dino@ddsw1.UUCP (Laura Watson) (10/06/87)
I was watching the movie "The Fly" the other night and it gave me
an idea of a way to solve a problem I've been trying to solve for
several years. Of course, the part that really got me started thinking
was when Brendelfly vomitted all over the other fellow's hand and foot
and made the body parts go away with fly digestive juices.
What I am wondering is this: Is there in existence an actual enzyme,
such as the digestive enzymes of some insect or another, which is
known to dissolve pine rosin? Pine rosin is always a sticky mess, and
hard to clean off of anything. Especially when one puts it into
"rosin" soldering flux......
I would appreciate any information anybody could suggest, or advice on
ways of getting the information.
--
-------
Laura Watson ...[ihnp4, rutgers!moss, clyde, ulysses, cbosgd]!burt!lkw
...ihnp4!ddsw1!dino
May you always have the strength to enjoy your weaknesses. mac@idacrd.UUCP (Bob McGwier) (10/07/87)
in article <240@ddsw1.UUCP>, dino@ddsw1.UUCP (Laura Watson) says: > Xref: idacrd sci.bio:665 sci.physics:2317 > Summary: An idea? Perhaps? > > I was watching the movie "The Fly" the other night and it gave me > an idea of a way to solve a problem I've been trying to solve for > several years. Of course, the part that really got me started thinking > was when Brendelfly vomitted all over the other fellow's hand and foot > and made the body parts go away with fly digestive juices. > > What I am wondering is this: Is there in existence an actual enzyme, > such as the digestive enzymes of some insect or another, which is > known to dissolve pine rosin? Pine rosin is always a sticky mess, and > hard to clean off of anything. Especially when one puts it into > "rosin" soldering flux...... > Laura Watson ...[ihnp4, rutgers!moss, clyde, ulysses, cbosgd]!burt!lkw Laura: Every few years, those of us who own timberland have a deadly beast that visits us. It is called the Southern Pine Beetle. It burrows quite effectively into pine and when the pine attempts to "clot its wound" with rosin, the beetles seem to counteract it. I would at least look into the possibility that they have some enzymatic approach to making a home and sustenance for themselves :-( Bob
greg@phoenix.PRINCETON.EDU (Gregory Nowak) (10/07/87)
In article <305@idacrd.UUCP> mac@idacrd.UUCP (Bob McGwier) writes: }in article <240@ddsw1.UUCP>, dino@ddsw1.UUCP (Laura Watson) says: }> What I am wondering is this: Is there in existence an actual enzyme, }> such as the digestive enzymes of some insect or another, which is }> known to dissolve pine rosin? Pine rosin is always a sticky mess, and }> hard to clean off of anything. Especially when one puts it into }> "rosin" soldering flux...... } It is called the Southern Pine Beetle. ... As I boy, I loved to climb pine trees ... and my hands would get covered with the stuff. Mom, as always, knew what to do -- use nail polish remover. Soak a cloth or cotton ball with it, and the stuff just wipes off. If you have lots of pine rosin problems, a good hardware store will sell you a quart of the active ingredient in nail polish remover (acetone) for a few bucks. Probably cheaper than collecting the digestive enzymes of nasty beetles ...;-) greg -- Due to troubles on mind, I'm temporarily greg posting from phoenix ... you can reply to ...!seismo!princeton!phoenix!greg , and ...!seismo!princeton!mind!greg is still good too ...
larry@kitty.UUCP (Larry Lippman) (10/08/87)
In article <240@ddsw1.UUCP>, dino@ddsw1.UUCP (Laura Watson) writes: > What I am wondering is this: Is there in existence an actual enzyme, > such as the digestive enzymes of some insect or another, which is > known to dissolve pine rosin? Pine rosin is always a sticky mess, and > hard to clean off of anything. Especially when one puts it into > "rosin" soldering flux...... Without considering any chemistry based upon an enzyme, there are a number of solvents which will dissolve rosin: ethyl alcohol, isopropyl alcohol, acetone, methyl ethyl ketone (MEK), perchlorethylene, various freon degreasing solvents, turpentine, and dilute sodium or potassium hydroxide solutions. The choice of solvent should be dictated by the susceptability of the item being cleaned to solvent damage. Isopropyl alcohol is probably the safest of any solvent, but is by no means the most effective. Acetone and MEK work like gangbusters, but will damage many types of paint and plastics. The use of dilute alkalies is particularly useful for removing sap from concrete driveways (save the runoff and make Pine-Sol :-) ). <> Larry Lippman @ Recognition Research Corp., Clarence, New York <> UUCP: {allegra|ames|boulder|decvax|rutgers|watmath}!sunybcs!kitty!larry <> VOICE: 716/688-1231 {hplabs|ihnp4|mtune|seismo|utzoo}!/ <> FAX: 716/741-9635 {G1,G2,G3 modes} "Have you hugged your cat today?"
dino@ddsw1.UUCP (Laura Watson) (10/09/87)
In article <2084@kitty.UUCP> larry@kitty.UUCP (Larry Lippman) writes: > Without considering any chemistry based upon an enzyme, there are >a number of solvents which will dissolve rosin: ethyl alcohol, isopropyl >alcohol, acetone, methyl ethyl ketone (MEK), perchlorethylene, various freon >degreasing solvents, turpentine, and dilute sodium or potassium hydroxide >solutions. > The choice of solvent should be dictated by the susceptability of >the item being cleaned to solvent damage. Isopropyl alcohol is probably >the safest of any solvent, but is by no means the most effective. Acetone >and MEK work like gangbusters, but will damage many types of paint and >plastics. The use of dilute alkalies is particularly useful for removing >sap from concrete driveways (save the runoff and make Pine-Sol :-) ). This is all very true, and the above solvents are all quite well known to me. However, in the application I am thinking of, solvents will not do the job because of their surface tension. On a "Surface-Mount" type of PC board, the chips, resistors, etc. are very close to the board. Close enough to create a capillary. Solvent removal of the rosin flux is possible, but very very difficult. You have to fill the capillary spaces and then break the surface tension over and over again to get the goo out. I figured with some kind of enzyme chemistry, I might only have to create and break the capillaries once. And thus, you know, like save money or something. -- Laura Watson ...ihnp4!ddsw1!dino May you always have the strength to enjoy your weaknesses.
larry@kitty.UUCP (Larry Lippman) (10/10/87)
In article <249@ddsw1.UUCP>, dino@ddsw1.UUCP (Laura Watson) writes: > > Without considering any chemistry based upon an enzyme, there are > >a number of solvents which will dissolve rosin: ethyl alcohol, isopropyl > >alcohol, acetone, methyl ethyl ketone (MEK), perchlorethylene, various freon > >degreasing solvents, turpentine, and dilute sodium or potassium hydroxide > >solutions. > > The choice of solvent should be dictated by the susceptability of > >the item being cleaned to solvent damage. > > This is all very true, and the above solvents are all quite well known to > me. However, in the application I am thinking of, solvents will not > do the job because of their surface tension. On a "Surface-Mount" type > of PC board, the chips, resistors, etc. are very close to the board. > Close enough to create a capillary. Solvent removal of the rosin flux > is possible, but very very difficult. You have to fill the capillary > spaces and then break the surface tension over and over again to > get the goo out. > > I figured with some kind of enzyme chemistry, I might only have to > create and break the capillaries once. And thus, you know, like > save money or something. I now understand your problem, but don't understand why you can find no solution [no pun intended]. I have seen SMD production lines, and most of them use a vapor cleaning machine to remove solder flux and solder mask (if the removeable variety). Vapor cleaning machines generally use a chlorinated aliphatic hydrocarbon solvent, similar to perchlorethylene. Such a heated vapor will penetrate areas around SMD pins quite nicely. What is wrong with vapor cleaning? Other SMD and standard PCB production facilities use non-rosin fluxes which are water-soluble (with detergent), and _literally_ wash the soldered boards in a dishwasher following soldering. Obviously, a detergent acts as a surfactant, lowering surface tension, and allowing penetration of the detergent and water into all areas of the PCB. What is wrong with using a non-rosin flux which is water-soluble? <> Larry Lippman @ Recognition Research Corp., Clarence, New York <> UUCP: {allegra|ames|boulder|decvax|rutgers|watmath}!sunybcs!kitty!larry <> VOICE: 716/688-1231 {hplabs|ihnp4|mtune|seismo|utzoo}!/ <> FAX: 716/741-9635 {G1,G2,G3 modes} "Have you hugged your cat today?"
dino@ddsw1.UUCP (Laura Watson) (10/13/87)
In article <2100@kitty.UUCP>, larry@kitty.UUCP (Larry Lippman) writes: > I now understand your problem, but don't understand why you can >find no solution [no pun intended]. Because I want to invent a better solution than the best of the existing ones available; they are just not quite good enough. As Hofstadter would put it, I want to "jump out of the loop." (This is sci.physics, isn't it?) > I have seen SMD production lines, and most of them use a vapor >cleaning machine to remove solder flux and solder mask (if the removeable >variety). Vapor cleaning machines generally use a chlorinated aliphatic >hydrocarbon solvent, similar to perchlorethylene. The best of this gamut I know of is Dow Chemical's Prelete (tm) which contains 1,1,1-trichlorethane and aliphatic alcohols. There are unsolvable (insoluble?) problems with it, however. It works, but not very well. It takes a cleaning cycle of >30 minutes for our application, and still leaves a lot of flux and residues behind (for reasons I will try to explain below). The second best of this type of cleaning material is the Alpha Metals 1003 (tm) azeotrope containing tetrafluorodichloroethane and n-propyl alcohol. But it has problems with acid formation and tends to corrode the cleaning equipment if you don't watch it like a hawk and replenish its acid inhibitors frequently. >Such a heated vapor >will penetrate areas around SMD pins quite nicely. What is wrong with >vapor cleaning? This is not true in our situation. The heated vapor cannot penetrate areas around the SMD solder legs (no pins) for one very simple reason: those areas are already filled with liquid solvent which does not run out because of the capillary effect! I am talking about components mounted from 1 to 8 mils off the board, averaging somewhere between 2 and 4 mils (1 mil = 0.001"). I am talking about square, flat, Leadless Chip Carrier (LCC) packages up to 1"x 1", with solder pads (no leads) on 25 and 50 mil centers. Most SMD applications have substantially more space than this; they don't have quite the same problem we have. When you put a room-temperature object into a heated solvent vapor at, say, 130 degrees C, the higher-temperature vapor starts to condense on the surface of the room-tempreature object. Condensation continues until the board reaches the same temperature as that of the vapor. The surfaces are covered with a film of liquid until that time. Don't forget, vapor and liquid coexist at the liquid's boiling point. And this liquid quickly fills the capillaries under the components. And the liquid stays put in there as long as you are at atmospheric pressure in solvent-saturated conditions. And even afterwards. What we find is that maybe a week after the boards are cleaned, enough of the solvent will evaporate to break the capillary. Boards that were ostensibly clean suddenly have puddles of flux/solvent mixture appear around the components. It was underneath all the time. > Other SMD and standard PCB production facilities use non-rosin >fluxes which are water-soluble (with detergent), and _literally_ wash the >soldered boards in a dishwasher following soldering. Obviously, a detergent >acts as a surfactant, lowering surface tension, and allowing penetration of >the detergent and water into all areas of the PCB. What is wrong with >using a non-rosin flux which is water-soluble? It is conceivaly possible that we could clean the rosin flux using an alkaline detergent solution and a dishwasher, but my experience has been that surfactants have a nasty habit of sticking to surfaces and not rinsing off completely. Which could cause problems with the adhesion of coatings applied to the board later. There are couple of very good reasons for sticking with rosin flux: The most important is probably the fact that we have a substantial bit of expertise built up around using a certain type of solder paste which contains rosin flux. We went through testing a lot of different paste solder compositions, including a few non-rosin ones, to even find one that would do the job without spewing massive quantities of solder balls all over the place. If we changed the material we are using, we'd have to go through a steep learning curve all over again, probably affecting relearning the paste application, reworking tooling, tightening sampling inspection criteria, etc. Besides that, I think that the rosin flux paste does a better soldering job -- fewer voids in the solder joints upon X-raying. Another big reason is that we are making this stuff for the military. It would be politically difficult, though probably not impossible, to get an agreement to deviate from all those military specifications which contractually require us to use rosin flux. Also, we seem to have a very conservative design team who are a little superstitious about flux. (And maybe I'm a smidge superstitious about it too.) Rosin flux has a lot of long-term studies behind it's use in high- reliabiliy applications. Non-rosin fluxes, the last time I checked, did not have 5 or 10-year long studies of the long term effects of their use, since they have only come out in the last 5 or so years. Water-soluble fluxes are generally thought to leave ionic residues which can degrade insulation resistance under harsh atmospheric conditions, such as at sea, on ships or in submarines. Rosin is unique because it is acid only at soldering temperatures. At room temperatures the abietic, pimaric, & etc. acid molecules actually change to a non-acidic configuration. So if you do have a few traces of it left somewhere, it doesn't hurt anything electrically. (But I think it may possibly present some heat transfer problems where heat transfer is very critical.) But all of this application-specific reasoning notwithstanding, I think the idea of enzymatic or other biotechnological cleaning agents would probably be worthwhile even on regular industrial cleaning of various sorts. Do you know how much money is spent in industry on exhaust hoods and ventilating equipment to keep the solvent vapors away from personnel? Do you know how much money is spent in industry on disposing of liquid waste solvents in hazardous waste landfills? Do you know what the maximum stack limit currently is for the emission of photochemically reactive solvents into the air? Do you how many salaries in industry are directly tied to educating workers on the safe handling of chemicals? Among those chemicals in the widest general use are cleaning solvents. Do you know that almost every time NIOSH tests a solvent-type chemical for carcinogenicity on rats, it ends up *tightening* the exposure limits for that chemical? Necessitating more and better ventilation? Solvents used to be cheap and easy to clean things with, but they really aren't any more. The people working on the detergent cleaners of various sorts are on the right track, they just aren't going anywhere. Wouldn't it be neat if I could get a tankful of those microorganisms that eat oil spills on the ocean cheaply enough to remove industrial oils from metal parts? Wouldn't it be biodegradable? Couldn't I wash it down the drain? Wouldn't it be less dangerous to people's health? Now that I have writ much more than I intended to on this subject, I guess I'll get back to my favorite salt mine. -- Laura Watson ...ihnp4!ddsw1!dino Contentment is the smother of invention.
larry@kitty.UUCP (Larry Lippman) (10/18/87)
[A discussion about the desire of finding an enzyme to dissolve pine rosin used as a soldering flux in electronic circuit assembly; objections were raised as to the efficacy of existing solvent cleaning processes due to the inability to adequate penetrate the contact areas around SMD (Surface Mount Devices)]. In article <255@ddsw1.UUCP>, dino@ddsw1.UUCP (Laura Watson) writes: > ... > Because I want to invent a better solution than the best of the existing > ones available; they are just not quite good enough. As Hofstadter > would put it, I want to "jump out of the loop." > ... > Rosin is unique because it is acid only at > soldering temperatures. At room temperatures the abietic, pimaric, & etc. > acid molecules actually change to a non-acidic configuration. At room temperature, the major constituent of rosin is d-pimaric acid, which upon heating undergoes a methyl migration and forms abietic acid. Further heating and chemical reaction of abietic acid with the solder and other flux components converts it to a relatively inactive meso triacid. > But all of this application-specific reasoning notwithstanding, I think the > idea of enzymatic or other biotechnological cleaning agents would probably > be worthwhile even on regular industrial cleaning of various sorts. At cursory glance, the use of an enzyme to facilitate dissolving rosin sounds like a good idea, but upon further reflection, I do not believe it feasible. First of all, an enzyme merely functions to catalize another reaction; an enzyme performs no action per se in this application. What reaction can we catalyze? Saponification is the first which comes to mind, but even if such an enzyme existed, it would have difficulty in "surviving" at the high pH necessary for saponification. Abietic acid, d-pimaric acid and other constituents of rosin are terpenes (diterpenes to be precise), and I don't know what to do with them other than dissolve 'em in a solvent or saponify 'em. I don't see how an enzyme can facilitate either of those two processes. What you might be thinking of are "enzyme detergents" which have been touted in various advertising campaigns. But the enzymes in these detergents are generally bacterial proteases which hydrolize proteins. While hydrolyzing proteins may help remove some fabric stains of organic origin, they won't touch diterpenes. So I don't know what to tell you other than I do not believe that enzymes will help in this area. > Wouldn't it be neat if I could get a tankful of those microorganisms that > eat oil spills on the ocean cheaply enough to remove industrial oils from > metal parts? Wouldn't it be biodegradable? Couldn't I wash it down the > drain? Wouldn't it be less dangerous to people's health? Now, a genetically-engineered bacteria may be the solution, but I suspect that such a bacteria - if possible to create - would only serve to complicate a circuit board cleaning process. And then the rate of reaction would be quite slow. I know very little about genetically-engineered bacteria, so perhaps someone else could comment in more depth on this possibility. > Now that I have writ much more than I intended to on this subject, I > guess I'll get back to my favorite salt mine. It certainly never hurts to ask questions, and pursue new horizons even though alleged experts say it can't be done. I have done the same thing myself, often finding success. Unfortunately, here *I* am the one saying it can't be done... <> Larry Lippman @ Recognition Research Corp., Clarence, New York <> UUCP: {allegra|ames|boulder|decvax|rutgers|watmath}!sunybcs!kitty!larry <> VOICE: 716/688-1231 {hplabs|ihnp4|mtune|seismo|utzoo}!/ <> FAX: 716/741-9635 {G1,G2,G3 modes} "Have you hugged your cat today?"