Brazing alloys for copper boilers

[Lakc]

Easy-flo No2 Ag 42, Cu 17, Zn 16, Cd 25, Melt 608-617 Deg. C,
Silver-flo 55 Ag 55, Cu 21, Zn 22, Sn 2, Melt 630-660 Deg C
Silver-flo 24 Ag 24, Cu 43, Zn 33 Melt 740-800 Deg. C

It does strike me as rather odd that the higher the melting point also has an increased amount of zinc, which I thought was a "bad thing" for boiler construction. 33% zinc is more then a lot of brasses.

 

[PTsideshow]

Here is a great on line brazing information site.
http://www.handyharmancanada.com/TheBrazingBook/contents.htm#Index

Here is another maker and their web site with a ton of info
http://www.lucasmilhaupt.com/

And another company with PDF information on copper brazing along with all their other products.
http://www.brazing.com/products/Braze_Copper/

;D

 

[Ned Ludd]

Hi Guys,
For UK residents;
http://www.cupalloys.co.uk/
Ned

 

[Dan Rowe]

Mr Rowe,

After receiving some information as to how you conduct yourself on other sites, I refuse to be further drawn into any argument or discussion with you, and my posting remains as I wrote it, with definitely no modifications required.

Bogs

Mr. Bogstandard,
I have read a few of your posts and I consider you an open minded person who gives good advice sometimes in a blunt manner.

I hope the gentleman who informed you of my conduct on other sites did the fair thing and linked you to the sites in question so you decision was based on how I actually conducted myself.

As I do not post many places the list is short to where I committed the offenses. Here are the links:
http://livesteam.proboards.com/index.cgi?board=newbie&action=display&thread=484
http://www.mylargescale.com/Community/Forums/tabid/56/afv/topic/aff/11/aft/83634/Default.aspx

If you are interested in Shay locomotives and some of my modeling skills check:
http://www.7-8ths.info/index.php You will need to be a member to see the Shay Project board.
http://groups.yahoo.com/group/LivesteamShays/?yguid=47378247 Shay discussion group

I am not looking for a fight I do not have the time. I am trying my best to give model engineers access to information I consider vital for copper boiler work.

If I am missing the mark of the reader that is not my intention I am learning some of this stuff as I go along. I make no claims to be an experienced model engineer or model boiler maker. However I would like to point out that all the readers might not even be members of the forum so all we can hope for is to attempt to supply the needs of readers who post responses.

I have been doing my best to do just that if you want to consider that a game of one upmanship so be it but please continue to play the game.

Respectfully
Dan Rowe

 

[GWRdriver]

Please check my last post for an important edit....Don't use Silphos on boilers. - Dave

Back in the early 1960's, Sil-Phos (aka, phos-copper brazing alloy) became popular in US live steam circles as a cheaper substitute for silver solder. Another attractive attribute was that it was flux-less for copper-to-copper joining. Inexpensive, flux-less, and readily available, wot's not to like? One of the reasons for phos-copper's popularity in the 1960's was that IIRC the original Little Engines Co (of Lomita CA) suggested it for use on their cast-in-1-piece bronze fireboxes and at that time perhaps 80% of live steam locomotives being built in the US were of one Little Engines design or another.

But after a few years a curoius thing appeared. Boilers assembled with phos-coppers began to spring pinhole leaks in the most inconvenient places, inside front firebox flue sheets for example. (Also, in fairness to phos-copper, the Little Engines 1-pc cast fireboxes were notoriously pourous.) To make a long story short, it was determined by the mfgs that phos-copper, which was originally intended for cold water plumbing, deteriorated in hot sulphurous atmospheres and what could be hotter and more sulphurous than the firebox of a coal-fired model locomotive. Naturally disagreement sprang up over its use (Disgareement amongst live steamers? Surely not?), and a few die-hards remain, but generally speaking phos-copper for live steam is no longer accepted.

 

[Dan Rowe]

I am not really trying to be a know it all, I just get bored with TV so I google the web.

Easy-flo is a trade mark of Handy and Harman based in White Plains NY. Here is an article written by the UK licensee of easy-flo which talks about the cadmium issue.
http://www.jm-metaljoining.com/pdfs-products/Time_for_Model_Engineering_to_go_Cadmium-free.pdf

This is the link to the Australian Association of Live Steamers technical buliten mentioned.
http://www.pnc.com.au/~wallison/AALS/Convention/2008Convention/30techinfosilsolder080408.pdf

This is the link to easy-flo in the US:
http://www.lucasmilhaupt.com/en-US/products/fillermetals/silverbasedcadmiumbearingfillermetals/9/

Notice there are several types of easy-flo to choose from but they all have AWS numbers like BAg-1, BAg-2, ect.

Dan

 

[Dan Rowe]

I did a lot of silver soldering on merchant ships. This work included copper pipe of various sizes and repair work of all types. Diesel generators vibrate a lot and parts literally fall off. This includes fuel lines, oil lines, valves or anything else bolted to the machine. One of the hardest jobs I did was to braze up a tube sheet on a condenser. The sheet was laced with pin holes and was paper thin. We needed this thing in service so I had no choice but to attempt a repair. With an oxy-acetylene torch and brazing rod I managed to build up the area and it held pressure. When we got to the next port a repair gang pulled the tube nest and replaced the tube sheet, but I got it working for the few days it took to get there.

Silver soldering on the ships was not really an issue… go get the silver solder, lay out the torch and then do the job. What could be simpler? Well I only just today worked out what type of silver solder I used on one class of ship. The welding vendor for that shipping line was Unitor and they only make 2 types of silver solder and I know it was flux coated with a pink color flux.

Only one of the Unitor silver solders is cadmium free and thinking about it we had to maintain the drinking water lines made from copper so we must have used the one without cadmium which is also for salt water copper service. The cadmium free Unitor silver solder is BAg-7 or what Kozo recommends for cadmium free.

I liked the stuff so much I bought a “similar” product from the local welding supply store in Austin TX. The stuff in my shop is Hi-Alloy #1300FC silver alloy, which, the only thing I know is that it is cadmium free and melts at 1145 to 1200 Deg. F. I found it on the web but no alloy content.

Now as I live in Texas and the size of boiler I am planning is exempt from the State Boiler Code if it is manually fired with a pressure gauge, sight glass and safety valve. So I know that I can use the silver solder I have and if it passes the hydro great.

Here is the question in my mind. Should I use an unknown food grade silver solder or start over and get the stuff Bogs or Kozo recommends?

Or have I over thought this whole thing and I just should have used the standard practice I learned at the Merchant Marine Academy and practiced as a working marine engineer?

Dan

 

[Lakc]

In my opinion the service duty in boilers is sufficiently unique, and my respect for pressure vessels is so great, that I would only use those rated solders for model boilermaking.
I have a family full of girls and only one, 2 year old grandson, who is quite interested in our hobby. 30 years from now he will be firing whatever boiler I make, and I want the best chance of keeping him healthy.
This is why I am so picky of alloy composition, and de-zincification. The brand names we use today may not even be around in 30 years, so names to me are just short term. Zinc composition in boiler solder is something I am still searching for empirical evidence on.

 

[steamer]

Hi Dan,

Due to availability, I use Harris products....generally Safety Silv 45. It's cadmium free and readiliy available. It has well documented properties.

Here is the rest of Harris's "High Silver" line.

http://www.harrisproductsgroup.com/consumables/alloys.asp?id=30

Here's the spec sheet for Safety silv 45

http://www.harrisproductsgroup.com/pdf/spec/BrazeAlloys/032008/Safety-Silv_45.pdf

Equivalent to BAg-5

Safety Silv 56 is equivalent to BAg-7


I would be with Lakc....At least know what the stuff is.....

Dave

 

[Dan Rowe]

Thanks for the feedback guys.

Dave, I checked the specs. of the alloy you linked and the specs. of the alloy I have.
http://www.inweldcorporation.com/HI-ALLOY/datasheets/Hi-Alloy 1300FC_&_1300.pdf

It does say FDA approved and gives a strength of 76,000 psi, but it is missing the ASME SFA 5.8 classification which because the ruling code for the US is the ASME Code I plan to make another selection.

It looks like I bought the right stuff to make a pressure cooker not a boiler. Rof}

I was wrong about the wiki entry there is a lot of code information on the site. I have been working a bunch of it out and will post a table with the information I have gleaned from the web.

Dan

 

[steamer]

"....but it is missing the ASME SFA 5.8 classification which because the ruling code for the US is the ASME Code I plan to make another selection....."


Your talking about the rod you have to hand currently, or the Harris stuff?

Harris claims compliance with ASME SFA 5.8 for the 45 and the 56 that I mentioned

Just bought (5) 1/16" diameter rods about 18" long of the Safety Silv 45 from a local weld shop for a project at work. It was $23... The 56 will be a bit more expensive because of the higher silver content.....but should still be under $30.

The product does work well and I have always had good luck with it. For Copper on stainless, or ferrous to non ferrous joints, I would use the 56.

In the end....If I was still wondering, I would make up a test piece and perform the fold over test on the joint until failure.

Then you'll know.

Dave

 

[Dan Rowe]

Dave,
I was talking about the rod I have on hand which is FDA aproved. The stuff is food grade and medical grade but the Federal Drug Administration does not know jack about boilers so I will get one of the ASME compliant silver solders.

Dan

 

[steamer]

Great! Post pictures! ;D

Dave