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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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I've used Metcal MX-500's at work for about 12 years now, and really love
them. I'm looking to do more electronics work at home when I retire soon, and need to replace my ancient Weller WTCP station. It works great, but isn't really suited to fine SMT devices. The dual ports on the Metcal also make it easy to switch back & forth from a fine tip to something a bit more brute force. I do a lot of RF work, with heavy ground planes, and the Metcal works fantastic for that sort of mixed application. I've used a variety on irons in the past, from Ungar's to Antex, PACE & Weller. Nothing I've tried compares to the Metcal. I figure I can get a Metcal on eBay for a reasonable price if I'm patient. However, it occured to me that they've been around for at least 12 years, and there _might_ just be something better out by now. I know Metcal also has a new design out with a display. It apparently has more power, but I think it works with the same tips. I'm willing to spend a couple hundred bucks for a really good setup. That probably sounds absurd to a lot of folks, but if you've ever struggled soldering something, & then tried a Metcal, it's worth a bit of investment. Is Metcal still the best out there, or has Hakko or somebody else got a decent competing product? Thanks! Doug White |
#2
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On Sun, 14 Feb 2010 22:56:39 GMT, Doug White
wrote: I'm willing to spend a couple hundred bucks for a really good setup. That probably sounds absurd to a lot of folks, but if you've ever struggled soldering something, & then tried a Metcal, it's worth a bit of investment. Soldering is usually not a problem. It's unsoldering that drives me to spend the money. If your price ceiling is about $200, you're below the level of Hakko or Weller hot air desoldering stations, which can cost $500 to $1000 and up with accessories. For cheap, I suggest: http://www.circuitspecialists.com/level.itml/icOid/7543 This is what you get for about $200: http://www.circuitspecialists.com/products/full/9766.jpg http://www.circuitspecialists.com/prod.itml/icOid/9766 However, I can't claim much experience with one of these. I've played with an older model, liked it, but have not torn it apart to see if it's junk or quality. The availablity of nozzles, replacement parts, and repair items is reassuring. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#3
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On Feb 14, 2:56*pm, Doug White wrote:
I've used Metcal MX-500's at work for about 12 years now, and really love them. *I'm looking to do more electronics work at home when I retire soon, and need to replace my ancient Weller WTCP station. *It works great, but isn't really suited to fine SMT devices. *The dual ports on the Metcal also make it easy to switch back & forth from a fine tip to something a bit more brute force. *I do a lot of RF work, with heavy ground planes, and the Metcal works fantastic for that sort of mixed application. *I've used a variety on irons in the past, from Ungar's to Antex, PACE & Weller. *Nothing I've tried compares to the Metcal. I figure I can get a Metcal on eBay for a reasonable price if I'm patient. *However, it occured to me that they've been around for at least 12 years, and there _might_ just be something better out by now. *I know Metcal also has a new design out with a display. *It apparently has more power, but I think it works with the same tips. I'm willing to spend a couple hundred bucks for a really good setup. * That probably sounds absurd to a lot of folks, but if you've ever struggled soldering something, & then tried a Metcal, it's worth a bit of investment. Is Metcal still the best out there, or has Hakko or somebody else got a decent competing product? Thanks! Doug White I thinks it's largely a personal choice. I haven't found anything that I like as well as my old hexacon therm-o-trac (http:// www.hexaconelectric.com/thermo.html). It's small enough that it isn't in my way, rugged enough that I can solder large heavy ground planes, and with delicate enough temperature control, that I can do fine smt work. You have to unscrew a retainer to change the tip. I used to use a small pair of pliers to change tips in a hurry. I think I bought it for 10 bucks when the company I worked at went down the tubes. We had a bunch of different wellers, and metcals at the board shop. I don't think anyone really liked the wellers. A lot of the solderers doing the smt really liked metcals, but it never felt like they kept the temp right to me, and the cords always seemed to be knotted up in everything. |
#4
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Jeff Liebermann wrote in
: On Sun, 14 Feb 2010 22:56:39 GMT, Doug White wrote: I'm willing to spend a couple hundred bucks for a really good setup. That probably sounds absurd to a lot of folks, but if you've ever struggled soldering something, & then tried a Metcal, it's worth a bit of investment. Soldering is usually not a problem. It's unsoldering that drives me to spend the money. If your price ceiling is about $200, you're below the level of Hakko or Weller hot air desoldering stations, which can cost $500 to $1000 and up with accessories. For cheap, I suggest: http://www.circuitspecialists.com/level.itml/icOid/7543 This is what you get for about $200: http://www.circuitspecialists.com/products/full/9766.jpg http://www.circuitspecialists.com/prod.itml/icOid/9766 However, I can't claim much experience with one of these. I've played with an older model, liked it, but have not torn it apart to see if it's junk or quality. The availablity of nozzles, replacement parts, and repair items is reassuring. Thanks for the suggestions. I'm figuring on picking up a used system on eBay, so list price isn't the issue. As for desoldering, I've had pretty good luck with the Metcal, liquid flux and solderwick. As I said, I mostly work on RF stuff, and I typically don't have a zillion leads to deal with the way the digital types do. Besides, once I have something unsoldered, I still need to get a replacement soldered down. I figured once I got a decent iron, I'd look into a hot air pencil. A lot will depend on how circuit work I end up doing. I will be assembling more than repairing (I hope). Doug White |
#5
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Sansui Samari wrote in
: On Feb 14, 2:56*pm, Doug White wrote: I've used Metcal MX-500's at work for about 12 years now, and really love them. *I'm looking to do more electronics work at home when I retire soon, and need to replace my ancient Weller WTCP station. *It works great, but isn't really suited to fine SMT devices. *The dual ports on the Metcal also make it easy to switch back & forth from a fine tip to something a bit more brute force. *I do a lot of RF work, with heavy ground planes, and the Metcal works fantastic for that sort of mixed application. *I've used a variety on irons in the past, from Ungar's to Antex, PACE & Weller. *Nothing I've tried compares to the Metcal. I figure I can get a Metcal on eBay for a reasonable price if I'm patient. *However, it occured to me that they've been around for at least 12 years, and there _might_ just be something better out by now. *I know Metcal also has a new design out with a display. *It apparently has more power, but I think it works with the same tips. I'm willing to spend a couple hundred bucks for a really good setup. * That probably sounds absurd to a lot of folks, but if you've ever struggled soldering something, & then tried a Metcal, it's worth a bit of investment. Is Metcal still the best out there, or has Hakko or somebody else got a decent competing product? Thanks! Doug White I thinks it's largely a personal choice. I haven't found anything that I like as well as my old hexacon therm-o-trac (http://www. hexaconelectric.com/thermo.html). It's small enough that it isn't in my way, rugged enough that I can solder large heavy ground planes, and with delicate enough temperature control, that I can do fine smt work. You have to unscrew a retainer to change the tip. I used to use a small pair of pliers to change tips in a hurry. I think I bought it for 10 bucks when the company I worked at went down the tubes. We had a bunch of different wellers, and metcals at the board shop. I don't think anyone really liked the wellers. A lot of the solderers doing the smt really liked metcals, but it never felt like they kept the temp right to me, and the cords always seemed to be knotted up in everything. The cords can be a bit tangly, but I think it's because they are longer than some, as well as limp & flexible. I've gotten used to them. Doug White |
#6
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On Mon, 15 Feb 2010 02:39:52 GMT, Doug White
wrote: http://www.circuitspecialists.com/prod.itml/icOid/9766 I'm figuring on picking up a used system on eBay, so list price isn't the issue. Figure again. It's not the hot air station that will empty your bank account. It's the accessories such as tips, filters, tips, and pump parts. You're highly likely to end up with a desoldering station that's missing these items, or has been used enough to require a pump rebuild or new heater element. Caveat emptor. For a tool that gets used so often, I would buy new. Here's another one that I've been looking at: http://hackaday.com/2009/02/20/tools-aoyue-968-3-in-1-soldering-and-rework-station/ http://www.sparkfun.com/commerce/product_info.php?products_id=76 also for about $200. As for desoldering, I've had pretty good luck with the Metcal, liquid flux and solderwick. Like this? http://www.curiousinventor.com/guides/Surface_Mount_Soldering/101 I still do it that way when I don't want to wait for my Pace desoldering station to warm up. I've done it like that since I first learned which end of the soldering iron to grab. It works, but once I tried using hot air, desoldering tweezers, and vacuum pickup tools, I was permanently spoiled. As I said, I mostly work on RF stuff, and I typically don't have a zillion leads to deal with the way the digital types do. I do plenty of RF also. Fixing cell phones (a masochistic and largely wasted exercise) really can't be done with solder wick, solder sucker, and big tip soldering iron. Besides, once I have something unsoldered, I still need to get a replacement soldered down. Ummm... you also have to clean up the mess you made on the board. Replacement is comparatively easy. I use a drop of super-glue to hold the part in place. When I hit it with the iron, it doesn't move. If I slop some on the pad, the heat from the iron just vaporizes the super-glue into a toxic cloud of eye irritating smog. (Hint: get your head out of the way or using a smog sucker hose on the iron). I figured once I got a decent iron, I'd look into a hot air pencil. A lot will depend on how circuit work I end up doing. I will be assembling more than repairing (I hope). It's a good plan except that both of the hot air stations I mentioned also include a soldering iron or gun. Incidentally, most of my assortment of irons are Weller. That's not because I like them. It's because I picked up a huge pile of broken Weller irons and stations and have been slowly raising them from the dead. I once joked that it was a lifetime supply, and may have been right. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#7
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Doug White wrote in
: Jeff Liebermann wrote in : On Sun, 14 Feb 2010 22:56:39 GMT, Doug White wrote: I'm willing to spend a couple hundred bucks for a really good setup. That probably sounds absurd to a lot of folks, but if you've ever struggled soldering something, & then tried a Metcal, it's worth a bit of investment. Soldering is usually not a problem. It's unsoldering that drives me to spend the money. If your price ceiling is about $200, you're below the level of Hakko or Weller hot air desoldering stations, which can cost $500 to $1000 and up with accessories. For cheap, I suggest: http://www.circuitspecialists.com/level.itml/icOid/7543 This is what you get for about $200: http://www.circuitspecialists.com/products/full/9766.jpg http://www.circuitspecialists.com/prod.itml/icOid/9766 However, I can't claim much experience with one of these. I've played with an older model, liked it, but have not torn it apart to see if it's junk or quality. The availablity of nozzles, replacement parts, and repair items is reassuring. Thanks for the suggestions. I'm figuring on picking up a used system on eBay, so list price isn't the issue. As for desoldering, I've had pretty good luck with the Metcal, liquid flux and solderwick. As I said, I mostly work on RF stuff, and I typically don't have a zillion leads to deal with the way the digital types do. Besides, once I have something unsoldered, I still need to get a replacement soldered down. I figured once I got a decent iron, I'd look into a hot air pencil. A lot will depend on how circuit work I end up doing. I will be assembling more than repairing (I hope). Doug White you shouldn't use solderwick(or solderpullts) on SMT boards,you'll lift the pads. too much dwell time,applies too much heat to the tiny pads. -- Jim Yanik jyanik at localnet dot com |
#8
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Jeff Liebermann wrote in
: Ummm... you also have to clean up the mess you made on the board. Replacement is comparatively easy. I use a drop of super-glue to hold the part in place. When I hit it with the iron, it doesn't move. If I slop some on the pad, the heat from the iron just vaporizes the super-glue into a toxic cloud of eye irritating smog. (Hint: get your head out of the way or using a smog sucker hose on the iron). small tip; I use a small fan to blow gently across my work,directing unhealthy vapors away from me.I bought a small fan from Wal-Mart for less than $10.You can get clip-on or one with a base. Or,like I used to do,wire a power cord and switch to a 120VAC "whisper fan" from an old instrument.(cooling fan,very quiet)I even use one for chopping onions in the kitchen; No tears! I figured once I got a decent iron, I'd look into a hot air pencil. A lot will depend on how circuit work I end up doing. I will be assembling more than repairing (I hope). It's a good plan except that both of the hot air stations I mentioned also include a soldering iron or gun. Incidentally, most of my assortment of irons are Weller. That's not because I like them. It's because I picked up a huge pile of broken Weller irons and stations and have been slowly raising them from the dead. I once joked that it was a lifetime supply, and may have been right. I've used the Pace vacuum desoldering system,too,while at TEK. Not inexpensive,though. And I still preferred my Antex 15w iron with a filed-down non-clad tip for soldering the small SMD stuff. The smaller SMD Pace tips (iron-clad)rotted out too quickly. -- Jim Yanik jyanik at localnet dot com |
#9
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On Sun, 14 Feb 2010 22:46:36 -0600, Jim Yanik
wrote: I use a small fan to blow gently across my work,directing unhealthy vapors away from me. Duz that really work with small components? I tried a recycled CPU fan with an alligator clip for mounting and found that even the slightest breeze causes difficulties soldering or desoldering. My home workshop does have a heater so I use a small electric heater and fan. When soldering, I have to turn it off. Also, I wasn't joking about the toxic smog from soldering super-glue. The stuff really reeks and seems highly irritating. Fortunately, I don't use much when soldering. Gently blowing it around the shop seems like an invitation to accidentally stick my head into one of the floating clouds of burnt super-glue. Without a fan, at least I know where not to put my head. I bought a small fan from Wal-Mart for less than $10.You can get clip-on or one with a base. Or,like I used to do,wire a power cord and switch to a 120VAC "whisper fan" from an old instrument.(cooling fan,very quiet)I even use one for chopping onions in the kitchen; No tears! Methinks tears from cutting onions is a basic ingredient of much of my cooking. Crying is part of the recipe. I've used the Pace vacuum desoldering system,too,while at TEK. I found an old Pace something desoldering station for peanuts at a thrift shop. They didn't know what it was. Works really nice. However, it's not a hot air desoldering system and is therefore fairly useless for SMT parts. Not inexpensive,though. No kidding. I replaced a few parts and had sticker shock. I now use vinyl hoses, fuel filters, and brazing tip cleaners, instead of the official Pace equivalents. And I still preferred my Antex 15w iron with a filed-down non-clad tip for soldering the small SMD stuff. The smaller SMD Pace tips (iron-clad)rotted out too quickly. I once tried to re-plate my collection of burned out tips. I also made some from scratch. The core metal is copper. On top of that is a layer of iron, then nickel, and finally solder plate. First, filing and an acid cleaning bath. I then slowly electroplated some iron, in a ferrous chloride plus calcium chloride bath, onto what was left of the tip. Electroless nickel dip followed. I also tried some electroless silver. I then masked off the tip, and hard black chromed the rest of the tip. It worked but wasn't worth the cost and effort. A new tip was considerably cheaper. The tip life appeared to be dependent on the thickness of the nickel or silver layer. Electroless plating just doesn't apply a thick enough layer. Silver seemed to last a bit longer. I was thinking of trying again, this time plating the nickel or silver layer. I'm not sure if the Pace tips are copper-nickel-iron, or the more common copper-iron-nickel. They may even be solid iron with no plating, which would certainly oxidize and pit rapidly. That might explain the short observed lifetime. I would check my Pace, but I only have the thru-hole desoldering tip. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#10
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On Mon, 15 Feb 2010 00:29:13 -0800, Jeff Liebermann
wrote: On Sun, 14 Feb 2010 22:46:36 -0600, Jim Yanik wrote: I use a small fan to blow gently across my work,directing unhealthy vapors away from me. Duz that really work with small components? I tried a recycled CPU fan with an alligator clip for mounting and found that even the slightest breeze causes difficulties soldering or desoldering. My home workshop does have a heater so I use a small electric heater and fan. When soldering, I have to turn it off. Also, I wasn't joking about the toxic smog from soldering super-glue. The stuff really reeks and seems highly irritating. Fortunately, I don't use much when soldering. Gently blowing it around the shop seems like an invitation to accidentally stick my head into one of the floating clouds of burnt super-glue. Without a fan, at least I know where not to put my head. Get one of these http://www.howardelectronics.com/xytronic/426dlx.html and position it, as shown, just behind your work area. I've been using the stand-alone model (sans iron) for years and love it. Or, rig your surplus CPU blower so that it takes a suction on, rather than blows over, where you're working. -- Rich Webb Norfolk, VA |
#11
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Jeff Liebermann wrote in
: On Sun, 14 Feb 2010 22:46:36 -0600, Jim Yanik wrote: I use a small fan to blow gently across my work,directing unhealthy vapors away from me. Duz that really work with small components? I tried a recycled CPU fan with an alligator clip for mounting and found that even the slightest breeze causes difficulties soldering or desoldering. My home workshop does have a heater so I use a small electric heater and fan. When soldering, I have to turn it off. the fans I've used were no problem.I didn't keep it close,it was about 20" away,and only gave a slight breeze(on Low). the "whisper fan"(4.7" muffin fan,low CFM) was very good for that,but it was salvaged from an old TEK scope,and I had to kluge a mounting for it. a CPU fan would be rather annoyingly noisy,too. Also, I wasn't joking about the toxic smog from soldering super-glue. The stuff really reeks and seems highly irritating. Fortunately, I don't use much when soldering. Gently blowing it around the shop seems like an invitation to accidentally stick my head into one of the floating clouds of burnt super-glue. Without a fan, at least I know where not to put my head. Well,my fan worked well with the fumes from soldering,I can't see it being any different with cyano fumes. I bought a small fan from Wal-Mart for less than $10.You can get clip-on or one with a base. Or,like I used to do,wire a power cord and switch to a 120VAC "whisper fan" from an old instrument.(cooling fan,very quiet)I even use one for chopping onions in the kitchen; No tears! Methinks tears from cutting onions is a basic ingredient of much of my cooking. Crying is part of the recipe. NAH. tears make it hard to use the knives without nicking myself.... ;-) I've used the Pace vacuum desoldering system,too,while at TEK. I found an old Pace something desoldering station for peanuts at a thrift shop. They didn't know what it was. Works really nice. However, it's not a hot air desoldering system and is therefore fairly useless for SMT parts. Not inexpensive,though. No kidding. I replaced a few parts and had sticker shock. I now use vinyl hoses, fuel filters, and brazing tip cleaners, instead of the official Pace equivalents. And I still preferred my Antex 15w iron with a filed-down non-clad tip for soldering the small SMD stuff. The smaller SMD Pace tips (iron-clad)rotted out too quickly. I once tried to re-plate my collection of burned out tips. I also made some from scratch. The core metal is copper. On top of that is a layer of iron, then nickel, and finally solder plate. First, filing and an acid cleaning bath. I then slowly electroplated some iron, in a ferrous chloride plus calcium chloride bath, onto what was left of the tip. Electroless nickel dip followed. I also tried some electroless silver. I then masked off the tip, and hard black chromed the rest of the tip. It worked but wasn't worth the cost and effort. Yeah,that IS a lot of effort. A new tip was considerably cheaper. The tip life appeared to be dependent on the thickness of the nickel or silver layer. Electroless plating just doesn't apply a thick enough layer. Silver seemed to last a bit longer. I was thinking of trying again, this time plating the nickel or silver layer. I'm not sure if the Pace tips are copper-nickel-iron, or the more common copper-iron-nickel. They may even be solid iron with no plating, which would certainly oxidize and pit rapidly. That might explain the short observed lifetime. I would check my Pace, but I only have the thru-hole desoldering tip. the PACE SMT tips I had at TEK were iron-clad,except for the really expensive IC removal tips. Not usually a problem except on the tiny tips.they would quickly lose their "wettability" and be terrible for soldering fine pitch leads.At least with the plain copper Antex tips,I could refile and retin them until they were too short. -- Jim Yanik jyanik at localnet dot com |
#12
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Jim Yanik wrote in
4: Doug White wrote in : Jeff Liebermann wrote in : On Sun, 14 Feb 2010 22:56:39 GMT, Doug White wrote: I'm willing to spend a couple hundred bucks for a really good setup. That probably sounds absurd to a lot of folks, but if you've ever struggled soldering something, & then tried a Metcal, it's worth a bit of investment. Soldering is usually not a problem. It's unsoldering that drives me to spend the money. If your price ceiling is about $200, you're below the level of Hakko or Weller hot air desoldering stations, which can cost $500 to $1000 and up with accessories. For cheap, I suggest: http://www.circuitspecialists.com/level.itml/icOid/7543 This is what you get for about $200: http://www.circuitspecialists.com/products/full/9766.jpg http://www.circuitspecialists.com/prod.itml/icOid/9766 However, I can't claim much experience with one of these. I've played with an older model, liked it, but have not torn it apart to see if it's junk or quality. The availablity of nozzles, replacement parts, and repair items is reassuring. Thanks for the suggestions. I'm figuring on picking up a used system on eBay, so list price isn't the issue. As for desoldering, I've had pretty good luck with the Metcal, liquid flux and solderwick. As I said, I mostly work on RF stuff, and I typically don't have a zillion leads to deal with the way the digital types do. Besides, once I have something unsoldered, I still need to get a replacement soldered down. I figured once I got a decent iron, I'd look into a hot air pencil. A lot will depend on how circuit work I end up doing. I will be assembling more than repairing (I hope). Doug White you shouldn't use solderwick(or solderpullts) on SMT boards,you'll lift the pads. too much dwell time,applies too much heat to the tiny pads. You certainly have to be careful. Solderpullets are a menace because of the recoil. The biggest problem I've had is with specialize RF material. The copper adhesion is usually much worse than FR-4, and it toasts easily. I probably won't be working with that stuff much at home. Doug White |
#13
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Jeff Liebermann wrote in
: On Mon, 15 Feb 2010 02:39:52 GMT, Doug White wrote: snip As for desoldering, I've had pretty good luck with the Metcal, liquid flux and solderwick. Like this? http://www.curiousinventor.com/guides/Surface_Mount_Soldering/101 I still do it that way when I don't want to wait for my Pace desoldering station to warm up. I've done it like that since I first learned which end of the soldering iron to grab. It works, but once I tried using hot air, desoldering tweezers, and vacuum pickup tools, I was permanently spoiled. As I said, I mostly work on RF stuff, and I typically don't have a zillion leads to deal with the way the digital types do. I do plenty of RF also. Fixing cell phones (a masochistic and largely wasted exercise) really can't be done with solder wick, solder sucker, and big tip soldering iron. Besides, once I have something unsoldered, I still need to get a replacement soldered down. Ummm... you also have to clean up the mess you made on the board. Replacement is comparatively easy. I use a drop of super-glue to hold the part in place. When I hit it with the iron, it doesn't move. If I slop some on the pad, the heat from the iron just vaporizes the super-glue into a toxic cloud of eye irritating smog. (Hint: get your head out of the way or using a smog sucker hose on the iron). I usually use a tiny dab of flux, which holds the part in place. I also have a "part holder" I built that I may put into production for sale when I retire. It uses an orange stick with a bit of pivoting weight to hold parts down. The orange stick can be whittled into any shape that suits, and when it gets toasted, you just replace it. The flux fumes can also be obnoxious, but no near as bad as super-glue. I find a fan blowing away from me helps without causing enough of a draft to affect my soldering. Pace must have improved their stuff. We bought a full setup in the mid- 80's, and it was a pain in the neck to use. It collected dust within 6 months. Doug White |
#14
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Jim Yanik wrote in
4: Jeff Liebermann wrote in : snip I once tried to re-plate my collection of burned out tips. I also made some from scratch. The core metal is copper. On top of that is a layer of iron, then nickel, and finally solder plate. First, filing and an acid cleaning bath. I then slowly electroplated some iron, in a ferrous chloride plus calcium chloride bath, onto what was left of the tip. Electroless nickel dip followed. I also tried some electroless silver. I then masked off the tip, and hard black chromed the rest of the tip. It worked but wasn't worth the cost and effort. Yeah,that IS a lot of effort. A new tip was considerably cheaper. The tip life appeared to be dependent on the thickness of the nickel or silver layer. Electroless plating just doesn't apply a thick enough layer. Silver seemed to last a bit longer. I was thinking of trying again, this time plating the nickel or silver layer. I'm not sure if the Pace tips are copper-nickel-iron, or the more common copper-iron-nickel. They may even be solid iron with no plating, which would certainly oxidize and pit rapidly. That might explain the short observed lifetime. I would check my Pace, but I only have the thru-hole desoldering tip. the PACE SMT tips I had at TEK were iron-clad,except for the really expensive IC removal tips. Not usually a problem except on the tiny tips.they would quickly lose their "wettability" and be terrible for soldering fine pitch leads.At least with the plain copper Antex tips,I could refile and retin them until they were too short. I'd forgotten about tip problems. I just don't seem to have them with the Metcals. I think I've only worn out one. The only other tips I've replaced in 12 years are fine point ones that some gorilla "borrowed" & bent. I also like the ability to "hot swap" a tip to a differeent shape in about 5 seconds. My recollection is that the Antex tips could do that, but some of the others (Weller & Pace) require unscrewing things, which gets more exciting when they are hot. Doug White |
#15
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Doug White wrote in
: Jim Yanik wrote in 4: Doug White wrote in : Jeff Liebermann wrote in : On Sun, 14 Feb 2010 22:56:39 GMT, Doug White wrote: I'm willing to spend a couple hundred bucks for a really good setup. That probably sounds absurd to a lot of folks, but if you've ever struggled soldering something, & then tried a Metcal, it's worth a bit of investment. Soldering is usually not a problem. It's unsoldering that drives me to spend the money. If your price ceiling is about $200, you're below the level of Hakko or Weller hot air desoldering stations, which can cost $500 to $1000 and up with accessories. For cheap, I suggest: http://www.circuitspecialists.com/level.itml/icOid/7543 This is what you get for about $200: http://www.circuitspecialists.com/products/full/9766.jpg http://www.circuitspecialists.com/prod.itml/icOid/9766 However, I can't claim much experience with one of these. I've played with an older model, liked it, but have not torn it apart to see if it's junk or quality. The availablity of nozzles, replacement parts, and repair items is reassuring. Thanks for the suggestions. I'm figuring on picking up a used system on eBay, so list price isn't the issue. As for desoldering, I've had pretty good luck with the Metcal, liquid flux and solderwick. As I said, I mostly work on RF stuff, and I typically don't have a zillion leads to deal with the way the digital types do. Besides, once I have something unsoldered, I still need to get a replacement soldered down. I figured once I got a decent iron, I'd look into a hot air pencil. A lot will depend on how circuit work I end up doing. I will be assembling more than repairing (I hope). Doug White you shouldn't use solderwick(or solderpullts) on SMT boards,you'll lift the pads. too much dwell time,applies too much heat to the tiny pads. You certainly have to be careful. Solderpullets are a menace because of the recoil. I've never had any recoil problems. I have two of the deluxe models. The biggest problem I've had is with specialize RF material. The copper adhesion is usually much worse than FR-4, and it toasts easily. I probably won't be working with that stuff much at home. Doug White the main problem shared by both wick and soldapullts is that you have to keep the IRON on the pad too long.(dwell time) -- Jim Yanik jyanik at localnet dot com |
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Doug White wrote in
: Pace must have improved their stuff. We bought a full setup in the mid- 80's, and it was a pain in the neck to use. It collected dust within 6 months. Doug White Yes,Pace has improved their product. The Pace gear I used back in the late 90's at TEK was reasonably easy to use.One big improvement was making the desoldering tips much longer,so they would not have solder buildup in the heating element itself,at the reservoir end of the tip. No need to use a foot pedal,either. I had two different Pace setups,one older,one newer. -- Jim Yanik jyanik at localnet dot com |
#17
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On Feb 15, 12:29*am, Jeff Liebermann wrote:
On Sun, 14 Feb 2010 22:46:36 -0600, Jim Yanik wrote: I use a small fan to blow gently across my work,directing unhealthy vapors away from me. Duz that really work with small components? *I tried a recycled CPU fan with an alligator clip for mounting and found that even the slightest breeze causes difficulties soldering or desoldering. *My home workshop does have a heater so I use a small electric heater and fan. *When soldering, I have to turn it off. Also, I wasn't joking about the toxic smog from soldering super-glue. The stuff really reeks and seems highly irritating. *Fortunately, I don't use much when soldering. *Gently blowing it around the shop seems like an invitation to accidentally stick my head into one of the floating clouds of burnt super-glue. *Without a fan, at least I know where not to put my head. I bought a small fan from Wal-Mart for less than $10.You can get clip-on or one with a base. Or,like I used to do,wire a power cord and switch to a 120VAC "whisper fan" from an old instrument.(cooling fan,very quiet)I even use one for chopping onions in the kitchen; No tears! Methinks tears from cutting onions is a basic ingredient of much of my cooking. *Crying is part of the recipe. I've used the Pace vacuum desoldering system,too,while at TEK. I found an old Pace something desoldering station for peanuts at a thrift shop. *They didn't know what it was. *Works really nice. However, it's not a hot air desoldering system and is therefore fairly useless for SMT parts. Not inexpensive,though. No kidding. *I replaced a few parts and had sticker shock. *I now use vinyl hoses, fuel filters, and brazing tip cleaners, instead of the official Pace equivalents. And I still preferred my Antex 15w iron with a filed-down non-clad tip for soldering the small SMD stuff. The smaller SMD Pace tips (iron-clad)rotted out too quickly. I once tried to re-plate my collection of burned out tips. *I also made some from scratch. *The core metal is copper. *On top of that is a layer of iron, then nickel, and finally solder plate. *First, filing and an acid cleaning bath. *I then slowly electroplated some iron, in a ferrous chloride plus calcium chloride bath, onto what was left of the tip. *Electroless nickel dip followed. *I also tried some electroless silver. *I then masked off the tip, and hard black chromed the rest of the tip. *It worked but wasn't worth the cost and effort. A new tip was considerably cheaper. *The tip life appeared to be dependent on the thickness of the nickel or silver layer. *Electroless plating just doesn't apply a thick enough layer. *Silver seemed to last a bit longer. *I was thinking of trying again, this time plating the nickel or silver layer. I'm not sure if the Pace tips are copper-nickel-iron, or the more common copper-iron-nickel. *They may even be solid iron with no plating, which would certainly oxidize and pit rapidly. *That might explain the short observed lifetime. *I would check my Pace, but I only have the thru-hole desoldering tip. -- Jeff Liebermann * * 150 Felker St #D * *http://www.LearnByDestroying.com Santa Cruz CA 95060http://802.11junk.com Skype: JeffLiebermann * * AE6KS * *831-336-2558 The fan should blow away from your work, not towards it... |
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On Mon, 15 Feb 2010 10:12:51 -0800 (PST), Sansui Samari
wrote: The fan should blow away from your work, not towards it... Next time you have a small fan handy, try blowing air away from your work as you suggest. At a distance of about 1ft or more, there's almost no air flow. Set fire to some paper and watch which way the air flows into the fan. It grabs air from all over the bench, but not at any great distance. The heated soldering or glue smog also tends to rise, thus making bench level air flow a marginal proposition. It would need to be located above the work, as is found in some combination magnifier, lamp, and fan combinations or suck LOTS of air as in a laminar flow hood. The best I've seen is a small metal vacuum hose close to the soldering tip. http://www.circuitspecialists.com/images/BK6000%20soldering%20iron%281%29.jpg I started to make my own version, but never found a suitable pump. Besides, if I wanted to use an open fan, I would need to clean up my messy bench. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#19
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On Mon, 15 Feb 2010 16:11:09 GMT, Doug White
wrote: I usually use a tiny dab of flux, which holds the part in place. I also have a "part holder" I built that I may put into production for sale when I retire. It uses an orange stick with a bit of pivoting weight to hold parts down. The orange stick can be whittled into any shape that suits, and when it gets toasted, you just replace it. The stick will need to have a tiny point as many components have shrunk to almost invisible sizes. Try using a tooth pick instead of a plastic stick. Maybe a spring loaded automatic test probe with a stainless tip. Not a bad idea, but I don't see it as a big seller. The flux fumes can also be obnoxious, but no near as bad as super-glue. The trick with both flux and super-glue is to use only as little as necessary. For super-glue, that means one tiny drop, not a huge blob. That's impossible with hardware store plastic tip dispensers. It's easy with a metal tube tip dispenser. http://www.micromark.com/1-OZ-BELLOWS-TYPE-GLUE-APPLICATOR-SET-OF-2,7051.html Both the plastic and metal tips will clog. However, cleaning the metal tip is easy. Just light a fire under the tip. The hardened glue will burn away, thus clearing the tip. Since I don't smoke tobacco, I have a difficult time explaining why I have a cigarette lighter on my bench and in my toolbox. I find a fan blowing away from me helps without causing enough of a draft to affect my soldering. I've tried that a few times without much success. It works acceptably for rosin fumes, but I still manage to get burned eyes with super-glue. Probably the clutter on the bench affecting the air flow. Pace must have improved their stuff. We bought a full setup in the mid- 80's, and it was a pain in the neck to use. It collected dust within 6 months. I have one of those from the 80's. It sucks, but was cheap. Until recently, I haven't used it often enough to justify anything better. The worst problems are that the foot pedal cord is too short, the desoldering tip clogs constantly, the vacuum filter clogs because it's too small, it takes 5 mins to get up to temperature, parts are expensive, etc. The newer models are allegedly better, but still quite expensive. http://www.pacedirect.com -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#20
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Jeff Liebermann wrote in
news ![]() Besides, if I wanted to use an open fan, I would need to clean up my messy bench. My muffin fan sat off to the side,but then I made a bracket to attach it to the rack next to my bench.It was about 18" above the bench top,aimed slightly down. My bench was always messy,too. You could make an arm to clamp on the end of the bench,mount the muffin fan to that.Or mount a 1x2 to the end of the bench,mount the fan to that. Better than breathing those fumes. -- Jim Yanik jyanik at localnet dot com |
#21
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Jeff Liebermann wrote in
: On Mon, 15 Feb 2010 16:11:09 GMT, Doug White wrote: I usually use a tiny dab of flux, which holds the part in place. I also have a "part holder" I built that I may put into production for sale when I retire. It uses an orange stick with a bit of pivoting weight to hold parts down. The orange stick can be whittled into any shape that suits, and when it gets toasted, you just replace it. The stick will need to have a tiny point as many components have shrunk to almost invisible sizes. Try using a tooth pick instead of a plastic stick. Maybe a spring loaded automatic test probe with a stainless tip. Not a bad idea, but I don't see it as a big seller. The big problem is that orange sticks & tooth picks aren't ESD safe. Even if youy only use it on the body of the part, there are a lot of shops that would freak at the mere thought. There is ESD safe teflon, and that might work. It still needs to be pointed. snip Pace must have improved their stuff. We bought a full setup in the mid- 80's, and it was a pain in the neck to use. It collected dust within 6 months. I have one of those from the 80's. It sucks, but was cheap. Until recently, I haven't used it often enough to justify anything better. The worst problems are that the foot pedal cord is too short, the desoldering tip clogs constantly, the vacuum filter clogs because it's too small, it takes 5 mins to get up to temperature, parts are expensive, etc. The newer models are allegedly better, but still quite expensive. http://www.pacedirect.com I figure they had to have made some improvements. I don't see how they could still be in business if they were selling the same machine we had. Your experience is pretty similar to ours. Constant clogging was the bigg issue. That & the tips were pretty big even in those days. Now, they'd be hopelessly huge. Doug White |
#22
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On Mon, 15 Feb 2010 22:27:04 GMT, Doug White
wrote: The big problem is that orange sticks & tooth picks aren't ESD safe. Wood is slightly conductive, which should be sufficient to remove any static charge. What it won't do is remove any leakage current from connected AC appliances. I once fixed a production line problem that was caused by induced voltage coming from a transformer located in near the base of a Luxo lamp. The field was sufficient to induce about 100mv of AC at a distance of about 8" to a probe card. I have a theory about blowing things up with static electricity (which is probably wrong but is worth thinking about anyway). It's the person, not the clothes and equipment that causes problems. I've only blown up a few things with static electricity (walking across a rug with a floppy in my hand. It drew an arc when I inserted it into the computah). I rarely do anything to protect against static, except when I'm playing with GaAsFET chips and xsistors. However, I know people who just walk into the room, and something blows up. One lady was literally a static generator. In the dark, you could see the sparks fly as she moved in her chair and touched things. I tried grounding, discharge mats, and even an ozone (ionized air) generator. Nothing worked. She would constantly blow up equipment. While this is an extreme example, I suspect there are various degrees between her and me. Just a theory. Even if youy only use it on the body of the part, there are a lot of shops that would freak at the mere thought. There is ESD safe teflon, and that might work. It still needs to be pointed. I've had some fun at such shops with an electrometer. http://en.wikipedia.org/wiki/Electrometer I would bring the meter to the bosses desk, and immediately determine that most everything he owns, that's made of plastic, is an ESD hazard. He usually spends the rest of the day chasing high voltage readings, which are not very consistent or repeatable. That gets him out of my way so I could get some work done. I managed to convince one manager to go home and change into something that doesn't have polyester. Just spray everything in sight with some kind of laundry anti-static spray and be done with it. Tap water in a household sprayer works fine. http://www.pacedirect.com I figure they had to have made some improvements. I don't see how they could still be in business if they were selling the same machine we had. Your experience is pretty similar to ours. Constant clogging was the bigg issue. That & the tips were pretty big even in those days. Now, they'd be hopelessly huge. They're good enough for most of what I do at home. I'm still mired in 1980's ancient technology, where you can actually see the parts and most everything is through-hole technology. My current ongoing nightma http://802.11junk.com/jeffl/MSF5000/MSF5000.html Might as well have a 1980's tool to work on 1980's technology. Incidentally, my lab is 1970's technology and is rapidly approaching the look of a test equipment museum. http://802.11junk.com/jeffl/pics/home/slides/lab.html The Pace desoldering station is now located in place of one of the Wiltron sweepers, which I stupidly tried to use without replacing all the dried out electrolytics. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#23
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Jeff Liebermann wrote in
: On Mon, 15 Feb 2010 22:27:04 GMT, Doug White wrote: The big problem is that orange sticks & tooth picks aren't ESD safe. Wood is slightly conductive, which should be sufficient to remove any static charge. What it won't do is remove any leakage current from connected AC appliances. I once fixed a production line problem that was caused by induced voltage coming from a transformer located in near the base of a Luxo lamp. The field was sufficient to induce about 100mv of AC at a distance of about 8" to a probe card. unfinished wood is not going to GENERATE a static charge. it will have around 10% moisture content,or more depending on your local climate. Teflon -will- generate a charge. I have a theory about blowing things up with static electricity (which is probably wrong but is worth thinking about anyway). It's the person, not the clothes and equipment that causes problems. it's the movement of certain materials that generates the static charge. People merely provide the movement. and the human body capacitance stores a nice charge. I've only blown up a few things with static electricity (walking across a rug with a floppy in my hand. It drew an arc when I inserted it into the computah). I rarely do anything to protect against static, except when I'm playing with GaAsFET chips and xsistors. However, I know people who just walk into the room, and something blows up. One lady was literally a static generator. In the dark, you could see the sparks fly as she moved in her chair and touched things. Probably the sort of clothing she typically wears. synthetics and blends are bad news for ESD. I tried grounding, discharge mats, and even an ozone (ionized air) generator. Nothing worked. She would constantly blow up equipment. While this is an extreme example, I suspect there are various degrees between her and me. Just a theory. from the ESD classes I've had at TEK,if you can feel a static discharge,it's at least 2KV.Many devices blow at less than 100v,some as low as 30v. In the Orlando Tek center,my colleagues had a harder time passing the ESD foot strap tester,while I passed right after putting it on.Had to test daily. We had an ESD mat on the bench,a floor ESD mat,wrist and foot straps,and a ESD-smock with metallic fibers.We also had the work areas marked with RED tape,where no one else could enter without having their ESD gear on. (like WKRP Les Nessman's imaginary office...) BTW,there are ESD-testers for the bench and floor mats.... they make ESD-safe chairs...they have a grounding chain that drags on your ESD floor mat.your typical office chair is not ESD safe at all. and you can buy ESD-shoes,too. Even if youy only use it on the body of the part, there are a lot of shops that would freak at the mere thought. There is ESD safe teflon, and that might work. It still needs to be pointed. I've had some fun at such shops with an electrometer. http://en.wikipedia.org/wiki/Electrometer I would bring the meter to the bosses desk, and immediately determine that most everything he owns, that's made of plastic, is an ESD hazard. He usually spends the rest of the day chasing high voltage readings, which are not very consistent or repeatable. That gets him out of my way so I could get some work done. I managed to convince one manager to go home and change into something that doesn't have polyester. Just spray everything in sight with some kind of laundry anti-static spray and be done with it. not a lasting solution. Risky,as you can't be sure of the level of protection. Tap water in a household sprayer works fine. http://www.pacedirect.com I figure they had to have made some improvements. I don't see how they could still be in business if they were selling the same machine we had. Your experience is pretty similar to ours. Constant clogging was the bigg issue. That & the tips were pretty big even in those days. Now, they'd be hopelessly huge. the last Pace station I used (in 1998)had different desoldering(DS) tips for SMD work,different than the older Pace station. And the thru-hole DS tips were LONG compared to the earlier ones,prevented clogging in the heater element. They're good enough for most of what I do at home. I'm still mired in 1980's ancient technology, where you can actually see the parts and most everything is through-hole technology. My current ongoing nightma http://802.11junk.com/jeffl/MSF5000/MSF5000.html Might as well have a 1980's tool to work on 1980's technology. Incidentally, my lab is 1970's technology and is rapidly approaching the look of a test equipment museum. http://802.11junk.com/jeffl/pics/home/slides/lab.html The Pace desoldering station is now located in place of one of the Wiltron sweepers, which I stupidly tried to use without replacing all the dried out electrolytics. -- Jim Yanik jyanik at localnet dot com |
#24
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On Mon, 15 Feb 2010 18:51:26 -0600, Jim Yanik
wrote: One lady was literally a static generator. In the dark, you could see the sparks fly as she moved in her chair and touched things. Probably the sort of clothing she typically wears. synthetics and blends are bad news for ESD. Nope. We did considerable experimentation with clothing, furniture, furniture covers, and anti-static mats. All of these would help, but she consistently failed the electrometer test. (I don't recall the readings). Even with a metal chair on an anti-static mat, she would throw sparks. I would try the same chair and mat and the electrometer would read nearly nothing. from the ESD classes I've had at TEK,if you can feel a static discharge,it's at least 2KV.Many devices blow at less than 100v,some as low as 30v. Yep. However, I tend to deal with components installed in PCB's, where the board leakage, and biasing components offer some protection. When replacing an active component, I'm sometimes careful to ground myself with just a simple wrist strap. I don't recall ever blowing anything up during assembly. Other people I worked with would blow up components by just staring at them. Since everything is the same except the person and possibly his clothes, it has to be something in the body chemistry causing the higher static buildup. In the Orlando Tek center,my colleagues had a harder time passing the ESD foot strap tester,while I passed right after putting it on.Had to test daily. Hmm... you're confirming my observations, suspicions and speculations. We had an ESD mat on the bench,a floor ESD mat,wrist and foot straps,and a ESD-smock with metallic fibers.We also had the work areas marked with RED tape,where no one else could enter without having their ESD gear on. (like WKRP Les Nessman's imaginary office...) BTW,there are ESD-testers for the bench and floor mats.... they make ESD-safe chairs...they have a grounding chain that drags on your ESD floor mat.your typical office chair is not ESD safe at all. and you can buy ESD-shoes,too. Maybe a tin hat or colander with a long grounding strap? In the lab, we used all metal stools with hard fiberboard seats. No ESD problem. We did have a consultant running around looking for ESD and other "safety" issues, but he never noticed the cotton Persian run in my office. Just spray everything in sight with some kind of laundry anti-static spray and be done with it. not a lasting solution. Risky,as you can't be sure of the level of protection. I would sometimes dump in some Photo-Flow or water immiscible oil to increase surface tension and reduce evaporation rate. That's roughly what the anti-static sprays are doing using soap and alcohol. I'm not sure what's in the current anti-static sprays to retard evaporation, but this might offer a clue: http://news.oneindia.in/2007/10/29/emulsion-film-coat-used-in-retarding-evaporation-in-water-bodies-1193658468.html Anyways, the electrometer showed that it would reduce static buildup on a carpet for about 6 hours, which was good enough. I vaguely recall that just tap water would last about 2 hours. the last Pace station I used (in 1998)had different desoldering(DS) tips for SMD work,different than the older Pace station. And the thru-hole DS tips were LONG compared to the earlier ones,prevented clogging in the heater element. Here's a photo of my Pace desoldering station. http://802.11junk.com/jeffl/crud/pace-desoldering-station.jpg The solder sucking hand piece is a model SX-25. I just found the manual. It's titled "No Clog Solder Extractor" The No Clog is a bad joke. The instructions include a section on how to pound out a broken tip with an 1/8" ramrod. Hopefully, I won't need to do that. -- # Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060 # 831-336-2558 # http://802.11junk.com # http://www.LearnByDestroying.com AE6KS |
#25
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On Feb 16, 5:24*pm, Jeff Liebermann wrote:
On Mon, 15 Feb 2010 18:51:26 -0600, Jim Yanik wrote: One lady was literally a static generator. *In the dark, you could see the sparks fly as she moved in her chair and touched things. * Probably the sort of clothing she typically wears. synthetics and blends are bad news for ESD. Nope. *We did considerable experimentation with clothing, furniture, furniture covers, and anti-static mats. *All of these would help, but she consistently failed the electrometer test. *(I don't recall the readings). *Even with a metal chair on an anti-static mat, she would throw sparks. *I would try the same chair and mat and the electrometer would read nearly nothing. from the ESD classes I've had at TEK,if you can feel a static discharge,it's at least 2KV.Many devices blow at less than 100v,some as low as 30v. Yep. *However, I tend to deal with components installed in PCB's, where the board leakage, and biasing components offer some protection. When replacing an active component, I'm sometimes careful to ground myself with just a simple wrist strap. *I don't recall ever blowing anything up during assembly. *Other people I worked with would blow up components by just staring at them. *Since everything is the same except the person and possibly his clothes, it has to be something in the body chemistry causing the higher static buildup. In the Orlando Tek center,my colleagues had a harder time passing the ESD foot strap tester,while I passed right after putting it on.Had to test daily. Hmm... you're confirming my observations, suspicions and speculations. We had an ESD mat on the bench,a floor ESD mat,wrist and foot straps,and a ESD-smock with metallic fibers.We also had the work areas marked with RED tape,where no one else could enter without having their ESD gear on. (like WKRP Les Nessman's imaginary office...) BTW,there are ESD-testers for the bench and floor mats.... they make ESD-safe chairs...they have a grounding chain that drags on your ESD floor mat.your typical office chair is not ESD safe at all. and you can buy ESD-shoes,too. Maybe a tin hat or colander with a long grounding strap? *In the lab, we used all metal stools with hard fiberboard seats. *No ESD problem. We did have a consultant running around looking for ESD and other "safety" issues, but he never noticed the cotton Persian run in my office. Just spray everything in sight with some kind of laundry anti-static spray and be done with it. * not a lasting solution. Risky,as you can't be sure of the level of protection. I would sometimes dump in some Photo-Flow or water immiscible oil to increase surface tension and reduce evaporation rate. *That's roughly what the anti-static sprays are doing using soap and alcohol. *I'm not sure what's in the current anti-static sprays to retard evaporation, but this might offer a clue: http://news.oneindia.in/2007/10/29/emulsion-film-coat-used-in-retardi... Anyways, the electrometer showed that it would reduce static buildup on a carpet for about 6 hours, which was good enough. *I vaguely recall that just tap water would last about 2 hours. the last Pace station I used (in 1998)had different desoldering(DS) tips for SMD work,different than the older Pace station. And the thru-hole DS tips were LONG compared to the earlier ones,prevented clogging in the heater element. Here's a photo of my Pace desoldering station. http://802.11junk.com/jeffl/crud/pace-desoldering-station.jpg The solder sucking hand piece is a model SX-25. *I just found the manual. *It's titled * "No Clog Solder Extractor" The No Clog is a bad joke. *The instructions include a section on how to pound out a broken tip with an 1/8" ramrod. *Hopefully, I won't need to do that. -- # Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060 # 831-336-2558 #http://802.11junk.com* * * * * * * #http://www.LearnByDestroying.com* * * * * * * AE6KS ESD induced problems usually don't show up right away, they generally show up later on in shortened component life. Our esd lines at most of the places I've worked usually use a conductive floor mat, or floor coating, with footstraps when an individual is all over the floor and wrist straps at work stations. De-ionization stations, and conductive work mats at each work station, with dual grounding for a tester. No synthetic clothing would be allowed, unless you wore a smock over it, and had short sleeves. No food packaging, or synthetic cups allowed at any work stations. No Styrofoam would be allowed, only pink non static foam, or black conductive foam. No plastic bags unless they were the pink plastic or conductive ESD bags. All ESD bags had to be folded over, or else they were worthless. No static producing tape allowed until boards were sealed in ESD bags. All carts had to have chains that would drag on the floor to keep them from becoming a vandergraph generator. Although, if they would have just made the wheels conductive, that probably wouldn't have been an issues. All trays &c... had to be conductive. One big misconception that a lot of people have, is that just because a component is on a substrate it's safe from ESD. Usually still a pretty big risk. Just soldering on the substrate, you can pass a large voltage from you to your iron. Bull****, bull****, yada, yada. |
#26
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Jeff Liebermann wrote in
: On Mon, 15 Feb 2010 18:51:26 -0600, Jim Yanik wrote: One lady was literally a static generator. In the dark, you could see the sparks fly as she moved in her chair and touched things. Probably the sort of clothing she typically wears. synthetics and blends are bad news for ESD. Nope. We did considerable experimentation with clothing, furniture, furniture covers, and anti-static mats. All of these would help, but she consistently failed the electrometer test. (I don't recall the readings). Even with a metal chair on an anti-static mat, she would throw sparks. I would try the same chair and mat and the electrometer would read nearly nothing. I still can't buy that her body generated static charges. from the ESD classes I've had at TEK,if you can feel a static discharge,it's at least 2KV.Many devices blow at less than 100v,some as low as 30v. Yep. However, I tend to deal with components installed in PCB's, where the board leakage, and biasing components offer some protection. When replacing an active component, I'm sometimes careful to ground myself with just a simple wrist strap. I don't recall ever blowing anything up during assembly. Other people I worked with would blow up components by just staring at them. Since everything is the same except the person and possibly his clothes, it has to be something in the body chemistry causing the higher static buildup. maybe her skin is really dry. In the Orlando Tek center,my colleagues had a harder time passing the ESD foot strap tester,while I passed right after putting it on.Had to test daily. Hmm... you're confirming my observations, suspicions and speculations. Probably that their feet didn't sweat as much as mine.... Or that they wore different socks. We had an ESD mat on the bench,a floor ESD mat,wrist and foot straps,and a ESD-smock with metallic fibers.We also had the work areas marked with RED tape,where no one else could enter without having their ESD gear on. (like WKRP Les Nessman's imaginary office...) BTW,there are ESD-testers for the bench and floor mats.... they make ESD-safe chairs...they have a grounding chain that drags on your ESD floor mat.your typical office chair is not ESD safe at all. and you can buy ESD-shoes,too. Maybe a tin hat or colander with a long grounding strap? In the lab, we used all metal stools with hard fiberboard seats. No ESD problem. We did have a consultant running around looking for ESD and other "safety" issues, but he never noticed the cotton Persian rug in my office. did you do electronic servicing in your office? Our office area had carpet,the service dept. had vinyl tile. (with a pattern that hid small dropped parts well...) Our printer guys used to do some repairs in their office area,on the carpet,and they really didn't pay much attention to ESD. Just spray everything in sight with some kind of laundry anti-static spray and be done with it. not a lasting solution. Risky,as you can't be sure of the level of protection. I would sometimes dump in some Photo-Flow or water immiscible oil to increase surface tension and reduce evaporation rate. That's roughly what the anti-static sprays are doing using soap and alcohol. I'm not sure what's in the current anti-static sprays to retard evaporation, but this might offer a clue: http://news.oneindia.in/2007/10/29/e...d-in-retarding -evaporation-in-water-bodies-1193658468.html Anyways, the electrometer showed that it would reduce static buildup on a carpet for about 6 hours, which was good enough. I vaguely recall that just tap water would last about 2 hours. the last Pace station I used (in 1998)had different desoldering(DS) tips for SMD work,different than the older Pace station. And the thru-hole DS tips were LONG compared to the earlier ones,prevented clogging in the heater element. Here's a photo of my Pace desoldering station. http://802.11junk.com/jeffl/crud/pace-desoldering-station.jpg The solder sucking hand piece is a model SX-25. I just found the manual. It's titled "No Clog Solder Extractor" The No Clog is a bad joke. The instructions include a section on how to pound out a broken tip with an 1/8" ramrod. Hopefully, I won't need to do that. I've had to do it. Man,that IS an ancient model! Of course,you could order a new handle assembly to use with your base. And the longer DS tips. BTW,I was wondering if the automotive high temp anti-seize lubricant made by Permatex would help with the tip seize problem? It's rated up to 1600degF. item 81343 It's made to go on spark plug and O2 sensor threads. It's got a lot of aluminum and graphite in it. -- Jim Yanik jyanik at localnet dot com |
#27
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On Wed, 17 Feb 2010 08:04:41 -0600, Jim Yanik
wrote: I still can't buy that her body generated static charges. I don't really understand the mechanism. My best guess(tm) is that her skin resistance is less than mine. She would present a high surface resistance (ohms/square) while I would present a somewhat lower resistance. I would tend to bleed off generated static, while she would tend to hold it. I've crudely tested this guess(tm) with an ohmmeter. Grabbing the probes between index thumb and index finger on both hands, I usually get about 4M Ohms. This lady would do about twice that. (Note: She died in 2007 so I can't retest). maybe her skin is really dry. Yep. Hmm... you're confirming my observations, suspicions and speculations. Probably that their feet didn't sweat as much as mine.... Or that they wore different socks. I don't know which articles of clothing cause the most ESD problems. My guess(tm) is that the seat of the pants, rubbing against the chair, would have the biggest effect. Google shows a few ESD safe socks, but far more emphasis seems to be placed on ESD safe shoes. I would think they would go together as an insulator in a problem with both socks and shoes. Plenty of heel grounders, but few ankle straps. Maybe a tin hat or colander with a long grounding strap? In the lab, we used all metal stools with hard fiberboard seats. No ESD problem. We did have a consultant running around looking for ESD and other "safety" issues, but he never noticed the cotton Persian rug in my office. did you do electronic servicing in your office? No. I slept on the office floor and the Persian rug (with foam pad underneath) made it far more comfortable. I sometimes dragged finished boards and products into the office for a show and tell, or interview, but there was no soldering or electronics work done in the office (mostly so as not to burn holes in the Persian rug). Our office area had carpet,the service dept. had vinyl tile. (with a pattern that hid small dropped parts well...) My office is all nylon carpet. I've measured the ESD potential with the electrometer and found that the carpet is not a serious problem. My guess(tm) is that it's because I haven't cleaned (or seen) the carpet in 20 years. Also, the RH is now about 85% and rarely drops below 30%, which helps considerably. Our printer guys used to do some repairs in their office area,on the carpet,and they really didn't pay much attention to ESD. Printer repair is mostly mechanical (which is why I like doing it). The electronic part is mostly board swapping. I also used to do it on the carpet, but when my back started protesting, I switched to a proper (low) table. However, one of my work tables is just a steel office desk. The formica or plastic top is a problem. I avoid using it for anything other than storage or paperwork: http://802.11junk.com/jeffl/pics/office/slides/radio-mess.html In my never humble opinion, the trick to ESD protection is to do some testing with an electrometer. There's no way to reduce ESD to what would be considered safe in a production environment, but testing will uncover some potential problems. http://802.11junk.com/jeffl/crud/pace-desoldering-station.jpg Man,that IS an ancient model! It cost me about $25 plus about $50 in parts about 20 years ago. At the time, comparable desoldering stations were going for perhaps $800. It may be old, it may clog, it may be clumsy, and it certainly is ugly, but it works. However, during the same time period, components and lead spacing have shrunk to the point where it's basically useless. I still use it for thru-hole component desoldering, but for SMT, I'm shopping for a hot air device. Of course,you could order a new handle assembly to use with your base. And the longer DS tips. Good idea as a longer tip would be better. I hate to admit that I'm still using the same 20+ year old tip. When I bought it, the original tip had to get pounded out and replaced. BTW,I was wondering if the automotive high temp anti-seize lubricant made by Permatex would help with the tip seize problem? It's rated up to 1600degF. item 81343 It's made to go on spark plug and O2 sensor threads. It's got a lot of aluminum and graphite in it. http://www.permatex.com/products/automotive/b_lubricants/specialty_lubricants/Permatex_Anti-Seize_Lubricant_a.htm The problem with that stuff is that it has copper, graphite, and aluminum in it. Fine for spark plugs in an aluminum or iron engine head. However, most soldering iron tips are either nickel or chromium (the non-solderable part) plated. The copper will eventually go into solution (galvanic corrosion) and create a ceramic like coating. Avoid the copper stuff. What methinks you want is a nickel based anti-seize to match the tip plating. http://www.drillspot.com/products/280558/Loctite_77124_Nickel_Anti_Seize_Lubricant http://www.drillspot.com/power-tools-and-metalworking/lubricants/anti-seize-compounds/ Permatex and Loctite both carry it. It's suppose to be for stainless and works to 2600F. I tried some on a big thermostatically controlled iron, with a huge threaded nickel plated copper slab of a tip, and it worked as expected. No stuck tips. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#28
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Jeff Liebermann wrote in
: My office is all nylon carpet. I've measured the ESD potential with the electrometer and found that the carpet is not a serious problem. My guess(tm) is that it's because I haven't cleaned (or seen) the carpet in 20 years. Also, the RH is now about 85% and rarely drops below 30%, which helps considerably. RH is the key. High RH allows the charges to bleed off as rapidly as they are generated. snip for brevity... http://802.11junk.com/jeffl/crud/pace-desoldering-station.jpg Man,that IS an ancient model! It cost me about $25 plus about $50 in parts about 20 years ago. At the time, comparable desoldering stations were going for perhaps $800. It may be old, it may clog, it may be clumsy, and it certainly is ugly, but it works. However, during the same time period, components and lead spacing have shrunk to the point where it's basically useless. I still use it for thru-hole component desoldering, but for SMT, I'm shopping for a hot air device. I used to have to use the same Pace handle on a smaller station to desolder all the IC sockets on a board,in order to remove bad sockets.It needed constant cleaning.Fortunately,we had a bin full of tips and filters. Of course,you could order a new handle assembly to use with your base. And the longer DS tips. Good idea as a longer tip would be better. I hate to admit that I'm still using the same 20+ year old tip. When I bought it, the original tip had to get pounded out and replaced. I'm pretty sure the longer tips will fit your older handle. I'd use that anti-seize with them,though. BTW,I was wondering if the automotive high temp anti-seize lubricant made by Permatex would help with the tip seize problem? It's rated up to 1600degF. item 81343 It's made to go on spark plug and O2 sensor threads. It's got a lot of aluminum and graphite in it. http://www.permatex.com/products/aut...specialty_lubr icants/Permatex_Anti-Seize_Lubricant_a.htm The problem with that stuff is that it has copper, graphite, and aluminum in it. Hmm,the package I have didn't say copper.I'll check the MSDS. Fine for spark plugs in an aluminum or iron engine head. However, most soldering iron tips are either nickel or chromium (the non-solderable part) plated. The copper will eventually go into solution (galvanic corrosion) and create a ceramic like coating. Avoid the copper stuff. What methinks you want is a nickel based anti-seize to match the tip plating. http://www.drillspot.com/products/28...ckel_Anti_Seiz e_Lubricant http://www.drillspot.com/power-tools...ricants/anti-s eize-compounds/ Permatex and Loctite both carry it. It's suppose to be for stainless and works to 2600F. I tried some on a big thermostatically controlled iron, with a huge threaded nickel plated copper slab of a tip, and it worked as expected. No stuck tips. -- Jim Yanik jyanik at localnet dot com |
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