Sil-Phos Identification

This forum is dedicated to the Live Steam Hobbyist Community.

Moderators: Harold_V, WJH, cbrew

jmpharrington
Posts: 71
Joined: Fri Oct 14, 2005 10:22 am
Location: Rockland County, NY

Sil-Phos Identification

Post by jmpharrington » Tue Sep 29, 2020 7:18 pm

I have a copper boiler for a to be completed 1" Scale LE Atlantic.
How can one determine if the solder used is (or hopefully isn't) sil-phos?

**EDIT**

As some additional information provided by the gentleman I bought it from:

Builder: Mr. Tom Stambaugh, Golden Gate Live Steamers
Date fabricated: Prior to 1973 (has not been operated since then)


Thanks,
Jimmy

FKreider
Posts: 181
Joined: Fri Feb 02, 2018 8:44 pm
Location: Sturbridge, MA

Re: Sil-Phos Identification

Post by FKreider » Tue Sep 29, 2020 7:40 pm

I think its fairly easy to identify by the look of it- it tends to be built up kind of like a weld bead vs. silver solder which spreads out thin and does not build up.

Is this a brand new boiler that has never been run?

If so then hydro test it to 1.5x working pressure and then run it. Sil-phos only starts to fail after exposure to sulfur in coal over time, its not going to happen overnight. I would say the longevity of your boiler will be how much you run it (on coal.)

If it is sil-phos its not going to explode, many many boilers were made using this process. Will it develop leaks over time and eventually need replacing? Yes- just like most boilers.

EDIT:

Just saw your updated info- I would personally hydro test it as mentioned above and run it until it develops any issues/leaks.
-Frank K.

User avatar
Sandiapaul
Posts: 457
Joined: Wed Jan 07, 2004 8:04 am
Location: Princeton, NJ

Re: Sil-Phos Identification

Post by Sandiapaul » Tue Sep 29, 2020 8:04 pm

Who is a vendor for sil-phos these days?

Harold_V
Posts: 18447
Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Re: Sil-Phos Identification

Post by Harold_V » Wed Sep 30, 2020 1:33 am

jmpharrington wrote:
Tue Sep 29, 2020 7:18 pm
How can one determine if the solder used is (or hopefully isn't) sil-phos?
Aside from the appearance of the beads, as has already been mentioned, color can be an indicator. Sil-fos is a red color (very similar to copper color) while silver solder is yellow.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

jmpharrington
Posts: 71
Joined: Fri Oct 14, 2005 10:22 am
Location: Rockland County, NY

Re: Sil-Phos Identification

Post by jmpharrington » Wed Sep 30, 2020 9:10 am

Picture attached...
I wouldn’t say the solder appears red or yellow. It is silver.
What does it appear I have here?
-Jimmy
Attachments
CB3ACD83-FFCB-4939-8C6D-135A6D3FDD0F.jpeg

User avatar
Bill Shields
Posts: 6002
Joined: Fri Dec 21, 2007 4:57 am
Location: Somewhere in the World
Contact:

Re: Sil-Phos Identification

Post by Bill Shields » Wed Sep 30, 2020 12:20 pm

that is sil phos.

Sil phos is not always red.

Phos Copper is more red (same problem around sulphur)

you can purchase it at any plumbing supply store...

frank is absolutely correct about failure mechanism.

run it on propane forever....

assuming the club inspector does not ban it...
Too many things going on to bother listing them.

jmpharrington
Posts: 71
Joined: Fri Oct 14, 2005 10:22 am
Location: Rockland County, NY

Re: Sil-Phos Identification

Post by jmpharrington » Wed Sep 30, 2020 2:26 pm

“ that is sil phos.”
Bummer.

Harold_V
Posts: 18447
Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Re: Sil-Phos Identification

Post by Harold_V » Wed Sep 30, 2020 4:26 pm

I agree with Bill's assessment.
I made mention of the color simply because the percentage of copper is much higher in sil-fos than it is in silver solder.

When metallic elements are mixed, the colors may or may not result in what you might expect. As an example, when silver and gold are combined in the proper ratio, the resulting color is green.

When gold and iron are combined in the proper ratio, the resulting color is blue. Gallium is also used to create blue.

Gold and nickel yield white gold. Gold and palladium yield white gold.

Purple gold? Alloy gold with aluminum.

The surface color of sil-fos assembled items may or may not be the color of the sil-fos. To determine the true color, you must remove surface oxides.

Edit:

While sil-phos may be correct, the maker packages and advertises the product as Sil-Fos

H
Wise people talk because they have something to say. Fools talk because they have to say something.

jmpharrington
Posts: 71
Joined: Fri Oct 14, 2005 10:22 am
Location: Rockland County, NY

Re: Sil-Phos Identification

Post by jmpharrington » Wed Sep 30, 2020 6:33 pm

Thanks.

Now for the subjective question(s)...

How long does it take? Would this take many years say if running 20 times a year, a few years, a year?
I completely understand that there are many variables, but are there Sil-Fos soldered copper boilers running on coal that have been doing so for many years, or should one expect a short service life?

Fire away with the speculation...

-Jimmy

FKreider
Posts: 181
Joined: Fri Feb 02, 2018 8:44 pm
Location: Sturbridge, MA

Re: Sil-Phos Identification

Post by FKreider » Wed Sep 30, 2020 7:01 pm

I think that is a pretty hard thing to estimate and I would be skeptical of any answers or advice you get unless the individual was the original builder of the engine and can tell you how often the engine was ran and for how long. Engines often change hands with little to no history known and passed on, especially when the original builder has passed away and it has sat for a number of years until the family decides to sell (pretty common story with old engines.)
-Frank K.

Tim B Guenther
Posts: 25
Joined: Mon May 08, 2017 1:09 pm

Re: Sil-Phos Identification

Post by Tim B Guenther » Wed Sep 30, 2020 7:44 pm

Sil-Phos is a trade marked brazing alloy of LucasMilhaupt. They make many different alloys for different applications. Website products here: https://www.lucasmilhaupt.com/EN/Produc ... Metals.htm

Sil-Phos 15 is 15% silver, 80% copper and 5% phosphorous. It is probably the typical product used for repairing copper boilers. Believe it or not, you can buy it on Amazon!

I have a 7-1/4" gauge steam engine built by Jim Turnbull in 1957. I repaired the front tube sheet of the original copper boiler with Sil-phos (not sure which alloy because it was supplied by a friend who had no idea what it was) in 2008. I ran it a lot on soft coal from 2009 to 2018 when I started a major overhaul. I replaced the boiler with steel this year for many reasons, including leaks in the front tube sheet which may have been caused by failure of the 2008 repair.

User avatar
Fender
Posts: 2833
Joined: Wed May 02, 2007 8:33 pm
Location: Chattanooga TN

Re: Sil-Phos Identification

Post by Fender » Thu Oct 01, 2020 9:34 am

It should be noted that the sil-fos on the outside areas is not the problem. It’s inside the firebox and on the tubesheets where the failure occurs. In principle, you could replace the guts of a failed copper boiler and salvage the outer shell, but this may not be practical.
Dan Watson

Post Reply