# Silver solder suggestions



## Suzuki4evr (Feb 3, 2020)

What kind of silver solder would our members suggest that would not break the bank, to use for making HSS boring or cutting tools? I always see *Harris Stay-Brite Silver Bearing Solder & Stay Clean Liquid Flux Kit on ebay. Is it any good and is there other similar  products like this that is worth looking at? Any suggestions would be appreciated. 

Thanks
Michael *


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## middle.road (Feb 3, 2020)

Link? 
Amazon has some good deals also.



Suzuki4evr said:


> What kind of silver solder would our members suggest that would not break the bank, to use for making HSS boring or cutting tools? I always see *Harris Stay-Brite Silver Bearing Solder & Stay Clean Liquid Flux Kit on ebay. Is it any good and is there other similar  products like this that is worth looking at? Any suggestions would be appreciated.
> 
> Thanks
> Michael *


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## benmychree (Feb 3, 2020)

Silver (bearing) solder is not what you want for the purpose stated, not at all!  It is made for soldering stainless steel and is mostly tin with a trace of silver; it is a "silver bearing soft solder".   What you need is a solder that is mostly silver and copper.  It would not use a liquid flux, but a white colored paste made (mostly) of borax.


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## Suzuki4evr (Feb 3, 2020)

benmychree said:


> Silver (bearing) solder is not what you want for the purpose stated, not at all!  It is made for soldering stainless steel and is mostly tin with a trace of silver; it is a "silver bearing soft solder".   What you need is a solder that is mostly silver and copper.  It would not use a liquid flux, but a white colored paste made (mostly) of borax.


 I see I have posted about this before, but do you have a suggestion for me Ben? All I know is this stuff is expensive around here asspecialy the Flux coated ones.


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## benmychree (Feb 3, 2020)

I do not think it is cheap anywhere --- I do not know what spec, exactly, but what I have used is called #1200, which is, I think, it's melting point; the flux, is simply called silver solder flux, I would not bother with the flux coated kind, I just use the bare wire coil, usually 1/16" diameter.


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## Suzuki4evr (Feb 3, 2020)

Is it called silver solder flux or is this just the flux? Sorry for all the questions.


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## Suzuki4evr (Feb 3, 2020)

Can I purchase this on ebay or aliexpress?


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## benmychree (Feb 3, 2020)

It is called silver solder flux.  I have always just bought it from the local welding supply store.


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## Dhal22 (Feb 3, 2020)

Hold on a minute.  I'm a master plumber (35 years) and also silver solder steel tubing for my model airplanes.  Which solder is this?  And for what metal?


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## JPMacG (Feb 3, 2020)

I think they are asking about high temperature silver soldering - more like brazing.  It is usually done with an acetylene-oxygen torch.  They are not talking about the low temperature tin/copper/silver alloy solder that replaced tin/lead solder for potable water.


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## Dhal22 (Feb 3, 2020)

Correct but I'm currently soldering steel tubing and have silver soldered copper, both very different from conventional copper soldering.


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## Dhal22 (Feb 3, 2020)

I'm soldering steel tubing with 56% silver solder and it must be red hot.   Extremely strong joints.


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## Dhal22 (Feb 3, 2020)

Straight acetelyne torch.


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## Dhal22 (Feb 3, 2020)

We could pay $50 each and just pass it around to look at it.   He might make $1000's that way.  I'm interested as well.


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## JPMacG (Feb 3, 2020)

Looks like you are making landing gear for a large-scale model.  Very nice.   I fly RC also - mostly 40 and 60 size glow engine stuff.


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## Dhal22 (Feb 3, 2020)

JPMacG said:


> Looks like you are making landing gear for a large-scale model.  Very nice.   I fly RC also - mostly 40 and 60 size glow engine stuff.




Yes! 1/3 scale Nelitz Cub build.  I decided to eliminate any wooden dowels between the engine/ landing gear and wing area.


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## Dhal22 (Feb 3, 2020)

JPMacG said:


> Looks like you are making landing gear for a large-scale model.  Very nice.   I fly RC also - mostly 40 and 60 size glow engine stuff.



I fly 60 size classic pattern planes (wheels up and on the pipe). WFO for non rc'ers.  Also 120cc and 170cc planes.


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## JPMacG (Feb 3, 2020)

Wow!   Very nice work.  I have not seen a model fuselage built up from steel tubes like that before.  The construction looks like a full-scale Cub.   

I toured the Piper museum in Lockhaven PA last year.  The factory is closed of course, but the buildings are still there.  That is where they built the Cubs - from the J3 to the PA18.


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## Dhal22 (Feb 3, 2020)

The Bob Nelitz 1/3 scale plans are exact scale.   His design just used brass tubing in the area of the landing gear connection points and some steel tubing in the wing support area.   I just decided to be sure and went nuts on steel tubing in critical areas.


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## Suzuki4evr (Feb 4, 2020)

WOW.....this discussion took a weird turn,from silver solder to model planes   .Tipical H-M. I would love to see the finished plane. I want to bond HSS toolbits to metal with a strong bond. Back when I used to work for a boss,we used flux coated silver solder  with a acetylene torch set not too high,but that stuff is too exciting for me. I  need something cheaper,but with strong bonding capabilities.


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## Dhal22 (Feb 4, 2020)

Who doesn't love a good thread drift? 

The steel tubing in those photos that I'm essentially butt joint welding is with 56% silver solder and appropriate flux.   Put a joint in a vise and beat it with a hammer and it might fail.   Maybe.   Very strong joints.


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## Technical Ted (Feb 4, 2020)

I got some of this from Amazon. You can use either the white or black flux depending on how hot you will heat things. I got a can of each from Amazon as well. Best prices I could find and great quality (Harris). I use it for making small, internal threading bars. 






						Harris Safety-Silv 56% 1/16 Silver Solder Brazing Alloy 1 Troy Ounce, 75310 5631 - - Amazon.com
					

Harris Safety-Silv 56% 1/16 Silver Solder Brazing Alloy 1 Troy Ounce, 75310 5631 - - Amazon.com



					www.amazon.com
				




Ted


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## Technical Ted (Feb 4, 2020)

People call it silver "soldering" but when using the higher temperature hard, higher percentage silver it is actually silver "brazing". The difference is the percentage of silver content and the temperature required to melt it. You want hard silver solder (silver brazing) for bonding a HSS tool bit to a steel or alloy bar. 

Ted


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## seasicksteve (Feb 4, 2020)

I would consider a  brazing paste take a look here
https://www.sra-solder.com/soldering-brazing-supplies/brazing
You might want to contact them for a recommendation for you application, I have used the fusion brazing paste in the past It should be ideal for your application


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## Technical Ted (Feb 4, 2020)

Here's the flux I bought, both white and black depending on the temperature needed:

Black:






						Harris SSBF1 Stay Silv Brazing Flux, 1 lb. Jar, Black: Amazon.com: Industrial & Scientific
					

Harris SSBF1 Stay Silv Brazing Flux, 1 lb. Jar, Black: Amazon.com: Industrial & Scientific



					www.amazon.com
				




White:






						Harris SSWF1 Stay Silv Brazing Flux, 1 lb. Jar, White: Amazon.com: Industrial & Scientific
					

Harris SSWF1 Stay Silv Brazing Flux, 1 lb. Jar, White: Amazon.com: Industrial & Scientific



					www.amazon.com
				




The flat ribbon solder is nice for brazing tool bits, but I went for best price and I also wanted the wire for brazing other things besides tool bits.

Ted


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## bill70j (Feb 4, 2020)

Technical Ted said:


> People call it silver "soldering" but when using the higher temperature hard, higher percentage silver it is actually silver "brazing". The difference is the percentage of silver content and the temperature required to melt it. You want hard silver solder (silver brazing) for bonding a HSS tool bit to a steel or alloy bar.
> 
> Ted


I have also used Harris Safety-Silv with the *black flux* to braze carbide to CRS.  Here's a pic of a RH boring bar for use in external turning using a boring head. The carbide is a piece from a damaged TPG insert.


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## ericc (Feb 4, 2020)

Dhal22 said:


> We could pay $50 each and just pass it around to look at it.   He might make $1000's that way.  I'm interested as well.



$50 for what?  I seem to have lost track of the thread.

Silver solder is not that expensive, since a little goes a long way.


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## Technical Ted (Feb 4, 2020)

ericc said:


> Silver solder is not that expensive, since a little goes a long way.



Yes, it doesn't take much! With a good, clean, tight fit the solder will suck right in.... don't over do it and end up with a puddle of silver on your bench or floor!

That Harris silver I bought will most likely last me the rest of my life (Yeah, I'm older, but hopefully around for quite a while longer!). 

Ted


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## benmychree (Feb 4, 2020)

The silver solder used to tip carbide tools commercially is a silver alloy/ copper /silver alloy sandwich; the copper shim provides a cushion  between the shank and the carbide bit, aside from that ideal solution, silver alloy strip would be the second best, wire after that.  After the silver flows, the carbide bit it pushed firmly against the shank until the silver is solidified.


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## Suzuki4evr (Feb 4, 2020)

Thanks everyone for your input. You have helped alot. I think I will go with the Harris safty-silv and black flux. I just need to see where I can get it cheapest considering I live in South Africa and shipping is a bit expensive from the US.


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## Suzuki4evr (Feb 4, 2020)

Can it be used without the flux and if not why?


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## Technical Ted (Feb 4, 2020)

You need the flux. The flux cleans the materials being bonded so the silver will adhere. Without it, the silver will just ball up and fall off.

Ted


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## middle.road (Feb 4, 2020)

Could use borax as flux. Black flux would be better, but if it costs an arm and a leg then. . .



Suzuki4evr said:


> Can it be used without the flux and if not why?


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## Dhal22 (Feb 4, 2020)

ericc said:


> $50 for what?  I seem to have lost track of the thread.
> 
> Silver solder is not that expensive, since a little goes a long way.




That was a reply to the wrong thread.


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## Suzuki4evr (Feb 5, 2020)

Technical Ted said:


> You need the flux. The flux cleans the materials being bonded so the silver will adhere. Without it, the silver will just ball up and fall off.
> 
> Ted


So it basically does the same as arc welding flux,am I right?


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## Technical Ted (Feb 5, 2020)

I'm not sure what you mean by arc welding flux... do you mean the coating on a stick electrode? I'm not sure it that would be a good comparison or not. Google is your friend. Just search for "why is flux needed for brazing". I did and this popped right up. There is a lot of info out there on brazing.

A fluxing agent (or a controlled atmosphere as found in furnace *brazing*) *is* required for all *brazing* and *soldering* applications. The purpose of the *flux is* to remove oxides from the base material and to prevent oxidation during the heating process, thus promoting the free flow of the *brazing* filler metal.


Ted


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## seasicksteve (Feb 5, 2020)

Try the silver bearing brazing paste you will love it. Clean the parts apply a small amount between the parts to be joined heat the joint till the brazing metal flows allow to cool. I use this stuff to attach handles to bolt bodies it is almost as simple as boiling water. If you opt for the hi temp silver solder and flux I would go with the black flux the white flux tends to scorch just a little past where the solder flows If your not careful and you burn the flux it wont join The black gives a little margin


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## Suzuki4evr (Feb 5, 2020)

Technical Ted said:


> I'm not sure what you mean by arc welding flux... do you mean the coating on a stick electrode? I'm not sure it that would be a good comparison or not. Google is your friend. Just search for "why is flux needed for brazing". I did and this popped right up. There is a lot of info out there on brazing.
> 
> A fluxing agent (or a controlled atmosphere as found in furnace *brazing*) *is* required for all *brazing* and *soldering* applications. The purpose of the *flux is* to remove oxides from the base material and to prevent oxidation during the heating process, thus promoting the free flow of the *brazing* filler metal.
> 
> ...


That is what I meant yes. I was taught the flux on the rod is for removing impurities so thats why I asked, but no probably not the best comparison.


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## Technical Ted (Feb 5, 2020)

Yeah, for welding you have a molten puddle of both base and filler metal. With brazing you only have filler metal that is fluid. Whatever solder/braze you decided to go with, made absolutely sure that the parts to be joined are perfectly clean. No flux will clean dirty metal. Hit them with emery paper or something. Plus, roughing up the surface will give the filler some nooks and crannies to adhere to.

Ted


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## Suzuki4evr (Feb 5, 2020)

Technical Ted said:


> Yeah, for welding you have a molten puddle of both base and filler metal. With brazing you only have filler metal that is fluid. Whatever solder/braze you decided to go with, made absolutely sure that the parts to be joined are perfectly clean. No flux will clean dirty metal. Hit them with emery paper or something. Plus, roughing up the surface will give the filler some nooks and crannies to adhere to.
> 
> Ted


Thankd Ted for all your help and advise. And all the other members too,thank you.


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