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Picture of Soldering iron tips from 6 AWG copper wire
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Like the Jedi of the Old Republic who constructed their own lightsabers, each customized to the needs and style of its owner, many Instructables members build their own soldering irons, or at least heavily modify them. Last time I checked there were approximately one jillion instructables on the subject of homemade soldering irons.

A well constructed lightsaber is, according to Wookiepedia , a Jedi's "single perfect weapon that he or she would keep and use for a lifetime."

If only I had such a "perfect" soldering iron that would last forever! In my experience, soldering irons are reliable enough, but far from perfect. The part of the iron that is consumed the fastest is the tip. Soldering iron tips wear down, burn up, diffuse into the solder, or something... Honestly I'm not certain where the mass of the tip goes. Intuition, and the law of conservation of mass+energy, tell me it has to go somewhere. Everything goes somewhere. Anyway, all I know for sure is that I start out with a perfect well-tinned tip like a shiny sharpened pencil, and several hours later I end up with a crusty burned-looking stub. Hence the motivation to replace the tip every now and again.

The soldering iron tips created in this instructable are made starting from 6 AWG solid copper electrical wire, and these tips are are approximately 4 mm (5/32 inch) in diameter. In this instructable, I show how to make two styles of 4mm tip, the slidey-style, and the screwy-style.

Step 1 takes a closer look at these two styles of soldering iron tips.
 
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Step 1: A tale of two tips

Picture of A tale of two tips
The picture below shows the two styles of 4mm (5/32 inch) soldering iron tip that I'll be making.

If your soldering iron doesn't look like one of these, well um... I never said this instructable would cover every soldering iron under the sun. So uh... what you see here is what you get.

I call the first one "slidey-style" because the tip slides in and out of the iron. This design uses a fat screw, set into the side of the iron, to secure the tip, keeping it from sliding out while soldering.

The second, I call "screwy-style" since the tip is threaded, and it screws in and out of the soldering iron.

I definitely prefer the slidey-style, for a number of reasons: (1) The slidey-style tips are easier to adjust. (2) This system holds the tip more securely. (3) The slidey-style tips are much easier to make.

So if you're new to this soldering iron stuff, and you're wondering which style is better. The answer is the slidey-style is superior, IMHO.

Step 2: Materials and tools used in this instructable

Picture of Materials and tools used in this instructable
material(s)
soldering iron in want of tip replacement
several cm or inches of 6 AWG solid (not stranded) copper electrical wire.

tool(s)
vise
hacksaw
small drill press
file, sandpaper, steel wool, etc

Note: The steps for making a threaded tip will require a die to make the threads. The thread for my screwy-style tip is metric 4mm-by-0.75, and this is the same thread as RadioShack(tm) part #64-2073

Regarding substitutions for materials or tools, if you want to use pliers instead of a vise, brass instead of copper, etc, that's cool ese, with the usual caveats about YMMV.

Step 3: Straighten the wire.

Picture of Straighten the wire.
The goal of this step is to take wire that may be crooked, and straighten it out. I use a vise for this task.

One important thing to keep in mind is the (very pure) copper used for electrical wire is somewhat soft, so if you try really hard you can crush it with the vise, and that would be undesirable. You want to hold the piece in place without marring or squashing it too much.

The simple act of closing the jaws will straighten the wire a little bit, but most of the fine adjustment is done by hand, bending the wire at the point where it enters-exits the side of the vise. The way I do this is by imagining a perfect straight line running right between and parallel to the jaws of the vise, and then bending the wire back towards this line if the wire veers away from it.

In the picture below I'm working on the wire where it touches the right side of the vice, just in that spot.

When that tiny segment looks straighter, I open up the vise and move the whole piece to the left a little bit, and clamp it down again. Then I straighten the next perceptible segment. As I do this, the wire to the left of where I'm working gets progressively straighter.

Then it's pretty much lather, rinse, repeat, until the wire looks like it's straight enough.

Step 4: Cut off a chunk.

Picture of Cut off a chunk.
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Cut of a chunk of the newly straightened wire using ye olde hack saw.

Every good hacker should have a hack saw. It's a tool that comes in handy.

I think the length of this chunk was approximately 65 mm or 2+1/2 inches.

The size will depend on the depth of the hole in the soldering iron it is intended to fill.

Step 5: Load the chunk into the drill press.

Picture of Load the chunk into the drill press.
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The goal here is to grind and shape the piece while the drill press is turning it. The process is sort of like using a lathe, except everything has been turned vertical instead of horizontal.

It's hard to tell from these pictures, but in all except the first and last pictures below, the spindle is actually spinning while I grind at it with the file, sandpaper, steel wool, etc.

The camera does a good job of capturing an instant in time. While working the piece I don't see what the camera sees. I just see a blur because the spindle is moving so quickly.

Step 6: Slim down the tip diameter.

Picture of Slim down the tip diameter.
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In the first picture, the cylindrical tip is just a hair too wide to fit into the body of the soldering iron.

So I load it back into the drill press, and I grind it down just a little bit, uniformly reducing the diameter the same amount across the length of the cylinder. This of course involves stopping to flip it upside down, to grind the part I couldn't touch the first time because the jaws of the chuck were in the way.

In the last picture, I check the fit again, and the tip slides neatly inside the body of the soldering iron.

BTW, 6 AWG wire (six gauge wire) is almost not exactly 4mm in diameter. It is 4.115 mm in diameter.
See: http://en.wikipedia.org/wiki/American_wire_gauge

Also the spec for the soldering iron might not be 4mm. It might be 5/32 inch, which is 3.969 mm

Step 7: Make it pointy.

Picture of Make it pointy.
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Want the tip to be pointy. So it's back to the old grind, er, so to speak.

Second picture shows the soldering iron and its new finished tip side by side.

Step 8: Steps for a threaded soldering iron tip

Make a nice cylinder. (Step 9. Similar to step 5)
Make threads. (Step 10)
Make pointy end. (Step 11. Similar to step 7)

Step 9: A nice little cylinder

Picture of A nice little cylinder
This little cylinder is about 2.5 cm (1 inch) long. It is destined to become a screwy-style soldering iron tip.

Step 10: Making threads

Picture of Making threads
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For this step its ok /necessary to really clamp the piece in vise tightly. I need to keep it from turning as I cut the thread into it. Marring the copper is not an issue because this spot will be ground away into pointyness in the next step.

I'm not sure what the verb is for cutting threads on the outside of a rod. I think it's "thread". It's not "tap". That's for holes, and the tool that does it is called a "tap". In this case the tool is called a "die", but I'm certain the verb isn't also "die", as in, "Here, could you die this rod for me?"

"Gee, I dunno boss. Looks like it's already dead."
;-P

BTW, the size of this thread is M4-by-0.75. That's 4mm with a pitch of 0.75. At full res, you can just barely see the inscription on the die in the second picture.

Step 11: Make the end pointy - trickier this time

Picture of Make the end pointy - trickier this time
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Now it's back to the drill press to make the end pointy. This is pretty much the same trick as shown before in Step 7.

The thing that is different this time is that I want to tighten the chuck right on top of my pretty newly cut copper threads. I don't want these threads to be crushed by the jaws of the chuck, so I have come up with a little contrivance to protect them. It's a little rolled up piece of beer-can-aluminum that goes around the outside of the piece to protect it by evenly distributing the forces of the chuck jaws.

Step 12: Done

Picture of Done
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And that's pretty much it, folks. These last two pictures show the slidey-style iron, and the screwy-style iron, side by side with their new tips

Step 13: Brass tips

Picture of Brass tips
You can also make soldering iron tips out of brass. The brass tips seem to last longer, but they don't conduct heat as well as pure copper.

The thermal conductivity of brass is only about 1/4 that of pure copper. See:
http://www.engineeringtoolbox.com/thermal-conductivity-metals-d_858.html
http://hyperphysics.phy-astr.gsu.edu/hbase/tables/thrcn.html
turbiny4 months ago

there is another type where the point is hollow in the middle so the heater core will be directly in the tip and its held by a screw like over the tip.
like this: http://www.upcraft.it/wp-content/uploads/2010/05/3-keep-those-soldering-iron-tips-shiny.jpg

Jack A Lopez (author)  turbiny4 months ago

Thank you for sharing that.

Jack A Lopez (author) 6 years ago
Also maybe worth mentioning:

I use a lamp dimmer to run my soldering iron at less than full power, with the belief that this makes the tips last longer.

Some instructables on the subject of lamp-dimmer style temperature throttling for soldering irons:
http://www.instructables.com/id/10ish_DIY_Variable_Temp_Soldering_Iron_Controller/
http://www.instructables.com/id/Recycling_your_old_dimmer_switch_as_a_variable_tem/
soldering-dimmer-01.jpgsoldering-dimmer-02.jpg

Works great if your stuck with a 40W iron.

Thanks very much for the #6 ground wire of copper. It works great, but do you know a way to make a conical point on the round wire? I make a 4-sided pointy tip with the Dremel, and then filed it conical. Is there an easy way? Mike

Jack A Lopez (author)  michael.neidich9 months ago

The first picture in Step 7 shows me grinding a cone shaped tip onto a short piece of copper wire. The piece of wire is held in the chuck of my drill press, and it is spinning, so pressing a file to it grinds away material in a way that is radially symmetric, kind of the same way a lathe works.

In this picture, I am holding a block of wood in one hand and a file in the other hand, with both pressing against the spinning copper. The reason for this technique is to sort of balance the forces on the copper work piece. Copper wire is soft. With just the file alone pressing on it, the wire has a tendency to bend somewhat. Essentially, the wood block prevents the copper wire from bending while it being ground down by the file.

Someone else was asking about this, in a comment below this one, and I drew some arrows on that picture, here,

http://cdn.instructables.com/FJM/VQCB/FX23V4KL/FJM...

to sort of indicate the direction of the pressing forces, since you can't "feel" force in pictures, because a picture is a visual thing.

eric m4 years ago
This is only a temp fix.

Copper/brass will be eaten by flux & solder. It's a pain to always tin a brass tip every 30 seconds.

Weller uses chrome on iron. It's superior.

Maybe you should find a steel or iron bit instead.
adamvan20006 years ago
OK, this may sound odd, but what about carbon rods, like the ones found in el-cheapo dollar store batteries? Will they conduct enough heat to be useful? I know they work great for those DIY cold-heat irons, but it just occurred to me how easy it'd be to make a new one of those. After all, to point them, all I do is use a pencil sharpener. May try this on my iron, just for kicks. ~adamvan2000
OK, first test says nope. All it did was smoke steadily, which I'm guessing was battery chemicals. Good thing for proper venting. I'm guessing that the carbon rods simply dissipate the heat too quickly for this to be an effective replacement for the regular or copper ones. ~adamvan2000
Jack A Lopez (author)  adamvan20006 years ago
This carbon rod idea seemed so zany, I thought I'd try it too. The carbon rod from a "heavy-duty" AA battery does happen to be just the right size (4mm diameter) to fit in my slidey-style soldering iron. Plus it was easy enough to file a conical point on to it. However, this new carbon tip doesn't conduct heat very well. I could barely get it to melt the solder.
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Interesting concept, and at first blush it seems carbon would be much less susceptible to oxidizing than traditional nickle or chrome tips, or at least what oxidation does occur, it would dissipate as a gas (CO or CO2 depending upon conditions I believe) which the occasional tip shaping is a lot less bothersome than constant tip wiping, tinning, etc etc not to mention the terrible performance an oxidized tip provides . That property alone seems worthwhile enough to not give up on the concept just yet.
If the thermal conductivity is good but the problem is in thermal retention, it seems the idea is already halfway there. I don't have any graphite off hand of a substantial enough diameter, but maybe someone who does could give this idea a try;
Turn (or file) graphite to desired profile, then chuck it from the other end if on a lathe or work some vise voodoo on a drill press, use peck drilling to form a cavity. Next, using either copper or iron most likely (for their ability to retain heat) match to the profile of the cavity in the graphite, possibly adding some groves to accommodate for thermal expansion if cracking occurs with a tight match. Basically the carbon tip idea with a metallic core. If anyone tries it out I'd be interested to hear how it works out, or if someone has the graphite but dosnt have the tools hit me up and I'll turn a few for both of us if it works out.
-Ed
Hey, we tried, right? It's funny, as the thermal conductivities of carbon and copper are 140 and 200, respectively, so they don't seem that far off. I seem to remember now reading somewhere that carbon dumps the heat too fast to be used this way, unless you're running a current through it and using it like a cold-heat soldering iron(one of my next projects). ~adamvan2000
unclelar6 years ago
The term used for cutting the threads,is simply "threading or to thread" an example ;would you thread this rod,or are you done threading that rod .Anyhow, good job on your instructable
Jack A Lopez (author)  unclelar6 years ago
So we tap threads into a hole with a tap, and we thread threads onto a rod with a die. God, I love the English language.
Exactly! Now You've got it.
crankyjew6 years ago
nice. i can see a drill clamped lightly in the vise as a good alternative for those of us without a drill press. also, copper electrical wire is usually dead soft. have you tried hardening the copper, and/or do you find it necessary?
Jack A Lopez (author)  crankyjew6 years ago
I don't do anything to harden the copper, and these homemade copper tips seem to work almost just like the factory made kind. Regarding the softness of copper, that reminded me of something. To keep from bending the piece while grinding, it can be helpful to have something pushing on both sides of it. This is the purpose of the piece of wood seen in some of the pictures.
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gmoon6 years ago
There are some really good "tips" in this one... thanks!
jman 316 years ago
Very nice instructable! I just may use this method in the future. I've noticed however that all the tips I use are coated with some sort of silver substance. I have found that they last pretty good until I sharpen and get down to the raw copper, then they seem to burn up pretty quickly. Any idea what that is?
Jack A Lopez (author)  jman 316 years ago
MIght be iron or nickel, with a thin layer of tin on top. Honestly I don't know.

But I recently found this:
http://www.patentstorm.us/patents/5553767/description.html
It's a 1996 patent for some kind of newfangled soldering iron tip. The "prior art" section mentions problems with soldering iron tip coatings, copper being soluble in tin at high temperatures, etc.

So maybe the legends of delicate tip coatings are true...
Thanks for the reply. I still think your idea is sound. As long as you keep a good point on it whenever you solder. Thanks for sharing!