Soldering iron wattage?

notCardio

I walk the line
By chance I happened to read the previous questions about soldering irons, and it got me to thinking. (I know, I actually do that on occasion)

A newbie question that's probably been asked about a thousand times but, what are the appropriate wattages for our common applications?

What wattage for the PCB on a pedal, what for cables, and what for controls on a guitar? Or will all of those take the same wattage?
 

Chili

Site Moderator
Those little 30 watt pencil irons are just fine for what you mentioned. If your cables are larger than 14 gauge, you might consider more watts.

I find the best tool for a good soldering job is bifocal reading glasses with a high magnification lens so I can see what I'm doing.
:D
 
I'd always recommend a 50-60W temperature controlled iron. The temperature control means that it won't be too hot for fine work but the higher power means that it will cope better with larger joints too. I spent my formative years struggling with the cheaper 25W irons that were often recommended so, when I started a Saturday job in a TV shop and tried the irons that the service engineers used I realised what I'd been missing.
 
I have used Weller products for many years and I do not often lift foils from boards. One must understand the thermodynamics of the iron as in when to us the broader section of the tip in comparison to the fine tip end. Using good solder like Kester 44 always helps. With a Weller I have changed those postage stamp sized chips with 84 pins up to the larger TO-3 transistors. The system is rated at 40 watts but is all depends on how you apply the 40 watts. In some cases like doing yard lights with 14 gauge wire the 40 watt iron will not do when it is winter out. That is when I get the Radio Shack 500Watt gun out and that will deal with the cold and larger wire. I still use Kester 44 as this stuff flows like solder should. Some Korean solder I have come across flowed as if it was slag. Slag is the garbage you remove from a vat when making bullets.
 

rob aylestone

Well-known member
25 Watt for me for audio stuff and circuit boards. 25W is too low to solder cable larger than 1.5mm2 - 35W will do it. I have never needed an iron higher wattage than that. I still have a huge drum of lead free solder that is maybe ten years old. The new lead free stuff I just cannot get on with.
 

dogooder

Member
What temperatures do the different wattages bring the tips to? I have a variable station and no indication of wattage, only temperature.
 

easlern

Boredom artist
A 40 watt works fine for me when working with older lead solder. The silver stuff though (newer, less hazardous type), I can’t even melt that. So I’d recommend more than 40.

Cables and guitars seem to still use through-hole components in my experience, so they’re easy to work on. Pedals are using surface mount since the 90s though I think, so I don’t bother with those. They require better eyes and steadier hands than mine.
 

Gtoboy

Well-known member
530 ish is melt point for 64/40, my brother is electro repair and he says on small joins/pcb board 620 to 700 depending on the size minimum. He says he usually leaves it set around 800 deg but will go up to 900 for large repairs. (all temps fahrenheit). To low a temp will force longer contact which can damage the board so start around 800 and lower if needed, but beware if it takes longer to melt, raise the temp
 

ecc83

Well-known member
Bit late on parade I know but, I used a 48W Weller station for over 40 years and soldered everything from steel chassis lugs to tiny transistors. Much later I used the same iron to change an SMT reverb chip in an amp. (yes! It worked!)

Thing is, peeps often confuse 'wattage' with temperature. My beefy Weller only gets to about the same temperature as the rubbish old 25W Henley Solon or the almost as bad Antex.

A components 'solderability' is defined as X deg' C for Y seconds. So long as you stay within those limits you won't damage anything. in fact a 50W iron allows you to make a briefer contact.

Dave.
 
There is yet another item to add to the equation. Tip size and shape. In working with small joints the tip will have a reduced temperature as it takes longer to heat recover than the more broad part of the tip, So not only does it help to have an adjustable iron temp but it also matters how you use it with what tip. I am using the conical sharp tip on a Weller WES51 which is now an old model but over the years these solder stations have soldered thousand of joints without lifting any patterns and all my joints look shiny in comparison to what I encounter on these wave soldered boards. The Solder I use is Kester 44 as obtained from Kimco. I know a pound of Solder can be seen at some suppliers for around $45 but when bought in bulk (25 rolls to a case) you can get it for about $20. I bought the case and have sold some rolls to my trainees who will not use as much as me. Most Japanese decks are so poorly soldered that sometimes I use a roll a month.
 
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