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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: Stuart 501 boiler
23/11/2017 09:47:31
Available ex stock from CuP Alloys.Keith
Thread: Midlands model engineering show
27/10/2017 10:41:55

Hi Sam,

Sorry you missed the talk. It was certainly well supported.

Was there anything specific you wanted to know?

If so, send me a pm and I'll try to help.



Thread: Silver soldering torches
05/10/2017 08:52:16

Hi Matt,

Sievert torches are certainly amongst the best in the world.

Look over the water not just the hedge for supplies

The cost of sending a box 25 x 25 x 25cm weighing 10 kg can from the uk to Ontario is about £50.

10 kg covers the weight of a torch, hose, regulator neck tube and a burner. It will cover the weight of several more burners.

Work out what you need and ask for a price.The ex-works prices are available here **LINK**

I will leave it to youto establish any import duty

Email Shaun or Glen. I've retired!



Thread: Can titanium be soldered to brass?
28/09/2017 06:53:06

one for gluing!


Thread: Bakers Fluid No3
22/09/2017 10:28:47

Borax melts and starts to remove oxides, essential to the brazing process, at 743 degC.

The most common silver solder sold to the model engineer starts to melt at 630 degC.

A major benefit of using a silver solder stems from its low melting point. It is quicker, there is less distortion, less metallurgical degradation. The use of a high melting point flux negates that benefit.

If this benefit is of no interest then don't waste your money. Make your joints with brass.

If it is of interest, along with better oorrosion resistance, colour match, then use a silver solder. But why not then use it properly? Use a flux that prepares the joint for metal flow before the flller metal melts. Why build up increased levels of oxide unnecessarily. You will get better joints.

I believe that Bakers Fluid 3 has undergone two levels of dilution from Bakers Fluid.

A concentrated form is readily available. Pick it up at exhibitions without the high delivery cost incurred because corrosive liquid fluxes cannot be sen in the post.


Thread: Propane / Oxy
17/09/2017 11:27:56

To prevent any confusion.

The oxy-turbo kit runs off disposal canisters of oxygen and mapp gas. The oxygen lasts about 20 minutes. The gas about 40 mins. Replacement canisters are available via CuP.

The demo at the Midlands featured preheating with a conventional propane torch before using an oxy-propane flame to reach brazing temperature and create the necesary heat pattern. This kit runs off larger refillable cylinders. One of the major benefits of this kit is that you own the cylinders which you simply pay for their refilling. There is no cylinder rental fee, no maintenance charges or contract. They are your cylinders. Refills are readily available from gas suppliers but not CuP.

Both are good products to meet different needs.


16/09/2017 10:07:50

Hello Bruce

Examine your joint design, heating technique and how and where the alloy is applied.

Remember to use the effect of capillary flow to create small, neat tidy joints.

I am reliably informed that a new book covering this aspect is being launched at the Midlands Exhibition on the CuP Alloys stand or why not just come and talk to us.



24/06/2017 16:33:28

The silver solder melts at 640 - 680 deg C. Most brasses melt about 850 deg C.

Bob, in your case you have too much heat. Fit a smaller burner.

It will probably have a more focussed flame with which you can control the heat better and not melt the edges of small components. That is why Sievert have the range of burners that they do.

For the same reason, people buy a range of spanners not an adjustable one.

One size does not fit all !


24/06/2017 07:56:44
Silverflo 452 is a 45% silver cadmium free alloy with 2% tin. It will produce strong joints but it behaves nothing like easiflo 2. It has a higher melting point and is not as fluid. Like anyone else who struggles with a cadmium free alloy fit a larger burner.
Thread: Help with Propane torch please
17/06/2017 18:39:08

Hello John.

I trust your local plumbing merchant was helpful!

I am told by Sievert that the burner thread is M20 x 1.

It is not a unique thread.



16/06/2017 07:54:18

Hello John,

Sievert have made some changes over the years but, as far as I understand, they have not related to the burner thread. The modifications have been at the other end of the torch.

For details of sievert burners visit **LINK**

They are normally available ex-stock


Thread: Silver Soldering Inverness or Elgin way
02/06/2017 12:34:58

Hello Michael

Re Thesscal A I fear it is a sad end.

Conversations with contacts within the trade, including the manufacturer of Thesscal A have confirmed my thoughts that it is no longer available.

If there is a need to soft solder aluminium or its alloys use the apprropiate soft solder flux with any soft solder. If a decent colour match is required use a silver tin alloy.

All products are readily available but save about £12 on the flux by ordering it for collection at an exhibition. Te delivery costs are very high as it cannot be sent by post.



31/05/2017 09:48:02

And finally,

Melting point of pure (99.99%) aluminium is660 deg C. Melting point of commercially pure (99.5%) i 635 deg C. Alloyed this can reduce further to 500 deg. Lowest melting point silver solder was 620 deg C (Now banned fpr sale) Currently the lowest is 652 deg C (56% silver).

How good is your heating technique ?smiley

Any soft solder can be used to solder aluminium. You only need the right flux. It is expensive to deliver. Visit the CuP Alloys Roadshow or get it at an exhibition. The savings will easily cover your entrance fee.

If the aluminium content of your bronze is higher than 2% but lower than 10% tweek your flux. Add 25% by weight of kitchen salt to your standard flux. When mixed with water into your paste, the extra chloride ions will remove the aluminium oxide, Alternatively buy a speciality flux and that is an expensive way to buy salt.

The search is on for a filler metal that melts about 450 deg C. Probably based on tin, copper zinc antimony alloy or whatever it will be an overnight winner guaranteeing the patent holder a fortune. As long of course that it is not as brittle as carrot!!

By the way, note that the link to the silver solder is for rods that are only 250 mm long!

The industry norm is 500mm so it is not a true comparison.




Edited By CuP Alloys 1 on 31/05/2017 09:51:50

Edited By CuP Alloys 1 on 31/05/2017 09:52:26

Edited By CuP Alloys 1 on 31/05/2017 10:10:05

Thread: CuP Alloys Roadshow in Scotland?
30/05/2017 10:40:05

We have been aware for a long time that we haven't done an promotional work in Scotland.

We have been singularly unsuccessful in finding an exhibition venue. Where do you visit or are you content to travel to Doncaster?

We are looking into bringing the roadshow to Scotland. The proposed plan is to attend an exhibition over a weekend and visit societies a few days either side of the exhibition with the talk aimed at brazing successfully.

What are the basic principles.? How do I achieve them?

Hopefully we can amortize the costs making it economically viable to the societies.

Your help and ideas to make this a success is requested..Is your society interested in a talk?

Get sound technical help from the number one supplier of brazing materials to the model engineer.

Please contact Shaun on 01909 547248 or



Thread: Silver Soldering Inverness or Elgin way
30/05/2017 08:55:49
Posted by Neil Wyatt on 29/05/2017 11:06:11:.

Yep, silver soldering becomes 'alloying' when attempted with aluminium



29/05/2017 10:03:32

Hi Carl

Two thoughts.


get to understand the principle of silver soldering - capilllary flow.What to do, why and how. Visit **LINK**

There is a short video clip to help you.


there is a separate video going into more detail about the principles and how it relates to boiler manufacture. The best of both worlds. Good technical advice and a demo from a true professional Helen Stait of Western Steam.

But for help at any time call us on 01909 547248



Thread: boiler leak
19/04/2017 13:15:29

Firstly that's good advice from Simon.

Secondly that good friend should not try to fix each leak in isolation. The whole area needs to be taken up to temperature. This will avoid any thermal stress caused by localized expansion. You have got three poor joints. It is possible that there are other weak joints caused by poor alloy penetration into the joints. This stress could quite easily cause other joints to fail and you end up on a merry-go-round chasing the next leak.!

You may need to use two torches. One, a propane torch to get the background heat in and oxy/something for the final lift to brazing temperature and create the necessary heat pattern to promote the capillary flow of filler to where you want it. The leaks at the firebox end may require the use of a cyclone propane that will stay lit in the confined spaces.

A ceramic blanket will help to get, and keep, heat n.

Yes use 455 alloy with 55% silver.

Use also HT5 flux to give you a good flux life and use plenty of it to clean the joints and protect the others.

Almost forgot ....... then allow to cool naturally



PS It's my guess that the boiler was originally put together with oxy/acetylene only and the basic principles of the brazing process not followed

Edited By CuP Alloys 1 on 19/04/2017 13:35:57

Thread: Braze or screw cut - which is stronger?
05/04/2017 07:26:41

Hi Andrew,

For more info on brazing go to **LINK**

Read it - load your printer - print it - and read again. Keep it by you. It will set you on your way to successful brazing with a clear understanding of what to do, why you have to do it and how to do it.

Do it right and the joint will be stronger than the parent materials,

You may not elect to use silver solder as your filler metal but a brass rod instead. No matter, the principles are identical. You are still brazing.

If you require any further help, then come back to us.


Thread: soldering stainless steel to copper
01/04/2017 08:02:11

Hello Roger

If you require only a small quantity use a suitably flux cored wire e.g. 2207.

A flux specifically for soldering stainless steel can be sent in the post.

2207 is a silver tin alloy with excellent flow characteristics to produce strong leak-tight joint with small neat fillets

It will also give a good colour match on your stainless.

It is readily available

For more info **LINK**



Thread: Silver soldering
17/03/2017 10:18:18


OK it does not require a flux on copper to copper joints.

OK it is cheaper than silver solder. If price is what floats your boat use a similar alloy but without any silver. Joint ductilitystrength is not compromised

You also get something else.

A hot sulphur bearing atmosphere above 200 deg C (like that produced from a coal fired boiler!) will go through the joint like a hot knife through butter. And there is no repairing it.





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