big issue is that with just a single tang they are unbalanced and apply force that is unbalanced too.

Are you sure you understand how it works? That mandrel looks balanced to me. Both sides will pull equally if you have shaped it correctly.

[BritishChemist]

Big issue is that with just a single tang they are unbalanced and apply force that is unbalanced too.

Are you sure you understand how it works? That mandrel looks balanced to me. Both sides will pull equally if you have shaped it correctly.

Are you sure you are thinking about the home-made tool mentioned by me, or maybe you're talking about the expensive tool with retractable (twin) tangs which looks well-balance to me too?.........

[NZChris]

The DIY tool made from a bolt.

[BritishChemist]

The DIY tool made from a bolt.

I think our wires are crossed somewhere: you reckon a shaft with a tang sticking out on one side is well-balanced and when applied to a hole won't apply an unbalanced force?

[SW_Shiner]

The "tang" sticks out both sides. Its a triangle. How are you only seeing it on one side?

[BritishChemist]

The "tang" sticks out both sides. Its a triangle. How are you only seeing it on one side?

Regarding the home-made tool (NOT the expensive, professional tool).........If it was a triangle, how in the heck would you get it into the hole before it was swaged wider?
The tang can only be on one side if it's to fit through the hole to be widened. Even then, you'd have to "wiggle" it in at an angle to get it into the initial hole.

I'm finding this rather incredible!!!!

[SW_Shiner]

The slot in the side is to feed it through a smaller hole at an angle.

flaring tool_small.jpeg (17.64 KiB) Viewed 1508 times

Think about getting a table through a doorway. You cant go straight through as its legs make it too wide. So you put the end of the leg through at an angle.

[OtisT]

You must not be good at puzzles. The tool is keyed (for lack of a better word) so you can snake it into the smaller hole. It’s like getting a large couch up spiral staircase. You have to move the couch around and flip it’s angle a few times to make it up and around the corner. From the side, that triangle looks a bit like a question mark. If you want a video of one of these, it will make sense then.

I’ve made and used one of these and as I said before, there can be a little cleanup required. Mainly some light file work on the extruded lip. You need to secure the pipe to the brace well and apply a firm and consistent pressure with the tool.

Edit: posted in parallel with the previous post.

[SW_Shiner]

Maybe a picture of a commercial one would be easier to see. Even though it looks almost identical the angle may be better.

https://www.plumberschoice.com.au/produ ... inch-only/

[zach]

Here is a photo of the commercial version ($358 US for 1/2")

[MooseMan]

The end of that DIY one would have been turned from the original bolt head, to a mushroom shape, (Meaning it would be dimensionally equal, not uneven as it looks in the picture) then flats ground to the sides, then finally the slot cut so that it can be inserted into a smaller hole drilled into the pipe ready to pull the shoulder.
It would definitely work but I'd anneal the copper first.

If you have nimble fingers, a bit of time and patience and ideally a set of bent nose needle pliers, you can do a passable job of it that way, but I wouldn't want to do a load of them!

I found it easier to flare the piece that's getting soldered onto the pipe with the hole, it's far simpler and provides lots of mating surface for the solder. I recently did it on a little Liebig water jacket when I had no suitable bits to hand so I had to get creative. Not pretty but my soldering never is! Lol

[quadra]

BC you may want to read up a bit more. Brazing has nothing to do with the rod composition- it is simply based on the temperature the filler rod melts at. Above 450C is brazing - below is soldering. The requirements of surface preparation and fit tolerances are also much higher with brazing, which is why I suggested the low temp solder vs what you were talking about above.
By convention when someone discusses soft, medium and hard solders they are usually talking about brazing solders ( material vs method ) with jewellers having 4 or 5 typical alloys ranging from mid 6 to low 800C and welders, machinists, plumbers, and Hvac trades have various alloys available as well, 15% being very common due to cost.

[quadra]

Nice job on that saddle Moose!

[BritishChemist]

Thanks all!
I now see the "broken triangle" aspect and that the tool can indeed be cut to enable it to be wiggled into the hole from the outside.

Unfortunately, it can only be used to make a 90 degree join using a pipe of a smaller diameter to the main pipe(s).
That introduces constrictions to the flow in the pipes, which I want to avoid.

Update.
Key Learning:
after a few short trials at building simple copper-copper bridges between parts via micro spot welding, it does indeed seem to be a lost cause - with cheap equipment anyway. Both high electrical conductivity and high thermal conductivity are working against us very effectively! If we put enough energy into the small weld to actually form a bridge, we're going to get our fingers burned (big time!).


So some form of jig is necessary.
The jig can be a solid one ideally with some form of mechanical fine-tuning of the final positioning (adjustment screws etc?), or maybe a temporary mouldable one (remember MooseMan's suggestion of using clay?) where the final positioning is done by hand and eye?

Because of the zig-zag nature of the component I want to make, it can be broken down visually into a series of "U Pieces", see diagram of one such U piece.

I'm now going to experiment using MooseMan's idea of making a mouldable jig, let it set and then try silver soldering on a test U piece.
This is a huge simplification of the jig required to accurately solder the whole item required! All of its bits need to be held in the precise positions necessary as the entire item is soldered up in one operation (to avoid remelting neighbouring joints).
Exactly how is in the lap of the gods right now, but I'll try some ideas out and report back on how it goes!

[jonnys_spirit]

Someone mentioned stuffing wet towel bits into the tubing which might be considered an impedance to the heat loosening existing joints in the area.

I have used this purpose made product with similar results with copper that had existing joints close by - it worked as advertised:
https://a.co/d/aCcx7uW

Cheers,
j

[Steve Broady]

My father is a highly respected scientist, published author, and patent holder. He is also so stubborn, arrogant, and dazzled by his own brilliance that he often cannot see and cannot be told how boneheaded he is being. Whether that is merely a personal anecdote or applicable to anyone here (myself included) I leave as an exercise for the reader.

It seems to me that you are trying to reinvent the wheel. If the goal is to form a 180 degree return in copper pipe, there are commercially available fittings which do just that. If the radius is too broad and the resulting spacing too wide, a street elbow and standard elbow could be trimmed to allow minimal (say, 1mm) overlap and still be far easier to assemble and solder than the design you propose. It may be that you have some specific reason for needing something which is impossible with any commercial fittings, but it might be worth a look at the range of options available before going down the 100% custom route.

[BritishChemist]

Someone mentioned stuffing wet towel bits into the tubing which might be considered an impedance to the heat loosening existing joints in the area.

I have used this purpose made product with similar results with copper that had existing joints close by - it worked as advertised:
https://a.co/d/aCcx7uW

Cheers,
j

You see what I see!
I will very likely be using them too, to keep the remote ends of workpieces as cool as I can. Especially now that it's much more obvious that as parts are made shorter, the time taken for heat to travel from one end to the other shrinks too!

[BritishChemist]

My father is a highly respected scientist, published author, and patent holder. He is also so stubborn, arrogant, and dazzled by his own brilliance that he often cannot see and cannot be told how boneheaded he is being. Whether that is merely a personal anecdote or applicable to anyone here (myself included) I leave as an exercise for the reader.

It seems to me that you are trying to reinvent the wheel. If the goal is to form a 180 degree return in copper pipe, there are commercially available fittings which do just that. If the radius is too broad and the resulting spacing too wide, a street elbow and standard elbow could be trimmed to allow minimal (say, 1mm) overlap and still be far easier to assemble and solder than the design you propose. It may be that you have some specific reason for needing something which is impossible with any commercial fittings, but it might be worth a look at the range of options available before going down the 100% custom route.

Interesting. I find it sad that you have such a low opinion of your father.

My late father was a gifted craftsman, not educated to a high degree academically, but respected for his skill-set and patience. He went out of his way to offer encouragement and explain his own thoughts in complimentary fashion rather than "holier than thou". He realised that learning was a gradual thing and open-mindedness to new things and approaches is always a key element of Progress.

Some feel that they must impose their own ideas, their own methods and even solutions onto others, without full knowledge of why a particular research and experiment route was chosen. They often yield to the temptation of misdirection from a Topic's subject matter too.
Maybe they feel that they have an obligation to direct others as they see fit? And expect obedience to all of their commands, however impertinent!
........Or maybe "like father like son" applies very strongly in their negative case.
Generally, obvious "smarminess" applies to their behaviour [see Google, UK terminology].

Whether that is merely a personal anecdote or applicable to anyone here (myself included), I also leave as an exercise for the reader.


Criticism or suggestions regarding my disclosed projects is perfectly acceptable and welcomed.
For those who don't like my experimentation or the approach I take, by all means offer alternatives and explanations but please find something to do other than to criticise my person. Directly or otherwise!
I have been known to bite back.

[shadylane]

Why not use a readily available 180' fitting?

[NormandieStill]

Some feel that they must impose their own ideas, their own methods and even solutions onto others, without full knowledge of why a particular research and experiment route was chosen.

The thing is, multiple people have very politely asked you to explain what you are doing in order to better help you. You asked for help with spot welding copper and it was explained that it most probably wouldn't work and other routes were offered. You ignored all the explanations until you had tried it yourself. You have refused to explain what you're trying to achieve, remaining secretive about the end goal.

And now you've been called on it. You don't appear to be stupid, but you do appear to be somewhat stubborn. The combined experience of even just the most forthcoming members of this forum can be measured in decades if not centuries. It would not be the worst of ideas to listen to them when they offer advice.

And if you really are trying to reinvent the wheel and have a good reason not to make it circular, then you might want to explain that so that advice offered can be tailored to whatever shape you have chosen.

[MooseMan]

Someone mentioned stuffing wet towel bits into the tubing which might be considered an impedance to the heat loosening existing joints in the area.

I have used this purpose made product with similar results with copper that had existing joints close by - it worked as advertised:
https://a.co/d/aCcx7uW

Cheers,
j

I've used strips of wet cotton wrapped around the area to very good success to protect adjacent joints, and you can keep a squeezy bottle of water handy to re wet them when they start to steam/smoke.

That putty is basically window putty with ceramic/refractory dust in it, used it many many years ago in the foundry industry.

[OtisT]

Based on the drawings you have provided, with a little practice it would be relatively easy to solder that U section without needing any special cooling heat syncs. Just solder the two joints in one sitting, then cool it before moving to the next U. If your at risk of melting solder at the other end of those long tubes, you are applying WAY too much heat. Just throw a wet towel across the long tubes if it concerns you.

A jig would be nice to hold the three parts, and super easy to fabricate from basic materials, like a fire proof spacer in the middle and a few lightly tightened clamps. It looks like it would be a piece of cake with little practice. I’m curious if you have tried just soldering these things yet to see how you do? It’s sounding like you are stuck in analysis paralysis.

I like the u fittings above. Quick, easy, done deal. This also keeps you from having to work out how to get a nice clean cut on those pipes for a flush mitre joint.

[NZChris]

Why not use a readily available 180' fitting?

The drawing shows the ends of the cross tubes as being open, if so, bends wouldn't be an option.

A plumbers' forum might be more useful.

[shadylane]

I wanted several 15mm diameter horizontal copper pipes stacked vertically and just 10mm apart. They are connected from top to bottom as a long "zig zag".
So how to make those compact "connectors" between levels? [Don't worry about the open ends - that's another story, another problem!]
The radius of a 180 degree pipe curve using a pipe bender is just much too large.

So, you need a really fast 180 turn, What is the zigzag copper tubing going to be used for?
Is it for art work, or is alcohol vapor involved?

[NZChris]

I hope you're not inventing a more difficult way of building something that we already know doesn't work.

[Yummyrum]

Sometimes you just have to get in the shed and try something .
Sorry no milling machines or lathes , so the fit is not perfect and I made the coupling too short .best I could do with a drill and a file

The point of the exercise was to see how hard it was to hold it all together while brazing .
Turns out the wire twitch method works perfectly and I even accidentally dropped it on the floor and it stayed together .

Alas because the gap between the pipes was too close , the brazing rod started to flow between the pipes .