++++++++++++++++++++ Date: Sun, 24 Mar 2002 12:12:05 +0000 From: "Leon Heller" To: K9nk at aol.com, qrp-l at Lehigh.EDU Subject: [123056] Re: Working with Surface Mount Components >I know these parts are really small. Can someone share the techniques of >holding a part down on the board and how to solder it. Anything I should >look out for that causes a mistake by a beginner?? You need the following: a decent soldering iron with a very fine tip, some really thin solder, some narrow desolder braid, a magnifier and a pair of stainless steel tweezers. Tin one of the pads lightly, position the component with the tweezers and tack down the lead on the tinned pad. Solder the other leads, holding the component in position if required with the tweezers then return to the tacked down lead and resolder it. With ICs tack down two diagonally opposite leads first to hold the chip in position, before soldering the remainder and returning to the tacked down leads. Clean up any shorts with the desoldering braid. With very fine pitch devices, tack them down and apply a suitable liquid flux, flood the leads with solder and remove the excess with the desolder braid. Remake any suspect joints by reheating with the soldering iron. 73, Leon -- Leon Heller, G1HSM Tel: +44 1327 359058 Email:leon_heller at hotmail.com My web page: http://www.geocities.com/leon_heller My low-cost Altera Flex design kit: http://www.leonheller.com +++++++++++++++++++ Date: Sun, 24 Mar 2002 08:01:56 -0500 From: "Ed Tanton" To: , "'Low Power Amateur Radio Discussion'" Subject: [123060] RE: Working with Surface Mount Components Perfect advice from Leon. Good magnifying specs are a big asset too. 73 Ed Tanton N4XY Ed Tanton N4XY 189 Pioneer Trail Marietta, GA 30068-3466 website: http://www.n4xy.com ++++++++++++++++ Date: Sun, 24 Mar 2002 08:34:11 -0500 From: David Hinerman To: qrp-l at lehigh.edu Subject: [123065] Re: Working with Surface Mount Components At 01:23 AM 3/24/02 EST, you wrote: >I am thinking about building one of the Embedded Research Tick Surface Mount Keyer kits. I've never worked with surface mounted components and thought this would be a good first project. > >I know these parts are really small. Can someone share the techniques of holding a part down on the board and how to solder it. Anything I should look out for that causes a mistake by a beginner?? > >Has anyone built this kit --- any comments?? Norm, I built the SMK-1 using a method someone on the list suggested - dip just the tip of a bamboo skewer in paste flux (I bought a tube of the stuff at Radio Shack) and lightly touch the component you're going to mount. the flux gives just enough adhesion to pick up the part, then you can move it, orient it, and hold it in place while you solder one lead to the board. Once one lead is attached, it'll hold the part in place until you can solder the remaining leads. (Unless you pull one of my tricks and heat the part so much that the soldered lead comes unsoldered - then the part sticks to the iron, and you have to pick it off and start over.) A good head- or bench-mounted magnifier does wonders, too. Dave ----------------------- Dave Hinerman WD8CIV at worldnet.att.net ++++++++++++++++++ Date: Sun, 24 Mar 2002 14:26:59 -0700 From: Dan Tayloe To: qrp-l at Lehigh.EDU, K9nk at aol.com Subject: [123087] Re: Working with Surface Mount Components I think I would also help to work on some low surface with perhaps a white sheet on the floor. I am becoming a bit fat fingered and once in a while a part zings off my tweezers. In that case, it helps if the work surface is a bit lower to the floor so it won't bounce quite to far, and to have the floor covered with a flat, white sheet so stray parts are easier to find. Dark carpet can simply swallow up a small SM part. I also suggest tinning both the pad and the first leg of that gets soldered down. That way you simply need to touch the iron to the first leg of the part part and its pad to soldered them together. As was mentioned previously, after you have the first leg soldered down, the rest is easily. Simply make sure you start soldering on the opposite side of the part from the leg you first soldered down. That minimizes reflowing the first pin and having the part come up. - Dan Tayloe, N7VE; Phoenix, Az; Az ScQRPions ++++++++++++++++++ Date: Mon, 25 Mar 2002 23:52:32 -0600 From: "Adrian Weiss" To: qrp-l at Lehigh.EDU Subject: [123223] Re: Work surfaces for SMT HI gang: Thought I'd add my two cents. The white or light surface to work on is a must. The need for sides is also clear. I've found that using white cloth taped taut is the best solution. When the part takes off, it doesn't bounce but thuds and stays put. That's for normal dinking. When you launch one out of the work space, that takes a white floor! 72, Ade W0RSP ++++++++++++++++++ Date: Tue, 26 Mar 2002 07:56:03 -0500 From: David Hinerman To: qrp-l at lehigh.edu Subject: [123233] Re: Work surfaces for SMT At 11:52 PM 3/25/2002 -0600, you wrote: >HI gang: > >Thought I'd add my two cents. The white or light surface to work on is a must. >The need for sides is also clear. I've found that using white cloth taped taut >is the best solution. When the part takes off, it doesn't bounce but thuds and >stays put. That's for normal dinking. When you launch one out of the work >space, that takes a white floor! Ade, That's why I liked the bamboo skewer + flux trick. The part isn't loaded into a catapult (i.e. steel tweezer jaws under tension) as soon as I pick it up. The skewer -is- still a good tiddlywink launcher if you press on the end of the component at the end instead of the center, but the parts don't fly as far. FWIW, our SMT techs at work use vacuum picks, but those aren't available at Radio Shack the last time I looked. Dave ++++++++++++++++ Date: Tue, 26 Mar 2002 09:43:05 est From: brian at iquest.net To: "Low Power Amateur Radio Discussion" Subject: [123241] Re: Work surfaces for SMT When I built my SMK-1, I used the lid from a Monopoly game as the "building arena". Cloth is an excellent idea! My lid kept me from losing parts, and I dropped about half of them. +++++++++++++++++