What solder do you guys use?

[AndrewT]

If Cardas is a genuine eutectic it should have a single temperature melting/freezing point, not a range that gives a partly frozen paste.
Most experiences I have had and seen are that the non lead solders are not so good at wetting and not so easy to use.
Similarly some of the best fluxes are being banned due to health concerns.
None of this is helping the solderability of components, particualarly for us amateurs.

 

[Allen Wright]

What you are experiencing with lead free solder is normal - the stuff is just horrible and we wouldn't use it if it wasn't for the heavy arm of the European law.

One can find one that is acceptable for initial constuction, but for amateur use where one may want to constantly rebuild things, it's near impossible to rework without excessive heat and risk of component damage.

We only use lead free in our commercial products, for our own hobbying around, we still use good silver loaded (4%) leaded solder.

Regards, Allen

 

[Bengali]

It's genuine cardas solder from percy audio. darn, I did not know lead free would be such as issue. I would have stuck to the old
stuff.

Even though it has a low melting point, it takes forever to get it to spread. I'm concerned I may have heated my electrolytic caps for too long, where the whole cap is completely hot to touch.

I guess I could try adding flux next time I use it. I bought this
soldering station:

http://www.web-tronics.com/didisostc.html


They had this one as well, Lead Free Soldering Station:

http://www.web-tronics.com/lesost.html

The tips were much more costly to replace so I went with
the normal one. Any ideas as to what make this a lead free
soldering station? They both use ceramic heaters. Ony difference
I see if easier tip replacement.

thx

 

[ak_47_boy]

Lead free solder is not very good. Silver content is needed for surface mount soldering plus it lowers the melting point. I don't know what the benefits of copper are. 62% tin, 36% lead and 2% silver seams ideal to me.

We should have a group buy if we can decide on what is best.

 

[ak_47_boy]

I read now that copper improves the "wetting" property's of the solder. I don't think this is a good thing.

 

[Bengali]

I bought the lead free without prior knowledge.

it's best to avoid it since it requires higher temperature to heat up. the cloudy look is also normal from the lack of lead, this coming from cardas support.

I'm sure the cardas solder with lead works great. WBT is great also. I'm thinking of trying a roll from partsexpress, dayton silver solder.

 

[wrenchone]

Some comments -

Chlorinated solvents of any sort are death on electrolytic capacitors. The stuff gets into the cap via the rubber seals and causes the cap innards to disintegrate. This caused some nasty RMA/failure issues in my last job. Isopropanol is safe. For a while, my last employer tried to make us engineers use no-clean flux at our benches, as a big customer had complained about flux residues on prototypes. However, no one used it for long, as the flux fumes are really irtritating if you're standing over a board manually soldering. I've also seen production boards churned out using no-clean, and they are really scummy-looking...

 

[Bengali]

I agree. No clean flux remover has a very nasty smell. I used it at work and have to open the door to vent fresh air everytime. still leaves the board sticky. I prefer Isopropanol with soft bristle brush.

 

[Gordy]

So if I want to be environmentally friendly and use a lead-free solder at home, and be able to make good joints without difficuly, which brand of solder should I buy?

 

[jneutron]

Lead free solder is not very good. Silver content is needed for surface mount soldering plus it lowers the melting point. I don't know what the benefits of copper are. 62% tin, 36% lead and 2% silver seams ideal to me.

I don't know why the silver would be needed for surface mount. I do not believe the dfference between 179 C and 183 C is all that much, so expect no difference at all.

I read now that copper improves the "wetting" property's of the solder. I don't think this is a good thing.

Wetting is not only a good thing, it is the entire reason for using flux and making an electrical connection. "wetting" is the act of the formation of a metallurgical bond.

Cheers, John

 

[wrenchone]

Silver loading is beneficial for surface mount parts in that it helps to prevent the end contacts from being leached away by the solder. Certain barrier metals on the part end terminations help, but you can't count on that degree of diligence from all manufacturers, especially in these penny-pinching days.

 

[jneutron]

Silver loading is beneficial for surface mount parts in that it helps to prevent the end contacts from being leached away by the solder. Certain barrier metals on the part end terminations help, but you can't count on that degree of diligence from all manufacturers, especially in these penny-pinching days.

While I recall reading this over the last 20 years in various industry publications, first with copper, then with silver... I haven't found it to be particularly true in practice.

Copper loading solder to reduce leaching of copper makes the process more difficult and starts to give copper-tin crystalline structure, which appears grainy.

Silver isn't much better.

If the end contact can be so easily removed in solution, I think soldering would be the least of the problems.

But I certainly agree with you on some manu practices..I especially love parts that have unsolderable surfaces hiding under a 3 to 5 microinch layer of gold...sigh...

Cheers, John

 

[wrenchone]

Of course, everthing is now changing with all the ROHS bull-hockey. No doubt, a whole new array of problems. I guess I should be stocking up on old school solder....

 

[jneutron]

Of course, everthing is now changing with all the ROHS bull-hockey. No doubt, a whole new array of problems. I guess I should be stocking up on old school solder....

I worry with all the parts now being made with a pure tin plated finish, as it is not possible to "mandate out" tin whiskers and tin pest. At least they haven't yet gotten rid of category 9 exemptions (I suspect they never will).

Replacement of lead in solders does indeed remove it from the waste stream, but it is creating a much larger waste stream due to failures associated with lead free.

I find the biggest issue for hobbyists with lead free isn't the actual constituents of the solder, but rather, the temperature required. The temp range is just above the useable domain of the old fluxes... close enough that it does work, but far enough to give us headaches.

Cheers, John

 

[lowtherdream]

I've been using the Cardas quad eutectik solder. Love the stuff.
flows very well, easy to use, great shiny joints !
The sell tri and quad eutectic solder. The tri is lead free.

Cardas solder and flux
http://www.cardas.com/content.php?area=oem&content_id=19&pagestring=Solder+and+Flux

Interesting article by George Cardas:
Cardas Solder vs crimped connections

 

[ak_47_boy]

Wetting is not only a good thing, it is the entire reason for using flux and making an electrical connection. "wetting" is the act of the formation of a metallurgical bond.

Cheers, John

The wetness of tin lead solder if good. If it is any wetter the solder joints will be thin, it won't bead up as well. I am assuming the wet term is referring to surface tension.

 

[jneutron]

The wetness of tin lead solder if good. If it is any wetter the solder joints will be thin, it won't bead up as well. I am assuming the wet term is referring to surface tension.

The term can be confusing, sorry. It is meant to convey the ability to bond to the base metal, as opposed to non wet or "beading up".

Without flux, liquid solder will bead up on the base metal. This is because the oxide of the base metal surface prevents any metallurgical bond between the solder and the base.

When flux is present, it attacks the oxide layer of the base metal, and the underlying pure metal can form compounds with the solder. Tin soldering to copper produces two intermetallic compounds with two different atomic ratios, those compounds are required to actually make the joint.

The flux must be able to clean the oxide at the correct temperatures for the solder. Using a flux designed to work for lead tin (183 degrees C eutectic) may prove difficult to use for tin/silver with it's 221 C eutectic point. If you do this, the flux will indeed activate and clean the surface prior to reaching 183, but it can easily burn before the surfaces reach 221. If it burns, it may destroy the clean oxide free surface that the solder needs when it reaches melt temp.

Go the other way, a high temp flux and lead tin, and the flux may not activate before the solder melts, and perhaps never.

The proper flux is absolutely required. If the flux is too old, it may not work..not enough, same thing..wrong temp, same.

Some fluxes are also optimized for the surface you wish to solder to..nickel, copper, gold, silver, aluminum.. Peruse a flux manu's site, you may find more details on this. The Superior Flux company had lots of details on their website, I haven't looked there in a decade or two..

Cheers, John

 

[DreadPirate]

I asked myself the same question when I got into this hobby (recently, if you must know) and decided Kester might be a good source of info. Here is a FAQ answering most questions I was concerned with:

http://www.kester.com/en-us/technical/knowledgebase.aspx?cid=68

In case link doesn't work:

When would I want to use 2% silver solder? Only when soldering silver or silver coated components.

When should I use 60/40 vs 63/37? For our application 63/37 is recommended, flows better. This is also stated more directly elsewhere on their site, but I could not find it.

Do you need to clean "44" flux? No, it is noncorrosive and nonductive, cleaning would be for cosmetic reasons only, BUT if the solder is reheated to 160 F, then it will liquify and become conductive. I personally like to clean it, I believe its the right thing to do.

Recommended tip temperature for 60/40 or 63/37: 700 F.

Does this stuff have a shelf life? 60/40 and 63/37 have a life of 3 years from manufacture if stored properly.

 

[DreadPirate]

I like the explanation here addressing why 63/37 might be better than 60/40 for "normal electronic soldering":

http://www.logwell.com/tech/servtips/solder.html

 

[Luke]

I had a huge roll of unnamed nice solder, flowed beautifully and now its out. I bought some 60/40 stuff locally and it doesnt flow and needs a high melting point. This could become an expensive business so I would like to know if anyone has tried this stuff and can recommend it.

http://newzealand.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=0551671