Introduction
On other pages, we've explored how to care for the tip of your soldering iron. We know there has to be some reason for all the shapes that are available, so the question is, "What tip shape should I choose?"
To answer this question, you need to think about what kind of soldering you are trying to do, as well as understanding the anatomy of a soldering iron tip.
Soldering Tip Anatomy
Every soldering iron tip is composed of a copper core, which often has an overall plating of iron, and a further plating of chrome on the non-working portion (the tip of the "tip"). Years ago, soldering iron tips were made from copper with no plating. Solder slowly dissolves copper, so the tips would become pitted and misshapen.
A thin iron plating solved that problem, as iron isn't as soluble in solder but it does conduct sufficient heat to melt it. This allows tips to last a great deal longer, as they are less prone to react with the solder. The chrome plating on the shaft is not as capable in wetting the solder and is not readily oxidized. You use the parts of the tip that have iron plating to solder with.
Wear occurs to the tip when the iron is hot and exposed to tin. The higher tin content of modern lead-free solder and the resulting higher soldering temperatures mean that tip wear is increased. However, modern advancements in tip manufacturing causes wear to be less of a concern when Best Practices are followed.
What Kind of Soldering
The best tip for you depends on what you are trying to do and the condition of the joint. Let's dig in.
- Joining two wires together
- Soldering on a Printed Circuit Board (PCB or PWB)
- Through hole devices (You can use a mechanical pencil to compare the lead diameter)
- Surface mount devices (SMD)
- Limited access to the joint
- Devices are clustered close together: Conical (small), Needle, Bent (small)
- Larger devices surround the device of interest: Needle
- Soldering surface mount devices with small distances between leads: Wedge (small), Needle, Bent
- Repairing a solder bridge: Beveled, Wedge, Knife
- Are you tinning component leads or wires? Beveled, Hoof, (possibly Wedge)
- Are you desoldering items with braids?
- Large devices with tabs or thick (0.75 mm) leads: Beveled (large), Wedge
- Small devices with normal (0.5 mm) leads: Beveled, Wedge
As you might notice, the Beveled and Wedge tips have great utility and are both a good general purpose choice, closely followed by the conical tip for general purpose smaller work.
The Tips
Below is a list of some tip types and their characteristics and suitability. Many times, more than one type will be suitable for a given job.
The names shown are merely common; there is no standard. We've included other common names to help with identification.
Also, while the tips are organized by shape, you can obtain different sizes of each shape, which affects suitability for a given job. Larger tips will be suitable for larger jobs, as long as the soldering iron has sufficient wattage to heat the joint.
There are somewhat accepted letter codes for each shape and those are indicated alongside the name.
Conical Shape (Type B)
Known Aliases: Cone, Round Cone
A good general purpose starter tip, this and the chisel shape are often found as the default tip. Frequently the side of the conical tip is used for soldering, as the very tip is often less efficient for heat transfer and runs cooler. Some conical tips will have a rounded off end which improves heat transfer in general use.
Beveled Shape (Type C)
Known Aliases: Chisel, Hoof (unusual)
Essentially a conical tip with a bevel on the end, it can be used for general soldering, and provides a useful flat spot for better heat transfer. It is especially helpful for heating contact pads on PCBs while providing heat transfer to the leads as well. In combination with the chisel shape, it provides more soldering angles to the user. This tip can also be found with a straight shank rather than a cone. You may even encounter tips which are only iron plated on the face of the bevel.
Wedge Shape (Type D)
Known Aliases: Chisel, Screwdriver
This shape is probably the most generally useful tip alongside the bevel shape, as it has both a wide flat profile and a narrow tip. The wide contact area makes this especially useful as the narrow tip is better suited to heat transfer than the point of a conical tip.
Needle Shape (Type I)
Used for very precise small work, they are suitable only for small joints as they cannot transfer a large amount of heat as their thermal mass is small. They can also reach in among crowded small components.
Bent Shape (Type J)
These tips allow you to reach into areas that would be more difficult with a straight tip. They also allow the tip to be used for drag soldering. They are usually made from needle or chisel points.
Knife Shape (Type K)
The knife shape looks like a small razor knife with a sharp beveled point. It is used mainly for repairing solder bridges and also for drag soldering. It can also be used for removing some kinds of flux residue, and cutting through shrink tubing.
Hoof Shape
The hoof or hollow point is very useful for soldering where a bead of solder is spread along while new solder is fed into the tip. A variation is the grooved point, which is like a chisel point with a notch out of one side. This works well for tinning leads, and any sort of "moving" type solder technique. Some tips are based on a bevel point with the center of the bevel hollowed out.
Additional Information
How to Solder and Desolder Connections
Soldering Iron Not Melting Solder
Additional Resources
Here is a link to a very informative page on soldering tip shapes from Hakko Incorporated. Hakko is a manufacturer of professional grade soldering equipment.
Here is a link to a page on soldering iron tips from Tameson, an industrial supply company.
Here is a link to a useful page about soldering iron tips from ElectronicsHub that also has tips about soldering as well.
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