# Questions on using solid silver for a soldering iron tip

#### Eddy Current

Joined Jan 25, 2017
25
Hi,

#12

#### Tonyr1084

Joined Sep 24, 2015
4,046
Little late to tell you this, but gold plated leads (which don't tarnish) WILL make solder brittle. That's the number one reason why they pre-tin the leads. Especially if the leads are gold plated. Google "Gold embrittlement" and see what comes up. It's been a problem in the electronics industry for some time.

#### Eddy Current

Joined Jan 25, 2017
25
What is your concern specifically regarding depletion? And is this a different process to the copper sublimation you mentioned?

I'm still using Sn-Cu, don't think I have any Sn-Ag-Cu, and definitely not high content silver solder. The iron has no temperature control though, and it is old, I have no idea what it's operating temperature is.

Dunno about beryllium fumes though also don't have an easy and cheap source, unlike silver. A 75x5mm pure silver rod is about $15, and I can keep on turning down the tip to a fresh point on my lathe. Thread Starter #### Eddy Current Joined Jan 25, 2017 25 I did it with gold when the leadfree became mandatory and surprise ! ... the gold dissolves as butter with the tin Yeah, the problems of the behaviour of gold were discussed in the thread I linked, but no detail on the silver. #### Tonyr1084 Joined Sep 24, 2015 4,046 I had a nickel plated tip that was made of copper. Eventually the nickel wore out and the solder and flux began eating the copper out of the nickel plated tip fast and furious. It now looks like a tooth with serious decay. The tip is gone and much of the internal copper is gone too. Also, using a copper soldering tip on a Weller soldering gun; those tips erode too. In one afternoon of rewiring a tractor trailer (just the trailer lights part) I went through TWO "Harbor Freight" copper soldering tips. Now, regarding my expertise on soldering irons - I HAVE NONE! Expertise that is. I only know that a tip made from silver, I SUSPECT would sublime during soldering. Not as fast as solder itself (silver solder) but I'd imagine it will go pretty fast. But like I keep saying - I DON'T KNOW THESE THINGS. I'm only offering a point for consideration. Maybe factual, maybe not. I'm not even positive that my soldering iron tips (professional tips) are nickel. They're shiny metal things that LOOK like nickel. I have a beryllium copper rod sitting in my cupboard right now. I'm considering throwing it on my drill press and boring a hole down the middle of it then turning it down to the same size as my good tips, then turn the end down till it forms a typical solder iron tip. Maybe. Maybe not. I'm just a little curious now since this subject has been broached. #### #12 Joined Nov 30, 2010 18,186 Silver and mercury are used to make dental fillings. Therefore, silver can form an amalgam. Copper dissolves in solder. I'll bet silver also dissolves in solder. Please let us know how this turns out. #### ian field Joined Oct 27, 2012 6,539 Hi, Saw this thread: http://forum.allaboutcircuits.com/threads/diy-soldering-iron-tip-the-best-material.105032/ where Alec_t mentions using solid silver as a soldering iron tip. Seems like a really good idea. Highest thermal conductivity, and a noble metal. I have a lathe and mill for shaping the bit, and and the silver is easy and cheap to source (about$2/cm).

My questions:
• I'm wondering if i need to "treat" the silver, or do anything to it before using it for soldering?
• Also, is there much difference between 99.9% and 99.99% for this purpose?
• Any other things I need to be aware of?
Cheers,

Ed
Silver has excellent thermal conductivity - I even heard of someone machining a motorcycle cylinder head out of a block of silver for a high stakes competition event.

I would expect silver to alloy into the solder, probably even faster than copper. You could have it iron plated just like they do with copper bits, but its going to be an expensive item to bin when the plating gives up.

A smear of heatsink thermal paste between the bit and element can give a worthwhile increase in thermal conductivity, and as long as you don't over do it, there's some protection against burnt flux residue seizing the bit in.

#### #12

Joined Nov 30, 2010
18,186
You could have it iron plated
I have had excellent results with "iron-clad" soldering tips. I think I ruined one in 20 years.
At that rate, an ounce of silver is a lifetime supply.

#### Alec_t

Joined Sep 17, 2013
10,746
I would expect silver to alloy into the solder, probably even faster than copper.
My silver tip hasn't eroded noticeably on a 15W non-temperature-controlled iron used for a hundred or so joints with 60/40 resin-cored solder.

#### ian field

Joined Oct 27, 2012
6,539
I have had excellent results with "iron-clad" soldering tips. I think I ruined one in 20 years.
At that rate, an ounce of silver is a lifetime supply.
Generalising is unwise.

In the past, my irons have led a hard life and short endurance of the iron plating wasn't too much of a surprise.

The quality of plating can vary enormously - some cheap irons only have plating on the circumference of the bit.

The Antex irons I've settled on are at least satisfactory, the 50W TC Antex has the original bit after over a decade - but I'll admit the iron leads a quieter life than it used to.

I gave up on Weller when a brand new element was wrecked by flaky plating on the bit that goes inside the element tube - the plating there doesn't even see any work.

#### shortbus

Joined Sep 30, 2009
7,357
I must be missing something in all of this. No matter what the tip is made of, it is still the irons element that makes the heat. Once the tip gets to that temperature, the elements temperature, how is the material the tip is made of going to make the solder work better? Since most quality irons use an iron/steel plated tip, why not just make a DIY tip from steel in the first place? No matter what material the tip is made of, it's the "tinned" layer that is actually touching both the work and the solder.

I'm sure some one will tell me where I'm wrong about this. Like #12 I have an old soldering iron that was used for more years than I can remember and never had to change the tip, because it's iron plated copper and I clean and re-tin it before putting it away. And it is just a cheap little Radio Shack one.

#### #12

Joined Nov 30, 2010
18,186
I must be missing something in all of this.
This whole conversation probably isn't worth much.

Silver has one of the fastest travel times for heat. If there is a large thermal mass behind the tip, the silver can move that heat to the front of the tip faster than most other metals...but who ever said there is a significant thermal mass behind the tip?

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#### GopherT

Joined Nov 23, 2012
8,012
I think, for less than \$10 of silver, it is an interesting experiment. And, @Alec_t already has proven that it works for 100 joints (one 4x6 pcb gets about 100 holes in my designs). What's needed now, is the durability testing and a clear benefit. If a lifetime durability is the benefit, it could be interesting. I don't think high thermal conductivity is a selling point - I've never been short on heat carrying capacity. The promise of long life could be most interesting to me. Is there more?

How could the lifetime be tested?

Any other issues? Like tarnish (silver oxide) causing solder to bead up on the component lead or pcb instead of wetting it and bonding.

#### #12

Joined Nov 30, 2010
18,186
How could the lifetime be tested?
Use a solder pot. Bring it up to temperature and use a small motor to move the DUT in circles in the melted solder.