paulc@boulder.Colorado.EDU (Paul Connally) (07/20/89)
Anybody know of a good solvent to clean rosin from PCB's? Paul Connally paulc@boulder.colorado.edu University of Colorado High Voltage Electron Microscope Lab MCDB - Box 347 "A higher potential for Boulder, CO 80309 better penetration."
vaso@mips.COM (Vaso Bovan) (07/20/89)
In article <10167@boulder.Colorado.EDU> paulc@boulder.Colorado.EDU (Paul Connally) writes: > > Anybody know of a good solvent to clean rosin from PCB's? > Dishwashing liquid does a reasonable job. If you want to End Life As We Know It, you can use a halogenated hydrocarbon solvent. eg "freon".
strong@tc.fluke.COM (Norm Strong) (07/21/89)
In article <10167@boulder.Colorado.EDU> paulc@boulder.Colorado.EDU (Paul Connally) writes: } } Anybody know of a good solvent to clean rosin from PCB's? For industrial use, the solvent of choice is Trichloroethylene. If you're just doing some spot cleaning by hand, use Methyl Ethyl Ketone (MEK). -- Norm (strong@tc.fluke.com)
erk@americ.UUCP (Erick Parsons) (07/22/89)
>From: paulc@boulder.Colorado.EDU (Paul Connally) Message-ID: <10167@boulder.Colorado.EDU> > > Anybody know of a good solvent to clean rosin from PCB's? Naptha works pretty good barring the health hazards that it poses. The fumes will send you into a low Earth orbit and I've been told that it is a Carcinogen. I've never tried to ignite it but judging from the fumes I would guess that it is flammable too. Can someone tell us, Is it a Carcinogen ? Flammable ? -- ------------------ // -----------Cut-Here---------------------------------- Erick Parsons // Words for the wise: *If it works don't fix it.* Sacramento Ca // mail to: ...pacbell!sactoh0!americ!erk ------------- \\// --------------------------------------------------------
mmm@cup.portal.com (Mark Robert Thorson) (07/22/89)
Kester makes a solder with water-soluble flux. Water and a brush are all you need to clean it off. I never use it because you gotta be careful not to breathe the smoke when soldering with it. I just leave the rosin on when I make stuff.
nagle@well.UUCP (John Nagle) (07/22/89)
Miller-Stephenson Chemical makes products for this purpose. Their
MS-190 and MS-190HD (heavy duty) solvent flux removers are available in
aeresol spray cans. MS-190HD contains trichlorotrifluoroethane,
dichloromethane, and dichlorodifluoromethane. These are somewhat safer
than MEK. The exposure limit for MS-190HD is 629ppm, averaged over
eight hours. (By comparison, the standard for dry cleaning fluid is
125ppm and may be dropped to 25 soon.)
I've been quite satisfied with this stuff.
Cans of this are available at retail outlets in Silicon Valley.
Elsewhere, you could call Miller-Stephenson at 203-743-4447.
John Naglebarry@hprmokg.HP.COM (Barry Fowler) (07/24/89)
We've found that most "flux removers" don't really remove the flux, they simply allow it to be spread over a larger area of the board when brushed on. Complete immersion can remove the flux but presents problems to some electronic components (such as aluminum electrolytic capacitors). We now just leave the flux on the board when replacing single components. Spreading the flux causes more contamination problems than leaving a small blob in a localized area.
brianr@tekig5.PEN.TEK.COM (Brian Rhodefer) (07/25/89)
In article <1254.AA1254@americ> erk@americ.UUCP (Erick Parsons) writes: > >Naptha works pretty good barring the health hazards that it poses. >The fumes will send you into a low Earth orbit and I've been told >that it is a Carcinogen. I've never tried to ignite it but judging >from the fumes I would guess that it is flammable too. Can someone >tell us, Is it a Carcinogen ? Flammable ? > 1) All that applying a rosin-dissolving solvent to dirty circuit boards does is to distribute the original clumps of rosin into thin coatings of rosin, depending on the area that the solvent spreads over. In order to actually CLEAN boards with solvent, you must either remove the "dirty" solvent before it evaporates and re-deposits the rosin, or dunk the board into such a huge quantity of solvent that the resulting "rosin concentration" is low enough that when the board is removed and dried, an insignificant amount of rosin remains. Naptha has an astonishingly high rate of evaporation, making it difficult to remove contaminated naptha before it evaporates and drops the rosin somewhere else. The best practical way of removing the contaminated solvent is to simply let it drain off the board, replacing it with a continual stream of fresh solvent until the rosin is gone. Obviously, if the solvent is noxious or expensive, this method has its drawbacks. There ARE water-soluable rosin fluxes available, however, which allow such a "one-pass" cleaning treatment with an inexpensive solvent (water). You just stick your dirty boards into a dishwasher, toss in some generic detergent (unless you object to drops that spot), and let 'er rip. For non-aqueous solvents, the best method is one of those vapor-phase degreasers, where the board is held in a refrigerated zone above a boiling vat of solvent. Pure solvent condenses on the board, dissolves rosin, and dribbles off into the vat. Pure solvent also condenses out on the refrigeration coils, and this winds up dribbling into a "pure tank", which acts as a reservoir to supply a spray gun. The spray gun can be used on the dirty boards to accelerate the cleaning process. Periodically, solvent from the "pure reservoir" is diverted into a holding tank, and the distillation process is driven until the goo in the boiling vat is a near-saturated rosin solution. The goo is disposed of, the solvent from the holding tank is returned to the vat, and the system is "topped off" to compensate for the various losses. Unfortunately, these machines are pretty serious emitters of ozone-harming substances (since the solvents generally used are blends of ethanol and chlorinated flourocarbons). 2) Some electronic components don't take well to these "mass-production" cleaning techniques. The lubricants of components with moving parts (e.g., switches and potentiometers) are often leached out along with the rosin, degrading the performance of the now un-lubricated parts. Also, some of the non-aqueous solvents can damage electrolytic capacitors, if they are able to leak in (through anti-explosion vents, for example). If you're serious about cleaning, you'll have to make sure that whatever process you choose won't harm your components. On the subject of naptha toxicity: While I was in college, I worked for a small firm that made instrument panels for aircraft. One of the manufacturing steps involved scrubbing the panels, by hand, in open vats of naptha, in a poorly ventilated work area. Rubber gloves were available for the workers, but not always used. I don't mean that I approve of such practices, or that there aren't many long-term health risks, but in the short term, the naptha fumes didn't seem to be as intoxicating as the original poster implies. At least, the employees in that part of the plant didn't seem outwardly affected. Brian Rhodefer
pwilcox@paldn.UUCP (Peter McLeod Wilcox) (07/28/89)
In article <1254.AA1254@americ>, erk@americ.UUCP (Erick Parsons) writes: > >From: paulc@boulder.Colorado.EDU (Paul Connally) Message-ID: <10167@boulder.Colorado.EDU> > > Anybody know of a good solvent to clean rosin from PCB's? > Naptha works pretty good barring the health hazards that it poses. > Can someone tell us, Is it a Carcinogen ? Flammable ? Naptha is flamable (very), but I don't think it is Carcinogenic - don't really know however. Most comercial PCB cleaners use either a pure CFC (Hydrocarbon with some or all of the hydrogen replaced by Clorine or Florine, also known as ozone depletion gas :-), or one mixed with alcohols. Naptha I would think would have the potential for destroying some plastic components like relays and switches. And, if you get a spark, you are asking for one hell of an explosion! Radio Shack sells a CFC/Alcohol cleaner in a spray can which works very well, non-toxic, and non-flammable. -- Pete Wilcox ...gatech!nanovx!techwood!paldn!pwilcox
ingoldsb@ctycal.COM (Terry Ingoldsby) (07/29/89)
Having been an electronics hobbiest for some years, I am going to ask
what is probably a *dumb* question. I have seen all the discussion
about methods of removing rosin from PC boards, but I've never had
any trouble with leaving it there. My understanding is that it is
an insulator. Is this not true? Does it have some high frequency
characteristics that I've never run into? Do people just dislike
how it looks?
--
Terry Ingoldsby ctycal!ingoldsb@calgary.UUCP
Land Information Systems or
The City of Calgary ...{alberta,ubc-cs,utai}!calgary!ctycal!ingoldsbstrong@tc.fluke.COM (Norm Strong) (07/31/89)
In article <422@ctycal.UUCP> ingoldsb@ctycal.COM (Terry Ingoldsby) writes: }Having been an electronics hobbiest for some years, I am going to ask }what is probably a *dumb* question. I have seen all the discussion }about methods of removing rosin from PC boards, but I've never had }any trouble with leaving it there. My understanding is that it is }an insulator. Is this not true? Does it have some high frequency }characteristics that I've never run into? Do people just dislike }how it looks? If you could be sure of exactly what flux is in your solder you'd be right. However, "Rosin core solder" is a generic term and covers a multitude of organic fluxes that may or may not need removing. And yes, it does look lousy--especially on a piece of commercial gear. -- Norm (strong@tc.fluke.com)
john@stiatl.UUCP (John DeArmond) (08/01/89)
>In article <422@ctycal.UUCP> ingoldsb@ctycal.COM (Terry Ingoldsby) writes: >Having been an electronics hobbiest for some years, I am going to ask >what is probably a *dumb* question. I have seen all the discussion >about methods of removing rosin from PC boards, but I've never had >any trouble with leaving it there. My understanding is that it is >an insulator. Is this not true? Does it have some high frequency >characteristics that I've never run into? Do people just dislike >how it looks? Terry, One of the absolute best solvents for most fluxes is 100% ethanol. This is available at your friendly liquor store as PGA (pure grain alcohol). I've found that not only does this stuff remove roson rather well, it leave no residue. I've tried other alcohols and dilute ethanol and none seem to work as well. The water seems to interefer with the solvent effects. My procedure is to first, before doing the repair, wash the area in Clorothane (1,1,1 tricloroethane) to remove any conformal coating that may be present. 1,1,1 won't remove the silicone or epoxy conformal coatings but these are not seen too much in commercial gear. Next do the repair work. Then, with the board horizontal, soak the area in ethanol and scrub with an acid brush (a cheap organic bristle brush so named because it was designed to apply acid for soldering sheet metal. Obtain at hardware store). The flux will appear to disappear but will actually be in solution. If you stop there, your board will dry with a white, powdery film. Hold the board vertical and hose the board thoroughly with ethanol. I use a lab wash bottle for the task. This will flush the board of the flux-laden fluid. Dry with a hair dryer or oven. I suggest a light conformal coating of Krylon crystal clear spray for non-critical boards and whatever the mfr. recommends for critical ones. I've used this technique for years in repairing even very sensitive nuclear instrumentation boards where no surface conductance at all is tolerated (resistors with >10E10 ohms are common). One final note. Don't get fooled at the liquor store into getting 196 proof votka. The 2% water content will foul up the process. The last time I bought some, I got the Absolut brand (russian, I think) which was the only thing they had. I've found that this works better than any of the freon or freon-alcohol mixes that are so expensive. Besides, if you get in a real mess, you can "deflux" the old stomach :-) John -- John De Armond, WD4OQC | Manual? ... What manual ?!? Sales Technologies, Inc. Atlanta, GA | This is Unix, My son, You ...!gatech!stiatl!john **I am the NRA** | just GOTTA Know!!!
mmm@cup.portal.com (Mark Robert Thorson) (08/01/89)
ingoldsb@ctycal.COM (Terry Ingoldsby) says: > Having been an electronics hobbiest for some years, I am going to ask > what is probably a *dumb* question. I have seen all the discussion > about methods of removing rosin from PC boards, but I've never had > any trouble with leaving it there. My understanding is that it is When I was designing graphics boards, which were produced in small quantity and assembled by hand, I asked the production dept. why they were spending so much time removing rosin. They said it caused corrosion. Frankly, I don't believe it. I think it is a purely cosmetic issue.
myers@hpfcdj.HP.COM (Bob Myers) (08/02/89)
Just a quick word regarding rosin/flux removal: You may note, in looking
at the insides of various pieces of gear, that some of the bigger names in
the electronics business (especially some Japanese manufacturers with a
reputation for quality products) are no longer bothering to wash the flux
off their PC boards. Yes, it *looks* bad - but often, the wash process is
more of a problem as far a quality/reliability goes than the flux is. Most
fluxes used in PC assembly are reasonably good insulators, and it doesn't hurt
anything to simply leave the stuff there. Certain washes, on the other hand,
can be damaging. One thing to pay particularly close attention to is NOT
to use cleansers containing halogens (such as fluorine or chlorine) on boards
containing aluminum electrolytic capacitors. If the seal on the caps isn't
perfect, and some of the cleaning solution gets inside, you can kiss your
caps goodbye after a fairly short time. (Unfortunately, NOT short enough
for the problem to show up before you ship the board off as "good"!)
Bob Myers KC0EW HP Graphics Tech. Div.| Opinions expressed here are not
Ft. Collins, Colorado | those of my employer or any other
myers%hpfcla@hplabs.hp.com | sentient life-form on this planet.larry@kitty.UUCP (Larry Lippman) (08/02/89)
In article <6236@stiatl.UUCP>, john@stiatl.UUCP (John DeArmond) writes: > One of the absolute best solvents for most fluxes is 100% ethanol. This > is available at your friendly liquor store as PGA (pure grain alcohol). > I've found that not only does this stuff remove roson rather well, it > leave no residue. I've tried other alcohols and dilute ethanol and none > seem to work as well. The water seems to interefer with the solvent > effects. > ... > One final note. Don't get fooled at the liquor store into getting > 196 proof votka. The 2% water content will foul up the process. The small percentage of water has no practicable bearing upon the solvent action of ethanol in this application. Absolute ethanol is highly hygroscopic, and will rapidly absorb water from the atmosphere until it ultimately forms an azeotropic mixture having a concentration of 95.6% ethanol and 4.4% water. I can assure you that absolute alcohol which has been sitting around for a while after having had its container opened is no longer "absolute". Rosin flux residue is NOT a single compound, but in fact a mixture of several compounds, primarily diterpenes such as abietic acid. In addition, rosin flux residue contains thermal decomposition products of these diterpenes. These compounds all have different characteristics, with ethanol not being an optimal, overall solvent. Without digressing into a discussion of the physical chemistry involved, isopropanol possesses a structure which is more suitable as a universal solvent for these compounds - without running risk of dissolving plastic materials on electronic components. 95% isopropanol is just fine. <> Larry Lippman @ Recognition Research Corp. - Uniquex Corp. - Viatran Corp. <> UUCP {allegra|boulder|decvax|rutgers|watmath}!sunybcs!kitty!larry <> TEL 716/688-1231 | 716/773-1700 {hplabs|utzoo|uunet}!/ \uniquex!larry <> FAX 716/741-9635 | 716/773-2488 "Have you hugged your cat today?"
iws@rayssdb.ray.com (Ihor W. Slabicky) (08/04/89)
In article <6236@stiatl.UUCP>, john@stiatl.UUCP (John DeArmond) writes: > > One of the absolute best solvents for most fluxes is 100% ethanol. This > is available at your friendly liquor store as PGA (pure grain alcohol). > I've found that not only does this stuff remove roson rather well, it > leave no residue. I've tried other alcohols and dilute ethanol and none > seem to work as well. The water seems to interefer with the solvent > effects. - stuff deleted - > > One final note. Don't get fooled at the liquor store into getting > 196 proof votka. The 2% water content will foul up the process. The last > time I bought some, I got the Absolut brand (russian, I think) which was > the only thing they had. From my experience with grain alcohol and liquor stores: I have bought Grave's Grain Alcohol which is 195 Proof and is USP grade. That is PURE (as in uncontaminated) alcohol - BUT it does have water in it!!! Why???? - because when alcohol is made to 200 Proof, it quickly absorbs water from the air until it settles down to 195 Proof. You can't get 200 Proof alcohol. Where did you find Absolut at 196 proof? Btw, Absolut is made in one of the Scandinavian countries, not Russia. So, which brand name of alcohol do you use for rosin removal? As an aside - does anyone have a homemade recipe for audio tape players head cleaner - denatured alcohol? What do you use? Ihor
jac@paul.rutgers.edu (Jonathan A. Chandross) (08/04/89)
iws@rayssdb.ray.com (Ihor W. Slabicky) > I have bought Grave's Grain Alcohol which is 195 Proof and is > USP grade. .... > So, which brand name of alcohol do you use for rosin removal? This is a very expensive way to clean boards. If you buy denatured alcohol or pure methanol, you'll get your boards clean and you won't have to pay a sin tax, either. You should wear gloves as well because the alcohol will wreck havoc with your skin. Don't use methylene chloride - it can attack some expoxy based components. Jonathan A. Chandross Internet: jac@paul.rutgers.edu UUCP: rutgers!paul.rutgers.edu!jac
strong@tc.fluke.COM (Norm Strong) (08/04/89)
In article <134@paldn.UUCP> pwilcox@paldn.UUCP (Peter McLeod Wilcox) writes: }In article <1254.AA1254@americ>, erk@americ.UUCP (Erick Parsons) writes: }> >From: paulc@boulder.Colorado.EDU (Paul Connally) Message-ID: <10167@boulder.Colorado.EDU> }> > Anybody know of a good solvent to clean rosin from PCB's? }> Naptha works pretty good barring the health hazards that it poses. }> Can someone tell us, Is it a Carcinogen ? Flammable ? } }Naptha is flamable (very), but I don't think it is Carcinogenic - don't }really know however. Most comercial PCB cleaners use either a pure CFC }(Hydrocarbon with some or all of the hydrogen replaced by Clorine or Florine, }also known as ozone depletion gas :-), or one mixed with alcohols. Naptha }I would think would have the potential for destroying some plastic components }like relays and switches. And, if you get a spark, you are asking for one hell }of an explosion! Radio Shack sells a CFC/Alcohol cleaner in a spray can }which works very well, non-toxic, and non-flammable. The very best way to remove rosin flux is to write to the manufacturer of the solder and ask for their recommendation. You'd be surprised how much they know about removing their own flux. :-) -- Norm (strong@tc.fluke.com)
nagle@well.UUCP (John Nagle) (08/07/89)
We covered this last month. There are good commercial flux removers.
They are far better than raw alcohol for this specialized job.
Here in Silicon Valley, they are available at your neighborhood electronics
supply store, such as Zack's, Fry's, or Hamilton/Avnet. For those in
backward areas, mail order may be necessary.
Miller-Stephenson Heavy Duty Solvent Flux Remover (MS-190-HD) is
very effective. It comes in a spray can. Cautions: skin irritation,
not flammable, CFC propellant. I've been very pleased with this.
Miller-Stephenson HQ is at 203-743-4447; ask them for a dealer near you.
The Zack Electronics catalog has a good selection of defluxing
products. (415-626-7976, VISA/MC accepted). Order a catalog. The
Zack catalog has several pages of defluxing products, including those
of Ersin, the well-known solder manufacturer. They even have a biodegradable
solder flux for board washing. (In a PC board manufacturing plant, the
board passes over a wave of molten solder and then through a machine much
like a dishwasher. The components that can't take this treatment, if any,
are added later, and they are usually such things as speakers. If you
do this yourself, use distilled water; you don't want to leave a mineral
residue.)
This is a totally solved problem if you use the right tool for the
job.
John Nagleneal@lynx.uucp (Neal Woodall) (08/08/89)
In article <2515@rayssdb.ray.com> iws@rayssdb.ray.com (Ihor W. Slabicky) writes: >In article <6236@stiatl.UUCP>, john@stiatl.UUCP (John DeArmond) writes: >> One of the absolute best solvents for most fluxes is 100% ethanol. This >> is available at your friendly liquor store as PGA (pure grain alcohol). >I have bought Grave's Grain Alcohol which is 195 Proof and is >USP grade. That is PURE (as in uncontaminated) alcohol - BUT >it does have water in it!!! Why???? - because when alcohol is >made to 200 Proof, it quickly absorbs water from the air until >it settles down to 195 Proof. You can't get 200 Proof alcohol. And you cannot get PGA (aka Everclear, aka Grain Alcohol) in the good old communist state of California at all! Seems that the good old state legislature, in one of their more pious moods, has decided that "pure drinking alcohol" is "BAD".....they would rather you not drink any alcohol at all, but if you must, you may not have PGA, even if you are an adult! I guess they think that is PGA is available to the general public via the corner liquor store, that everybody and their cousins will be spending all of their time drunk. Just another way in which the state of CA is fu*ked! Now, I am not going to lecture at length about how screwed up California is... this is just not the newsgroup to do that. But, it seems kind of short-sighted to me for the damn state legislature to decide that PGA has no place in this state. I like to drink PGA mixed with daquiri mix...it is also useful as a good solvent for things like the aforementioned fluxes....it is good for cleaning CD's with. There are many things that PGA is good for cleaning that denatured alcohol will screw up (ie, will disolve in some way). Another way the CA state legislature has screwed the public in an attempt to justify their own existance! Neal