Return-Path: robot-board@oberon.com Received: by media.mit.edu (5.57/DA1.0.4.amt) id AA17354; Fri, 29 Oct 93 07:14:09 -0400 Received: from ([127.0.0.1]) by oberon.com (4.1/SMI-4.1_Armado.MX) id AA03294; Fri, 29 Oct 93 07:09:44 EDT Date: Fri, 29 Oct 93 07:09:44 EDT Message-Id: <9310291108.AA03217@oberon.com> Errors-To: gkulosa@oberon.com Reply-To: JGRAHAM@UNODE2.NSWC.NAVY.MIL Originator: robot-board@oberon.com Sender: gkulosa@oberon.com Precedence: bulk From: JEFFREY S. GRAHAM To: Multiple recipients of list Subject: Summary of soldering tips/techniques/dos/donts X-Listprocessor-Version: 6.0b -- ListProcessor by Anastasios Kotsikonas Status: O The following is a compilation of responses to my cry of help for soldering advice. Sincere thanks to everyone who replied: Gary Noel Boone sbrock@zombie.intel.com (Scott Brock, SC9-37 x59159) Stephen Lee strohm@mksol.dseg.ti.com (john r strohm) "Andrew Dennison" Karl Altenburg cmartin@aol.com gkulosa@oberon.com SOLDER: 1) Thin. Several definitions of "thin" a. size of 20-24 gauge wire b. 0.028 inch c. slightly larger than the diameter of a pencil lead. 2) Resin core 60/40 lead/tin. 3) Ersin brand multicore solder, labeled SN60 (60/40) The manufacturer is: Multicore Solders Richardson, Texas 75081 You can get this from Digikey. EQUIPMENT: 1) 15, 25 watt iron is ok, narrow tip 2) wet sponge 3) iron holder 4) solder wick 5) solder sucker TECHNIQUE: 1) Practice soldering on a cheap Radio Shack printed circuit board. 2) Practice desoldering with the fine braid, size #2 solder wick. This is where one can really damage those delicate pads on a printed circuit board. When applying the wick to a solder joint, leave about 3/8" margin of clean wick at the tail-end. This way one can roll the iron a little in either direction as the solder melts. The used wick will then curl away from the PCB as it soaks up the melted solder. Fresh wick can be fed into the melted solder if necessary. 3) Find someone to teach you. Local Ham radio clubs are a good source. 4) Apply the soldering iron to one side of the joint, making sure the tip is touching the pad AND the component lead. Apply the solder from the OPPOSITE SIDE of the joint. This ensures that the joint is hot enough; don't just melt the solder on the iron. solder from iron from this side \ / this side \ | / ------------------|---------- PCB ------------------|---------- 5) Bend the leads to hold the components in place then clip the leads short 1 - 2mm (1/16") after you solder. 6) Use a bit of metho and an old toothbrush to remove the flux from the board when you are finished. 7) Assuming through hole components and not surface mount: First do the resistors. Insert a resistor, bend leads slightly to hold in place. Repeat five times or so. Reheat to seat properly if not flush with board. Then trim the leads. Repeat until done with resistors. Next do the dip sockets. Insert all the dip sockets into the board, place a thin piece of cardbord on top of the dips and the board and quickly flip the board over. This will keep all the dip sockets in place. Then tack each corner of the socket: solder two pins on opposite corners first, reheat to make socket flush,then solder all pins on the socket. Next, capacitors. etc... The order selected the lowest profile component first, the next highest next, and so forth. This allows the component to be held flush against the board during soldering by the board itself. 8) The best technique for desoldering is to use a solder sucker to remove as much as you can. Then, carefully, heat up the joint, then bang(??) the board, whatever, against the table. DOs: 1) use a fan to ventilate toxic fumes 2) keep the tip clean(free from black residue and accumulated flux and solder) by frequently poking/rubbing the tip on a wet sponge 3) tin the tip properly 4) if the solder joint looks lumpy or dull it is "cold". rework it. 5) use a heat sink to insulate the components 6) Clean the tip at the end of the soldering session 7) wash your hands after the soldering session DONTs: 1) breath the fumes 2) file down the tip (general consensus) 3) apply solder to the tip and wait for it to flow into the joint 4) use acid-core solder for electronics work 5) use radio shack solder 6) solder connections as soon as the iron can melt solder Return-Path: robot-board@oberon.com Received: by media.mit.edu (5.57/DA1.0.4.amt) id AA25170; Wed, 27 Oct 93 20:52:03 -0400 Received: from ([127.0.0.1]) by oberon.com (4.1/SMI-4.1_Armado.MX) id AA11958; Wed, 27 Oct 93 20:47:43 EDT Date: Wed, 27 Oct 93 20:47:43 EDT Message-Id: <9310272030.tn20718@aol.com> Errors-To: gkulosa@oberon.com Reply-To: cmartin@aol.com Originator: robot-board@oberon.com Sender: gkulosa@oberon.com Precedence: bulk From: cmartin@aol.com To: Multiple recipients of list Subject: Soldering X-Listprocessor-Version: 6.0b -- ListProcessor by Anastasios Kotsikonas Status: RO The following are my personal and professional observations about soldering from the last 30 years. Solder: For electronic soldering use only 60/40 (tin/lead), rosin core. Thin is good, about the size of 20-24 gauge wire. Thicker solder is wrong for PCB work. Thinner solder can't be fed fast enough. Avoid Radio Shack solder like the plague (the last time I used it, the resin fumes about took the paint off the wall). Soldering Iron: A good 25 watt pencil iron with a fine plated tip is best (my personal preference is Weller). The tip will never corrode, period. Never, ever file a plated tip (you won't need to anyways). Invest in a soldering iron holder with sponge, preferably a celulose sponge, as it won't melt if dry. It keeps every thing together, reduces the risk of placing your hand (or something else) on it and makes it harder to knock of the table. Avoid the fumes. They are presumably toxic, carcinogenic and may even hurt you. They'll also make your eyes burn after awhile. Fumes always seem to seek out your face, no matter how much you duck 'em, they get you. I use a small 12V equipment fan to keep a steady stream of air blowing across the work area. Wash your hands after soldering, that is lead in the solder you've been handling. A little solder on the tip of the iron helps. It increases thermal conductivity. Wipe the tip on the wet sponge occasionally to clean off flux and excess solder. If it is a copper tip (not plated), tin it immediately. Don't be impatient waiting for an iron to heat up. You don't want to solder connections as soon as the iron can melt solder, give it another few minutes. The best technique for desoldering something is to use a solder sucker to remove as much as you can. Then, carefully, heat up the joint, then bang the board, whatever, against the table. It may sound strange, but it is the most consistent way of removing solder I've found. Return-Path: robot-board@oberon.com Received: by media.mit.edu (5.57/DA1.0.4.amt) id AA22655; Tue, 26 Oct 93 14:39:19 -0400 Received: from ([127.0.0.1]) by oberon.com (4.1/SMI-4.1_Armado.MX) id AA16050; Tue, 26 Oct 93 14:30:52 EDT Date: Tue, 26 Oct 93 14:30:52 EDT Message-Id: <199310261828.AA23838@vision1.cc.gatech.edu> Errors-To: gkulosa@oberon.com Reply-To: gboone@cc.gatech.edu Originator: robot-board@oberon.com Sender: gkulosa@oberon.com Precedence: bulk From: Gary Noel Boone To: Multiple recipients of list Subject: Re: 6.270 assembly (soldering) X-Listprocessor-Version: 6.0b -- ListProcessor by Anastasios Kotsikonas Status: O Hi. I don't know about the lead to tin ratio, but here are some other tips: 1) You should get _thin_ solder and a big role of it. Blow the three bucks! Thin is easier to work with for those small solder pads. 2) Soldering is a skill. Become good at it. You should be able to run through dips at about one per second. 3) Hone your tools. I keep a file and a sponge near my $8 Radio Shack soldering iron. The secret to fast/clean joints is to keep the heat flowing. Whenever the tip gets old-solder or caked-on-flux dirty, file it down to a new shiny flat edge. Note that it may never be a point; the tip has some inner secret substance that melts. Don't use the point anyway. Use the sides to get a good area of heat flow. After filing down, re-tin by liberally applying solder. This forms a blob on the hot tip. Whack it on the edge of your table and the blob flies off into the sponge, leaving a nice tinned tip. Ready to solder. Don't apply solder to the tip and wait for it to flow onto the joint. Instead, heat the component wire until it's hot enough to melt the solder. Now apply a little bit onto the wire so that it goes into the joint. This will help heat the pad in those situations where you can't get the tip to touch both the pad and the wire. Once both are melting the solder, apply solder completely. As you solder, the flux forms black crud on your tip. Jam it into the sponge and twist to keep the tip clean. Be quick so you don't burn your sponge! BTW, this suggestions probably don't apply to expensive soldering guns. You probably shouldn't file down expensive equipment. Also, try not to breathe the solder fumes. It makes you try to solder tips at the rate of 1 per second. Good luck, Gary Return-Path: robot-board@oberon.com Received: by media.mit.edu (5.57/DA1.0.4.amt) id AA25312; Tue, 26 Oct 93 15:09:53 -0400 Received: from ([127.0.0.1]) by oberon.com (4.1/SMI-4.1_Armado.MX) id AA16645; Tue, 26 Oct 93 15:02:32 EDT Date: Tue, 26 Oct 93 15:02:32 EDT Message-Id: Errors-To: gkulosa@oberon.com Reply-To: slee@u.washington.edu Originator: robot-board@oberon.com Sender: gkulosa@oberon.com Precedence: bulk From: Stephen Lee To: Multiple recipients of list Subject: Re: 6.270 assembly X-Listprocessor-Version: 6.0b -- ListProcessor by Anastasios Kotsikonas Status: O I use Ersin brand multicore solder. It's labeled SN60 which means it is 60% lead and 40% tin. I prefer the very narrow .028 inch diameter solder and a 15 watt iron. A 25 watt iron will do the job just as well. Avoid using a wide tip. Practice on a cheap Radio Shack printed circuit board. Learn what overheating does to a pad with the cheap Radio Shack PCB. Heat the work momentarily before applying the solder. If the solder joint looks lumpy or dull, you've probably got what's called a cold solder joint. Rework those cold solder joints. Different brands of 60/40 solder tend to have varying characteristics. Ersin has been very dependable. The manufacturer is: Multicore Solders Richardson, Texas 75081 Keep a damp sponge or damp paper towels handy to wipe off excess solder and flux from the tip of your heated iron. For longer tip life, always leave a small amount of solder on the tip when it is not immediately being used. This is part of a process called tinning the iron. You'll also want to purchase some Solder Wick and practice desoldering with that. I use the fine braid, size #2. This is where one can really damage those delicate pads on a printed circuit board. When applying the wick to a solder joint, leave about 3/8" margin of clean wick at the tail-end. This way one can roll the iron a little in either direction as the solder melts. The used wick will then curl away from the PCB as it soaks up the melted solder. Fresh wick can be fed into the melted solder if necessary. Relax, develop your technique, and good luck! Return-Path: robot-board@oberon.com Received: by media.mit.edu (5.57/DA1.0.4.amt) id AA24092; Tue, 26 Oct 93 20:36:04 -0400 Received: from ([127.0.0.1]) by oberon.com (4.1/SMI-4.1_Armado.MX) id AA23454; Tue, 26 Oct 93 20:27:24 EDT Date: Tue, 26 Oct 93 20:27:24 EDT Message-Id: Errors-To: gkulosa@oberon.com Reply-To: ADEN@mechman.mm.swin.edu.au Originator: robot-board@oberon.com Sender: gkulosa@oberon.com Precedence: bulk From: "Andrew Dennison" To: Multiple recipients of list Subject: Re: 6.270 assembly (soldering) X-Listprocessor-Version: 6.0b -- ListProcessor by Anastasios Kotsikonas Status: O [lots of stuff deleted] > > As you solder, the flux forms black crud on your tip. Jam it into the > sponge and twist to keep the tip clean. Be quick so you don't burn > your sponge! > Try using a damp sponge. Every few joints give the tip a quick wipe to remove accumulated flux and solder. This should also be the last thing you do before you switch off your iron, keeps it nice and clean for next time. You shouldn't have to file your tip to often (at all?) if you do this. Apply the soldering iron to one side of the joint, making sure the tip is touching the pad AND the component lead. Apply the solder from the OPPOSITE SIDE of the joint. This ensures that the joint is hot enough; don't just melt the solder on the iron. solder from iron from this side \ / this side \ | / ------------------|---------- PCB ------------------|---------- One last tip: Bend the leads to hold the components in place then clip the leads short 1 - 2mm (1/16") BEFORE you solder. Another last tip: Use a bit of metho and an old toothbrush to remove the flux from the board when you are finished. Happy soldering! Andrew ------------------------------------------------------------------- Andrew Dennison, The CIM Centre, Melbourne, AUSTRALIA Phone: + 61 3 819 8296 Fax: + 61 3 819 4949 aden@mechman.mm.swin.edu.au -- or -- avrd@stan.xx.swin.oz.au Return-Path: robot-board@oberon.com Received: by media.mit.edu (5.57/DA1.0.4.amt) id AA25539; Wed, 27 Oct 93 10:38:14 -0400 Received: from ([127.0.0.1]) by oberon.com (4.1/SMI-4.1_Armado.MX) id AA29993; Wed, 27 Oct 93 10:34:21 EDT Date: Wed, 27 Oct 93 10:34:21 EDT Message-Id: <9310271430.AA13767@merlin.psych.wisc.edu> Errors-To: gkulosa@oberon.com Reply-To: jeffb@merlin.psych.wisc.edu Originator: robot-board@oberon.com Sender: gkulosa@oberon.com Precedence: bulk From: Jeff Bartig To: Multiple recipients of list Subject: Re: 6.270 assembly (soldering) X-Listprocessor-Version: 6.0b -- ListProcessor by Anastasios Kotsikonas Status: O > Try using a damp sponge. Every few joints give the tip a quick wipe > to remove accumulated flux and solder. This should also be the last > thing you do before you switch off your iron, keeps it nice and clean > for next time. You shouldn't have to file your tip to often (at > all?) if you do this. An engineer I use to work with told me that you should never file your soldering iron tips. He said that the tips are made of copper and steel. If you file through the thin outter layer of steel, you will expose the copper insides. Once the copper is exposed, the tip quickly deteriorates. I don't do a lot of soldering, but I've been able to keep my tip in good shape by following the above advice of wiping the hot tip clean on a wet sponge. When I am done soldering, I always clean the tip on the sponge and re-tin it by applying a small amount of solder. Jeff -- Jeff Bartig | (608) 244-1254 Software Engineer | E-Mail: jeffb@merlin.psych.wisc.edu