Dave, I can highly recommend Chipquik - for multilegged devices. For devices with only 2 leads, I believe it is overkill (but it will work). My objections with Quickchip is that one *must* clean up the site before applying new solder - or the new solder will not stick.. The cleanup task is not to be minimized, but is necessary,
Chipquik is not inexpensive, but samples are available. Give it a try for devices having more than 2 solder connections - but for 2 legged devices, I stand by my conclusion that the cleanup is more work than the effort required using other means. YMMV. 73, Don W3FPR On 4/19/2012 10:29 PM, Dave Lankshear wrote: > I'm surprised no-one has mentioned Chipquik to ease the pain of SMT removal. > It is a low temperature alloy (something like Wood's metal - the melting > teaspoon in a hot drink prank etc.), supplied in small diameter "wires" > together with a special flux. Melt a little Chipquik onto an existing > soldered joint and then melt the other end with the iron. The Chipquik-ed > end stays molten, so removal is a breeze, as is cleanup. I've removed and > replaced a 64-pin chip quite easily with it. I won't say more, but visit > the website, www.chipquik.com<http://www.chipquik.com/> and take up their > free sample offer; it's enough to help remove several components. > > > > As for crunching up SMT's, that doesn't sit easy with me, but the quality of > Elecraft's boards means they will take some hammer before foil separates > from the substrate. I sure have hammered, but to date, I've never lifted a > trace or pad on an Elecraft PCB, although I know a few folks who have. Just > tonight, I removed a diode on a small, made in China PCB. Simply heating > both ends of the component's solder caused the pads to separate from the > board; such was its dire quality. I used a wire ended diode to replace the > dud and had to be a bit crafty as to where the ends were tacked, but it's > working again. > > > > For a quick hold-down of a component, I often use a cocktail stick, taking > care to keep it absolutely vertical above the component. Use tweezers with > care because they make fine component launchers and tracking down the > launched component is like looking for a needle in a haystack. Little > vacuum pencils are sold on Ebay for a couple of bucks and are handy for > lifting or keeping hold of stuff like SMT ICs - the big stuff Hi! > > > > While I'm on a roll, here are more tips, qualified by the usual disclaimer - > YMMV. > > > > Small wattage soldering irons have so much thermal lag that components can > be barbecued before the solder melts. I use and recommend a temperature > controlled iron of around 50 watts. Go for something that has a fine tip, > but not a needle tip, as there's not much metal to conduct heat to the tip, > so thermal lag again. Look for a short taper. > > > > Get a GOOD solder sucker. I have a small stock of Soldapullts from Edsyn. > Take a look at www.edsyn.com<http://www.edsyn.com/> and check out the last > few pages of their clearance items. You should find some very inexpensive, > end of line, high quality solder suckers listed. Get a spare tip or two > with the order. > > > > Invest in a liquid flux pen. It makes such a difference to have wiped a > spot on pads before soldering and wiping along the next bit of solder braid > you're using makes the braid much more effective. > > > > 73 Dave G3TJP > > > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
