Silver Solder

[Reddirt62]

Has anyone ever used silver solder in an alloy? Any advantage, disadvantage? Thanks.

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[psweigle]

I've used it for gun repair, but I've not even thought about using it for casting. I would think that if I needed a werewolf bullet, I would just buy one.

Seriously, I would think that silver solder would be bad for the barrel once it hardens. I'm curious to see how hard it would make a cast bullet if it indeed does mix.

[Tom W.]

When I worked at the sawmill I used it to solder carbide tips on to circular saws. When the roll got too small to use I'd take the scraps home. I never could get them to melt in my lead pot.

[country gent]

Silver blends with lead acting much as tin does in the alloy only small amounts percentage wise are required or blend in well. I can remember oldtimers saying one silver dime to a 10 or 20 pound pot was all that was needed. Like copper or antimony it may need to be in a dust or pre melted form to alloy into the lead. SIlver is around 1200* melt temp so..... Lymans cast bullets handbook list silver as an alloy and its advantages in it.

[Bullwolf]

Has anyone ever used silver solder in an alloy? Any advantage, disadvantage? Thanks.

I think it's worth pointing out that there are two different kinds of silver solder out there. Silver Solder with an actual Silver content, and Lead-free "silver solder" which is often used in plumbing. Lead-free solder contains no actual Silver, and is mostly made up of Tin.

I've used Lead-free plumbing solder before (mostly Tin) as an expensive way to add a small quantity of Tin (1-2%) to a Lead alloy.

Lead-free plumbing solder is also commonly called silver solder, which can be confusing.

I'll give 2 commonly found in hardware store examples here.

1. Benzomatic Silver Solder


2. Oatey Safe-Flo Lead-free Silver Solder


Both these commonly found plumbing solders are called silver solder, but are mostly composed of Tin, and don't contain any actual Silver.

1lb of this type of Lead-free plumbing "Silver Solder" will run your around $36 bucks. Making it an expensive way to add Tin to your alloy.



And we also have actual Silver based, Silver Solder, which is less useful for us in a typical casting alloy.

The actual Silver Solder that I have used comes in either sheets or strips, and looks something like this.



I often cut the Silver sheet solder, into even smaller pieces for my intended usage.

Silver Solder may also be purchased with different ratios of Silver content. Solder with more Silver content will of course have a higher melting point.

Silver Solder melting point Examples:

56% Silver - 1205 ºF - Easy
65% Silver - 1335 ºF - Medium Easy
70% Silver - 1360 ºF - Medium
75% Silver - 1450 ºF - Hard

As you can see from the list above, actual Silver Solder has a much higher melting point than plumbing lead free (Tin) solder.



It's much more expensive to purchase Silver Solder, because it contains actual Silver, and you would usually only purchase a small amounts of it. Typically, real Silver Solder costs around $10 or so for a ¼ ounce.

True Silver Solder can be used in gunsmithing, such as for soldering the top rib onto shotgun barrels, or even sometimes soldering a front bead sight on. It's also used often in jewelry work.

I'm not a gunsmith, but I've done some jewel crafting work with Silver Solder. I had to use an Oxygen/Acetylene torch to melt actual Silver Solder. A propane torch just doesn't get hot enough to do it. It may be possible using MAAP gas, but not having tried that myself, I can't say for certain.

Because Lead-free (Tin) plumbing solder is also called "Silver Solder" it can often confuse a new caster, or someone who is not familiar with solder in general.

While actual Silver Solder (made from Silver) has the same name. If your not sure which one you are using, let the price and the melting point tell you the difference. Also, actual Silver Solder with Silver in it tends to come in flat strips, instead of on a roll.

Hope that helps clear up some of the confusion between the two different types of solder with the same name.



- Bullwolf

[Reddirt62]

Thanks You! This is silver solder @ 45% Ag. That Sir, is a lot of excellent info. I don't think this guy know what he has because he is asking $20 for a good size roll of it.

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[alamogunr]

I've got about 5 lbs of silver solder(?) in small rectangular sticks in a plastic tube. It was used to solder copper piping in air conditioning units. I will go to the shop in the morning and check the label to see what the silver content is. I've never been tempted to try to use it in boolit metal.

[Drm50]

Grinding a metal to powder will not cause it to melt at a lower tempature. Powdered silver would
Just float on molten lead at approx 400 degrees. You can look up the temp required to alloy the
various metals which I don't know offhand, but it won't be done in a lead pot.

[Bulldogger]

Grinding a metal to powder will not cause it to melt at a lower tempature. Powdered silver would
Just float on molten lead at approx 400 degrees. You can look up the temp required to alloy the
various metals which I don't know offhand, but it won't be done in a lead pot.

My understanding is that if the high-temp metal is already alloyed with a lower melting temperature metal (such as tin or lead) then it will alloy with lead in a pot at the upper end of lead melting temperatures. This I recall from another thread discussing copper and babbit alloys, and I cannot remember if silver was discussed there.

That a pure metal (silver) ground to dust would not alloy easily, as stated, is also my understanding.

Bulldogger

[dbosman]

I love that someone here knows just about anything. Now I understand why my "silver solder" doesn't work and the Oatey does. I acquired a roll of Welco #5 when we bought our house in 1992, probably at a thrift shop. I had several copper pipes to fix. I switched to MAPP gas and torch trying to use this stuff. It never did work properly so I bought an Oatey kit at the big box store. I still hate soldering water pipes, but never knew why.

Welco #5, according to an old post here, is 94% tin and 6% silver. I think it just became generic pewter.

[psweigle]

I've got about 5 lbs of silver solder(?) in small rectangular sticks in a plastic tube. It was used to solder copper piping in air conditioning units. I will go to the shop in the morning and check the label to see what the silver content is. I've never been tempted to try to use it in boolit metal.

I'm going to bet 56%.

[alamogunr]

Well! I looked at the stuff in the shop. It is Harris Stay-Silv® 15. 80% Cu, 5% Phosphorus and 15% Ag. Technical data gives the liquidus(melting point?) as 1480ºF. I knew there was some reason I had ignored it all these years. No way am I going to add any of this stuff to my casting pot. I probably need to give it to a HVAC repairman.

[BK7saum]

Well! I looked at the stuff in the shop. It is Harris Stay-Silv® 15. 80% Cu, 5% Phosphorus and 15% Ag. Technical data gives the liquidus(melting point?) as 1480ºF. I knew there was some reason I had ignored it all these years. No way am I going to add any of this stuff to my casting pot. I probably need to give it to a HVAC repairman.

I wonder if you could hit it with a maap gas torch on top of a hot smelt and get it to alloy. Guys have gotten copper wire into solution once it's been tinned.

[alamogunr]

I wonder if you could hit it with a maap gas torch on top of a hot smelt and get it to alloy. Guys have gotten copper wire into solution once it's been tinned.

Maybe, but I've got enough other stuff to make just about any alloy I might want. I don't experiment too much with alloys. Usually, WW with some solder to add tin.