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Member postings for CuP Alloys 1

Here is a list of all the postings CuP Alloys 1 has made in our forums. Click on a thread name to jump to the thread.

Thread: Soldering 304 grade stainless steel
19/10/2020 09:56:07

Hi Andy,

See personal message

Keith

Thread: Mechanical properties of soft solders.
18/10/2020 11:22:06

Hi Robin

The success of brazing and soldering is covered in BS EN 14324 available from BSI at £254!

Alternatively a more readable book based on the BS is currently undergoing another print run and drawing on 50+ years in the business.

See pm for more information.

Keith

Thread: Copper tube for boiler
18/10/2020 10:03:00

Hi Sam,

Neil offers sound advice. Practice using steel tube. If you can produce sound joints, copper will present no problems.

But use C101 or C106 grade to avoid the pitfalls associated with cheaper grades.

Carry out your brazing procedure using the principle of capillary flow.

Follow the guidelines in

BS EN 14324 available from BSI at £254.

Alternatively see PM

Keith

Thread: Mechanical properties of soft solders.
16/10/2020 16:44:21

Hi Howard,

Does 50+ years in this business count as someone who might know?

Of course joints in tension rely on the bulk strength of the solder and are relatively weak. Joints in shear are much stronger. It is the reason that soldering and brazing have been such popular means of joining metal components for the last 5000 years.

No guesswork involved.

Mortice and tenon joints are ideal for exploiting this fact.

A more comprehensive answer and the reasoning will be found in my book!

Keith

Thread: In flight social distancing
16/10/2020 10:21:39

Just got back from Mallorca using Ryanair both ways. Despite about 30% capacity there was no social distancing immediately prior to boarding, on board or upon disembarking. We were able to change seats.

Despite the mandatory wearing of masks at all times, the purchase of a drink or sandwich negates this!

The extra travel documentation required (for track and trace) is examined on the outbound flight because it is checked at Palma. No document= no entry = potential problem for Ryanair (?)

The extra documentation is not checked leaving Mallorca. It is not checked at Manchester. No potential problem for the airline!

There are still the hardy, brave and invincible ones traveling who defy any mandatory regulations. They look as if they would deck anyone who challenges that invincibility. They go unchallenged.

Want to stay safe?

It's all down to you.

Thanks for asking, yes we enjoyed our break despite now being stuck in the house for another 10 days and awaiting food and wine deliveries. We are planning a return for Christmas and New Year. It will definitely not be with Ryanair and we will keep ourselves safe.. No one else will.

Didn't we hear that the filters on an aircraft air-conditioning system were capable of removing a virus from the atmosphere?

Ifthat is the case, why do Ryanair no longer have price lists or issue receipts? Cost cutting?

Keith

Thread: Mechanical properties of soft solders.
16/10/2020 09:12:35

Hi Robin

Mortice and tenon joints - ideal as any load will be held in shear.

Will the joint carry the load? I'm sure it will as long as the joint is a good one! Remember the basic principle of soldering and brazing - CAPILLARY FLOW.

Make a sample joint to set your mind at ease.

If you want a black joint use tin/lead. If you want a white one use tin/silver. The joint strength of both will be adequate for what you want.

Keith

Thread: Soldering stainless steel
08/10/2020 10:14:10

There are numerous fluxes available "for lead free solders".

Very few are suitable for stainless steel. Those will remove chromium oxide. It's a chemistry/metallurgy thing!

Easyflo flux doesn't work particularly well unless the chromium content of the steel is low. That is why silver solder suppliers have a bespoke flux. Again it's a chemistry metallurgy thing.

Good luck with getting hold of easyflo silver solder. Its sale was banned years ago. HSE and Trading Standards still have a more than passing interest in its availability. I, like a lot of people, still have some but it's not for sale.

Using it is not illegal. Selling or giving it away is.

If you want more information, then get my book!

Keith

Thread: joining metals
01/10/2020 15:21:03

Hi Peter.

See personal message.

Keith

29/09/2020 22:18:33

Hi Peter.

My 50+ years in the brazing/soldering business says ;

1) Don't use tenacity or similar flux.

2) Don't use lead bearing solder.

There are far easier ways to achieve what I think you want to achieve. Strong, neat, invisible joints?

Avoid having to scramble hard to rectify things. Get it right first time.

Email me to set up a 1:1 conversation.

Keith

PS Check personal profile 🤔

Edited By CuP Alloys 1 on 29/09/2020 22:20:38

Thread: Blowtorch problems
19/09/2020 19:57:39

Hi Ian,

Have you spoken to rothenburger?

But, as I understand it, there are two gas streams.

One isn't working.

Back to Mr R!

Thread: Brass to mild steel, expansion issues?
15/09/2020 20:28:47

Hi Tony

And the temperature change is?

Keith

Thread: Solder ???
08/09/2020 16:06:40

Hi Ian,

What does Johnson matthey suggest 🤔?

Keith

Thread: Brazing brass help
05/09/2020 09:46:17

Rough guide to types of solder.....

Check out the literature of any manufacturer. In 50 years never seen these figures before!

Joint strength has nothing to do with the silver content.

But yes, the more silver, the higher you pay for the material.

However that does not necessarily mean your joints cost more.

Keith

04/09/2020 07:44:29

Clamps are used to support joints and allow for thermal expansion. Clamping will cause more distortion.

Clamping to steel creates a massive heat sink making any joining technique involving heat more difficult than necessary. The link to the tutorial is great and will point you in the right direction for making good, strong joints.

Have you considered adhesives. Once the letter box is in place what stresses are being put on any joints? Superglue a nut to a piece of sheet and try to knock it off?

Other adhesives are available 😀.

Keith

Thread: PRIMUS 8842 BURNER
24/08/2020 21:17:20

Michael,

Concise and to the point.

Nothing more needs to be added.

Keith

Thread: Copper mig wire and boilers etc
18/08/2020 09:13:22

For too many years, the longitudinal seam on domestic copper hot water cylinders has been welded using the MIG welding process. Initially the wire was 0.2% Si, 0.2%Mn, bal Cu. The shielding gas was argon.

Argon is expensive.

Replacing the Si and Mn with Ti and Al allowed the use of nitrogen as the shield gas - much cheaper. When we became the second UK supplier, the wire became more readily available to the industry, it was no longer rationed and we picked up a substantial volume of brazing alloy business.

However all the other joints tops, bottoms, and bosses are, I believe, still brazed. This is due, in part, that in order to cope with the increasing gap on a circular weld, the volume of filler that needed to be put down increased. This is at odds with a wire feed mechanism delivering wire at a constant rate.

Whilst at Johnson Matthey, we spent many hours trying to automate the brazing of copper cylinders using a wire feeder but all to no avail.

You can TIG a boiler, but MIG ..........?

Keith

Thread: What quantity of silver solder needed
16/08/2020 10:04:15

I'll buy the need for a fillet on cosmetic grounds. Keep it small by using a narrow melting range silver solder. Just as well because these alloys are the most expensive.

A boiler inspector normally wants to see a "witness" of silver solder on a joint that implies total penetration of the silver solder through the joint and a sound strong joint. That is not the same as wanting to see a "fillet". Personally I'd question the the integrity of any joint with a manufactured fillet at both ends.

Undercutting in the joint area is normally caused by the filler metal dissolving the parent materials. This in turn is caused by a poor temperature/time profile in the furnace that leaves the molten filler in contact with the parent metals for extended periods.

Undercutting is a potential problem with all vacuum and controlled atmosphere furnaces.

The number of model engineers using a furnace for brazing is very small.

This is not a problem that the vast majority of modellers will encounter.

Keith

15/08/2020 09:04:41

Why do you want a fillet?

If your joint design is right, your heating technique is correct, you achieve the necessary capillary flow, you will produce a sound joint that carries the stresses in shear.

That is the strongest joint possible.

Why do you want a fillet?

It's a shareholders bonus. Colman's made more money from the mustard left on the plate than that put on the meat.

Silver solder is expensive enough without wasting it.

For more information, read my book or attend our lectures.

Keith

Thread: Spectacles and solder.
04/08/2020 08:08:30

The problems associated with lead and silver solder has nothing to do with the formation of an "amalgam" type compound that eats into the silver solder.

The problems are that lead has the tendency to work against the fundamental principle of successful silver soldering (capillary flow) and alloy selection.

Lead and silver solder is a recipe for disaster. Simples!

Regards

Keith

Thread: Capillary gaps required for silver soldering.
04/08/2020 07:47:34

The joint gap is fundamental to the success of silver soldering.

The laws of thermodynamics explain why silver solder flows to where it is hottest.

The flux does not create the gap.

This is explained in my book along with techniques on creating and maintaining gaps.

There is 53 years experience of silver soldering between the book's covers.

For more information, or to obtain a copy, send me a message.

Regards

Keith

Usual disclaimer does not apply!

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