Ah yes killed spirits, Tricene tinning flux.
To me the most amazing thing about tin cans is not how they were made, but
that the tin opener wasn't invented for another hundred years or so after
the can. What did they do in the meantime?
Best Wishes
Mike
-----Original Message-----
From: Brian Ellis [mailto:[log in to unmask]]
Sent: Wednesday, May 08, 2013 5:02 PM
To: [log in to unmask]
Cc: 'TechNet E-Mail Forum'
Subject: Re: [TN] Flux classification question
Yes indeed, Mike, your message has caused one of my synapses to fire. I
had forgotten about the abortive Hughes flux. I think that the only
reason that it raised interest at that time was because of the name
which, in the public perception, was synonymous with good products.
On reflection, it is quite astonishing that many Toms, Dicks and
Harries, who knew next to nothing about soldering or flux chemistry
dreamt up some flux formulations, and this goes back over a century! A
very few of them made it into the mainstream! Some of them were even
quite dangerous, containing such substances as aniline and hydrazine -
and even methanol as solvent. Was it not Gray who said that a little
learning was a dangerous thing? In other words, leave it to those who
know what they're doing!
A little while ago I watched a video on the history of tin cans for food
preservation and it showed a reconstruction of how the earliest tin cans
were made, filled with beef and sealed in the mid-1800s. Even Queen
Victoria was impressed! It made me wonder how the steel was tinned and
then I thought about the itinerant thinkers who tinned copper pots for
households. Apparently, they used sal ammoniac in conjunction with a
moleskin. I assume the copper was cleaned by the formation of an
ammonium complex. However, this would not work with steel, so I assume
that some acid was used, probably hydrochloric. I wonder who had the
idea of adding some zinc to it? Of course, we Brits would say that it
was Mr Baker! Necessity is the mother of invention!
Brian
On 08.05.2013 18:13, Mike Fenner wrote:
> Hello Brian
> I waited before answering....
> Your brainbox might not be going all the way to peak revs but it's on all
> cylinders, so you are right - as usual :)
> I have a less secure memory of a new wonder flux brought out by Hughes [as
> then was] based on citric which was wonderful in tests but in practice had
> shortcomings. This would be early/mid 90s? It was taken up under licence
by
> an established flux supplier but quickly dropped. I also remember a
> critique, I think on this forum so it had to be by you, explaining why it
> was no good. Something to do with double bonds and insolubility.
> So far as Zeva was concerned their machines were a triumph of good German
> engineering over bad operating principal (they had no choice because of
> patents), but so far as I recall the only reason for buying their fluxes
was
> because they were part of a package. They were good for engineers to come
up
> with, but were relatively easy for a specialist materials supplier to
> displace. I should have said:
> .... Citric acid ... has a place on the scale, but is not much used in
> fluxes THESE DAYS.
>
> Best Wishes
>
>
>
> Mike
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Brian Ellis
> Sent: Wednesday, May 08, 2013 1:12 PM
> To: [log in to unmask]
> Subject: Re: [TN] Flux classification question
>
> If my aged brainbox is right, ZEVA in Germany made a flux with citric
> acid activator for their drag soldering machines, going back 40-50
> years. It is interesting as being a common tricarboxylic acid, therefore
> quite a powerful reducing agent. It is also quite a good chelating
> agent, so can "capture" difficult-to-dissolve heavy metal salts,
> including both lead and tin ones, so it has a double-whammy effect. It
> works best as an additive (say 20-30%) to conventional dicarboxylic acid
> (e.g. adipic), rather than by itself.
>
> Brian
>
> On 08.05.2013 14:57, Mike Fenner wrote:
>> HI
>> The difficulty of explaining chemistry to non chemists is not to over
>> explain it. This just confuses. I usually talk of strong and weak acids,
>> weak being natural acids - those found in life usually with quite big
>> formulas, and strong or mineral acids which are usually quite simple.
> Using
>> a scale (logarithmic) to illustrate where on the scale these things go
and
>> where fluxes would be. Also add in things from daily life which people
are
>> familiar with Fruit juices, vinegar, cola.
>> Citric acid is naturally found in citrus fruits - oranges lemons - has a
>> place on the scale, but is not much used in fluxes, it can have wash off
>> problems.
>>
>> Best Wishes
>>
>>
>>
>> Mike
>>
>> -----Original Message-----
>> From: Sue Powers-Hartman [mailto:[log in to unmask]]
>> Sent: Tuesday, April 30, 2013 6:21 PM
>> To: [log in to unmask]
>> Subject: RE: [TN] Flux classification question
>>
>> Mike,
>>
>> I like what you wrote. While teaching J-Std001 class, I try to define
the
>> different Fluxes. Would you further define organic and inorganic? It is
>> difficult to find what they are made of, tho I have been told that
organic
>> fluxes are citrus based.
>>
>> Thanks
>>
>>
>> Sue Powers-Hartman
>> Certified IPC Trainer: J-STD-001E, J-STD-001ES,
>> IPC-A 600H, IPC-A-610E, IPC/WHMA-A-620A,
>> IPC 7711-7721B,
>> Killdeer Mountain Manufacturing
>> 233 Rodeo Drive
>> Killdeer ND 58640
>> 701-764-5651 ext 128
>>
>>
>>
>> -----Original Message-----
>> From: TechNet [mailto:[log in to unmask]] On Behalf Of Mike Fenner
>> Sent: Tuesday, April 30, 2013 10:45 AM
>> To: [log in to unmask]
>> Subject: Re: [TN] Flux classification question
>>
>> The term "Resin" describes a group of chemicals which includes natural
>> materials such as shellac from beetles and synthetic materials such as
>> epoxies. The natural material we are most familiar with in soldering is
>> rosin - aka colophony - which is extracted from pine trees in much the
> same
>> way as rubber is tapped. Some of the first soldering fluxes were made
from
>> rosin which has nearly all the attributes needed for electronic
soldering.
>> It does not have quite the oxide removal properties to be totally
>> satisfactory and so more active chemicals are blended with it, these are
>> known as activators. The amount and type added is controlled to avoid too
>> much activity which can lead to corrosion. This gave us the old style R
>> (pure rosin) RMA (mildly activated and RA (fully activated) designations.
>> You can tell the military was involved in these because mildly activated
>> rosin would more naturally be abbreviated MAR rather than RMA. :) .
>> These old style specs were based on composition, basically they said if
> you
>> use these materials in these proportions and they meet compositional
tests
>> (e.g. less than a certain amount of activator or leachable acid then they
>> were considered safe. In other words pragmatic based on a few decades of
>> finding out what worked and what didn't.
>> Modern no clean technology requires more than just chemical and
electrical
>> properties, clear light residues for example and these are more easily
met
>> by using other resins. If you look at current specifications you will see
>> that the no clean classification is the same for rosin or resin
containing
>> materials. Whether or not a flux meets modern specs is not so much
> concerned
>> with what is in the flux as supplied, but what the residues do after
> reflow.
>> So the test criteria are surface insulation resistance (SIR) of reflowed
>> test pieces and so on. The post solder tests for no cleans were based on
> how
>> RMA fluxes behaved. The RE and RO in flux designations is really now for
>> information only and help provide continuity from the previous spec
regime
>> and flux types to the ones we use now. [Also for those still doing legacy
>> work for those requiring MIL spec fluxes.] This explanation is somewhat
>> oversimplified for clarity. Hope it helps.
>>
>> Regards
>>
>> Mike Fenner
>> Bonding Services & Products
>> M: +44 [0] 7810 526 317
>> T: +44 [0] 1865 522 663
>>
>> -----Original Message-----
>> From: TechNet [mailto:[log in to unmask]] On Behalf Of Graham Collins
>> Sent: Tuesday, April 30, 2013 2:13 PM
>> To: [log in to unmask]
>> Subject: [TN] Flux classification question
>>
>> Flux gurus, can you tell me the difference between ROLO and RELO fluxes?
>>
>> (Dewey, I know - the second letter is different, that isn't helpful!)
>>
>> Is a RELO more active or less? Or does the E mean something else?
>>
>> --
>> regards,
>>
>> Graham Collins
>> Senior Process Engineer
>> Sunsel Systems
>> (902) 444-7867 ext 211
>>
>>
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