Member postings for Keith Hale

Hi Robin

See personal message.

Regards

Keith

Hi Robin,

In order to get you on your way as quickly and efficiently as possible, I would like to have a bit more background. It takes the guesswork out of it as there are a few answers that could help you, but I would rather give the help that WILL help.

Please send a pm with contact details. I will get back to you.

Regards

Keith

Hi folks

Words fail.

There's an expression involving a horse and water but I can't recall it at the moment.

Perhaps I should just keep my thoughts to myself. Is that the bugler playing "The Last Post"?

Borax is a great material but if the working temperature of your filler metal or casting alloy is above approx 750 Deg, it will not provide the required level of oxide removal.

OK - don't throw it in the bin - it could prove to be a good pan scourer - but it's no good for using with a low or medium melting point silver solder!

Keith

Borax can be used to silver solder silver. We are considering silver soldering brass.The silver solders used when making joints on hallmarked items have higher melting points than those used by the vast majority of model engineers. Hallmarking quality silver solder can be fluxed with borax.

The two main criteria that a flux has to meet are that it is compatible with the parent materials and the melting point of the filler metal.

Borax does not meet those of the filler. The silver solder and joint has to be needlessly overheated in order for the flux to become effective.

Let me modify my earlier comment - unless you are making sterling silver jewelry that is to be hallmarked - throw the borax in the bin unless the filler metal is brass.!

Keith

Hi Ken.

The root cause of all silver soldering difficulties lies in one place - behind the torch. Poor joint design.fluxing, heating technique, alloy selection to name but four!

Make the joints correctly first time and there is no need for any rectification.

Ask yourself - where did I go wrong. A poor joint is the product of a deviation from the basic principles of the process. Appreciate that and you are well on the way to successful brazing.

An oxy-propane torch may enable you to recover the situation but it inevitably produces local thermal stresses that can cause other problems. Be aware of that and react accordingly.

Instead of trying to put over the situation in a few lines on a forum, why not discuss it with people who know? Old fashioned it may be, but talk-talk is better than chalk-chalk.

And the next statement is aimed at all model engineers. Can you spare 10 minutes to get help quickly. Why not use Skype or a video call to show us the problem?

Keith

Hi Ken

Take the time, make the effort, understand the process. Learn what you have to do and why.

There are no shortcuts. These inevitably lead to poor and expensive joints.

There is no better source of information than CuP Alloys. Their livelihood depends on their customers being successful. We have guys who have, between them, over 100 years experience of promoting efficient brazing on a daily basis.

Ring 01623 707955.

Or see them at ally pally.

They are more accessible than a forum

Success is at the end of a very short tunnel!

Keith

Hi Chris,

Do not use borax flux with silver solder. It does not start to work until you have overheated the joint and alloy.

If using easiflo you will certainly be boiling cadmium from the alloy. These fumes can,a eventually wil, kill you. It was this hoo-haw that led to the banning of the sale of easiflo and other cadmium bearing alloys.

Ring CuP Alloys on 01623 707955 for more information. To get specific information on your problem ask them for the contact details to enable you to set up a video link via Skype or WhatsApp.

Alternatively go speak to them at Ally pally over the weekend.

But put that borax in the bin unless your filler metal is brass.

Keith

Hi Chris

Save yourself a lot of time and money, frustration and poor joints by getting to understand the process.

Silver soldering is a very simple process as long as you understand what you are doing and why. Then do it.

BUT IF YOU DEVIATE FROM THE BASICS OR TAKE SHORTCUTS (and there are lots of them on the forums!) YOU WILL RUN INTO DIFFICULTIES.

CuP Alloys have a good book (I wrote it!) that will definitely point you in the right direction.

Taking a little bit of time now will reap great rewards in the future.

Regards

Keith

A quick check also reveals the absence of the multitude of eBay suppliers. What an opportunity they miss to relate to the hobby and to understand where their products are used, to show clearly the quality and to provide all the technical information for their safe and efficient use. But that costs money which in some circles is considered to be "value for money" or "quality".

Others call it savvy shopping.

I'm sure that the organizers could find small stands in remote dark areas by quick exit doors!

Or look for them outside the tube station. at the bottom of the hill or in the carparks.

Oh well, can't have it all!

Keith

PS Look for the exhibition coming to a farmer's field near you. Four people and a car for £1. What a bargain. Rock bottom prices (supplier makes no profit), organizers make no money. Savviness at its finest.

Oops!

Wrong thread!

Edited By CuP Alloys 1 on 14/01/2020 10:13:43

General consensus?

Soldering stainless steel is no more difficult than soldering copper.

You just need the right materials. Beware the cheap products and bargains available on eBay. If they don't work, they are very expensive and make the job difficult or impossible!

I bet the royal mail don't know that acid is being sent through the post!

Best of luck with the bakers fluid.

Keith

Bakers no. 3 is a diluted"general purpose" flux for soft soldering copper/brass/mild steel.

Not for stainless steel.

More info available via M Mouse on eBay or any related supplier!

Alternatively get the right stuff first time and all the information you may need from CuP. It will be cheaper at the end of the day.

The bakers fluid cannot be sent by post (ask royal mail)so collect it from CuP at ally pally.

Not going to the exhibition, CuP can send the flux as a cored wire. The solder has a low melting point and an excellent colour match to the steel.

Again check this out with Mr Mouse.

CuP will ensure that you are successful. Declaration of interest - I used to own the company!

Keith

Hi Bob

If you have a joint that is suspect, then at some point you did something that hindered the capillary flow of the silver solder.

Did you use a flux that suited the parent materials?

Did the whole of the joint achieve brazing temperature? Did the alloy get it's heat from the joint not the torch?

Did you create a heat pattern to promote the required alloy flow?

For more information see the videos http://www.cupalloys.co.uk

**LINK**

Regards

Keith

Edited By CuP Alloys 1 on 05/12/2019 09:23:31

Edited By CuP Alloys 1 on 05/12/2019 09:24:44

Hi Chris,

The concept of silver soldering is very simple.

But have no illusions, it is a skillful process. There is no shortcut to experience gained through practice.

Jason is partly right in his recommendations but what works for one person may not be suitable for another. Question why he has made this recommendation. I suspect that he has done so because it works for him and, more importantly, the way he uses it.

Like Jason, you will only be successful if you adopt and adhere to the underlying principle of the process - capillary flow. These forums are full of problems involving silver soldering. In every case the problem lay in one place - behind the torch!

Everything that you do to make your joints should promote capillary flow of the alloy. That statement holds for any alloy you use or from where you buy it.

Check on your joint design. Set the right length and gap

Check that your joint is clean and oxide free at 650 deg C. That is the role of the flux - not you! Your job is to pick the right one. EF flux is sold by a company CuP Alloys, with which I have strong connections, but it may not be the right one. They have others.

Check on your heating technique to ensure that there are no cold spots. It's a hot spot you require to get the alloy to flow where you want it - into the joint! Heat the joint not the rod. 50 years experience in this field has taught me that in the hands of an amateur an oxy-gas torch being used in isolation will create more problems (cracks, leaks) than it perceives to solve.

Ask yourself, what do I want from the alloy? Do I need to perform any other silver soldering operations subsequently? Do I have sufficient heat to make the joint? Propane is good for the vast majority of joints and more flexible and forgiving. 455 is sold by CuP Alloys, but it is not always the best alloy for every application. Others, perhaps more suitable and cheaper, ones are available.

Now make your alloy selection. One thing you can ignore with silver solder is joint strength. Braze properly and all silver soldered joints will have a greater strength than the parent materials.

Decide where you are going to apply the alloy. Do you want rod or wire? What size? These are all simple questions with simple answers as long as you apreciate what you want to achieve.

There are folks about who depend on giving sound technical advice, selling the right materials and ensuring you produce high quality joints in order to pay their mortgages and pension contributions.

But please beforehand, understand what you are doing and why. Then go and do it.

You will be successful

**LINK**

**LINK**

Keith

Regular readers of these pages will know that I have, for many years, been banging on about how to achieve strong leak tight joints by sticking to the basic principle of silver soldering - namely capillary flow. This principle applies no matter which alloy you use or from where you get it.

Now my good friends at CuP Alloys have transferred the written words into two video clips to show this principle in operation

The first shows metal flowing under capillary action to produce the joint.

The second shows the flame characteristics of various propane burners (possibly used in association with oxy-gas torches) that will produce the heat patterns to promote the metal flow.

**LINK**

Silver soldering is a simple, albeit skillful, operation. It requires no shortcuts. To attempt to do so will, and does, only result in tears! Every model engineer should aquaint themselves of the content of the videos and apply it.

They also have an excellent book that explains why sticking to the principles is so important.

And for those who demand transparency - I am retained by CuP Alloys and the book is mine!

Fruitful viewing and reading!

Regards

Keith

Hi John

Talk to these people.

They have rods from 0.7 to 3.0mm plus wires, foil and paste.**LINK**

Regards

Keith

Link

**LINK**

regards

keith

Your requirements are precisely those circumstances that the cyclone is designed to meet

Alternatively, use an oxy-acetylene torch.

It's a no brainer!

Keith