Would you be peeved? (Flux) - Page 1
Forum section: electronics / general

author: orbiter
author_rank: Frequent Contributor
timestamp: December 15, 2015, 01:54:05 pm
content: Today I have received some new Amtech 559 flux which I have been eager to try out. The flux is in a 30CC syringe which cost me just over £30. Now the Amtech 559 fluxhas a recommended shelf life of around 12 months as do many fluxes which is fine, however the expiry date on the flux I received was June 2016.Leaving me with a 5 month window to use it up. I know this is not an exact expiry date period but I feel that I should be expecting a little longer than that as I probably won't use it all inthat time..?Would you guys have any gripes about a rather short use-by period?

author: SeanB
author_rank: Super Contributor
timestamp: December 15, 2015, 05:53:33 pm
content: Not like it is an injectable with a short shelf life, just keep it refrigerated when not in use. Just be thankful that it is not some nuclear medication, with a shelf life measured in minutes.

author: Shock
author_rank: Super Contributor
timestamp: December 15, 2015, 06:45:35 pm
content: Sounds expensive, hope you didn't get ripped off. I assume you didn't buy it through an authorized distributor.You have to watch out for unscrupulous sellers who grab cheap product or try to offload their old expiring product onto you. I would expect that flux has been sitting around a year before you got it. Watch out also for reselling fake flux from China. Expect some lame excuses anyway.Probably best to get the batch number and date and contact Amtech.

author: orbiter
author_rank: Frequent Contributor
timestamp: December 15, 2015, 07:04:19 pm
content: Thanks for the opinions fellas...No I don't feel ripped off as the flux is genuine USA made stuff from an authorised distributor. And £30 for 30cc is not so bad really imo.Think I will contact them though and express my disappointment in the short shelf life I got.

author: Macbeth
author_rank: Super Contributor
timestamp: December 15, 2015, 07:29:55 pm
content: Is this stuff like food - a "best before" date or a "use by" date.Because I've got plenty of food in tins and bottles YEARS passed the best before date and I've found nothing wrong with them. Some have improved with age past the "best before" (I'm looking at you, HP "Guinness" brown sauce!)I imagine as a hobbyist you could stretch the flux usage well past the expiry date. A volume manufacturer will expect a constant profile from the stuff whereas as an individual you can just adapt.

author: Macbeth
author_rank: Super Contributor
timestamp: December 15, 2015, 07:33:59 pm
content: The other one to consider is if the 12 months applies AFTER you have opened it. Like my bottle of sauce with a 2 year best before expiry, once opened, should then be refrigerated and used within 8 weeks or something like that?

author: IanB
author_rank: Super Contributor
timestamp: December 15, 2015, 07:39:18 pm
content: I don't particularly see what could go wrong with flux. The only thing I can think of is that it dries out and becomes harder to squeeze from the syringe.But £30 for 30 cc of flux? What is it made from? Unicorn tears? I have no idea why you wouldn't just buy a large bottle of liquid flux and supply your own syringe (or eye dropper).

author: orbiter
author_rank: Frequent Contributor
timestamp: December 15, 2015, 08:33:58 pm
content: Quote from: IanB on December 15, 2015, 07:39:18 pmI think the Amtech 559 flux may have the importing duties bunged onto the price as it's rather hard to get hold of in the UKI usually buy Loctite/Multicore PC21A flux in a 5 litre container, this does me for a couple of years normally and it's excellent stuff. I just fancied a change so thought I'd try the Amtech 559 as I'dheard good reports about it. I actually thought £30 for 30cc was quite good especially as the likes of Chip Quik is £10 for 10cc.I suppose against the Loctite PC21A stuff it works out expensive though as that's only £70 for 5 litres.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 15, 2015, 08:59:28 pm
content: Not knowing about that flux specifically:Fluxes, in general, contain volatiles: usually a solvent base, and light weight organic acids. The rest is 'body' (petroleum jelly, poly glycols, etc.), and heavy acids (the crusty part of rosin). The solvents can always be added back in -- usually something like isopropanol or ethyl acetate is good enough. (Not that it can really be mixed in, in syringe form!) The acids are the active ingredients, and the lighter weight ones are the most reactive and therefore the strongest fluxing. Once those are gone, you're left with a gummy product that's not much better than used goo already on the board.Since after all, there are two main differences between fresh and "used" flux: heat exposure, and some dissolved metal oxides and miscellaneous insoluble crud. The heat activates the acids, making them react, but mostly, it just drives them off, leaving a crusty, less reactive deposit.Conversely, keeping those volatile components inside means tight sealing and low temperatures. Low temp might not be required, but it won't hurt -- often, solvents diffuse out of their containers even when perfectly sealed, and diffusion is a thermally driven process. Getting it out of the 'fridge every use might be rather inconvenient though, especially since it'll probably be a lot thicker when cold, too. But as long as you remember to put it away each session.So if it's an ordinary rosin-based flux, this should be what's going on. If it's not, similar chemistry is likely at work, but even just compatibility with organic solvents may be very different, I don't know.Tim

author: sleemanj
author_rank: Super Contributor
timestamp: December 15, 2015, 09:06:02 pm
content: Quote from: orbiter on December 15, 2015, 01:54:05 pmPersonally, no I wouldn't, because unless you are working in the industry and NEED your flux to meet it's stated specifications because your processes demand it, then I really don't think it's that important.It's still going to work just fine for typical hobbiests a long long time after it's expiry date, just don't expect it to meet the exact numbers in it's datasheet.If I was in industry and did need it to meet spec, I think I'd be a bit miffed but also I'd probably be buying a lot more than 30cc at a time.

author: Augustus
author_rank: Regular Contributor
timestamp: December 15, 2015, 09:13:30 pm
content: The price is similar to what you have to pay for it here in Germany. Genuine Amtech 223 and 559 tacky gel fluxes are between 50...60€ for a 100g jar. There are other brands who set you back 100€ (or more) for the same amount of flux, the Amtech ones are rather on the cheaper side, afair... What do you guys in the US and Australia have to pay for these?

author: orbiter
author_rank: Frequent Contributor
timestamp: December 15, 2015, 10:04:16 pm
content: I appreciate all the comments and suggestions as always guys. Thank you.

author: miguelvp
author_rank: Super Contributor
timestamp: December 16, 2015, 01:41:27 am
content: Storage and Handling according to this datasheet if it's the right one.http://www.amtechsolder.com/pdf/TDS%20NC-559-ASM-TF.pdfQuoteNo refrigeration, that's more for solder paste.

author: Macbeth
author_rank: Super Contributor
timestamp: December 16, 2015, 02:30:40 am
content: Also note the emphasis on "should" instead of "must". i.e., these are just guidelines...

author: IanB
author_rank: Super Contributor
timestamp: December 16, 2015, 02:47:44 am
content: Is there a particular reason to prefer tacky flux over liquid flux, given that tacky flux is apparently ~100x more expensive?

author: Macbeth
author_rank: Super Contributor
timestamp: December 16, 2015, 03:34:06 am
content: I'm an old school 60/40 multicore solder kind of guy so using seperate flux is a new one on me. It used to be left to plumbers.But from what I can tell, to re-solder a BGA is going to be easier with tacky rather than liquid because its going to be much easier to just plop into position and then rely on the characteristics of the tacky flux and solder to just align the chip and solder balls into place nicely. If you use liquid it will just drain away and also as soon as hot air is applied it will burn away quickly.However, I have never attempted BGA rework so I don't have a clue. It seems to make some sense though.

author: RobertHolcombe
author_rank: Frequent Contributor
timestamp: December 19, 2015, 08:28:55 am
content: I have a syringe of Kester 741 at work which is just over 18 months old - Kester specified shelf life is 6 months. I haven't noticed any deterioration over that time. I store it on my bench which is probably at around 20-25 degrees during work hours.

author: Psi
author_rank: Super Contributor
timestamp: December 19, 2015, 08:33:26 am
content: i've been quite impressed with loctite branded soldering products.flux, paste, solder wick etc.Lately the chemtronics wick hasn't been working as well as it used to.But the loctite stuff is working great.

author: JGAN
author_rank: Contributor
timestamp: December 21, 2015, 07:34:30 am
content: Quote from: IanB on December 16, 2015, 02:47:44 amNot all tacky flux is so expensive. I prefer it way more than liquid flux because it doesn't run everywhere nor burn up as fast, and it helps hold BGA chips and other SMDs in place when using hot air.

author: RobertHolcombe
author_rank: Frequent Contributor
timestamp: December 21, 2015, 09:17:41 am
content: Quote from: JGAN on December 21, 2015, 07:34:30 am+1My perception when using liquid flux is that I am "wasting" most of it because it flows in areas I'm not actually working, compared to gel flux which stays exactly where it is applied. I additionally then have to spend additional time and cleaning consumable to remove the excess liquid flux.Personally I find the convenience and time saved offsets the increased cost of gel flux when used in rework

author: nanofrog
author_rank: Super Contributor
timestamp: December 21, 2015, 05:47:34 pm
content: Both have their place.The issue with liquid flux running all over the place can be mitigated by using the right dispensing tool IME.Here's a review of what I use (Bon Pen BON-102):https://youtu.be/mQPkw711WhoI find it much cleaner & precise than a needle bottle, and both more convenient and less wasteful than just dipping a brush in flux.For flux, I use the following Kester products:RF741 paste/gel*EP256 solder paste (63/37;CML Supply** breaks this into hobbyist friendly sized syringes)1544 (RA, same as in Kester 44)186 (RMA, but close to RA)* CML Supply sells smaller syringes of this (6ml)**They also sell through eBay.

author: zapta
author_rank: Super Contributor
timestamp: December 21, 2015, 06:09:02 pm
content: Quote from: nanofrog on December 21, 2015, 05:47:34 pmJust a side note, beware of Chinese clones of the Bon Pen.

author: nanofrog
author_rank: Super Contributor
timestamp: December 21, 2015, 06:18:32 pm
content: Quote from: zapta on December 21, 2015, 06:09:02 pmVery true (good catch BTW).Best to stay off of eBay and similar sites, and go with an authorized distributor. For the US, All-Spec is a good source IME (depending on the model, they go for ~$15 - 20 for singles[BON-102-1]; they also sell 5 packs).There's also the ChemtronicsCW7000for those that would prefer a traditional felt pen that's refillable (2 pack, and comes with 2 spare tips).

author: KE5FX
author_rank: Super Contributor
timestamp: December 21, 2015, 08:06:23 pm
content: Expiration dates, refrigeration, and all that stuff makes the difference between a five-sigma process and a six-sigma one. If you're not building something by the millions, don't worry about it.

author: RobertHolcombe
author_rank: Frequent Contributor
timestamp: December 22, 2015, 07:54:25 am
content: Those bonkote pens look greatElement14 AUD pricing is a little bizarre thoughBON102 x1 ~$30BON102 x5 pack $186lolHave you had to replace the tip?

author: nanofrog
author_rank: Super Contributor
timestamp: December 22, 2015, 10:17:39 am
content: Quote from: RobertHolcombe on December 22, 2015, 07:54:25 amRegarding those prices, someone's lost their mind.As per tip replacement, mine's a couple of years old and still all original (don't use it 8+hrs/day though). You could use a single pen body and swap out heads/tips though if you wanted more than one shape as a means of saving a few bucks. But there's not a lot of price difference however, so you'd probably prefer the convenience of each being complete (grab the one you want & go).

author: zapta
author_rank: Super Contributor
timestamp: December 22, 2015, 06:30:35 pm
content: Quote from: nanofrog on December 21, 2015, 06:18:32 pmI learned it from one of your older posts ;-)Got mine from All Spec. It works better with thiner fluxes. MG Rosin is super sticky and clogged it, maybe because I don't use it daily. I cleaned it with IPA and am now using a Kester flux.

author: nanofrog
author_rank: Super Contributor
timestamp: December 22, 2015, 09:38:51 pm
content: Quote from: zapta on December 22, 2015, 06:30:35 pmI forgot to mention it this time.I ran out of MG Chemicals Rosin 835 before I bought the BON-102, so I've not tried it. The Kester is thin enough it works beautifully as you've discovered, and as long as I can get it in small quantities, I'll continue to opt for it vs. MG Chemicals.Should it thicken, just add a few drops of acetone or alcohol as needed to thin it (or clean the brush out, which should be more frequent as hobbyist users).Since you're in the US, you might want to consider using Kleen Strip's Denatured Alcohol, as it's much cheaper than 99% IPA and easier to get (i.e. any Home Depot for ~$16 - 17 per gallon last I checked). It's a 50/50 mix of ethanol & methanol, so it's also a bit more aggressive than IPA = makes it easier to clean flux residue off IME.Same brand of acetone (I get the 1 quart size), as well as xylene (mix ~20% with alcohol makes an even better flux cleaner that's safer for plastics than mixing in acetone; doesn't evaporate as fast either).

author: zapta
author_rank: Super Contributor
timestamp: December 22, 2015, 10:47:31 pm
content: Quote from: nanofrog on December 22, 2015, 09:38:51 pmThis one, as is? I will give it a try.http://amzn.com/B000SL3S6Y

author: KL27x
author_rank: Super Contributor
timestamp: December 22, 2015, 10:59:55 pm
content: You can buy IPA very cheap in bulk, too. I use denatured, primarily because its convenient to buy in the can while at the hardware store, and the odor is less objectionable to me.QuoteAlso, if I understand it correctly, 99% IPA will eventually absorb water from the air and move towards 91%. Denatured alcohol starts and stays around 95% when open to the air.If I try to thin my RA with too much denatured, some solids precipitate out of solution. I have some 99% IPA somewhere, but I haven't tried it, yet. I have some lighter fluid, which I shall have to try, as well.I haven't tried a Bon pen, yet. I have made do with what I have on hand. If you tie a bit of twine into a knot and run the end through a plastic syringe tip, you get a decent brush tip that can't accidentally squirt flux 2 feet through the air. Then you can melt the plastic with hot air and smoosh it down around the knot, so the brush can't back out. A dip brush works great for passives, but with the syringe brush, you can lay down thicker beads for the IC pads. I am sure you can do the same thing with the Bon pen by squeezing it.

author: nanofrog
author_rank: Super Contributor
timestamp: December 23, 2015, 11:16:42 am
content: Quote from: zapta on December 22, 2015, 10:47:31 pmYes, that's the stuff.Any brand will do, but the content may be a bit different (more commonly is just ethyl alcohol as the active component + bittering agent). The methanol in the Kleen Strip brand makes it's activity just a bit higher without becoming too aggressive. And as it's available in any Home Depot (and other places), it's the easiest to find on a shelf IME. Top it off with reasonable prices, and it's a no-brainer for me at least (no one carries IPA in anything greater 91% in 1qt containers; cheapest this way at Sam's Club in my location). Price is ~ the same.Quote from: KL27x on December 22, 2015, 10:59:55 pmBest I can do is 91% for about the same money as denatured, which I opt for due to the improved performance. Convenience also plays a roll (no shipping costs = drives up the cost buying online), but the Home Depot and Sam's Club are within minutes of each other where I live, so it's a wash.BTW, last I checked prices for the 99% stuff, it was ~$30 for a 1gallon can before shipping.Quote from: KL27x on December 22, 2015, 10:59:55 pmThis is my understanding as well, but I wouldn't think it's an issue unless it's open and left out (would think a properly sealed metal container wouldn't let moisture in).Quote from: KL27x on December 22, 2015, 10:59:55 pmTry adding some acetone instead, and see if that doesn't solve the precipitate (xylene should do too).Quote from: KL27x on December 22, 2015, 10:59:55 pmA syringe with a needle does pretty well too at dispensing precise amounts from what I understand (makes sense to me at any rate). They make inexpensivebrush bottles specific for flux dispensing(not as much control as a Bonpen), and you could also use a nail polish type of brush bottle (can get new empty ones on eBay cheap).

author: IanB
author_rank: Super Contributor
timestamp: December 23, 2015, 12:56:31 pm
content: Quote from: nanofrog on December 23, 2015, 11:16:42 amIf you leave the container open and out you will end up with 0% IPA. It all evaporates. Trust me. Been there, done that

author: KL27x
author_rank: Super Contributor
timestamp: December 23, 2015, 07:58:08 pm
content: QuoteCheapest I have ever seen was is in the local grocery store. Comes out to $16.00 a gallon. But they don't keep a gallon on the shelf. Only a few 8 oz bottles at $0.99 each. After coming up empty handed at 3 other drugstore/grocers, I was surprised to see this. I thought the price would be ridiculous.But most grocery stores only carry 91%, so 99% really is not very convenient to buy. Apparently, this is partly because it is used in the manufacture of certain drugs.QuoteTrue. But I'm thinking if you dispense only small amounts out of a large container, the contents would eventually go down in concentration. Or if you use a little push dispenser type of containter that isn't airtight, or some other open container like a squirt bottle that has a small opening to allow air exchange.

author: zapta
author_rank: Super Contributor
timestamp: December 23, 2015, 08:08:01 pm
content: Quote from: KL27x on December 23, 2015, 07:58:08 pmHere is a good video about solvent. At one point he explains that water is added to the IPA so it can devolve also stuff that IPA alone doesn't.

author: KL27x
author_rank: Super Contributor
timestamp: December 23, 2015, 08:19:18 pm
content: Water has to be removed in the manufacturing process. So they don't have to actually add any. They have to remove less to make 91%.99% is so hydrophilic, it absorbs water directly from the air.

author: pcm81
author_rank: Regular Contributor
timestamp: May 31, 2023, 10:42:28 pm
content: I realize that this is an 8 year old thread, but i have more than 8 years of data to report!Back in 2010 I bought a gallon of Kester 2331-ZX flux. Been storing it in my garage in florida in original well sealed bottle and poring off a little at a time as i need it. Still works.