Resistance Soldering question

[Ian PParticipant @ianp]

Posted by Tim Stevens on 08/10/2019 18:16:19:

I wonder whether there is a source of confusion here ?

Could the term 'soldering' as used by the OP mean 'hard soldering' – or what we might call 'silver soldering' ?

Tim

I've loosely followed this thread and just had a quick skim through but I'm still a bits confused (not an unusual state for me) about the joining methods involved.

I think whatever is used to (very securely) attach a small component to a larger one it will be a challenge to do so without marring some surface in one way or another.

Welding where the two metals are not the same really complicates matters but there are methods of welding that take place so quickly that the heat hardly escapes the joint surfaces (spot welding and in particular stud welding) can often be performed with hardly any external marks.

Soldering which involves using a 'solder' requires heat to melt the solder. Heating can be done by a myriad of methods one of them being the 'resistance soldering' discussed here.

What I am not sure of is where the resistor part of the process is and what bit actually gets to do the heating.

Is it the poor conductivity of the metals being joined (like in spot welding) or is it from the tip of a carbon electrode in contact with (one half of) the joint?

Ian P

[Patrice LeméeParticipant @patricelemee72098]

Roger, thanks for the explanation, much appreciated.

Ian, here is a link to the company's website where they explain it better than I ever could in the FAQ. (I'd confuse you more believe me since I am myself a bit confused by the whole process. And like you confusion is a natural state for me)

**LINK**

[Keith HaleParticipant @keithhale68713]

Hi Patrice,

What do American Beauty (the supplier) have to say?

Is the clamping pressure too high?

Googling American Beauty only shows a film involving Kevin Spacey?

Regards

Keith

[Michael GilliganParticipant @michaelgilligan61133]

Posted by CuP Alloys 1 on 10/10/2019 09:23:52:

[…]

Googling American Beauty only shows a film involving Kevin Spacey?

Regards

Keith

.

Try here, Keith: **LINK**

https://americanbeautytools.com/Resistance-Brazing-Systems

MichaelG.

[Brian GParticipant @briang]

Hi Patrice.

I'm not sure that the link answers Tim's question about hard (silver alloy) or soft (tin, lead or iridium alloy) solder. I suspect that the terminology used in the UK may be unfamiliar to you?

Perhaps the questions to ask are:

what temperature solders you are using ? (or just their alloy composition or brand names)

do you use solid solder or solder paint/cream?

and what flux do you use?

Brian

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Patrice Lem�e on 06/10/2019 14:23:44:

[…]

Ok let me try and address all your suggestions.

Gas welding is not possible because of insurance. My shop is part of my house and I can not have something like OA. That’s one reason I went with resistance soldering.

[…]

I have a 1800W unit which is a high powered one in their lineup. Throws in a lot of heat and should do the job, I did not want to buy an underpowered unit like you said Jason.

.

Just for info ^^^

That would appear to be this model: **LINK**

https://americanbeautytools.com/Resistance-Plier-Systems/106/tech

MichaelG.

[Tim StevensParticipant @timstevens64731]

The term 'soldering' with no other words is often interpreted as soft or lead soldering, with a melting point around 200C – because in ordinary (non-specialist) workshops soft soldering is a much more 'normal' practice. It is also the case here that the OP (original poster) may not rely on English as his 'mother tongue'. Clearly the amount of heat involved here is greater than soft soldering requires, and looking at the job illustrated, would not be strong enough.

My comment was not intended in any way as a criticism of the original message, but I hope to clarify the use of the term 'soldering'.

Hope this, er, clarifies?

Tim

[Patrice LeméeParticipant @patricelemee72098]

First of all let me apologize for all the confusion. It is partly because of language as some have mentioned but also the fact that I don’t have any formal training in any of this so I am basically a hack.

I’ll try to include more info in the future, maybe that will help.

Let’s try to answer some questions.

CuP Alloy 1: The supplier says that it has to do with good surface contact and enough of it. That means mating the electrode to the surface as much as possible. When it is a flat surface that’s fine but with my sculptures it’s going to be curved most of the time and reshaping the electrode for every part is not feasible. They do say that light pressure is enough.

Brian: I am sorry the link was to answer Ian’s question about the process itself that’s why I linked to the website. I can’t even be clear about something simple like soldering can you imagine the mess I would make of trying to explain resistance soldering especially when I only have a basic idea of what’s happening.

I use Stay-Brite silver solder which has a melting temp of 430F. It is a solid solder not a paste. It’s 96% tin and 4% silver.

I use Wiseman’s Everflux which is a paste flux.

Michael Gilligan: Thanks that’s exactly the machine I use.

Tim: You are right, French is my mother tongue and that shows sadly. I did not see your post as criticism don’t worry, I know you are just trying to clarify things to help and I appreciate.

A softer solder might be strong enough now that you mention it. My reason for using Stay-Brite is mostly because it does just that, stays bright. But if I could find something that does that with a lower melting temp maybe that could work for non structural parts?

Once again I really appreciate all you help and apologize for not being clear in my explanations or questions.

[VidarParticipant @vidar]

With that ,melting temperature, and that level of silver, it is indeed soldering and not brazing. Then it should just be about dumping heat into a small area quickly using any controlled means.

As the insurance seems to prevent some of the more normal and sane methods I do have one more slightly unusual suggestion: Induction heating.

Induction heating can be directed quite accurate using the shape and position of the leads, and its applications goes from tiny to huge. It can dump immense heat into a tiny specific area very quickly. Which explains you probably have many such induction brazed items already around your home. A typical example is carbide sawblades where each carbide tip is induction braced onto the steel.

Apart from small units looking more like electronic project from China, there are also various trade scale units available. Dentist and jewelers use small units for melting cast metal, there are units used by mechanics to get loose stuck nuts and bolts, and plumbers also have portable version for joining plumbing.

Shaping and placing the leads to get the desired results is a bit of dark magic, but there is an old book from the 60s that goes into great detail about it. Some day I might remember the name of it or stumble over it around here. (Anyone knows about other books please share the info

It is pure electrics so no trouble with your insurace per se… That said, left to itself for too long these machines will reach silly temperatures, so literally keep an eye on them at all times. (I use one to melt stainless steel – that is at about 1650C).

Edited By Vidar on 10/10/2019 19:41:16

[Kiwi BlokeParticipant @kiwibloke62605]

I apologise if what follows is rubbish, but I haven't looked up details about your particular resistance soldering equipment.

My limited knowledge about this technique is that the heat is produced in a resistive carbon 'lump' that is held onto the surface to be heated. Heat is transferred from carbon to workpiece, therefore there should be good thermal contact, to avoid local over-heating. Current flows across the interface. I think there may be another type, where current flows through the carbon 'lump' only. Either way, it looks as though your workpiece is getting locally over-heated, whilst the bulk of the workpiece remains cold. In other words, too much temperature, not enough heat. It may be possible to reduce local overheating by slowing the whole process down (lower current), to allow the temperature to build up in the large heat-sinking workpiece.

If current is flowing across the carbon / workpiece interface, over-heating here should be reduced by ensuring the electrical resistance at the interface is minimised. This means getting the surface area of the interface to be as large as possible and making good contact all over. Yes, this means shaping the electrode, however unpalatable.

Can you change the order of assembly so that this awkward joint is made early, when you could, for example, cook the whole thing up in an oven, without fear of melting already-soldered joints?

[Patrice LeméeParticipant @patricelemee72098]

Vidar I am not sure I understand the difference? What this machine does is induction heating. The electrical current only purpose is heating the piece.

Kiwi No rubbish, every bit of information helps me understand (I am not the sharpest tool in the shed). It was suggested to me to slow the process down by pulsing on and of for a few seconds to build up temp. It is a variable current machine so I will also try to start with lower current to warm up the piece first and then up it for the final push.

As far as order of assembly that could be an option but complicates things a lot and my sculptures are getting more and more complex as it is so I would like to avoid having to do that, it would let me focus on other things.

Thanks again all, I am slowly getting there with all your help.

[VidarParticipant @vidar]

My understanding of this resistance soldering (after watching some youtube video) is that it heat up the tools tip which then transfer heat to the work through physical contact. Induction heating on the other hand is in no physical contact with the part to be heated, and the tool itself keeps a lot cooler than the workpiece.

(This is very analog to comparing an old style electrical resistance stove to a induction stove. The resistance one heats up the plate and then the casserole through physical contact. The induction one heats up the casserole directly).

All that said I think I would have opted for a jeweler style gas based torch as first choice. With insurance stopping that the choice would be a small TIG welding torch; you will note that they too only use electricity and an inept gas like argon. The advantage would be direct transfer of the heat into the workpiece so any contact issues are avoided and thus better utilization of the power available – which for TIG can be a lot more than 1800w. And while it is a welding torch you can use it for all kinds of heating.

(1800w is the magic number for 110v AC house circuits so that might still be a limiting factor I guess).

 

Edited By Vidar on 11/10/2019 21:54:40

[Kiwi BlokeParticipant @kiwibloke62605]

Patrice, just how restrictive is your house insurance? I can understand acetylene being frowned upon, perhaps also big bottles of propane, etc., but are you allowed a gas cooker, barbeque, gas cigarette lighter (and is it size-limited?), paraffin (kerosene) blowlamp, spirit blowlamp, jeweller's spirit lamp (or candle) and blow-pipe? Just trying to think of other sources of pre-heat…

I have done naughty things in the past with welding transformers. You might be able to get the job done by making very good electrical contact with the small and large part (thus avoiding local over-heating), so the current flows across the joint area. Electrical resistance here will be high, relative to other areas, so will heat up. It might be quite spectacular, because you're less than one step away from an improvised spot-welder (which is another avenue to explore…), so current-control would be a necessary addition. A 12V car battery may also work. I think you may be approaching suggestion-overload… Apologies for adding to this, but it's an interesting problem, and it's making people think!

[Patrice LeméeParticipant @patricelemee72098]

Vidar I do have a TIG with small torch and it is very useful for certain situations but not this one. That may be because of the way the machine itself operates or because of my lack of skills or maybe some of both. That's why I decided to add resistance soldering to my arsenal.

Kiwi Heating the whole sculpture could be done but it introduces other problems. Other components, be it desoldering or coloration/oxydation and even melting in instances where they are very small. Of course all this could be worked around to a point with some more planning, design, time cleaning up (where possible) but you can imagine how time consuming this is and I would like to spend that time making my sculptures better if I can find s way to locally heat it up. I am very interested by your suggestion to contact both parts. I asked the company if this was ok and they said yes and that even contact with the solder is ok. I will do some more tests using this technique.

On a general note I did solder the bird's little feet and it worked great as far as the solder, very strong. Just a little marking which I am confident I can minimize with time. In large part thanks to all your help, thanks again.

PS: I must add a very big thanks to Virgil at American Beauty Tools. He has helped me a lot with countless emails and I could not be more satisfied with their customer support and machine. I greatly recommend them if you need some soldering equipment.

[Patrice LeméeParticipant @patricelemee72098]

A small update

I tried to make contact with both parts with the electrodes as Kiwi suggested. Well it did not work. The smaller part heats up faster and the solder flows to it first and never to the large part or not well. It seems to work better if the large part heats up first. The only hard part about that is getting the electrodes close enough but not too close. That is probably going to get easier with practice like any other skill as well as playing with the shape of the electrode.

[Graham Williams 12Participant @grahamwilliams12]

Hi Patrice, beautiful work!

I may be way out of line here and this may be a total no no in your book, but does it have to be welded or soldered at all?

If I was looking at this problem and analysing what it has to do – in terms of strength etc. – I would drill some small holes in the correct position and use Loctite Bearing Retainer (high strength). That would never move even if you wanted it to (unless you apply quite a bit of heat).

Or alternatively, drill small fixing holes and tin the small copper part as others have suggested (soft solder?), plug into holes and gently heat the large part till flow.

JMTPW. Graham

[Nick Clarke 3Participant @nickclarke3]

Are the tips on your soldering plier removable or replaceable?

If so could you make two fine pointed tips to be applied applied to the larger piece, on one side of the joint? This would need to be held in contact with the smaller one of course.

Single sided spotwelding is sometime done in car repair, but at far higher temperatures of course.

[Patrice LeméeParticipant @patricelemee72098]

Thanks Graham

As far as other ways to attach the parts I will look for the lowest temp solder I can work with if I can find some lower than this one (435F) that would work. I don't want to go the Loctite route cause it sounds like cheating for a metal sculpture if that makes any sense. Maybe that's just me. Plus since these are metal, folks have the impression that they are indestructible and may not treat them like they would another piece of art with as much care so I am making sure they are as solid as I can make them,

[Patrice LeméeParticipant @patricelemee72098]

Nick yes they are and that is something I need to play around with to see if I can't improve the heat transfer. As I said before though I need contact with only the larger piece, the small one will just get destroyed by the time I get the large one to temp if I make contact with it,

I did not research spot welding yet but I will if not for this particular problem as another way to attach parts. Thanks.

[Michael GilliganParticipant @michaelgilligan61133]

Hello again, Patrice

I have just noticed these modules available from several sellers on ebay:

**LINK**

https://www.ebay.co.uk/itm/Digital-LED-LCD-Spot-Welder-Machine-Time-Control-Module-Pulse-Encoder-40A-100A/273889365063

This looks useful, and may be the answer to your prayer.

Hopefully someone on the forum will have had practical experience of using one.

MichaelG.

[Patrice LeméeParticipant @patricelemee72098]

Thanks Michael I appreciate but sadly that's way over my paygrade, I would have no idea where to even start using that.

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