Sil Phos Plumbing?

Dale Pickard

I'm wondering if anyone can tell me if the use of the silver / phosphorous brazing alloys, (sil/phos 5, 15, 18 etc.) are suitable for use with potable water systems. Sil Phos 18 is an alloy of 17.6% silver, 6.5% phosphorous and the balance is copper except for .15% "other" elements.

It is cadmium free, so that's not an issue but I don't know that it's suitable for joining potable water plumbing. Lucas Milhaupt can't tell me. Do any of the tubing manufacturers that also sell potable water tubing and manifolds use this type of brazed copper manifolds for potable water?
Thanks,
Dale

Alan(CaliforniaRadiant)Forbes

When we work

in San Francisco, we have to use SilPhos when we braze the underground water service.

You probably know this already, but clean your fittings well, use no flux, don't use wrot fittings and don't overheat your work if you're using oxy-acetylene; you're sure to melt the pipe and fittings.

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Mike Kraft_2

Alan?

Real dumb question.Don't use wrought fittings???What to use?I'm thinking you mean cast fittings are a no no?!

cheese

hr

Check out

www.jwharris.com

I started useing the Harris Blockade product to replace the sil-phos. Melts at 228°, flows and caps nicer than sil-phos. Click on the silicone brazing alloys at the above website.

They have MSDS at this site also to answer you question.

hot rod

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Dale Pickard

Yeah,
I should just check the MSDS. Sounds like it's ok. We've made brazed copper heating manifolds for a long time, but not for plumbing. I don't like to take some chances.
When used for plumbing, how do you clean the oxides out of the inside of the pipe? Is it your practice to shield with argon? In the field?

What is Blockade? Did you say 228 F?? That's sounds too low. It must be a solder???

I've been using Sil-Phos 18 because it melts nice and low. solidus/liquidus @ 1190F It's 18% silver. I think the 5% stuff melts a few hundred degrees hotter...I'll look it up.
It doesn't have any working range and flows thin like solder. It requires close tolerances .001-.003" which we produce when we bore the mainifolds on our mill. Makes for a really strong joint that sweats more than brazes. Not bead forming.
We use a gas fluxer as well. It helps pull the brazing temp down another couple hundred degrees.

Dale

hr

1178-1247°F

for Blockade. Not a lot cooler than the stuff you use, but it works a lot like their soft Bridgit. Good for forming caps and loose fittings, or T-Drills

In the Sil Phos, the lower the silver content the hotter the temperatures, as you mentioned. 0 or 5% needs about 1300°.

Be interesting to try the Blockade with your gas fluxer. Might be your best choice yet!

As for the black on Sil-Phos joints, generally a good water flush clears it. I use those Hercules handi wipes on the outside. After it cools off

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Jon_2

Sil-flos

If you want keep the inside real nice use a nitrogen flush while brazing. You do not need much pressure, 1" or 2" WG is sufficent and the inside will not need a clean-up. We use it on refrigeration lines all the time to keep the scale out.

Dale Pickard

Thanks for the responses, it sounds like it's safe enough for plumbing.

I had thought that they used nitrogen on refrigerant lines. I didn't know if argon was neccessary. I've never been that concerned for heating applications as it's easy enough to get the excess flaky scale out. I'm more concerned if it were to be used for potable water.

The gas fluxer prevents the scale on the outside, wherever the flame goes. I probably mis spoke when I said that it helps lower the brazing temp a couple hundred degrees. It really facilitates the brazing process so the joint can be sweat in a short time without pouring too much heat into it. It sounds strange but the flame is wet. See www.gasflux.com

Dale

Weezbo

under ground and outside applications go brazing

it cleans up from the outside so clean it doesnt look like the mess one normaly sees. runing low pressure gas through the fitting keeps the pipe and fitting clean as theres nothing to burn:) and flushing it with water , now... i figure that is s.o.p. welcome to the wonderful world of potable water requirements:)