+++++++++++++++++ From: "Don Brown" To: "Steve Dyer" , "Elecraft" Subject: Re: [Elecraft] Deflux? Date: Thu, 15 Aug 2002 09:04:34 -0500 Hi I agree with Tom I usually clean my boards with denatured alcohol. This will clean the boa= rd but will sometimes deposit a white residue. I have found by adding a s= quirt of WD-40 to the alcohol prevents this and makes it clean better. I= use a 1 inch paint brush with the bristles cut to about 3/4 inch long to= scrub the board. Then blow the board off with an air gun or hair dryer. = I have been using this technique for many years and it works very well. =20 WARNING!!! WARNING!!! Will Robinson - Do not clean the front panel board.= the dissolved flux will get into the switches and on the LCD display and= cause all sort of problems. The switches are not sealed. The flux will a= ct like glue and make them stick. If you get the flux on the display it i= s just about impossible to get it off causing it to look bad. Do not clea= n any of the boards while attached to the painted panels. The dissolved f= lux will get on the paint and discolor it and/or make it sticky. =20 THE DISCLAIMER AND FINE PRINT SECTION The reason Elecraft does not recommend cleaning the boards is because of = the potential problems of using the wrong cleaner or using a cleaner in t= he wrong place (front panel). It will do no harm to leave the flux on the= board. If you decide to clean your boards you do so at your own risk. Th= ere are several things I do when building a K2/K1 that Elecraft does not = recommend. Cleaning the boards an using no-clean solder are two of them. = Elecraft must write it's manual for all levels of experience. Unless you = have a lot of experience with a technique and know how to make it work, i= t is best to go strictly by the book. =20 Don Brown KD5NDB 4 K2's 3 K1's all options 2 KPA100's ----- Original Message ----- From: Tom HammondN=D8SS Sent: Wednesday, August 14, 2002 10:44 PM To: Steve Dyer; elecraft at mailman.qth.net Subject: Re: [Elecraft] Deflux? Steve: >Any recommendations on defluxing juice and where to get it? > >Want to pretty up my board. I seldom attempt to clean up... too much chance the dissolved rosin will =20 wind up in something it's not supposed to be in, and then bad things REAL= LY =20 DO happen! But, when I DO want to tidy up a bit, I use denatured (wood) alcohol, and= =20 then dry the board immediately with my XYL's hair drier! Using 'solvents' which can melt plastics is not a good thing, as several = K2 =20 owners can attest. 73, Tom Hammond N0SS +++++++++++++++++ Date: Thu, 15 Aug 2002 14:18:05 -0700 From: "John, KI6WX" Subject: Re: [Elecraft] Deflux? To: Elecraft Mailing List Many alcohol products are not pure alcohol and may contain additives. These additives will leave a residue on the board and may cause circuit failures at some point in the future. For instance, the isopropyl alcohol you buy in the drugstore is generally only 70% pure. If your alcohol container isn't labeled as to its purity, it probably contains additives and shouldn't be used to clean electronic circuit boards. The best alcohol to use to clean the flux off a circuit board is Anhydrous Isopropyl Alcohol which should be labeled as 99.9% pure. This type of alcohol will not leave any residue from the alcohol and easily dissolves flux. I would be very cautious about other cleaning products for the boards; you will probably be better off not cleaning them rather than using the wrong cleaner, which is why Elecraft recommends not cleaning your circuit boards. -John KI6WX +++++++++++++++++ Date: Thu, 15 Aug 2002 11:52:45 -1000 From: John Buck Cc: Elecraft Subject: Re: [Elecraft] Deflux? After watching the continued discussion from people wanting to deflux their boards, I decided that it is necessary to jump in. When reasonably good solder with rosin core flux and good solder technique are used, deflux is totally unnecessary. If you are really concerned about flux build up in a few places, wait for several days or a few weeks. The flux sets up and will flake off using a small blade screwdriver and a gentle scrape. The flux is benign and will not short anything out or cause corrosion. I do prefer to remove obvious buildup in areas where the circuit impedance may be multi megohm. Using solvents is very poor practice. The solvent may convert the residue to a less desirable material than you started with. It may move the insulating material to places you do not want it. It will react with paint, lettering, and anything else around. The solution will get into unsealed parts, switches, encoders, pots, variable capacitors, glue transformer slugs, and insulate connector contacts. Bottom line. Follow the Elecraft instructions. Do not use solvents. I you feel absolutely compelled to violate the instructions and use some sort of solvent, pay attention to what others have said to help minimize the damage. My conclusion is DO NOT USE SOLVENT on the boards. Aloha, John KH7T ++++++++++++++++ From: "Don Brown" To: "John, KI6WX" , "Elecraft" Subject: Re: [Elecraft] Deflux? Date: Thu, 15 Aug 2002 17:09:34 -0500 Hi Yes you are correct about the stuff you buy at the drug store. The other = 30% is water and it will not clean the board very well. When I worked at = a PC board assembly house years ago we used Freon TF to clean boards it w= as a blend of Freon and 99% isopropyl alcohol. When Freon was outlawed va= rious forms of alcohol took its place. The 99% isopropyl may be hard to f= ind but denatured alcohol is in every hardware store. It is pure grain al= cohol (ethanol) with a small amount of wood alcohol (methanol) added to m= ake it poisonous so you can't drink it. It will work as well as the isopr= opyl and will not cause any problems. The white residue I was talking abo= ut is the dissolved flux drying on the board not additives in the alcohol= . Don Brown KD5NDB ++++++++++++++ Date: Thu, 15 Aug 2002 18:17:22 -0700 From: "John, KI6WX" Subject: Re: [Elecraft] Deflux? To: Elecraft Mailing List I was involved in a multi-million dollar product recall that was caused by a low level contaminant in the flux cleaning process of some boards we had manufactured. The problem was intermittent and very difficult to track down. It eventually required hand cleaning of the failing boards. Denatured alcohol sold in hardware stores is designed for uses such as dissolving shellac. It is not manufactured to the same purity as the material used in cleaning electronics, and may contain contaminants that are detrimental to electronic circuits. The rubbing alcohol sold in drugstores not only contains water, but often has fragrances added to it (at least your boards will smell nice). Rule #1: Don't clean the flux off of your boards. Elecraft radios are not likely to be used in an environment in which the flux would cause circuit problems. If you do need to remove the flux, follow Rule #2. Rule #2: Follow the recommendations of the electronics industry, which has spent millions of dollars investigating the alternatives. The standard for hand cleaning boards in the electronics industry is Anhydrous Isopropyl Alcohol, which is specifically manufactured to meet the purity standards of the industry. Use a cotton tipped swab to wipe the section of the board which you wish to clean. If you choose to use alternative cleaning agents, they will probably work most of the time. However, when they fail, you may have a radio that intermittently hiccups and you will have a very difficult time figuring out why. -John KI6WX ++++++++++++++++ Reply-To: From: "Ron D'Eau Claire" To: Subject: RE: [Elecraft] K2 Cleaning PCB Date: Sat, 17 May 2003 08:35:22 -0700 Hi Rick! You might want to check what the K2 manual says on this subject in the section on soldering (page 11 in the latest version).=20 This is the "official" word from Wayne: "(DO NOT use acidcore solder, water-soluble flux solder, additional = flux, or solvents of any kind, which will void your warranty)" Flux remover of any kind, including alcohol, is a "solvent".=20 When circuit boards came into use, a decision was made by NASA to clean = the boards. I've heard endless reasons for this being done. The one that = made the most sense, at least back in the 60's, was to reduce the amount of debris that could "migrate" (float around) and get into other things. In extreme cold rosin gets very hard and brittle. Under vibration, or = thermal stress, flakes can come off.=20 The decision to clean boards required using only electronic components = that would not be harmed by the solvent. I don't know whether all the = components Elecraft uses meet these criteria.=20 In any case, the debate about whether or not there is any value at all = in cleaning a board has raged on for decades, and will likely do so for a = long time to come. When I worked in the field servicing equipment, I = carefully checked the manufacturer's instructions because a LOT of them have a statement like the one above in the Elecraft manual.=20 Even manufacturers building gear to be used in the relatively corrosive (salt air), humid atmosphere on a ship often voided their warranty if = there was any evidence of flux having been removed. I suspect it was because = many people in the field sprayed the boards with all sorts of strong stuff in = an effort the clean them off quickly - stuff that could do a lot of = collateral damage. I never had a chance to ask a manufacturer if that was so. Since = I expected the manufacturer to stand behind their equipment if I had = problems fixing it, I followed their instructions for working on it.=20 Ron AC7AC K2 # 1289 -----Original Message----- Hi all, I'm about to start in on my RF board. There are a lot of references to flux removal but I don't know what the prevailing opinion is on the subject. Perhaps a poll on how many attempted flux removal during the building process? At NASA soldering class we were taught to clean everything with pure alcohol (and only pure alcohol) and a stiff acid brush. Sometimes the final board would be immersed in an alcohol bath/ultrasonic cleaner for final cleaning. I don't think a K2 has been launched to deep space yet so the standards don't have to be so rigorous! If nothing else a flux-free PCB sure looks better IMO! So should I bother or do the risks out way the rewards in this case. Thanks=20 Rick N3IKQ K2 #3465=20 ++++++++++++++++++