Buying solder - recommended brand/store. unreg?

[unreg]

Hi, this isn’t a guitar wiring question, but the solder WILL be used for guitar wiring.

I recently purchased a 40 watt soldering iron bc my 25 watt didn’t heat up enough every time (short somewhere). The problem is that I only have a roll of RadioShack 0.032 diameter Light-Duty Rosen-Core solder. That solder turns black almost instantly when trying to tin the iron’s tip. I’m guessing that’s bc it is Light-Duty and so it can only withstand heat from 25 watt soldering irons.

What store do you recommend buying solder from? RadioShack’s website charges $5.00 for shipping and the roll of 0.032 diameter Silver Lead-Free Rosen-Core solder is only $5.00... so I need a store, but even though Walmart sells solder, the reviews are not 5 star. Any brands of solder do you recommend?

The shipping delay will extend this guitar repair even more; I wish RadioShack’s Electronics Plus was much closer. 50+ miles to buy solder?!

[blademaster2]

That does not sound normal. The solder itself would not be turning black, but the flux might be. A higher wattage iron usually provide more heat energy to maintain its temperature while more solder is being warmed up and taking away that heat, but not by going hotter. Higher wattage irons usually are larger with more metal at the tip and therefore more mass to store heat energy, and that way they maintain their temperature closer to the melting point as the solder takes away that heat.

When I solder I actually use flux as a separate thing in a squeeze bottle in addition to the flux in the solder core. Mildly activated rosin flux (RMA) is able to be left on the metal and will not be corrosive so you need not clean it (other types of flux might eventually eat away at the metal and should be cleaned off after soldering). Also - clean the soldering tip using a moistened sponge after every time it melts solder, and after you are done, so the flux will not remain there and oxidize or corrode the tip.

Digikey has wire-type, flux core solder. Personally, I would also choose Sn63Pb37 leaded solder rather than lead-free since it melts at lower temperature and is easier on the parts (just wash your hands after touching it to avoid lead contamination). I have purchase many brands, but Kester brand solder like their 24-6337-9756 seems reasonable and Digikey has it in stock and can ship to you.

Also, whatever you get make sure it is for electronics and not acid-core plumber's solder.

[Deleted]

i find the ones with more lead in them chew better

[blademaster2]

Kidding aside, I knew kids in highschool who would chew on solder. I can only imagine how much they damaged their brains with lead poisoning.

[unreg]

blademaster2, hmm... I read that cleaning the tip with a damp sponge can be hurtful too since the hot iron will be briefly touching the cold damp sponge. That’s only bad if I clean the tip often, at least that’s what I read.

The Rosen Solder has flux inside; that might be burning?

Hmm... the soldering iron’s package says my 40 watt heats up to 900 degrees Fahrenheit; while, the 25 watt equivalent (the same maker) reaches 750 degrees Fahrenheit. So, it definitely gets hotter. At least, that’s what it seems to me right now.


angeIsbunny, haha you are too funny


edit: blademaster2, your first paragraph is very interesting... so my iron’s extra 150 degrees Fahrenheit doesn’t make the solder hotter; rather, it provides a stronger presence of heat but keeps the iron at the solder’s melting point?

[blademaster2]

There is a range of soldering temperatures used, but 900F seems on the high side (I had a PC board manufacturer express surprise when I set an iron to 800F, saying it should have been below that). It will indeed drop once the solder has started to accept heat from it to melt, but that seems still on the high side. It could be a function of the thickness and mass of the soldering iron tip, too, but you probably only get good temperature regulation in the temperature-controlled tips of more costly soldering stations and not the soldering pens that just dump power into a heater without a thermostat.

Having said all that, guitar parts are not as fragile and sensitive to heat shock as tiny ICs and chip-type capacitors and resistors so as long as the soldering is done quickly it might not be a concern.

There are other methods to maintain a clean tip besides the damp sponge, such as a bunch of curled metal like steel wool that scrapes off the flux, but a NASA-certified inspector with whom I worked was perfectly happy with the sponge (he insisted that the sponge be very clean and rinsed off before and after each use). His primary concern was cleanliness for the solder and the joints not becoming contaminated.

[unreg]

Thank you blademaster2!

So, if the 900 degrees Fahrenheit max is due to the very wide thick tip that it came attached... and since I unattached that tip and attached one of the tiny tips it came with... does that mean the iron won’t be at the too high 900 degrees Fahrenheit?

I got a 40 watt thanks to this guy: <that’s an excellent how-to-solder-correctly video!

The iron won’t be touching the solder much bc the solder always runs toward heat, as that smart guy taught.


Oh and thank you, blademaster2, for the solder recommendation and teaching me that lead-free solder is rougher on components.

[blademaster2]

Hmmm. That video is okay but a few items there would alarm me. You do not usually want the tip as hot as you can get, for reasons I already mentioned (but the wire he was soldering is not likely to be hurt). The iron tip he uses looks *filthy*.

I get my iron to heat up the part so that the solder melts onto the part just as he says, but first I tin the soldering iron tip with a small amount of solder so that its thermal connection to the part and therefore its ability to transfer heat to it is improved. You do not want to spend a long time heating things up because then the added heat travels everywhere and everything else starts to get hot, which is how damage can happen to the other parts farther away (i.e. like the volume control parts). Also, the solder will not flow "toward" the heat source, but rather it flows along the metal up or down with the heat and the flux like capillary action (which is why I also use separate flux in addition to the flux in the solder core). Good flux and cleanliness are key to getting a good joint as much as the heat is.

[BTW, I am not a soldering expert nor am I certified to the NASA standard, but I have done soldering that has passed NASA inspection and is currently orbiting the Earth.]

[unreg]

Thank you blademaster2! I will try to keep my tip clean! And that’s really amazing that some of your soldering is orbiting earth... WOW!

[unreg]

blademaster2, wow... 1 pound of solder = ~$191

That’s a lot of soldering... guess I’ll pay RadioShack’s $5.00 shipping and change to leaded silver solder... that’s only ~$10 total

Thank you though for all of your expertise you’ve shared with me!

[frets]

Funny name but good solder, I use Whizzo Tech 60/40 Tin Lead Rosin Core Solder Wire Electrical Sn60 Pb40 Flux .032"/0.8mm. Comes in a pound for $17.99.

[thetragichero]

that's a good price. i pay 30 bucks per pound from circuit specialists. they generally have stuff that if you order the shipping for your whole order is free, so i order some crap 63/37 no flux solder for two bucks and get free shipping

[unreg]

I remember from the periodic table that Pb is lead... so does soldering with 40% lead result differently than soldering with 37% lead?

[thetragichero]

probably? the two types i have aren't really comparable as the one without flux i think would be horrible even if it were 60/40

[unreg]

Ahh, ok thetragichero, after looking it up Sn is tin. Would soldering with more lead make the solder less abrasive? And so the components are less damaged?

Rosen core means the solder has flux mixed in so “Rosen” is crucial bc the flux helps the solder to stick/bond with the metal? That’s what I’ve learned.


edit: Now after thinking about it, the 40%-lead solder would leave less room for the conductive tin. Hmm... I think I would rather more conductivity in my solder bc I’m not going to attempt to cover a lot of space with the solder. AND I’m going to get Silver solder (Rosen with lead) bc Silver seems to be more conductive than tin, according to that smart yt guy.

final-edit: Silver is Ag on the Periodic Table

[sumgai]

Apr 15, 2020 22:06:34 GMT -5 unreg said:

... AND I’m going to get Silver solder (Rosen with lead) bc Silver seems to be more conductive than tin, according to that smart yt guy.

Do get back to us on how that silver solder works out for you, eh?

Any solder that contains silver in amounts greater than about 5% is going to require a lot of heat, like as much as 1200deg F. One or two percent, and the question becomes, why did you bother? I suggest that you read up on welding, brazing, and soldering, both in terms of techniques and materials, as well as the reasons for when and where to use each.

Oh, and even when used properly, silver solder gives off toxic fumes. Thought I should warn you about that, so be safe.


One more thing..... it's rosIn, not rosEn.

HTH





sumgai

[unreg]

sumgai, thank you!

I ended up buying: “SnPbAg 62/36/2 Silver-Bearing Rosin-Core Solder, 0.022" Diameter - 1.5 oz.” from RadioShack.

It was only $2.00 more and, from what that yt guy said, it’s much better for electronics. Yes, it’s only 2% silver, but it will work and I’m happy.

I only bought 1.5 oz of solder bc I barely use it... there is a ton left on my 2.5 oz 60/40 Light-Duty roll.


I’ll definitely post results. And I’ll open the windows and use a fan, thank you!

[sumgai]

Apr 15, 2020 23:56:56 GMT -5 unreg said:

And I’ll open the windows and use a fan, thank you!

At the low of a percentage of silver, you're probably OK, but it's always wisest to be safe rather than sorry.


The one thing that silver does is to provide better conductivity*, that's true. However, do recall what I said previously - solder is not meant to provide a conductive path, it's meant to reinforce mechanical strength. One of the greatest false claims in guitar-dom is that soldering a ground wire to the back of a pot is perfectly fine. No, it's not. It's accepted because that's the way the non-engineering crowd did it, back in the 1910s and '20s.** Hard to argue with what appears to be acceptable results. But also notable is the fact that such a joint is that it is rarely physically stressed. Compromise is.


For those who can remember how and why this Forum came into being, you'll note that John Atchley's biggest claim to fame was the star ground and capacitor trick.  But do you recall what he said about connecting all those ground wires to the washer?  That's right, he said "wrap them around the ring washer at least once, before soldering them in place".  'Nuff said.

HTH




sumgai


* In fact, about 8% better. Meaning that silver can conduct about 8% more charge than copper, the usual conductivity standard. The reason we don't use silver as the standard is because it has the one property we don't want in making connections - it self-tarnishes over time. As part of a compound, such effects are relatively non-problematic. But all by itself....    Oh, and expense also plays a part in that, as you might've guessed.

** But push come to shove, one has to admit that it would've been pretty difficult to find an Electrical Engineer in 1910! At that point, pretty much everyone was no more than a hobbyist.

[reTrEaD]

Apr 15, 2020 14:32:33 GMT -5 unreg said:

blademaster2, hmm... I read that cleaning the tip with a damp sponge can be hurtful too since the hot iron will be briefly touching the cold damp sponge. That’s only bad if I clean the tip often, at least that’s what I read.

Wherever you read this nonsense, be sure to take anything they say with a grain of salt.

The only issue you might have with a damp sponge is if the 'sponge' is made of some sort of plastic foam which might melt.

Apr 15, 2020 14:32:33 GMT -5 unreg said:

The Rosen Solder has flux inside; that might be burning?

The flux in solder is meant to perform several useful functions. Among them removing oxygen from oxides by a chemical process known as reduction. Also it dissolves oils, grease and floats away surface contaminants so that intimate metal-to-metal contact can be made on a microscopic level and a proper and conductive bond will be created.

The resultant 'soup' will naturally be carried away to the exterior of the joint but with extended heating, it (including the flux itself) can breakdown into ugly black residue which will cause problems. Getting rid of the spent flux from the soldering iron tip is crucial. Hence the necessity of cleaning with a damp sponge.

[reTrEaD]

Apr 15, 2020 23:41:13 GMT -5 sumgai said:

One or two percent, and the question becomes, why did you bother?

The reason you would 'bother' is when using surface-mount devices or any situation where the surface to be soldered is plated with silver.

www.kester.com/knowledge-base/faq#45312-2-silver-when-a-silver-alloy-is-recommended

Since most surfaces we encounter are not plated with silver, a 63/37 or 60/40 lead/tin alloy is appropriate.

When in doubt, refer to Kester's knowledge base. They've been doing this shiz for over a century and they've made a science of it.

You can certainly buy suitable products from RadioSchmuck, but as for me, I always buy from Kester to support a valuable resource.

[reTrEaD]

Apr 15, 2020 17:00:16 GMT -5 blademaster2 said:

Hmmm. That video is okay but a few items there would alarm me. You do not usually want the tip as hot as you can get, for reasons I already mentioned (but the wire he was soldering is not likely to be hurt). The iron tip he uses looks *filthy*.

I would say the video was "okay". (note the use of quotation marks)

There were some things that were basically correct. But like you, I was appalled at how filthy the tip of his iron was. Also, I only have one heating element which has a conical tip, reserved for rare circumstances). Most of my elements have a chisel tip installed. It's far more versatile. When heating a large surface you can use the flat surface of one face of the chisel to improve the contact area and apply heat more quickly. For medium size surfaces you can use the flat edge at the end. For even more targeted application, you can use a corner of the chisel.

I agree that one can go overboard with the available temperature and that also brings added difficulty in keeping the tip clean and free of oxides. But better slightly too hot than just barely hot enough. Low temperature elements will require longer time of heating of the joint while the heat dissipates into the surrounding areas. Get it, get up to temperature, flow, and get out!

Apr 15, 2020 17:00:16 GMT -5 blademaster2 said:

I get my iron to heat up the part so that the solder melts onto the part just as he says, but first I tin the soldering iron tip with a small amount of solder so that its thermal connection to the part and therefore its ability to transfer heat to it is improved.

Yep.

Also, when dealing with something like the back of a pot, I find it best to pre-tin the surface of the pot before soldering a wire to it. (Sorry sumgai , I don't wrap the wire once around the pot. lol) That way if you see a ton of pinholes, you'll know to take a step back and mechanically clean the oxides from the surface by use of a wire-wheel or grinding stone, or sanding disc on a Dremel.

However, I usually can tell by how shiny or dull the surface is, whether mechanically cleaning is necessary before I even start. But I still pre-tin the surface.

[unreg]

reTrEaD, thank you so much for your kester site link! . Also on that page, is a “Sn60 vs Sn63” answer that says, in the middle, “Sn63Pb37 is eutectic and as such has no plastic range.”

That’s wonderful to know! I surely didn’t like the plasticity of my 60/40 solder. Can’t wait for this new solder to arrive! It should perform as that yt video-guy’s solder did.


Sumgai and reTrEaD, there is so much more to reply to... will have to when I get more time.


edit: If I buy more solder, I’ll probably support kester too, reTrEaD.

[unreg]

Apr 16, 2020 11:43:01 GMT -5 sumgai said:

Apr 15, 2020 23:56:56 GMT -5 unreg said:

And I’ll open the windows and use a fan, thank you!

At the low of a percentage of silver, you're probably OK, but it's always wisest to be safe rather than sorry.

Thank you sumgai

Apr 16, 2020 11:43:01 GMT -5 sumgai said:

For those who can remember how and why this Forum came into being, you'll note that John Atchley's biggest claim to fame was the star ground and capacitor trick.  But do you recall what he said about connecting all those ground wires to the washer?  That's right, he said "wrap them around the ring washer at least once, before soldering them in place".  'Nuff said.

After thinking about this, I’m not going to wrap the wires once around the washer bc:

1.) That washer is also providing ground to the electronics cavity’s black conductive “paint” so it needs, in my opinion to be flush against the black part of the wall.

2.)The washer is very wide, in order to provide lots of contact with the black part of the wall, so wrapping the wires around once would require a large amount of extra wire.

[reTrEaD]

Apr 16, 2020 11:43:01 GMT -5 sumgai said:

Apr 15, 2020 23:56:56 GMT -5 unreg said:

And I’ll open the windows and use a fan, thank you!

At the low of a percentage of silver, you're probably OK, but it's always wisest to be safe rather than sorry.

Silver is non-toxic so its inclusion in any alloy presents no health concerns. However ...

'Silver Solder' is an alloy of Silver, Copper, Zinc, and Cadmium. The first three metals are benign. The last is toxic. en.wikipedia.org/wiki/Cadmium_poisoning

[unreg]

Thank you reTrEaD!

The solder just arrived; it says “SILVER BEARING” and “Do not breath fumes. Use only with adequate ventilation.” So I will keep the windows open today when soldering happens.