By continuing to use this site, you agree to our use of cookies. Find out more

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: Silver Soldering - A Simple Process Made Difficult
30/09/2018 08:49:02
You tube-unlikely.
Website - definitely.
27/09/2018 15:10:02

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

Thread: Silver soldering
09/09/2018 13:13:05

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.



Thread: Solder..?
24/08/2018 08:29:05
Hi john. After melting, silver solder ALWAYS flows to where it is hottest. Examine your heating technique to create the best heat pattern.
PS The book will guide you!😏
Thread: Pickle
25/07/2018 09:07:15

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

All getting a bit personal now.

It will be handbags at dawn next.

Get me a ticket! Can't wait!


23/07/2018 09:19:42

10 gms of citric acid salt per litre of water.

Check it out at the local wine shop or supermarket or eBay or welding distributor!

Yes I'm sure.

22/07/2018 07:35:21
Hi John.
Answering the original question..

10 gms per litre of water and
Get it from


Thread: Want to put a brass union in a Stainless Steel? tube
05/07/2018 16:02:36
Make sure you use a non magnetic steel to a avoid crevice corrosion.
Then use 455 silver solder and HT 5 flux.
Thread: Silver soldering problem
02/07/2018 14:37:37
Hi Bob.
Email details to me with the grade of silver solder you are using.
If the solder melts but don't wet the brass you have a flux problem. The flux is not compatible with the solder/heating technique/parent materials.
Thread: Soft Solder Paste
02/05/2018 09:29:13

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.




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?

Thread: Silver soldering contradiction
13/04/2018 00:26:22

Hi All,

Forgive me


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)



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.



Thread: blowtorch
03/04/2018 08:34:24

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?



Thread: Eutecrod 1600FC (Eutectic - Castolin)
23/03/2018 10:28:27

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.




Thread: Fabrication of solder wires
20/03/2018 08:05:31

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!


Thread: How do you fix a leak in steam loco copper fire box?
19/03/2018 11:58:10
Hi Simon. Why not ask your supplier of soldering materials? That's the reason CuP Alloys have the standing they have. They can help with this sort of problem. Keith
Thread: Help with silver soldering (Yorkshire area)
19/03/2018 11:51:06
Hi Tony. That's why we do these evenings. Looking forward to seeing you.
17/03/2018 18:01:20
Hi Antony.
Why not ring us at CuP Alloys? When you buy from us you get a full technical backup. For information the number is 01909 547248!
Thread: Tig Brazing Copper
25/02/2018 11:53:15

My no.1 tip for silver soldering/brazing using a TIG torch as the heat source is DON'T

The heat source is too localized. The whole joint does not get to temperature to facilitate capillary flow. You will not achieve full penetration of the alloy into the joint. You will create a weak joint with an in-built crack.

The shield gas will not remove oxides from the component surfaces which is essential to get the filler metal flowing. You still need a separate flux.

Betcha end up melting the copper and overheating the alloy. You don't melt parent materials when brazing and you don't heat the rod. It is very easy to overheat the alloy and boil off the zinc. (In this instance thank god you're not using a cadmium bearing alloy.)

If you want to weld - then weld. Use a copper welding rod.

If you want to braze - then braze.

But no matter which option you choose - do it properly




Thread: Brazing
25/02/2018 11:26:08

Hi Alan,

Carbon deposits - from brazing?

Where did they come from? Not the gas, nor silver solder nor the copper.

Or is it that the flux esidues are black? In this case neither citric acid nor sulphuric will help. A more likely explaination is that the flux has been heated too long or to too high a temperature and degraded.

Use a stiff wire brush or other mechanical means to clean things up. Inspect and test the joints.

Stop it happening again by using a longer life flux like HT5



Thread: silver solder
12/02/2018 11:07:59

Hi Nigel,

Those who have attended the "CuP Alloys Roadshow" over the years will know that we have been banging on since the start about achieving the minimum spend on silver solder. That is best achieved by using it properly and hence efficiently.

Take a little time to appreciate what you are trying to do, why and how to do it it.

Silver soldering is a very simple process but skillful. Stick to the principles and you will be successful. You will produce strong leak-free joints first time , every time and use the minimum amount of this expensive filler metal. Deviate from them and you will not be and the process becomes complicated and difficult.

There have been many a boiler made that should have been hallmarked.

Avoid fillets, examine your joint designs, heating technique and alloy placement.

How much alloy will you use?

Are you planning to use two alloys of differing melting temperature?

Use the thinnest rod practical.

Do not skimp on flux.

You will find all the information you require on the website and in our publications. Call 01909 547248 for a chat. There is the widest range of materials, sizes and 48 years experience in the silver soldering business.

Can't get that on ebay! Or anywhere else for that matter!



Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

Latest Forum Posts
Support Our Partners
Eccentric July 5 2018
Tee London LMES 6th Dec
Eccentric Engineering
Allendale Electronics
Subscription Offer

Latest "For Sale" Ads
Latest "Wanted" Ads
Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.

Click THIS LINK for full contact details.

For subscription issues please see THIS LINK.

Digital Back Issues

Social Media online

'Like' us on Facebook
Follow us on Facebook

Follow us on Twitter
 Twitter Logo

Pin us on Pinterest