Member postings for Keith Hale

BRAZING IS A PROCESS.

It is identical to soldering. It is only an undocumented international convention that distinguishes between the two. Quite simply, if you are making your joints at a temperature below 450 deg C then you are soldering.

Above 450 deg C then you are brazing.

BRAZING HAS NOTHING TO DO WITH THE FILLER METAL USED.

IT HAS NOTHING TO DO WITH THE HEATING TECHNIQUE. Gas torch, furnace (vacuum or atmospheric), electrical resistance, induction are all viable heating techniques to produce brazed joints

Jet engines are brazed with gold/palladium brazing alloys.

Automotive components are brazed with copper and copper brazing alloys (this includes brass!)

Nuclear reactor components are brazed with nickel brazing alloys.

Steam boilers, bogies, clocks, are brazed with silver brazing alloys.

Look up the term "brazing" in any source and you will find that in the definition there are two words that repeat and those two words are "CAPILLARY ATTRACTION"

iF YOU ARE NOT USING CAPILLARY FLOW TO EFFECT THE JOINT THEN YOU ARE NOT BRAZING.

All too often silver brazing alloys and brass alloys are not used to braze two components together. They are used to stick two components together and block a hole and that is expensive. Look at some bicycle frames, office furniture and the multitude of joints made in steel using brass rod and oxy-acetylene torches.

I have supplied, in the past and for over 18 months, a company in excess of 200 kg per month of a silver brazing alloy that was used to do precisely that. The financial risk became too great and the orders were passed directly to my supplier.

The customer refused to change the joint design and to use the alloy as a brazing alloy.

In doing so they failed to take advantage of the many technical advantages of using the process. Silver solder, because of the price, is only used because it satisfies a technical requirement.

It will join a wider range of parent materials than welding.

It is carried out at lower temperatures - less distortion.

As a filler metal, it is more corrosion resistant.

It produces leak free joints.

It produces joints stronger than the parent materials.

It offers better strength at elevated temperatures.

It offers a good colour match to parent materials.

It can be carried out using relatively inexpensive equipment. Propane/air torches are fine.

If none of the above are important then save your money and use soft solder, or glue or screws!

In all cases, the use of a silver solder, despite its price, produces the cheapest cost per joint. If as an individual you can't reach this conclusion, you are are not using the product correctly. Examine your joint design (gap and length), examine your heating technique to get the alloy to flow precisely where you want it, examine the form in which the silver brazing alloy is being used. There is more than 1.5mm dia rod.

As regards, other companies ceasing to sell silver solder, I believe that was due in no small way to CuP Alloys. They passed on the benefits of their large buying power with German and Spanish suppliers to the model engineer and backed that up with good sound technical back up.

For more information, there is a book available from CuP Alloys.

"A Guide to Brazing and Soldering - everything you wanted to know about Silver Soldering but were afraid to ask"

I cannot speak too highly of it!

Keith

PS Brass strip and borax will produce excellent joints. But please "braze" with it and not simply stick the pieces of steel togerther

Edited By CuP Alloys 1 on 28/10/2018 11:30:45

But as Shaun has said prices are made as competitive as possible but that will not satisfy some.

True Story from the Midlands Exhibition.

"I'm not paying that. I'll wait and get it off the internet"

The product is not available, nor will be legally, on the internet. What he meant was,

"I'll wait til somebody robs you and I'll pay the thief"

There you go.

Keith

Edited By CuP Alloys 1 on 21/10/2018 11:44:27

Hi Ron,

One of the better answers will be found by googling

mapp gas

Regards

Keith

Silver Soldering - A Simple Process made difficult is the title of the latest talk from the CuP Alloys Roadshow aimed at increasing the knowledge of the subject with the model engineer.

It discusses how to make a simple process difficult by not adhering to the basic principles. Follow them and you will be successful. There will be plenty of opportunity to ask any questions. Don't be afraid to do so.

There will also be news of a recent directive from Brussels that will affect the model engineer.

The talk can be heard Thursday, Friday and Saturday at the forthcoming Midlands Model Engineering Exhibition at The Fosse.

Edited By CuP Alloys 1 on 27/09/2018 15:11:28

The biggest problem to be overcome when brazing carbide is the effect of the very different coefficients of expansion of the two materials that could cause cracking.

Help yourself by using the lowest brazing temperature ie something like 455.

Create a thicker joint than you would normally. Say aim for 0.2mm.

Don't quench the joint. Let it cool as slowly as you can. Immerse it in dry sand or wrap it in some insulation material like a clay wool blanket.

Regards

Keith

WOW ..............

All getting a bit personal now.

It will be handbags at dawn next.

Get me a ticket! Can't wait!

Keith

Hi Martin,

Paste is sold in syringes or other containers that can be pressurized to expel the paste as required.

Paint is sold in small pots. To use, shake well and brush on. (See instructions on the tin!)

They are two totally different products. We need to be clear on what we have. Paste or paint

A fortune awaits he/she that simply adds soft solder powder to an aqueous solution of zinc chloride, shakes it well, and packs into syringes/pots. The world is their oyster!

But wait ....what keeps the powder in suspension and usable over time as a solder/flux combination?

What dries out of the paste or paint (soft or silver solder) is the organic binder that holds the two components together. It is immiscible with water.

Methylated spirit will only thin it and allow the solder to separate. Think gloss paint

If you want longevity from a solder paste or paint, keep it airtight in the first place.

Regards

Keith

PS

I am sure there is some dried out paint in my shed. I've got some water, meths and a bit of paintwork that wants touching up around the house.

You wouldn't. Would you?

Hi All,

Forgive me

NO GAP = NO METAL FLOW = NO JOINT

Keith Hale

BSc Hons (Metall) (for those who want info from a metallurgist!)

The chap from CuP Alloys that does the lectures!

49 years in the brazing/silver soldering business

ex JM Sales Technical Services

ex Product Manager Sheffield Smelting Co (Thessco) and Engelhard Industries

ex MD oc CuP Alloys Ltd and

ex MD CP Alloys Ltd (manufacturerer of brazing alloys)

NO GAP = NO METAL FLOW = NO JOINT

Keith

PS Yes alloy can take other capillary routes eg capillary paths around tube/plate joints around screw heads but if you want the best strongest joints, the filler matal needs to penetrate through the joint not simply around it. Recognize the problem of leaks around stays or boiler tubes? You don't get them if the alloy penetrates the joint.

Out!

KH

If the canister is not empty, the answer may well lie in your description of the torch - cheap!

Such torches can starve themselves of air as the cylinder tilts and becomes horizontal. The flame goes out.

What does the company that has your money say?

Regards

Keith

Eutecrod is/was a tradename used by Castolin/Eutectic Company.

1600 is described on page 72 of their data book as a high temperature, wide melting range, low silver content alloy. This book came into my posession in the early 70's when I worked for Johnson Matthey.

The information indicates to me that it is an alloy that cannot be neither sold legally nor "placed on the market" (ie given away) legally..

I would not expect it to have the brazing characteristics you have described. It doesn't do what it says on the tin!

Leave it with you. You seem to have bought a "pig in a poke!" Worse case scenario is that it could shorten your life expectancy.

Bargain?

Regards

Keith

Hi Martin.

A 30 tonne press is more than enough. In the late 80's when I was manufacturing brazing rods in a factory near Chesterfield, I had such a press. We extruded copper phosphorus wire from a 50mm dia billet down to 1.5mm in one stroke. In order to do this, we had to produce 16 strands simultaneously.

You may have to adopt a similar technique but it's not difficult.

You may have to warm the billet or slug to ease fabrication. I doubt if you will get sufficient heat into the slug simply by heating the die.

We also started to extrude silver solder rods succesfully in a similar manner before I made the mistake of misplacing trust in a bank and business partner and credit in the wrong place.

C'est la vie!

Keith