Silver Solder for Marine Use ?

[bassman1956]

Just curious...

I need to make up one more leeboard pivot, to match the 1 example I have. They are brass. I've lined up the welder. My biggest question is where to get cheap brass round stock. But that's not my post here.

What I couldn't help thinking was, could these be brazed? It's 1-3/8" diam with a 1-1/8" diam branch into it. Like a piping reducing tee, only solid. Or, like a king pin assembly.

As a piping engineer, I work with a lot of brass/bronze/copper. We'd readily hi-temp braze something like this with sil-phos (silver phosphorus), or even silver solder if sil-phos wasn't a 'go'. I know such is not good if you are looking at steam service instead of ambient tempo water and similar fluids. But what about boat use?

Question:
Can brass and marine use handle braze joints? If so, are either of these alloys useful? Or are special alloy rods required?

Yes, I can call my vendors, who will call their factory, who will get back to me... This place has a lot of knowledge. What are your experiences?

[delmarrey]

With a large contact area (wide overlap) it should be OK if you can get the silver to flow thru-out.

[PAR]

Sil-Phos is quite strong and possibly up to the task, I use it frequently, like last weekend when I had to replace the A/C air handler in the attic (140 degree attic here in mid summer).

I question your desire for brass. This material is the weak knee, redheaded step child to bronze. I wouldn't use brass on a boat unless it was a cup hook or a picture frame tack. Now bronze, a little Sil-Phos, tight fitting joints and plenty of heat can fix a mighty load of problems. Brass just can't tolerate a marine environment, unless kept from the wet stuff, which a leeboard pivot pin would likely not be able to avoid.

Did you get white, live or red oak over at Owl's?

[bassman1956]

White.

[bassman1956]

Originally Posted by PAR

...

I question your desire for brass. This material is the weak knee, redheaded step child to bronze. I wouldn't use brass on a boat unless it was a cup hook or a picture frame tack. Now bronze, a little Sil-Phos, tight fitting joints and plenty of heat can fix a mighty load of problems. Brass just can't tolerate a marine environment, unless kept from the wet stuff, which a leeboard pivot pin would likely not be able to avoid....

Brass is what they were originally made of, used and sailed for 10 or 12 years or so. I have one. Other than showing dings and witness marks from use, it's in fine shape. The other got lost somehow in the cleaning out of the estate.

Thing is, I do not know which brass alloy it is, plain yellow brass, or a naval brass. I suspect naval brass. I do not have a test kit to tell. There are a couple shops I was going to try, see if they have some scrap stock I could pick up cheaper than mail ordering a small quantity. Also am hoping one of them may have a test kit.

[delmarrey]

Some metal sales dealers have a hand held x-ray spectrometer to ID metals. I know Alaska Copper has one. Call around! I'll bet what you have is a bronze.


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[cdennyb]

why wouldn't stainless work? just curious.

[bassman1956]

Originally Posted by cdennyb

why wouldn't stainless work? just curious.

I'd need 2 out of stainless. And it has it's own requirements. I'm not looking to redesign mounts. Simplest, cheapest would be to replace the missing 1 if I can.

[S&S]

Google "online metals" and get some Silicon bronze. silphos is fine- use at least 20% (Staysilv 20)

[PAR]

Naval brass is usually about 60%copper, 1 - 2% tin and 38 to 39% zinc. While yellow brass is typically 65% copper, 35% zinc. The seemingly small differences between these two metals makes for a fairly significant difference in strength and machinability. Yellow brass, as any one that's attempted to mill it will attest, can't "stand" before a tool, while naval brass can.

Both metals are copper alloys, but bronze is a copper/tin combination, while brass is a copper/zinc alloy. As a rule the brass alloys commonly seen, have less copper content then the bronzes. For example, gun metal bronze (nice stuff) is 85 - 88% copper, 7 - 10% tin and 5 - 8% zinc. This would be a common mixture if asking a foundry to make up some high strength, bronze parts for you.

With Sil-Phos, you should use the highest silver content you can. The stuff I use is 45% and very strong. Take the part to a shop that does prop reconditioning. They'll know how to handle it and have the good filler material.

[bassman1956]

Thanks, PAR. This time around, I'll be simply replicating what I have, so it will be naval brass and a welded joint.

My greatest concern with silver soldering for structural anything in copper-brass- bronze is the annealing that occurs. It's not uncommon for silver solder or sil-phos work to leave even castings dead soft. So how do you get that hardness back? Coppers tend to prefer work hardening over heat treatment. And what you can do with heat treatment would need oven time around 550C for a few hours, beyond my scope in the garage.