Solder Pot Insert

HI to all my old friends and buds!

Recently purchased a solder pot for tinning wires.
To charge the pot takes a pound of bar solder which would more than double the investment. Did not want to spend the money or heat up that much solder to tin a few wires. What follows is how I made the solder pot more suitable for hobbyist use.
This thing is designed to hold a lb of liquid metal which is inherently dangerous. My modification significantly reduces the amount of liquid metal. Safety Nazis need not respond.

I wanted a smaller pot. So I turned aluminum on the metal lathe to fit the pot and drilled a blind 9/16" hole 1 inch deep. Solder to fill this is about 1 1/4 oz. For good heat transfer I cranked the pot temperature all the way up and melted a bit of lead in the bottom and set the aluminum into it.
The lead is denser than the aluminum which floats on the lead. The lead melting point is about 100C higher than the solder so the lead does not remelt in use. I used a bit too much lead which caused the aluminum to stick up more than planned but the unit seems ok with it. Not melting an entire lb of solder may help it heat up faster too. While the aluminum heats up too it does not need the state change energy, "Heat of Fusion", that the solder would. The thing heats surprising fast and is slow to cool down. EDIT: Room temperature to liquid solder is 12 minutes.

Lead tin solder does not stick to aluminum so the pot should clean nicely. The lead in the bottom is printers lead which I fluxed with saw dust. Because I did not use an corrosive flux the steel pot should last indefinitely.

This might be done without a metal lathe. Use round aluminum stock that fits into the pot. Wire down the aluminum so it is just a bit off the bottom and pour lead into the gap.

Nice... Good to see you again...

Nice work 3v0! Good to see you!

My old job was tossing one of its old solder pots (they just didn't need it anymore - still worked just fine) so I snagged it. It's a small one though, only holds a few oz of solder at a time, but is still larger than I'd need. I've considered putting in some sort of steel (?) plug, but I don't know my metals and wouldn't know what's safe to use in this sort of application. I'm also not convinced the temperature control is very good, so I'd be concerned about overheating.

Hope you're staying healthy these days!

Matt

How have you been? That is one really slick modification. I agree a 1 Lb bar will tin a small mountain of wires and was simply overkill.

Ron

You might have problems down the line using aluminum for your pot. Solder dissolves aluminum and then gets contaminated by it. They had many solder pots on assembly lines where I worked and the "dippers" that pushed the wire into them couldn't be made from aluminum because of the problem. They ended up making the dippers from Teflon instead. This PDF talks about the problem -

shortbus= said:

You might have problems down the line using aluminum for your pot. Solder dissolves aluminum and then gets contaminated by it. They had many solder pots on assembly lines where I worked and the "dippers" that pushed the wire into them couldn't be made from aluminum because of the problem. They ended up making the dippers from Teflon instead. This PDF talks about the problem -

https://www.kester.com/Portals/0/Documents/Knowledge%20Base/EffectsofMetallicImpurities.pdf

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The paper cited is about wave soldering and says this about hand soldering "The technician or assembler using a hand soldering iron had much better control over the soldering situation since he could control join-to-joint heating to complete properly soldered connections." I will have to use the rig for a while and see how long it takes the problem to develop. As small as the pot is some of the contamination is removed through solder use. This should slow it down but given that the solder well is all aluminum that is a lot of surface area.

If it is enough of a problem I can revisit this and turn a new pot from a more suitable metal.
And thanks for pointing this out. Forewarned sort of thing.

Matt, Ian, and Ron,
So good to see more of the old crew. Have caught up with a few of the people who used to use ETO chat elsewhere. Doing what we can to make it out the other end of the pandemic. Still puttering around with foundry and machining. Adding a ELS or Electronic Lead Screw designed by Clough42 on the 10" Atlas lathe. Uses a LAUNCHPAD TMS320F280049C EVAL BD. It is kind of fun to get back to electronics. The major advantage of the ELS is that one can cut thread pitch by selecting it from the menu. Should the thread be odd enough that it is not in the menu I can modify the code to make it happen. Fun times.

3v0

3v0 said:

Matt, Ian, and Ron,
So good to see more of the old crew. Have caught up with a few of the people who used to use ETO chat elsewhere. Doing what we can to make it out the other end of the pandemic. Still puttering around with foundry and machining. Adding a ELS or Electronic Lead Screw designed by Clough42 on the 10" Atlas lathe. Uses a LAUNCHPAD TMS320F280049C EVAL BD. It is kind of fun to get back to electronics. The major advantage of the ELS is that one can cut thread pitch by selecting it from the menu. Should the thread be odd enough that it is not in the menu I can modify the code to make it happen. Fun times.

3v0

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Glad you are keeping busy. I am back and forth between here and ETO along with a few gun forums I am active in. Going on 9 years since I retired and sitting here in NE Ohio freezing. My outdoor range is a frozen tundra and we just cancelled a cruise to warm because of all the COVID restrictions. They managed to suck the fun out so maybe next winter. Been playing around with micro controllers to stay amused and keep my brain from turning to mush. Nice to see you show up here.

Ron

3v0 said:

The paper cited is about wave soldering and says this about hand soldering "The technician or assembler using a hand soldering iron had much better control over the soldering situation since he could control join-to-joint heating to complete properly soldered connections." I will have to use the rig for a while and see how long it takes the problem to develop. As small as the pot is some of the contamination is removed through solder use. This should slow it down but given that the solder well is all aluminum that is a lot of surface area.

If it is enough of a problem I can revisit this and turn a new pot from a more suitable metal.
And thanks for pointing this out. Forewarned sort of thing.

Click to expand...

Historically wave soldering was unreliable on other than small joints, and the large number of dry joint problems was due to that. You could look in a new TV and pretty well spot where dry joints were going to occur - decent hand soldering cured the problem, particularly if you used high temperature solder.

A number of TV manufacturers started hand soldering certain parts after the boards were wave soldered, but I suspect it was more a case of where it might burn a hole through the board, and the potential fire risk.

Nigel Goodwin said:

Historically wave soldering was unreliable on other than small joints, and the large number of dry joint problems was due to that. You could look in a new TV and pretty well spot where dry joints were going to occur - decent hand soldering cured the problem, particularly if you used high temperature solder.

A number of TV manufacturers started hand soldering certain parts after the boards were wave soldered, but I suspect it was more a case of where it might burn a hole through the board, and the potential fire risk.

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Thanks Nigel that puts more perspective on the problem. It looks like the solder will be used fast enough so as not to cause problems. Could place a short steel rod in with the solder and further reduce the volume but at this point I am curious to see how this works out.

3v0

Reloadron said:

Glad you are keeping busy. I am back and forth between here and ETO along with a few gun forums I am active in. Going on 9 years since I retired and sitting here in NE Ohio freezing. My outdoor range is a frozen tundra and we just cancelled a cruise to warm because of all the COVID restrictions. They managed to suck the fun out so maybe next winter. Been playing around with micro controllers to stay amused and keep my brain from turning to mush. Nice to see you show up here.

Ron

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We are having a bit of a cold spell but it seldom gets cold like it does in the north and midwest. Quite dry but that is not unusual. We had been lucky on the Covid front. That luck seems to have run out recently. I should drop by microcontrollers and see what people are doing.

3v0

3v0 said:

We are having a bit of a cold spell but it seldom gets cold like it does in the north and midwest.

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It's fairly chilly here in the UK, but nothing like you get in places in the USA - a cousin of mine lives in Canada, and his wife posted a picture of him clearing two foot of snow the other day

We did have snow the other week, just enough for a covering, that was all.