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Soldering - Choosing the right power and choosing the right tip

Choosing the right power and choosing the right tip.

Like so many things basic soldering is simple, grab an iron, melt the solder, and connect components.

So why is there so much choice on irons and power and tips, if it’s that easy?

Get it right first time.

The Weller soldering iron range is extensive and knowing what to use and when can seem daunting, with these tips and our new web tools and selection guides we can help to remove the guess work.title

Best practice is always size your tip to pad size this gives you the maximum amount of heat transfer, faster heat transfer - equals less strain on the board and less time exposing components and wiring to heat. That’s fine in an ideal world but what about access; you can’t always get a large tip in. Well, profile of the tip then comes into play, if you have a good access then use the largest flat type; poor angle? Then a chisel or single sided tip (often angled at 45 or 60 degrees) can help. A conical or rounded tip will often get into connectors and still offer a good hot solution. 

Not all soldering tasks are as simple as that; what about soldering down a RF Shield or “canning” a component, a great tip for this task is a knife tip, its “V” shaped edge allows access into cavities that you can’t reach with a conventional tip, a knife tip can also be used for J lead components or for cutting and sealing frayed edges on reinforced cloth.

Gullwing, bucket or drag solder tips can make short work of surfaced mount components allowing multiple pads to be soldered whilst preheating the next allowing a “drag” of solder across more pads. The same tip can be used for cleaning up as the bucket can be used empty and will pull excess solder from potential bridges. Any further bridges can be removed with non wettable tips which won’t stick to components.

Weller laser mark all their soldering tips so you can have confidence that you are buying Genuine Weller tips.

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The same principles also apply to de-soldering as well. Heat transfer is key when trying to remove connectors or through-hole components, it’s important to make sure all the heat is transferred to all of the solder. This video shows the Weller WP120 using thermal imagery transferring heat to a component; with 120 watts it is capable of very fast heat delivery but you can see that the size of the component means it still takes time to heat all the way down. Trying to remove this component too early would result in damage to the component or the board calling for a repair or even scrappage.

The full range catalogue can be downloaded here with products available through the RS Web site.

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 So we have an idea on tips types what about the iron?

OK, let’s talk power. No one wants to spend longer doing a job than they need to, you wouldn’t dig a hole with a dessert spoon so why would you use an underpowered iron to heat a large heat dissipating connector. Choosing the right power for the majority of you work is a must.

Weller’s extensive range of soldering irons gives you that choice and puts you in control.

Requirements vary considerable so let’s ask some questions

  1. Are you always using your iron above 380degcC?
  2. Does your iron ever “freeze” onto what you are soldering?
  3. Are you oxidising or burning out tips quickly?

If your answers are mostly yes then your soldering iron may well be underpowered and a higher wattage will improve your processes. An underpowered soldering iron may be creating dry joints and soldering is not just an electrical process but a mechanical one too, a poorly soldered joint will fail earlier under mechanical stress without a properly soldered joint.

At Weller we offer three different heaters with sensor positions suited to task and cost requirements.

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Plastic case connectors and single and dual sided PCBs can be soldered with a 65W or 80W iron, such as the Weller WP65 (fast response design) and WP80 (silverline) these irons will perform comfortably at this level and still have sufficient power to allow larger tasks to be completed, tip sizes for these irons range from 0.1 to 4.6mm.

 Will you be working on similar sized connections but with heavier cases or multi-layered boards? Then a WP120 (fast response type) offer bigger reserves of power and a higher mass tip range from 0.8 to 6mm. The WSP150 and WP200 (fast response) offer power in abundance and provides large mass tips to match larger terminals with tips up to 10mm.

Working with 0603s and 0402s? The micro range of tools, WMRP, and WMRT (WX range -WXMP WXMT) will support this function through active tip technology.

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If a helping hand is required Weller now have the brand new web apps, Weller Tool selector and Weller Application finder, a pair of interactive tools to help you fine tune your requirements.

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And finally working with RS we have a created the Weller selection tool a great summary of irons and solder joint sizes.

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