Solder Questions [Archive]

tvdude310

Mar 26, 2008, 07:43 PM

60/40 resin core is a great all-purpose electronics grade solder. I prefer the very thinnest I can find, but you certainly don't have to go to that extreme. As mentioned above, NEVER use acidic flux on electronics.
And the 60/40 refers to the ratio of lead to tin (if I remember correctly).
Good luck!

ZAGNUT

Mar 26, 2008, 08:02 PM

And the 60/40 refers to the ratio of lead to tin (if I remember correctly). you remembered backwards... ;)

a bottle of flux is also a great thing to have, makes things so much easier. the kester 186 is pretty much the best all around and also comes in a pen but i prefer the bottle with a needle or to use a dave brown CA applicator.

dave

tvdude310

Mar 26, 2008, 08:26 PM

...well, the last time I heard it was 1978, so I'm just glad I remembered it was tin and lead!
Thanks for correcting me, I hate to give bad info.
Rob

village_idiot

Mar 26, 2008, 09:39 PM

Kester 44 rosin core solder. The 44 rosin is activated so it really helps to make the solder flow. If you use a lot it will goop up the tip of your iron, but it worked real well for the stuff that you want to do. Mouser, Digikey, etc. should have it.

gigelus2k3

Mar 27, 2008, 02:51 AM

Rodney

Mar 27, 2008, 12:01 PM

I have a can of Kester rosin paste flux that is at least 20 years old and still enough left to do a lot of connections.

ZAGNUT

Mar 27, 2008, 04:34 PM

The water-soluble Kester (http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=KE1808-ND) flux is best, everything else is just inferior in what a flux is supposed to do. This thing has an awesome ability of reducing the surface tension and a little hot water will completely wash it away, leaving behind perfect, shiny joints.

[in the tone and mimic of H. Belafonte on Muppets] trust me!

Serban

IIRC (now my memory is going...) the water soluble stuff is highly corrosive if even a tiny trace is left behind. while this shouldn't be a problem on boards it is a BIG problem when soldering connectors to wire leads as the wire strands will happily wick the flux up under the insulation where it can't be cleaned off.

dave

cwil58

Mar 27, 2008, 08:12 PM

you remembered backwards... ;)

a bottle of flux is also a great thing to have, makes things so much easier. the kester 186 is pretty much the best all around and also comes in a pen but i prefer the bottle with a needle or to use a dave brown CA applicator.

davethanks for all the help I just purchased a butane soldering tool kit from MAC tools with 60/40 thin solder. this kit is awsome and can be purchased from mac for about 120... part number ST150B

jeffs555

Mar 27, 2008, 09:27 PM

the water soluble stuff is highly corrosive if even a tiny trace is left behind.

Dave is absolutely correct about this. I recently found a prototype board at work that I had partly assembled using water soluble flux and never finished and not cleaned. All of the lands had been completely eaten away. The water soluble requires complete and thorough cleaning, and this can be very difficult under large fine pitch IC's. I have stopped using it for this reason. I use either no-clean flux or else rosin paste which I clean off with alcohol.

Jeff

Rodney

Mar 28, 2008, 12:55 PM

That water soluble flux is not rosin, it is an acid and should never be used on any electonics.

gigelus2k3

Mar 28, 2008, 01:49 PM

That water soluble flux is not rosin, it is an acid and should never be used on any electonics.

I seriously doubt that the Kester is acid-based. At my place of work we're using ONLY the w.s. type; if you're dealing with high impedance circuits, you have no alternative to it. In the past 10 years I have yet to see one PCB where the copper has been eaten away, even if the board was not washed.

I just took a look at the first LiPo I bought some 4 years ago; for obvious reasons, the joints have not been washed. It still looks good, without any corrosion being present.

It's possible though that some manufacturers offer corrosive, acid-based w.s. flux, maybe that's what you had the bad luck to use.

Serban

jeffs555

Mar 28, 2008, 02:48 PM

The Kester flux you referenced is acid based. It must be completely cleaned or it can corrode metal. That is the flux I used, and it did corrode the lands off a board when not cleaned. Read the MSD.

http://www.kester.com/Data%20Sheets/Fluxes/Water%20Soluble%20Alcohol-Based/2331-ZX%20Flux%20Pen%20Global%20(04Jun07).pdf
http://www.kester.com/MSDS/USA%20and%20Canada/English/Fluxes/MSDS%202331%20US%20(16Aug06).pdf

tvdude310

Mar 28, 2008, 02:52 PM

Guys,
Whatever its composition is, it should be labelled. If it's acid based, it should say so on the lid somewhere.
If it is, then the previous statement about not using it on electronics is valid.

You'd be surprised at how frigile the thin solder runs are. Someone at work spilled a soda on a control panel of a tape deck and didn't think it was worth mentioning...a week later at least a dozen traces had vanished from the boards and ribbon cables. I use resin core only, and I STILL wash it with flux remover just to be sure. I know, it's overkill. But when the tape deck costs over $100,000 it pays to be safe.

gigelus2k3

Mar 28, 2008, 03:04 PM

Jeff,

Looking at the datasheet, I stand corrected. We are using the 2224-25 (http://www.kester.com/Data%20Sheets%5CFluxes%5CWater%20Soluble%20Alcohol-Based%5C2224-25%20Global%20(05Oct07).pdf) flux instead, similar formulation.

However, my long time experience with it has been excellent, with corrosion never occurring. For what a flux is supposed to do, the results are spectacular. Washing the boards with hot tap water afterwards is easy and safe. And in the cases where I can't do that (soldering Dean plugs to LiPo packs), I couldn't detect any corrosion.

Serban

jeffs555

Mar 28, 2008, 03:28 PM

That 2224-25 is still an acid based flux and as far as I know all of the water soluble fluxes are. If it can't be completely cleaned off you are asking for trouble. Where it is exposed and heated to soldering temperatures, most of it will evaporate so it will be less of a problem. However, like Dave said earlier, it will wick into the wires and under the insulation where it cannot be cleaned. You have probably just been lucky, and if you peel back some of the insulation you will possibly see some of the green corrosion starting to form on the copper.

As far as labeling goes, most of the ws flux I have seen are just labeled organic liquid flux and don't say acid on them anywhere even though they are acid based. They are designed for electronics, but only where they can be completely cleaned with water.

http://www.kester.com/MSDS/USA%20and%20Canada/English/Fluxes/MSDS%202224-25%20US%20(20Feb07).pdf

PS In defense of the WS flux, they do work great and can allow soldering where other flux won't. They just need to be thoroughly cleaned off with water afterward.

ZAGNUT

Mar 28, 2008, 04:29 PM

maybe the water soluble stuff is similar to the "no clean" fluxes in that they are perfectly inert if the residue is left alone but once you disturb it you had better get it ALL off?? something to do with the corrosive elements being safely entrapped in the residue until tampered with?

never tried either of the above and don't really see the need for them in basic soldering. the reason why i like the liquid rosin in a squirt bottle is the ability to really douse the area being soldered which can be really helpful when working with surface mount parts. this "more is merrier" method also keeps the rosin from burning into a hard crust that's difficult to remove. either way i try to clean the board as soon as i'm done soldering to keep the residue from drying out and this means the board will get multiple cleanings if i don't solder all the parts in one sitting. for cleaning i like pure alcohol that i can buy at the hardware store or in the booze isle at the supermarket.

dave

Rodney

Mar 28, 2008, 04:49 PM

What tvdude310 said, if you have the original container, it should tell you wether or not it is acid based, I think Kester makes both types but I have not shopped for flux for years so am not current on what is available.

Ron van Sommeren

Mar 28, 2008, 07:15 PM

When/if acid-based wicks in litze/braided wire, no amount of rinsing can get it out.

Prettig weekend ;) Ron

ray foley

Mar 31, 2008, 10:17 AM

hi there from Toledo

I contacted my pcboard manufacturer the other day and he wanted to know if my boards needed to be ROHS complient. This appears to be a european requirement for new equipment aimed at eliminating lead from the manufacturing process.

Okay, that's fine but what shall we use for solder? and what flux, etc?

Any input?

ciao -rjf

rmteo

Mar 31, 2008, 10:39 AM

Take a look at Kester K100LD lead-free solder. See here:
http://www.stanleysupplyservices.com/product-group.aspx?id=13275

Ron van Sommeren

Mar 31, 2008, 11:53 AM

Maybe this will get you on the way Ray, Wikipedia on the "Restriction of Hazardous Substances Directive", lots of links:
http://en.wikipedia.org/wiki/Restriction_of_Hazardous_Substances_Directive

qmulus

Apr 09, 2008, 06:44 PM

Ray,
If your product does not need to be RoHS compliant, then getting lead free PCBs will just cost you more. I design and build products sold world-wide, so we need to be RoHS compliant on all of our boards. Right now, you CANNOT legally sell electronic products in Europe containing lead. If you use lead free solder, all of the components need to be RoHS certified, as the higher temperatures used for the lead-free solder can damage components not designed for the RoHS soldering process, especially if PCAs are waved or oven soldered. You can use solder containing lead on RoHS compliant components, but not vice versa. For production, a water soluble flux is used and the PCAs are machine cleaned. For rework, a rosin flux is used. On my bench I have some Kester lead-free solder with no clean flux. It works OK, but doesn't flow like lead solder. I also use higher temp tips in my METCAL irons.

FWIW, most all mass marketed products are now lead free. One tip off is the dull looking finish of the solder.

HTH!

Steve

hi there from Toledo

I contacted my pcboard manufacturer the other day and he wanted to know if my boards needed to be ROHS complient. This appears to be a european requirement for new equipment aimed at eliminating lead from the manufacturing process.

Okay, that's fine but what shall we use for solder? and what flux, etc?

Any input?

ciao -rjf

mjsas

Apr 09, 2008, 09:13 PM

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vintage1

Apr 09, 2008, 09:31 PM

Ray,
If your product does not need to be RoHS compliant, then getting lead free PCBs will just cost you more. I design and build products sold world-wide, so we need to be RoHS compliant on all of our boards. Right now, you CANNOT legally sell electronic products in Europe containing lead. If you use lead free solder, all of the components need to be RoHS certified, as the higher temperatures used for the lead-free solder can damage components not designed for the RoHS soldering process, especially if PCAs are waved or oven soldered. You can use solder containing lead on RoHS compliant components, but not vice versa. For production, a water soluble flux is used and the PCAs are machine cleaned. For rework, a rosin flux is used. On my bench I have some Kester lead-free solder with no clean flux. It works OK, but doesn't flow like lead solder. I also use higher temp tips in my METCAL irons.

FWIW, most all mass marketed products are now lead free. One tip off is the dull looking finish of the solder.

HTH!

Steve

I dont think this is entirely correct: I think certain classes of product are exempt. Its the usual silly catch all greenwash type Eurocrat legislation, that keeps the greens happy, and lots of people break anyway, and enough exemptions are lobbied for so that you can get around it if you have to.

The ine that got me is 'no more lead shot for water fowl'

Tungsten instead, and that puts up the price of a wild duck soethig shocking! I think I paid $ 8 a bird..ruinous. ;)

tvdude310

Apr 09, 2008, 10:11 PM

We're having a lot of issues here at work making the conversion. We need to have two of everything. We've got plenty of old equipment working right alongside plenty of new equipment. We have solder stations setup for silver, others for lead. As stated above, the higher heat needed for lead free solder can ruin the semiconductors on the older gear unless you're a real whiz at soldering (I am, but I've been doing it for almost 40 years). The newer guys have had issues toasting chips because of it.
I'm glad we're getting rid of lead, but I sure wish the new silver solder flowed like the old stuff. But practice makes perfect, and we can't shy away from the new ways.

qmulus

Apr 10, 2008, 01:44 PM

I dont think this is entirely correct: I think certain classes of product are exempt. Its the usual silly catch all greenwash type Eurocrat legislation, that keeps the greens happy, and lots of people break anyway, and enough exemptions are lobbied for so that you can get around it if you have to.

The ine that got me is 'no more lead shot for water fowl'

Tungsten instead, and that puts up the price of a wild duck soethig shocking! I think I paid $ 8 a bird..ruinous. ;)

IME, you can get exemptions in some cases, as some devices are not yet available lead-free, but that is a real PITA. Our products are for the automotive market, so we could theoretically get some exemptions. Considering that big 20LB chunk of lead acid battery, it will be quite a while before automobiles are lead free. IMO, it is all or nothing with our products, so we are converting all of our production for US and abroad to lead free. It costs more, but it makes things simpler. The downside is that I have about $2k worth of leaded parts that I can't use anymore and nobody else wants.

I don't mind working with the lead free solder. It does melt at a higher temp, doesn't flow as well, and even good joints look dull like a cold (lead) solder joints, so you need to relearn a little. Paying $50 for a roll of solder is a little hard to stomach though. Our assembly facility had to purchase $100k+ in new equipment, like a new reflow oven that had much tighter temperature control and new rework stations to keep leaded and lead free processes segregated.