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Silver Solderin

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John Besley28/12/2013 18:34:25
49 forum posts

I need some help please, I am in the process of building a boiler for my Wilesco Traction engine rebuild and want to silver solder this together, the originals are all soft soldered but I am wary of this particularly when I start adding in various blanks for mounting parts that if the boiler is soft soldered then it may well fail on some of the joints.

I have soft soldered and whitemetal soldered for the last 35 years so not afraid to try something new, my question is what type of torch do i need and where can these be obtained from, what do most use for gas bottles ...

I have looked up a number of you tube tutorials and will pick up silver solder Easy Flo No2 and flux from EKP.

John Rudd28/12/2013 18:41:28
1396 forum posts
6 photos

John,

you could do no worse than chat to the guys at Cupalloys....they really are the guys in the know....

personally I use a butane torch for small stuff, but then use a propane torch where more heat is required...on bigger stuff.

GaryM28/12/2013 21:08:59
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314 forum posts
44 photos

Hi John,

Topic has been covered in lots of threads. See here

**LINK**

Ignore first result as that is this thread.

Gary

CuP Alloys 129/12/2013 10:47:09
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258 forum posts

Hi John

go to www.cupalloys.co.uk/best_practice/

Any further help? Call us or talk to us at Alexander Palace in January

Regards

Keith

John Rudd29/12/2013 17:15:43
1396 forum posts
6 photos
Posted by John Rudd on 28/12/2013 18:41:28:

John,

you could do no worse than chat to the guys at Cupalloys....they really are the guys in the know....

personally I use a butane torch for small stuff, but then use a propane torch where more heat is required...on bigger stuff.

Should have read no better.... I think..whatever.....I best stop digging....

...errm basically, they are the boys!!

Edited By John Rudd on 29/12/2013 17:16:36

John Besley30/12/2013 08:15:25
49 forum posts
Posted by MICHAEL WILLIAMS on 29/12/2013 11:11:22:
Hi John ,

No point in repeating advice given many times before on the actual process so just a related thought :

You don't say where you live but if its in mainland UK there is very likely to be someone in your vicinity that will give you a first hand demo of silver soldering and perhaps let you use their equipment .

You won't get much help from most clubs but there are plenty of lone hands out there ( including me ) that would be more than willing to help with silver soldering or indeed any workshop problems .

Keep your actual address to yourself but let us know the district and see if anyone volunteers .

Regards ,

MikeW

Hello Mike

I live in South Devon in Paignton, anyone out there who can help?

John

John Besley30/12/2013 08:48:53
49 forum posts

Very helpfull tread will follow up the links and have bookmarked these to comeback to, once again thanks for the advice.

Brian John08/05/2014 05:15:12
1455 forum posts
579 photos

What percentage silver solder is required for model steam boilers and pipe work ? My local hardware store has a range of silver solders : 2%, 5% and 15%. Are these adequate ?

JasonB08/05/2014 07:34:04
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18873 forum posts
2077 photos
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Brian the low % solders are typically used for refrigeration and air conditioning, they are a copper phosphorous alloy and not what you want for a boiler. You want a 55% designated ISO 17672 Ag 155. Not sure what makes are available in Australia but something like Harris Safty-silv55 would do.

shaun meakin 108/05/2014 09:26:42
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45 forum posts
1 photos

HI Brian. As usual Jason gives very good advice. The range of alloys held by your hardware shop are the silver copper phosphorous alloys designed for the fluxless brazing of copper to copper in industries such as refrigeration or air conditioning. However, before you get excited by the fact that you are wanting to join copper to copper, these alloys suffer rapid corrosion in hot sulphur-containing atmospheres, eg a coal fired boiler! They should not be used by Model Engineers for their boilers.if coal fired. The Ag155 alloy with 55% silver (or as we call it 455) is the lowest melting point alloy commercially available in the EU. If you are in Australia you should still be able to buy the cadmium bearing alloys of which the 42% silver alloy has a slightly lower melting point still. As posted earlier on this thread, if you require any further advice or assistance please do not hesitate to contact us.

shaun@cupalloys.co.uk

 

Edited By shaun meakin 1 on 08/05/2014 09:27:16

Brian John08/05/2014 10:51:25
1455 forum posts
579 photos

I live in Cairns, Australia. There is 45% silver solder available on ebay but it is expensive stuff ! I will look around for the cheapest supplier in either the UK or the US.

Ian S C08/05/2014 11:25:41
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7468 forum posts
230 photos

John, from the wording of your initial question etc. I take it that you are building a new boiler, and? making it from copper. Yes as Brian says It's expensive, but you don't need too much, and it's good to do the job correctly. Take note of the advise, if any metal to be silver soldered has tin lead solder on it DON"T, not at least until ALL the old solder is removed. Other wise you may as well use low temp solder, because the joint will be stronger than the contaminated one. Ian S C

shaun meakin 108/05/2014 11:26:42
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45 forum posts
1 photos

John, many thanks for the info. In truth the same apples, as the silver copper phos range of alloys will also join brass but with flux. However, again the joint will suffer rapid corrosion in a hot sulphur atmosphere so they should not be used in a coal fired boiler.

Brian, you can get a 45% cadmium free alloy in the UK (our 445) but I don't think you will be able to source cadmium bearing alloys in the UK. This is because the demand now is so low (ie only to countries outside the EU) that it is not stocked, not to mention that the EU manufacturers cannot by law supply UK customers with these alloys, regardless of where they are ultimately sold on to.

Shaun.

John Besley08/05/2014 20:53:25
49 forum posts
Posted by Ian S C on 08/05/2014 11:25:41:

John, from the wording of your initial question etc. I take it that you are building a new boiler, and? making it from copper. Yes as Brian says It's expensive, but you don't need too much, and it's good to do the job correctly. Take note of the advise, if any metal to be silver soldered has tin lead solder on it DON"T, not at least until ALL the old solder is removed. Other wise you may as well use low temp solder, because the joint will be stronger than the contaminated one. Ian S C

I have bitten the bullet and spent money on a torch and silver solder from Cup Alloys (great firm only to ready to help) haven't got round to trying silver soldering yet but will make a couple of small parts that need silver soldering so will see how it goes.

John Besley17/05/2014 18:56:12
49 forum posts

Have now silver soldered my first couple of parts as a trial some spare copper plumbing parts, next question I have a 50g packet of Citric Acid Monohydrate powder, I need to make up a solution to pickle the parts soldered - how much do you mix up and what proportion.

Neil Wyatt17/05/2014 21:10:04
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Moderator
18232 forum posts
714 photos
77 articles

I've often seen a few tablespoons i in a gallon recommended, which seems very weak to me, given how much is in the average kettle descaler packet, but apparently this works well and if you make it stronger it can go a bit funny..

Neil

John Besley17/05/2014 22:07:09
49 forum posts

Ok what is a few is that ?

Ian S C18/05/2014 11:52:38
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7468 forum posts
230 photos

John, stick about half your 50g packet in a plastic bucket. After you'v used it, you can store it, put it in bottles, it will last for ages, might get mouldy on top, just scrape it off, and as it evaporates, just add water. Ian S C

Tim Stevens18/05/2014 16:35:58
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1268 forum posts

If the boiler is being re-built from one which has been soft soldered, you may have a serious problem. When heated above its (low) melting point the lead or tin (etc) from the slightest trace of soft solder left in place is liable to soak into the surrounding brass (or copper) giving a very odd alloy which will not take the hard solder.

Secondly, battery acid (dilute sulphuric) is perfectly good to remove hard-solder flux residues. Half an hour should be enough. Use the acid as it comes (new and not out of a battery) or let it down 50/50. And as it is dilute acid, do not panic about adding water to acid or vice versa. But do resist the temptation to plunge the still-hot job into the acid - the splashes will make holes in your jeans, your vest, and anything else around. Was away any splashes with a solution of washing soda (Sodium Carbonate) or baking soda (Sodium bicarbonate).

And do practice hard soldering first, on some off-cuts of the material you are using. Get both sides to the same 'just red in the dark' temperature, and remember that the solder will flow into the hottest part of the joint.

Hope this helps.

Cheers, Tim

shaun meakin 119/05/2014 10:53:07
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45 forum posts
1 photos

John, we sell 100gr packets of cleaning salts which make approx 1 gallon. Therefore (with my shoes and socks off) I calculate 50gr to make up about 4 pints!!!

Also thanks for the kind words.

Shaun.

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